diff --git a/Source/Demo/Common/DemoUtils.cs b/Source/Demo/Common/DemoUtils.cs
index 682f325f5..a14b33b3f 100644
--- a/Source/Demo/Common/DemoUtils.cs
+++ b/Source/Demo/Common/DemoUtils.cs
@@ -74,8 +74,8 @@ public static string GetStylesheet(string src)
                     a:link { text-decoration: none; }
                     a:hover { text-decoration: underline; }
                     .gray    { color:gray; }
-                    .example { background-color:#efefef; corner-radius:5px; padding:0.5em; }
-                    .whitehole { background-color:white; corner-radius:10px; padding:15px; }
+                    .example { background-color:#efefef; border-radius:5px; padding:0.5em; }
+                    .whitehole { background-color:white; border-radius:10px; padding:15px; }
                     .caption { font-size: 1.1em }
                     .comment { color: green; margin-bottom: 5px; margin-left: 3px; }
                     .comment2 { color: green; }";
diff --git a/Source/Demo/Common/HtmlRenderer.Demo.Common.csproj b/Source/Demo/Common/HtmlRenderer.Demo.Common.csproj
index 7a66b29ab..7128e4a70 100644
--- a/Source/Demo/Common/HtmlRenderer.Demo.Common.csproj
+++ b/Source/Demo/Common/HtmlRenderer.Demo.Common.csproj
@@ -42,6 +42,34 @@
     <EmbeddedResource Include="Resources\pdf.png" />
     <EmbeddedResource Include="Resources\stopwatch.png" />
     <EmbeddedResource Include="Resources\image32.png" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSans-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSans-Bold.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSans-Italic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSans-BoldItalic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSerif-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSerif-Bold.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSerif-Italic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationSerif-BoldItalic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationMono-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationMono-Bold.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationMono-Italic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\LiberationMono-BoldItalic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSans-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSans-Bold.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSans-Italic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSans-BoldItalic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSerif-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSerif-Bold.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSerif-Italic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\NotoSerif-BoldItalic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\Pacifico-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\DancingScript-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\Caveat-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\IndieFlower-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\ComicNeue-Regular.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\ComicNeue-Bold.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\ComicNeue-Italic.ttf" />
+    <EmbeddedResource Include="Resources\Fonts\ComicNeue-BoldItalic.ttf" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="TestSamples\01.Header.htm" />
@@ -66,12 +94,14 @@
     <EmbeddedResource Include="TestSamples\20.Fonts decorations.htm" />
     <EmbeddedResource Include="TestSamples\21.Bullets.htm" />
     <EmbeddedResource Include="TestSamples\22.RTL.htm" />
+    <EmbeddedResource Include="TestSamples\23.Media queries and color scheme.htm" />
     <EmbeddedResource Include="TestSamples\30.Misc.htm" />
     <EmbeddedResource Include="TestSamples\31.ACID 1.htm" />
     <EmbeddedResource Include="TestSamples\32.Image in css content.htm" />
     <EmbeddedResource Include="TestSamples\33.Fixed position.htm" />
     <EmbeddedResource Include="TestSamples\34.Breaking pages 1 - Paragraphs.htm" />
     <EmbeddedResource Include="TestSamples\35.Breaking pages 2 - Tables.htm" />
+    <EmbeddedResource Include="TestSamples\36.Float wrap.htm" />
     <EmbeddedResource Include="Samples\00.Intro.htm" />
     <EmbeddedResource Include="Samples\01.History.htm" />
     <EmbeddedResource Include="Samples\02.Text.htm" />
diff --git a/Source/Demo/Common/Resources.cs b/Source/Demo/Common/Resources.cs
index 6370c567c..0a8552d25 100644
--- a/Source/Demo/Common/Resources.cs
+++ b/Source/Demo/Common/Resources.cs
@@ -38,6 +38,27 @@ public static byte[] CustomFont
             }
         }
 
+        /// <summary>
+        /// Reads one of the bundled <c>Resources\Fonts\*.ttf</c> demo fonts (Liberation/Noto/whimsical -
+        /// see <c>Resources\Fonts\README.md</c> for the full list and provenance) by file name, e.g.
+        /// <c>GetFontBytes("LiberationSans-Regular.ttf")</c>.
+        /// </summary>
+        public static byte[] GetFontBytes(string fileName)
+        {
+            var stream = GetManifestResourceStream("Fonts." + fileName);
+
+            var buffer = new byte[16 * 1024];
+            using (var ms = new MemoryStream())
+            {
+                int read;
+                while ((read = stream.Read(buffer, 0, buffer.Length)) > 0)
+                {
+                    ms.Write(buffer, 0, read);
+                }
+                return ms.ToArray();
+            }
+        }
+
         public static Stream Comment16
         {
             get { return GetManifestResourceStream("comment16.gif"); }
diff --git a/Source/Demo/Common/Resources/Fonts/Caveat-Regular.ttf b/Source/Demo/Common/Resources/Fonts/Caveat-Regular.ttf
new file mode 100644
index 000000000..f84acf2ce
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/Caveat-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/ComicNeue-Bold.ttf b/Source/Demo/Common/Resources/Fonts/ComicNeue-Bold.ttf
new file mode 100644
index 000000000..378eb2004
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/ComicNeue-Bold.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/ComicNeue-BoldItalic.ttf b/Source/Demo/Common/Resources/Fonts/ComicNeue-BoldItalic.ttf
new file mode 100644
index 000000000..8c437a353
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/ComicNeue-BoldItalic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/ComicNeue-Italic.ttf b/Source/Demo/Common/Resources/Fonts/ComicNeue-Italic.ttf
new file mode 100644
index 000000000..72d9b0b82
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/ComicNeue-Italic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/ComicNeue-Regular.ttf b/Source/Demo/Common/Resources/Fonts/ComicNeue-Regular.ttf
new file mode 100644
index 000000000..88e9417f0
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/ComicNeue-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/DancingScript-Regular.ttf b/Source/Demo/Common/Resources/Fonts/DancingScript-Regular.ttf
new file mode 100644
index 000000000..9f521e7fb
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/DancingScript-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/IndieFlower-Regular.ttf b/Source/Demo/Common/Resources/Fonts/IndieFlower-Regular.ttf
new file mode 100644
index 000000000..547ca5803
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/IndieFlower-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationMono-Bold.ttf b/Source/Demo/Common/Resources/Fonts/LiberationMono-Bold.ttf
new file mode 100644
index 000000000..2e46737ac
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationMono-Bold.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationMono-BoldItalic.ttf b/Source/Demo/Common/Resources/Fonts/LiberationMono-BoldItalic.ttf
new file mode 100644
index 000000000..d1f46d7cd
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationMono-BoldItalic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationMono-Italic.ttf b/Source/Demo/Common/Resources/Fonts/LiberationMono-Italic.ttf
new file mode 100644
index 000000000..954c39436
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationMono-Italic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationMono-Regular.ttf b/Source/Demo/Common/Resources/Fonts/LiberationMono-Regular.ttf
new file mode 100644
index 000000000..e774859cb
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationMono-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSans-Bold.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSans-Bold.ttf
new file mode 100644
index 000000000..dc5d57f15
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSans-Bold.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSans-BoldItalic.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSans-BoldItalic.ttf
new file mode 100644
index 000000000..158488a12
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSans-BoldItalic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSans-Italic.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSans-Italic.ttf
new file mode 100644
index 000000000..25970d9d5
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSans-Italic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSans-Regular.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSans-Regular.ttf
new file mode 100644
index 000000000..e6339859d
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSans-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSerif-Bold.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSerif-Bold.ttf
new file mode 100644
index 000000000..3c7c55b57
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSerif-Bold.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSerif-BoldItalic.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSerif-BoldItalic.ttf
new file mode 100644
index 000000000..6b35d9f7c
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSerif-BoldItalic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSerif-Italic.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSerif-Italic.ttf
new file mode 100644
index 000000000..54d516481
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSerif-Italic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/LiberationSerif-Regular.ttf b/Source/Demo/Common/Resources/Fonts/LiberationSerif-Regular.ttf
new file mode 100644
index 000000000..5e5550c0a
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/LiberationSerif-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSans-Bold.ttf b/Source/Demo/Common/Resources/Fonts/NotoSans-Bold.ttf
new file mode 100644
index 000000000..aae7546dc
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSans-Bold.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSans-BoldItalic.ttf b/Source/Demo/Common/Resources/Fonts/NotoSans-BoldItalic.ttf
new file mode 100644
index 000000000..6f685b2e5
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSans-BoldItalic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSans-Italic.ttf b/Source/Demo/Common/Resources/Fonts/NotoSans-Italic.ttf
new file mode 100644
index 000000000..7f5313334
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSans-Italic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSans-Regular.ttf b/Source/Demo/Common/Resources/Fonts/NotoSans-Regular.ttf
new file mode 100644
index 000000000..f27f4ff59
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSans-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSerif-Bold.ttf b/Source/Demo/Common/Resources/Fonts/NotoSerif-Bold.ttf
new file mode 100644
index 000000000..352b80735
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSerif-Bold.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSerif-BoldItalic.ttf b/Source/Demo/Common/Resources/Fonts/NotoSerif-BoldItalic.ttf
new file mode 100644
index 000000000..f0fbb6fb9
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSerif-BoldItalic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSerif-Italic.ttf b/Source/Demo/Common/Resources/Fonts/NotoSerif-Italic.ttf
new file mode 100644
index 000000000..ee42fc10e
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSerif-Italic.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/NotoSerif-Regular.ttf b/Source/Demo/Common/Resources/Fonts/NotoSerif-Regular.ttf
new file mode 100644
index 000000000..123a8c576
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/NotoSerif-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/OFL-Caveat.txt b/Source/Demo/Common/Resources/Fonts/OFL-Caveat.txt
new file mode 100644
index 000000000..6e5220c95
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/OFL-Caveat.txt
@@ -0,0 +1,93 @@
+Copyright 2014 The Caveat Project Authors (https://github.com/googlefonts/caveat)
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.
diff --git a/Source/Demo/Common/Resources/Fonts/OFL-ComicNeue.txt b/Source/Demo/Common/Resources/Fonts/OFL-ComicNeue.txt
new file mode 100644
index 000000000..1a1fefa43
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/OFL-ComicNeue.txt
@@ -0,0 +1,93 @@
+Copyright 2014 The Comic Neue Project Authors (https://github.com/crozynski/comicneue)
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.
diff --git a/Source/Demo/Common/Resources/Fonts/OFL-DancingScript.txt b/Source/Demo/Common/Resources/Fonts/OFL-DancingScript.txt
new file mode 100644
index 000000000..07ff8df96
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/OFL-DancingScript.txt
@@ -0,0 +1,93 @@
+Copyright 2016 The Dancing Script Project Authors (https://github.com/googlefonts/DancingScript), with Reserved Font Name 'Dancing Script'.
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.
diff --git a/Source/Demo/Common/Resources/Fonts/OFL-IndieFlower.txt b/Source/Demo/Common/Resources/Fonts/OFL-IndieFlower.txt
new file mode 100644
index 000000000..5d36552c7
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/OFL-IndieFlower.txt
@@ -0,0 +1,93 @@
+Copyright 2010 The Indie Flower Authors (kimberlygeswein.com),
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.
diff --git a/Source/Demo/Common/Resources/Fonts/OFL-LiberationFonts.txt b/Source/Demo/Common/Resources/Fonts/OFL-LiberationFonts.txt
new file mode 100644
index 000000000..aba73e8a4
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/OFL-LiberationFonts.txt
@@ -0,0 +1,102 @@
+Digitized data copyright (c) 2010 Google Corporation
+	with Reserved Font Arimo, Tinos and Cousine.
+Copyright (c) 2012 Red Hat, Inc.
+	with Reserved Font Name Liberation.
+
+This Font Software is licensed under the SIL Open Font License,
+Version 1.1.
+
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+
+PREAMBLE The goals of the Open Font License (OFL) are to stimulate
+worldwide development of collaborative font projects, to support the font
+creation efforts of academic and linguistic communities, and to provide
+a free and open framework in which fonts may be shared and improved in
+partnership with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves.
+The fonts, including any derivative works, can be bundled, embedded,
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works.  The fonts and derivatives,
+however, cannot be released under any other type of license.  The
+requirement for fonts to remain under this license does not apply to
+any document created using the fonts or their derivatives.
+
+ 
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such.
+This may include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components
+as distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting ? in part or in whole ?
+any of the components of the Original Version, by changing formats or
+by porting the Font Software to a new environment.
+
+"Author" refers to any designer, engineer, programmer, technical writer
+or other person who contributed to the Font Software.
+
+
+PERMISSION & CONDITIONS
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,in
+   Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+   redistributed and/or sold with any software, provided that each copy
+   contains the above copyright notice and this license. These can be
+   included either as stand-alone text files, human-readable headers or
+   in the appropriate machine-readable metadata fields within text or
+   binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+   Name(s) unless explicit written permission is granted by the
+   corresponding Copyright Holder. This restriction only applies to the
+   primary font name as presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+   Software shall not be used to promote, endorse or advertise any
+   Modified Version, except to acknowledge the contribution(s) of the
+   Copyright Holder(s) and the Author(s) or with their explicit written
+   permission.
+
+5) The Font Software, modified or unmodified, in part or in whole, must
+   be distributed entirely under this license, and must not be distributed
+   under any other license. The requirement for fonts to remain under
+   this license does not apply to any document created using the Font
+   Software.
+
+
+ 
+TERMINATION
+This license becomes null and void if any of the above conditions are not met.
+
+ 
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT.  IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM OTHER
+DEALINGS IN THE FONT SOFTWARE.
+
diff --git a/Source/Demo/Common/Resources/Fonts/OFL-NotoFonts.txt b/Source/Demo/Common/Resources/Fonts/OFL-NotoFonts.txt
new file mode 100644
index 000000000..261eeb9e9
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/OFL-NotoFonts.txt
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
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+      "License" shall mean the terms and conditions for use, reproduction,
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+   4. Redistribution. You may reproduce and distribute copies of the
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+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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+      risks associated with Your exercise of permissions under this License.
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+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
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+   9. Accepting Warranty or Additional Liability. While redistributing
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+      on Your own behalf and on Your sole responsibility, not on behalf
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+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
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+   Copyright [yyyy] [name of copyright owner]
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+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
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+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/Source/Demo/Common/Resources/Fonts/OFL-Pacifico.txt b/Source/Demo/Common/Resources/Fonts/OFL-Pacifico.txt
new file mode 100644
index 000000000..33864cc8d
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/OFL-Pacifico.txt
@@ -0,0 +1,93 @@
+Copyright 2018 The Pacifico Project Authors (https://github.com/googlefonts/Pacifico)
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.
diff --git a/Source/Demo/Common/Resources/Fonts/Pacifico-Regular.ttf b/Source/Demo/Common/Resources/Fonts/Pacifico-Regular.ttf
new file mode 100644
index 000000000..27765d02a
Binary files /dev/null and b/Source/Demo/Common/Resources/Fonts/Pacifico-Regular.ttf differ
diff --git a/Source/Demo/Common/Resources/Fonts/README.md b/Source/Demo/Common/Resources/Fonts/README.md
new file mode 100644
index 000000000..bfbd42cd3
--- /dev/null
+++ b/Source/Demo/Common/Resources/Fonts/README.md
@@ -0,0 +1,18 @@
+# Bundled demo fonts
+
+All fonts here are open source (SIL Open Font License 1.1 - see the accompanying `OFL-*.txt` files,
+one per family/foundry since copyright holders differ) and are used to exercise the `@font-face` demo
+sample (`TestSamples/20.Fonts decorations.htm`) and the integration test suite, without depending on
+whatever fonts happen to be installed on the machine running them.
+
+| Family | Faces | Source |
+| --- | --- | --- |
+| Liberation Sans/Serif/Mono | Regular, Bold, Italic, Bold Italic | https://github.com/liberationfonts/liberation-fonts, release 2.1.5 (`liberation-fonts-ttf-2.1.5.tar.gz`) |
+| Noto Sans/Serif | Regular, Bold, Italic, Bold Italic | https://github.com/notofonts/notofonts.github.io, `fonts/<Family>/hinted/ttf/` |
+| Pacifico | Regular | https://github.com/google/fonts, `ofl/pacifico/` |
+| Dancing Script | Regular (variable font, default instance) | https://github.com/google/fonts, `ofl/dancingscript/` |
+| Caveat | Regular (variable font, default instance) | https://github.com/google/fonts, `ofl/caveat/` |
+| Indie Flower | Regular | https://github.com/google/fonts, `ofl/indieflower/` |
+| Comic Neue | Regular, Bold, Italic, Bold Italic | https://github.com/google/fonts, `ofl/comicneue/` |
+
+Plain TTF only (no WOFF/WOFF2) - this project's `@font-face` support doesn't decompress WOFF/WOFF2 in v1.
diff --git a/Source/Demo/Common/Samples/00.Intro.htm b/Source/Demo/Common/Samples/00.Intro.htm
index 894052814..bc14d7616 100644
--- a/Source/Demo/Common/Samples/00.Intro.htm
+++ b/Source/Demo/Common/Samples/00.Intro.htm
@@ -4,7 +4,7 @@
         <title>Intro</title>
         <link rel="Stylesheet" href="StyleSheet">
     </head>
-    <body style="background-color: #333; background-gradient: #707; background-gradient-angle: 60; margin: 0;">
+    <body style="background-image: linear-gradient(60deg, #333, #707); margin: 0;">
         <h1 align="center" style="color: white">
             HTML Renderer Project - $$Platform$$
             <br />
diff --git a/Source/Demo/Common/Samples/07.Additional features.htm b/Source/Demo/Common/Samples/07.Additional features.htm
index fcc209e82..db4854fe2 100644
--- a/Source/Demo/Common/Samples/07.Additional features.htm	
+++ b/Source/Demo/Common/Samples/07.Additional features.htm	
@@ -6,20 +6,18 @@
         <style>
         <!--
             .g1, .g2, .g3, .g4, .g5 {
-                background-color: red;
-                background-gradient: yellow;
                 padding: 22px;
             }
 
-            .g1 { background-gradient-angle: 0; }
+            .g1 { background-image: linear-gradient(0deg, red, yellow); }
 
-            .g2 { background-gradient-angle: 45; }
+            .g2 { background-image: linear-gradient(45deg, red, yellow); }
 
-            .g3 { background-gradient-angle: 90; }
+            .g3 { background-image: linear-gradient(90deg, red, yellow); }
 
-            .g4 { background-gradient-angle: 135; }
+            .g4 { background-image: linear-gradient(135deg, red, yellow); }
 
-            .g5 { background-gradient-angle: 180; }
+            .g5 { background-image: linear-gradient(180deg, red, yellow); }
 
             .c1, .c2, .c3, .c4, .c5 {
                 background-color: olive;
@@ -28,16 +26,16 @@
                 vertical-align: middle;
             }
 
-            .c1 { corner-radius: 0px; }
+            .c1 { border-radius: 0px; }
 
-            .c2 { corner-radius: 10px; }
+            .c2 { border-radius: 10px; }
 
-            .c3 { corner-radius: 0px 10px 10px 0px; }
+            .c3 { border-radius: 0px 10px 10px 0px; }
 
-            .c4 { corner-radius: 18px; }
+            .c4 { border-radius: 18px; }
 
             .c5 {
-                corner-radius: 10px;
+                border-radius: 10px;
                 border: outset #BBBB00 2px;
             }
 
@@ -60,24 +58,17 @@ <h1>
             <h2>
                 Graphic features</h2>
             <p>
-                I have always wanted the W3C to add this features to the CSS spec (and so far, not
-                there yet :)</p>
+                Standard CSS backgrounds and border radii, same as any modern browser.</p>
             <ul>
                 <li><b>Gradients on backgrounds</b></li>
                 <li><b>Rounded corners</b></li>
             </ul>
-            <p>
-                And I think many many web designers would agree. Is it so hard or what?.</p>
             <h3>
                 Background Gradients</h3>
             <p>
-                It is a simple two color linear gradient, achieved by the adding of two CSS properties:</p>
-            <ol>
-                <li><code>background-gradient: (#Color)</code> - Second color of the gradient background,
-                    the first one is given by <code>background-color</code>. Not inherited.</li>
-                <li><code>background-gradient-angle: (number)</code> - Angle (in degrees, clockwise) of
-                    the gradient. Not inherited. Initial value:90</li>
-            </ol>
+                A <code>background-image</code> can be a <code>linear-gradient()</code> (or
+                <code>repeating-linear-gradient()</code>) function: an angle or <code>to &lt;side&gt;</code>
+                direction, followed by two or more comma-separated color stops.</p>
             <b>Some examples</b>
             <!-- Gradients table -->
             <table width="300px">
@@ -95,19 +86,19 @@ <h3>
                 </tr>
                 <tr>
                     <td>
-                        0 degrees
+                        0deg
                     </td>
                     <td>
-                        45 degrees
+                        45deg
                     </td>
                     <td>
-                        90 degrees
+                        90deg
                     </td>
                     <td>
-                        135 degrees
+                        135deg
                     </td>
                     <td>
-                        180 degrees
+                        180deg
                     </td>
                 </tr>
             </table>
@@ -120,18 +111,18 @@ <h3>
                 website you visit nowadays makes use of rounded corners, where a not very nice trick
                 with images and tables must be used.</p>
             <p>
-                In this renderer, the rounded corners are achieved by adding this CSS properties:</p>
+                In this renderer, the rounded corners are achieved with the standard CSS properties:</p>
             <ul>
-                <li><code>corner-ne-radius: (length)</code> Indicates the radius of the north-east corner.
-                    Not ineritted</li>
-                <li><code>corner-se-radius: (length)</code> Indicates the radius of the south-east corner.
-                    Not ineritted</li>
-                <li><code>corner-sw-radius: (length)</code> Indicates the radius of the south-west corner.
-                    Not ineritted</li>
-                <li><code>corner-nw-radius: (length)</code> Indicates the radius of the north-west corner.
-                    Not ineritted</li>
-                <li><code>corner-radius: (length){1,4}</code> Shorthand for the other corner properties.
-                    Not ineritted</li>
+                <li><code>border-top-left-radius: (length){1,2}</code> Indicates the radius of the top-left
+                    corner. Not inherited</li>
+                <li><code>border-top-right-radius: (length){1,2}</code> Indicates the radius of the top-right
+                    corner. Not inherited</li>
+                <li><code>border-bottom-right-radius: (length){1,2}</code> Indicates the radius of the bottom-right
+                    corner. Not inherited</li>
+                <li><code>border-bottom-left-radius: (length){1,2}</code> Indicates the radius of the bottom-left
+                    corner. Not inherited</li>
+                <li><code>border-radius: (length){1,4} [ / (length){1,4} ]?</code> Shorthand for the other
+                    corner properties, with an optional "/" for elliptical corners. Not inherited</li>
             </ul>
             <!-- Corners table -->
             <b>Some examples</b>
@@ -161,11 +152,11 @@ <h3>
                 </tr>
             </table>
             <pre>.c1, .c2, .c3, .c4, .c5 { background-color:olive; border:0px; color:white; vertical-align:middle; }
-.c1  { corner-radius: 0px }
-.c2  { corner-radius: 10px }
-.c3  { corner-radius: 0px 10px 10px 0px }
-.c4  { corner-radius: 18px }
-.c5  { corner-radius: 10px; border: outset #bb0 2px; }</pre>
+.c1  { border-radius: 0px }
+.c2  { border-radius: 10px }
+.c3  { border-radius: 0px 10px 10px 0px }
+.c4  { border-radius: 18px }
+.c5  { border-radius: 10px; border: outset #bb0 2px; }</pre>
         </blockquote>
     </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/Source/Demo/Common/Samples/08.Tooltip.htm b/Source/Demo/Common/Samples/08.Tooltip.htm
index 096bde29a..c6fc759d8 100644
--- a/Source/Demo/Common/Samples/08.Tooltip.htm
+++ b/Source/Demo/Common/Samples/08.Tooltip.htm
@@ -22,9 +22,8 @@ <h2>Default tooltip style</h2>
             <pre>
 .htmltooltip {
     border:solid 1px #767676;
-    background-color:white;
-    background-gradient:#E4E5F0;
-    padding: 8px; 
+    background-color:#E4E5F0;
+    padding: 8px;
     Font: 9pt Tahoma;
 }</pre>
             <h2>Examples</h2>
diff --git a/Source/Demo/Common/TestSamples/12.Text.htm b/Source/Demo/Common/TestSamples/12.Text.htm
index f2fa41205..9eb3fa640 100644
--- a/Source/Demo/Common/TestSamples/12.Text.htm
+++ b/Source/Demo/Common/TestSamples/12.Text.htm
@@ -1,79 +1,79 @@
-<!DOCTYPE html>
-<html>
-    <head>
-        <title>Text</title>
-        <link rel="Stylesheet" href="StyleSheet">
-        <style>
-            .right {
-                text-align: right;
-                border-width: 1px;
-                border-style: solid;
-                border-color: blue;
-            }
-        </style>
-    </head>
-    <body>
-        <h2>Case 1</h2>
-        <p>
-            <font size="5" color="red">Warning:</font>P tags must be closed. In fact all tags with the
-            end tag <a href="http://www.w3.org/TR//REC-html401-19991224/index/elements.html">marked as optional</a>, must be closed. It may be fixed by next release.
-        </p>
-        <hr />
-        <h2>Text align justify with background colors</h2>
-        <p style="text-align: justify">
-            Lorem ipsum dolor sit amet, <span style="background-color: gold;">consectetur</span> adipisicing
-            elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua tempor incididunt ut labore et dolore magna aliqua incididunt ut labore et dolore magna aliqua.
-        </p>
-        <hr />
-        <h2>Right align adjusts</h2>
-        <table style="border-spacing: 0px;">
-            <tr>
-                <td class="right">978</td>
-            </tr>
-            <tr>
-                <td class="right">32</td>
-            </tr>
-        </table>
-        <hr />
-        <h2>Transparent text</h2>
-        <p style="color: rgba(255, 0, 0, 100)">
-            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur ornare mollis elit. Integer sagittis. Fusce elementum commodo felis. Vivamus lacinia eleifend libero. Donec 
-            lacus. Nam sit amet urna. Nullam nulla. Donec accumsan porta magna. Mauris a dolor eu elit rutrum commodo. Nam iaculis turpis non augue. Nullam lobortis egestas risus. Nulla 
-            elementum dolor ac mauris. Ut tristique. In varius volutpat metus. Integer leo dolor, tristique a, dignissim ac, iaculis eget, elit. Donec arcu.
-        </p>
-
-        <p style="background-color: rgba(255, 215, 0, 50)">
-            <span style="color: rgba(0, 255, 0, 140)">
-                Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur ornare mollis elit. Integer sagittis. Fusce elementum commodo felis. Vivamus lacinia eleifend libero. Donec 
-                lacus.
-            </span>
-            <br />
-            <span style="color: rgba(0, 0, 255, 100)">
-                Nam sit amet urna. Nullam nulla. Donec accumsan porta magna. Mauris a dolor eu elit rutrum commodo. Nam iaculis turpis non augue. Nullam lobortis egestas risus. Nulla 
-                elementum dolor ac mauris. Ut tristique. In varius volutpat metus. Integer leo dolor, tristique a, dignissim ac, iaculis eget, elit. Donec arcu.
-            </span>
-        </p>
-        <p style="background-color: #a33; background-gradient: rgb(255, 215, 0); background-gradient-angle: 0">
-            <span style="color: rgba(0, 255, 0, 140)">
-                Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur ornare mollis elit. Integer_sagittis_Fusce_elementum_commodo_felis_Vivamus_lacinia_eleifend_libero_Donec 
-                lacus.
-            </span>
-            <br />
-            <span style="color: rgba(0, 0, 255, 100)">
-                Nam sit amet urna. Nullam nulla. Donec accumsan porta magna. Mauris a dolor eu elit rutrum commodo. Nam iaculis turpis non augue. Nullam lobortis egestas risus. Nulla 
-                elementum dolor ac mauris. Ut tristique. In varius volutpat metus. Integer leo dolor, tristique a, dignissim ac, iaculis eget, elit. Donec arcu.
-            </span>
-        </p>
-        <hr />
-        <h2>RTL text</h2>
-        <p style="text-align: right; direction: Rtl;">
-            <span>בדיקה של טקסט ימין לשמאל</span>
-        </p>
-        <p>
-            <span dir="rTL" lang="HE">בדיקה של טקסט ימין לשמאל</span> normal text
-        </p>
-        <p>
-            <span>בדיקה של טקסט ימין לשמאל</span> normal text
-        </p>
-    </body>
-</html>
\ No newline at end of file
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Text</title>
+        <link rel="Stylesheet" href="StyleSheet">
+        <style>
+            .right {
+                text-align: right;
+                border-width: 1px;
+                border-style: solid;
+                border-color: blue;
+            }
+        </style>
+    </head>
+    <body>
+        <h2>Case 1</h2>
+        <p>
+            <font size="5" color="red">Warning:</font>P tags must be closed. In fact all tags with the
+            end tag <a href="http://www.w3.org/TR//REC-html401-19991224/index/elements.html">marked as optional</a>, must be closed. It may be fixed by next release.
+        </p>
+        <hr />
+        <h2>Text align justify with background colors</h2>
+        <p style="text-align: justify">
+            Lorem ipsum dolor sit amet, <span style="background-color: gold;">consectetur</span> adipisicing
+            elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua tempor incididunt ut labore et dolore magna aliqua incididunt ut labore et dolore magna aliqua.
+        </p>
+        <hr />
+        <h2>Right align adjusts</h2>
+        <table style="border-spacing: 0px;">
+            <tr>
+                <td class="right">978</td>
+            </tr>
+            <tr>
+                <td class="right">32</td>
+            </tr>
+        </table>
+        <hr />
+        <h2>Transparent text</h2>
+        <p style="color: rgba(255, 0, 0, 100)">
+            Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur ornare mollis elit. Integer sagittis. Fusce elementum commodo felis. Vivamus lacinia eleifend libero. Donec
+            lacus. Nam sit amet urna. Nullam nulla. Donec accumsan porta magna. Mauris a dolor eu elit rutrum commodo. Nam iaculis turpis non augue. Nullam lobortis egestas risus. Nulla
+            elementum dolor ac mauris. Ut tristique. In varius volutpat metus. Integer leo dolor, tristique a, dignissim ac, iaculis eget, elit. Donec arcu.
+        </p>
+
+        <p style="background-color: rgba(255, 215, 0, 50)">
+            <span style="color: rgba(0, 255, 0, 140)">
+                Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur ornare mollis elit. Integer sagittis. Fusce elementum commodo felis. Vivamus lacinia eleifend libero. Donec
+                lacus.
+            </span>
+            <br />
+            <span style="color: rgba(0, 0, 255, 100)">
+                Nam sit amet urna. Nullam nulla. Donec accumsan porta magna. Mauris a dolor eu elit rutrum commodo. Nam iaculis turpis non augue. Nullam lobortis egestas risus. Nulla
+                elementum dolor ac mauris. Ut tristique. In varius volutpat metus. Integer leo dolor, tristique a, dignissim ac, iaculis eget, elit. Donec arcu.
+            </span>
+        </p>
+        <p style="background-image: linear-gradient(to right, #a33, rgb(255, 215, 0))">
+            <span style="color: rgba(0, 255, 0, 140)">
+                Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur ornare mollis elit. Integer_sagittis_Fusce_elementum_commodo_felis_Vivamus_lacinia_eleifend_libero_Donec
+                lacus.
+            </span>
+            <br />
+            <span style="color: rgba(0, 0, 255, 100)">
+                Nam sit amet urna. Nullam nulla. Donec accumsan porta magna. Mauris a dolor eu elit rutrum commodo. Nam iaculis turpis non augue. Nullam lobortis egestas risus. Nulla
+                elementum dolor ac mauris. Ut tristique. In varius volutpat metus. Integer leo dolor, tristique a, dignissim ac, iaculis eget, elit. Donec arcu.
+            </span>
+        </p>
+        <hr />
+        <h2>RTL text</h2>
+        <p style="text-align: right; direction: Rtl;">
+            <span>בדיקה של טקסט ימין לשמאל</span>
+        </p>
+        <p>
+            <span dir="rTL" lang="HE">בדיקה של טקסט ימין לשמאל</span> normal text
+        </p>
+        <p>
+            <span>בדיקה של טקסט ימין לשמאל</span> normal text
+        </p>
+    </body>
+</html>
diff --git a/Source/Demo/Common/TestSamples/13.Tables.htm b/Source/Demo/Common/TestSamples/13.Tables.htm
index fc896eda6..a58ac927c 100644
--- a/Source/Demo/Common/TestSamples/13.Tables.htm
+++ b/Source/Demo/Common/TestSamples/13.Tables.htm
@@ -3,7 +3,7 @@
     <head>
         <title>Tables</title>
         <style type="text/css">
-            .header { font: 12pt; }
+            .header { font-size: 12pt; }
 
             .key {
                 color: #404080;
diff --git a/Source/Demo/Common/TestSamples/16.Borders.htm b/Source/Demo/Common/TestSamples/16.Borders.htm
index f1a0007cd..f32281730 100644
--- a/Source/Demo/Common/TestSamples/16.Borders.htm
+++ b/Source/Demo/Common/TestSamples/16.Borders.htm
@@ -11,11 +11,11 @@
             <div style="padding: 5px; border: 3px solid red">
                 simple border 3px
             </div>
-            <div style="padding: 5px; border: 1px solid black; corner-radius: 5px;">
-                border 1px with corner-radius 5px
+            <div style="padding: 5px; border: 1px solid black; border-radius: 5px;">
+                border 1px with border-radius 5px
             </div>
-            <div style="padding: 5px; border: 2px solid black; corner-radius: 10px;">
-                border 2px with corner-radius 10px
+            <div style="padding: 5px; border: 2px solid black; border-radius: 10px;">
+                border 2px with border-radius 10px
             </div>
             <div style="padding: 5px; border: 1px dotted blue;">
                 dotted border 1px
@@ -26,8 +26,8 @@
             <div style="padding: 5px; border: 1px dashed darkred;">
                 dashed border 1px
             </div>
-            <div style="padding: 5px; border: 2px dashed darkred; corner-radius: 10px;">
-                dashed border 2px with corner-radius 10px
+            <div style="padding: 5px; border: 2px dashed darkred; border-radius: 10px;">
+                dashed border 2px with border-radius 10px
             </div>
         </div>
     </body>
diff --git a/Source/Demo/Common/TestSamples/20.Fonts decorations.htm b/Source/Demo/Common/TestSamples/20.Fonts decorations.htm
index b58e2a8c6..8f388de6c 100644
--- a/Source/Demo/Common/TestSamples/20.Fonts decorations.htm	
+++ b/Source/Demo/Common/TestSamples/20.Fonts decorations.htm	
@@ -2,235 +2,188 @@
 <html>
     <head>
         <title>Fonts Decorations</title>
+        <style>
+            @font-face {
+                font-family: "Demo Liberation Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSans-Regular.ttf);
+                font-weight: normal;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Liberation Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSans-Bold.ttf);
+                font-weight: bold;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Liberation Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSans-Italic.ttf);
+                font-weight: normal;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Liberation Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSans-BoldItalic.ttf);
+                font-weight: bold;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Liberation Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSerif-Regular.ttf);
+                font-weight: normal;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Liberation Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSerif-Bold.ttf);
+                font-weight: bold;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Liberation Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSerif-Italic.ttf);
+                font-weight: normal;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Liberation Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationSerif-BoldItalic.ttf);
+                font-weight: bold;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Liberation Mono";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationMono-Regular.ttf);
+                font-weight: normal;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Liberation Mono";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationMono-Bold.ttf);
+                font-weight: bold;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Liberation Mono";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationMono-Italic.ttf);
+                font-weight: normal;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Liberation Mono";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.LiberationMono-BoldItalic.ttf);
+                font-weight: bold;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Noto Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSans-Regular.ttf);
+                font-weight: normal;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Noto Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSans-Bold.ttf);
+                font-weight: bold;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Noto Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSans-Italic.ttf);
+                font-weight: normal;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Noto Sans";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSans-BoldItalic.ttf);
+                font-weight: bold;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Noto Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSerif-Regular.ttf);
+                font-weight: normal;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Noto Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSerif-Bold.ttf);
+                font-weight: bold;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Noto Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSerif-Italic.ttf);
+                font-weight: normal;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Noto Serif";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.NotoSerif-BoldItalic.ttf);
+                font-weight: bold;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Comic Neue";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.ComicNeue-Regular.ttf);
+                font-weight: normal;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Comic Neue";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.ComicNeue-Bold.ttf);
+                font-weight: bold;
+                font-style: normal;
+            }
+            @font-face {
+                font-family: "Demo Comic Neue";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.ComicNeue-Italic.ttf);
+                font-weight: normal;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Comic Neue";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.ComicNeue-BoldItalic.ttf);
+                font-weight: bold;
+                font-style: italic;
+            }
+            @font-face {
+                font-family: "Demo Pacifico";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.Pacifico-Regular.ttf);
+            }
+            @font-face {
+                font-family: "Demo Dancing Script";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.DancingScript-Regular.ttf);
+            }
+            @font-face {
+                font-family: "Demo Caveat";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.Caveat-Regular.ttf);
+            }
+            @font-face {
+                font-family: "Demo Indie Flower";
+                src: url(embedded://HtmlRendererDemoCommon/TheArtOfDev.HtmlRenderer.Demo.Common.Resources.Fonts.IndieFlower-Regular.ttf);
+            }
+        </style>
     </head>
     <body>
-        <h2>All fonts with different decorations</h2>
-        <p><span style="font-family: 'Aharoni'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Aharoni'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Aharoni'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Aldhabi'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Aldhabi'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Aldhabi'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Algerian'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Algerian'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Algerian'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Andalus'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Andalus'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Andalus'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Angsana New'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Angsana New'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Angsana New'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'AngsanaUPC'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'AngsanaUPC'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'AngsanaUPC'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Aparajita'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Aparajita'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Aparajita'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Arabic Typesetting'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arabic Typesetting'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arabic Typesetting'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Arial'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Arial Black'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial Black'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial Black'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Arial Narrow'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial Narrow'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial Narrow'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Arial Unicode MS'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial Unicode MS'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Arial Unicode MS'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Baskerville Old Face'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Baskerville Old Face'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Baskerville Old Face'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Batang'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Batang'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Batang'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'BatangChe'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'BatangChe'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'BatangChe'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Bauhaus 93'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bauhaus 93'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bauhaus 93'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Bell MT'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bell MT'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bell MT'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Berlin Sans FB'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Berlin Sans FB'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Berlin Sans FB'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Berlin Sans FB Demi'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Berlin Sans FB Demi'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Berlin Sans FB Demi'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Bernard MT Condensed'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bernard MT Condensed'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bernard MT Condensed'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Bodoni MT Poster Compressed'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bodoni MT Poster Compressed'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bodoni MT Poster Compressed'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Book Antiqua'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Book Antiqua'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Book Antiqua'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Bookman Old Style'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bookman Old Style'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bookman Old Style'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Bookshelf Symbol 7'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bookshelf Symbol 7'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bookshelf Symbol 7'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Bradley Hand ITC'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bradley Hand ITC'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Bradley Hand ITC'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Britannic Bold'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Britannic Bold'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Britannic Bold'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Broadway'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Broadway'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Broadway'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Browallia New'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Browallia New'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Browallia New'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'BrowalliaUPC'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'BrowalliaUPC'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'BrowalliaUPC'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Brush Script MT'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Brush Script MT'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Brush Script MT'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Buxton Sketch'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Buxton Sketch'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Buxton Sketch'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Calibri'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Calibri'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Calibri'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Calibri Light'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Calibri Light'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Calibri Light'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Californian FB'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Californian FB'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Californian FB'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Cambria'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cambria'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cambria'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Cambria Math'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cambria Math'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cambria Math'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Candara'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Candara'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Candara'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Centaur'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Centaur'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Centaur'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Century'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Century'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Century'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Century Gothic'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Century Gothic'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Century Gothic'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Chiller'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Chiller'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Chiller'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Colonna MT'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Colonna MT'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Colonna MT'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Comic Sans MS'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Comic Sans MS'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Comic Sans MS'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Consolas'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Consolas'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Consolas'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Constantia'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Constantia'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Constantia'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Cooper Black'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cooper Black'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cooper Black'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Corbel'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Corbel'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Corbel'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Cordia New'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cordia New'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Cordia New'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'CordiaUPC'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'CordiaUPC'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'CordiaUPC'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Courier New'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Courier New'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Courier New'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'DaunPenh'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DaunPenh'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DaunPenh'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'David'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'David'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'David'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'DFKai-SB'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DFKai-SB'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DFKai-SB'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'DilleniaUPC'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DilleniaUPC'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DilleniaUPC'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'DokChampa'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DokChampa'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DokChampa'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Dotum'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Dotum'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Dotum'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'DotumChe'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DotumChe'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'DotumChe'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Ebrima'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Ebrima'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Ebrima'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Estrangelo Edessa'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Estrangelo Edessa'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Estrangelo Edessa'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'EucrosiaUPC'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'EucrosiaUPC'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'EucrosiaUPC'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Euphemia'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Euphemia'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Euphemia'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'FangSong'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'FangSong'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'FangSong'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'FontAwesome'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'FontAwesome'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'FontAwesome'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'MingLiU_HKSCS-ExtB'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'MingLiU_HKSCS-ExtB'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'MingLiU_HKSCS-ExtB'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'MS PMincho'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'MS PMincho'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'MS PMincho'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'MV Boli'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'MV Boli'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'MV Boli'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Myanmar Text'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Myanmar Text'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Myanmar Text'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Narkisim'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Narkisim'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Narkisim'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Niagara Engraved'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Niagara Engraved'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Niagara Engraved'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Niagara Solid'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Niagara Solid'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Niagara Solid'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Nirmala UI'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Nirmala UI'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Nirmala UI'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'NSimSun'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'NSimSun'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'NSimSun'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Nyala'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Nyala'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Nyala'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Old English Text MT'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Old English Text MT'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Old English Text MT'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Onyx'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Onyx'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Onyx'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Palatino Linotype'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Palatino Linotype'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Palatino Linotype'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Papyrus'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Papyrus'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Papyrus'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Parchment'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Parchment'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Parchment'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Plantagenet Cherokee'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Plantagenet Cherokee'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Plantagenet Cherokee'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'PMingLiU'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'PMingLiU'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'PMingLiU'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'PMingLiU-ExtB'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'PMingLiU-ExtB'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'PMingLiU-ExtB'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'Pristina'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Pristina'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Pristina'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'Ravie'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Ravie'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Ravie'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'Segoe Print'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe Print'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe Print'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Segoe Script'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe Script'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe Script'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Segoe UI'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Segoe UI Light'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI Light'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI Light'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Segoe UI Semibold'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI Semibold'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI Semibold'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Segoe UI Semilight'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI Semilight'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Segoe UI Semilight'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
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-        <p><span style="font-family: 'Trebuchet MS'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Trebuchet MS'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Trebuchet MS'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Tunga'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Tunga'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Tunga'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Urdu Typesetting'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Urdu Typesetting'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Urdu Typesetting'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Utsaah'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Utsaah'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Utsaah'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Vani'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vani'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vani'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Verdana'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Verdana'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Verdana'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Vijaya'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vijaya'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vijaya'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Viner Hand ITC'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Viner Hand ITC'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Viner Hand ITC'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Vivaldi'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vivaldi'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vivaldi'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Vladimir Script'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vladimir Script'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vladimir Script'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Vrinda'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vrinda'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Vrinda'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Webdings'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Webdings'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Webdings'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Wide Latin'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wide Latin'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wide Latin'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Wingdings'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wingdings'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wingdings'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Wingdings 2'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wingdings 2'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wingdings 2'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-        <p><span style="font-family: 'Wingdings 3'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wingdings 3'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Wingdings 3'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
-    
-        <!--
-            var sb = new StringBuilder();
-            foreach (var family in FontFamily.Families)
-            {
-            sb.Append("<p>");
-                           sb.AppendFormat("<span style=\"font-family: '{0}'; text-decoration: overline\">Text, ABCgjwzqh. 1230</span>", family.Name);
-                           sb.Append(" | ");
-                           sb.AppendFormat("<span style=\"font-family: '{0}'; text-decoration: line-through\">Text, ABCgjwzqh. 1230</span>", family.Name);
-                           sb.Append(" | ");
-                           sb.AppendFormat("<span style=\"font-family: '{0}'; text-decoration: underline\">Text, ABCgjwzqh. 1230</span>", family.Name);
-                           sb.Append("</p>");
-            sb.AppendLine();
-            }
-            var str = sb.ToString();
-            -->
+        <h2>@font-face fonts with different decorations</h2>
+        <p><span style="font-family: 'Demo Liberation Sans'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Liberation Sans'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Liberation Sans'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Liberation Serif'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Liberation Serif'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Liberation Serif'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Liberation Mono'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Liberation Mono'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Liberation Mono'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Noto Sans'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Noto Sans'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Noto Sans'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Noto Serif'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Noto Serif'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Noto Serif'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Comic Neue'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Comic Neue'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Comic Neue'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Pacifico'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Pacifico'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Pacifico'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Dancing Script'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Dancing Script'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Dancing Script'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Caveat'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Caveat'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Caveat'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
+        <p><span style="font-family: 'Demo Indie Flower'; text-decoration: overline">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Indie Flower'; text-decoration: line-through">Text, ABCgjwzqh. 1230</span> | <span style="font-family: 'Demo Indie Flower'; text-decoration: underline">Text, ABCgjwzqh. 1230</span></p>
 
+        <h2>@font-face weight and style matching (proves nearest-face selection, not just decoration)</h2>
+        <p><span style="font-family: 'Demo Liberation Sans'">Regular</span> | <span style="font-family: 'Demo Liberation Sans'; font-weight: bold">Bold</span> | <span style="font-family: 'Demo Liberation Sans'; font-style: italic">Italic</span> | <span style="font-family: 'Demo Liberation Sans'; font-weight: bold; font-style: italic">Bold Italic</span></p>
+        <p><span style="font-family: 'Demo Liberation Serif'">Regular</span> | <span style="font-family: 'Demo Liberation Serif'; font-weight: bold">Bold</span> | <span style="font-family: 'Demo Liberation Serif'; font-style: italic">Italic</span> | <span style="font-family: 'Demo Liberation Serif'; font-weight: bold; font-style: italic">Bold Italic</span></p>
+        <p><span style="font-family: 'Demo Liberation Mono'">Regular</span> | <span style="font-family: 'Demo Liberation Mono'; font-weight: bold">Bold</span> | <span style="font-family: 'Demo Liberation Mono'; font-style: italic">Italic</span> | <span style="font-family: 'Demo Liberation Mono'; font-weight: bold; font-style: italic">Bold Italic</span></p>
+        <p><span style="font-family: 'Demo Noto Sans'">Regular</span> | <span style="font-family: 'Demo Noto Sans'; font-weight: bold">Bold</span> | <span style="font-family: 'Demo Noto Sans'; font-style: italic">Italic</span> | <span style="font-family: 'Demo Noto Sans'; font-weight: bold; font-style: italic">Bold Italic</span></p>
+        <p><span style="font-family: 'Demo Noto Serif'">Regular</span> | <span style="font-family: 'Demo Noto Serif'; font-weight: bold">Bold</span> | <span style="font-family: 'Demo Noto Serif'; font-style: italic">Italic</span> | <span style="font-family: 'Demo Noto Serif'; font-weight: bold; font-style: italic">Bold Italic</span></p>
+        <p><span style="font-family: 'Demo Comic Neue'">Regular</span> | <span style="font-family: 'Demo Comic Neue'; font-weight: bold">Bold</span> | <span style="font-family: 'Demo Comic Neue'; font-style: italic">Italic</span> | <span style="font-family: 'Demo Comic Neue'; font-weight: bold; font-style: italic">Bold Italic</span></p>
     </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/Source/Demo/Common/TestSamples/23.Media queries and color scheme.htm b/Source/Demo/Common/TestSamples/23.Media queries and color scheme.htm
new file mode 100644
index 000000000..501f1c3d2
--- /dev/null
+++ b/Source/Demo/Common/TestSamples/23.Media queries and color scheme.htm	
@@ -0,0 +1,99 @@
+<html>
+<head>
+<style>
+    body { font: 10pt Tahoma; margin: 10px; }
+
+    .card {
+        border: 1px solid #767676;
+        padding: 10px;
+        margin-bottom: 12px;
+    }
+
+    h3 { margin: 0 0 6px 0; font-size: 12pt; }
+    .note { color: #555555; font-size: 8pt; }
+
+    /* --- prefers-color-scheme -------------------------------------------------
+       The light styling below is the baseline. On GDI+ and WPF the adapter reports
+       the Windows app theme, so switching Windows to Dark and reloading should
+       flip this card to the dark palette. PdfSharp always reports light. */
+    .scheme {
+        background-color: #ffffff;
+        color: #111111;
+        border-color: #cccccc;
+    }
+    .scheme .verdict:after { content: "light"; }
+
+    @media (prefers-color-scheme: dark) {
+        .scheme {
+            background-color: #1e1e1e;
+            color: #f0f0f0;
+            border-color: #555555;
+        }
+        .scheme .verdict:after { content: "dark"; }
+    }
+
+    /* --- media type ----------------------------------------------------------
+       The adapter also supplies the media type: "screen" for GDI+/WPF, "print"
+       for PdfSharp. Exactly one of these two cards should be visible. */
+    .screen-only { display: none; }
+    .print-only { display: none; }
+
+    @media screen {
+        .screen-only { display: block; background-color: #e8f4ff; }
+    }
+
+    @media print {
+        .print-only { display: block; background-color: #f4f4f4; }
+    }
+
+    /* --- feature evaluation --------------------------------------------------
+       A feature the matcher cannot evaluate drops its whole block, so this card
+       must never turn red. */
+    @media all and (scan: interlace) {
+        .unsupported-feature { background-color: #ff0000; color: #ffffff; }
+    }
+
+    /* --- viewport width ------------------------------------------------------
+       Evaluated against the container's available width. */
+    .width-probe { background-color: #f0f0f0; }
+    @media (min-width: 400px) {
+        .width-probe { background-color: #e6ffe6; }
+        .width-probe .verdict:after { content: "viewport is at least 400px wide"; }
+    }
+    @media (max-width: 399px) {
+        .width-probe .verdict:after { content: "viewport is under 400px wide"; }
+    }
+</style>
+</head>
+<body>
+
+<div class="card scheme">
+    <h3>prefers-color-scheme</h3>
+    This card follows the platform colour scheme. Reported scheme: <b class="verdict"></b>.
+    <div class="note">GDI+ and WPF read the Windows app theme; PdfSharp always reports light.</div>
+</div>
+
+<div class="card screen-only">
+    <h3>@media screen</h3>
+    Visible because the adapter's media type is <b>screen</b>.
+</div>
+
+<div class="card print-only">
+    <h3>@media print</h3>
+    Visible because the adapter's media type is <b>print</b>.
+</div>
+
+<div class="card unsupported-feature">
+    <h3>Unsupported media feature</h3>
+    This card stays neutral. A media feature the matcher cannot evaluate drops its whole block
+    rather than applying the rules inside it, so the red styling in
+    <code>@media all and (scan: interlace)</code> must not win.
+</div>
+
+<div class="card width-probe">
+    <h3>Viewport width</h3>
+    <span class="verdict"></span>
+</div>
+
+</body>
+</html>
diff --git a/Source/Demo/Common/TestSamples/36.Float wrap.htm b/Source/Demo/Common/TestSamples/36.Float wrap.htm
new file mode 100644
index 000000000..60ac3c7c0
--- /dev/null
+++ b/Source/Demo/Common/TestSamples/36.Float wrap.htm	
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>Float wrap</title>
+    </head>
+    <body>
+        <div style="float: left; width: 80px; height: 80px; background-color: #4a90d9; margin: 0 10px 10px 0;"></div>
+        <div style="float: right; width: 80px; height: 60px; background-color: #d94a4a; margin: 0 0 10px 10px;"></div>
+        <p style="margin: 0;">This paragraph wraps around a blue box floated left and a red box floated right, so its lines should narrow to avoid both floats until the text runs past their bottom edges and returns to the full available width for the remaining lines of text in this paragraph.</p>
+        <div style="clear: both; background-color: #cccccc; padding: 4px;">This div has clear: both and should start below both floated boxes, not overlap them.</div>
+    </body>
+</html>
diff --git a/Source/Demo/WPF/DemoWindow.xaml.cs b/Source/Demo/WPF/DemoWindow.xaml.cs
index 168ac351b..be75f0372 100644
--- a/Source/Demo/WPF/DemoWindow.xaml.cs
+++ b/Source/Demo/WPF/DemoWindow.xaml.cs
@@ -116,13 +116,13 @@ private void OnGenerateImage_Click(object sender, RoutedEventArgs e)
         /// <summary>
         /// Create PDF using PdfSharp project, save to file and open that file.
         /// </summary>
-        private void OnGeneratePdf_Click(object sender, RoutedEventArgs e)
+        private async void OnGeneratePdf_Click(object sender, RoutedEventArgs e)
         {
             var config = new PdfGenerateConfig();
             config.PageSize = PageSize.A4;
             config.SetMargins(20);
 
-            var doc = PdfGenerator.GeneratePdf(_mainControl.GetHtml(), config, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoadPdfSharp);
+            var doc = await PdfGenerator.GeneratePdf(_mainControl.GetHtml(), config, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoadPdfSharp);
 
             var tmpFile = Path.GetTempFileName();
             var pdfFile = Path.ChangeExtension(tmpFile, ".pdf");
diff --git a/Source/Demo/WPF/GenerateImageWindow.xaml.cs b/Source/Demo/WPF/GenerateImageWindow.xaml.cs
index 0520b23d4..d41ef87ad 100644
--- a/Source/Demo/WPF/GenerateImageWindow.xaml.cs
+++ b/Source/Demo/WPF/GenerateImageWindow.xaml.cs
@@ -11,6 +11,7 @@
 // "The Art of War"
 
 using System.IO;
+using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Media.Imaging;
 using TheArtOfDev.HtmlRenderer.Demo.Common;
@@ -33,7 +34,7 @@ public GenerateImageWindow(string html)
 
             InitializeComponent();
 
-            Loaded += (sender, args) => GenerateImage();
+            Loaded += async (sender, args) => await GenerateImage();
         }
 
         private void OnSaveToFile_click(object sender, RoutedEventArgs e)
@@ -53,16 +54,16 @@ private void OnSaveToFile_click(object sender, RoutedEventArgs e)
             }
         }
 
-        private void OnGenerateImage_Click(object sender, RoutedEventArgs e)
+        private async void OnGenerateImage_Click(object sender, RoutedEventArgs e)
         {
-            GenerateImage();
+            await GenerateImage();
         }
 
-        private void GenerateImage()
+        private async Task GenerateImage()
         {
             if (_imageBoxBorder.RenderSize.Width > 0 && _imageBoxBorder.RenderSize.Height > 0)
             {
-                _generatedImage = HtmlRender.RenderToImage(_html, _imageBoxBorder.RenderSize, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoad);
+                _generatedImage = await HtmlRender.RenderToImageAsync(_html, _imageBoxBorder.RenderSize, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoad);
                 _imageBox.Source = _generatedImage;
             }
         }
diff --git a/Source/Demo/WPF/MainControl.xaml.cs b/Source/Demo/WPF/MainControl.xaml.cs
index bce20029e..6aebecc43 100644
--- a/Source/Demo/WPF/MainControl.xaml.cs
+++ b/Source/Demo/WPF/MainControl.xaml.cs
@@ -383,10 +383,23 @@ private void OnLinkClicked(object sender, RoutedEventArgs<HtmlLinkClickedEventAr
         /// <summary>
         /// Set html syntax color text on the RTF html editor.
         /// </summary>
+        /// <remarks>
+        /// Both branches must go through <see cref="HtmlSyntaxHighlighter.Process"/>, not just the
+        /// <c>color</c> one: <c>_htmlEditor</c> (an <c>xctk:RichTextBox</c>) parses its <c>Text</c> setter
+        /// as RTF, and the old <c>!color</c> branch (<c>text.Replace("\n", "\\par ")</c>) produced neither
+        /// a valid RTF header nor escaped literal <c>{</c>/<c>}</c> characters - harmless for markup-only
+        /// samples, but any sample whose <c>&lt;style&gt;</c> block is brace-dense (e.g. a page with many
+        /// <c>@font-face { ... }</c> rules) had its RTF group structure corrupted right at those braces,
+        /// silently truncating/mangling the <c>&lt;style&gt;</c> content that <see cref="GetHtmlEditorText"/>
+        /// later reads back out - which is what fed a mangled stylesheet into PDF export. Using the same
+        /// uniform (uncolored) color for every element still produces valid, correctly-escaped RTF.
+        /// </remarks>
         private void SetColoredText(string text, bool color)
         {
             var selectionStart = _htmlEditor.CaretPosition;
-            _htmlEditor.Text = color ? HtmlSyntaxHighlighter.Process(text) : text.Replace("\n", "\\par ");
+            _htmlEditor.Text = color
+                ? HtmlSyntaxHighlighter.Process(text)
+                : HtmlSyntaxHighlighter.Process(text, System.Drawing.Color.Black, System.Drawing.Color.Black, System.Drawing.Color.Black, System.Drawing.Color.Black, System.Drawing.Color.Black, System.Drawing.Color.Black);
             _htmlEditor.CaretPosition = selectionStart;
         }
 
diff --git a/Source/Demo/WinForms/DemoForm.cs b/Source/Demo/WinForms/DemoForm.cs
index b408d3176..b68da61f6 100644
--- a/Source/Demo/WinForms/DemoForm.cs
+++ b/Source/Demo/WinForms/DemoForm.cs
@@ -138,13 +138,13 @@ private void OnGenerateImage_Click(object sender, EventArgs e)
         /// <summary>
         /// Create PDF using PdfSharp project, save to file and open that file.
         /// </summary>
-        private void OnGeneratePdf_Click(object sender, EventArgs e)
+        private async void OnGeneratePdf_Click(object sender, EventArgs e)
         {
             PdfGenerateConfig config = new PdfGenerateConfig();
             config.PageSize = PageSize.A4;
             config.SetMargins(20);
 
-            var doc = PdfGenerator.GeneratePdf(_mainControl.GetHtml(), config, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoadPdfSharp);
+            var doc = await PdfGenerator.GeneratePdf(_mainControl.GetHtml(), config, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoadPdfSharp);
 
             var tmpFile = Path.GetTempFileName();
             var pdfFile = Path.ChangeExtension(tmpFile, ".pdf");  // Preserves the full path
diff --git a/Source/Demo/WinForms/GenerateImageForm.cs b/Source/Demo/WinForms/GenerateImageForm.cs
index f4e8a4577..dcdb915dc 100644
--- a/Source/Demo/WinForms/GenerateImageForm.cs
+++ b/Source/Demo/WinForms/GenerateImageForm.cs
@@ -16,6 +16,7 @@
 using System.Drawing.Drawing2D;
 using System.Drawing.Text;
 using System.Reflection;
+using System.Threading.Tasks;
 using System.Windows.Forms;
 using TheArtOfDev.HtmlRenderer.Core;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
@@ -71,31 +72,31 @@ private void OnSaveToFile_Click(object sender, EventArgs e)
             }
         }
 
-        private void OnUseGdiPlus_Click(object sender, EventArgs e)
+        private async void OnUseGdiPlus_Click(object sender, EventArgs e)
         {
             _useGdiPlusTSB.Checked = !_useGdiPlusTSB.Checked;
             _textRenderingHintTSCB.Visible = _useGdiPlusTSB.Checked;
             _backgroundColorTSB.Visible = !_useGdiPlusTSB.Checked;
             _toolStripLabel.Text = _useGdiPlusTSB.Checked ? "Text Rendering Hint:" : "Background:";
-            GenerateImage();
+            await GenerateImage();
         }
 
-        private void OnBackgroundColor_SelectedIndexChanged(object sender, EventArgs e)
+        private async void OnBackgroundColor_SelectedIndexChanged(object sender, EventArgs e)
         {
-            GenerateImage();
+            await GenerateImage();
         }
 
-        private void _textRenderingHintTSCB_SelectedIndexChanged(object sender, EventArgs e)
+        private async void _textRenderingHintTSCB_SelectedIndexChanged(object sender, EventArgs e)
         {
-            GenerateImage();
+            await GenerateImage();
         }
 
-        private void OnGenerateImage_Click(object sender, EventArgs e)
+        private async void OnGenerateImage_Click(object sender, EventArgs e)
         {
-            GenerateImage();
+            await GenerateImage();
         }
 
-        private void GenerateImage()
+        private async Task GenerateImage()
         {
             if (_backgroundColorTSB.SelectedItem != null && _textRenderingHintTSCB.SelectedItem != null)
             {
@@ -105,17 +106,11 @@ private void GenerateImage()
                 Image img;
                 if (_useGdiPlusTSB.Checked)
                 {
-                    img = HtmlRender.RenderToImageGdiPlus(_html, _pictureBox.ClientSize, textRenderingHint, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoad);
+                    img = await HtmlRender.RenderToImageGdiPlusAsync(_html, _pictureBox.ClientSize, textRenderingHint, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoad);
                 }
                 else
                 {
-                    EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = DemoUtils.OnStylesheetLoad;
-                    EventHandler<HtmlImageLoadEventArgs> imageLoad = HtmlRenderingHelper.OnImageLoad;
-                    var objects = new object[] { _html, _pictureBox.ClientSize, backgroundColor, null, stylesheetLoad, imageLoad };
-
-                    var types = new[] { typeof(String), typeof(Size), typeof(Color), typeof(CssData), typeof(EventHandler<HtmlStylesheetLoadEventArgs>), typeof(EventHandler<HtmlImageLoadEventArgs>) };
-                    var m = typeof(HtmlRender).GetMethod("RenderToImage", BindingFlags.InvokeMethod | BindingFlags.Static | BindingFlags.Public, null, types, null);
-                    img = (Image)m.Invoke(null, objects);
+                    img = await HtmlRender.RenderToImageAsync(_html, _pictureBox.ClientSize, backgroundColor, null, DemoUtils.OnStylesheetLoad, HtmlRenderingHelper.OnImageLoad);
                 }
                 _pictureBox.Image = img;
             }
diff --git a/Source/HtmlRenderer.PdfSharp/Adapters/GradientBrushAdapter.cs b/Source/HtmlRenderer.PdfSharp/Adapters/GradientBrushAdapter.cs
new file mode 100644
index 000000000..b92bf73d3
--- /dev/null
+++ b/Source/HtmlRenderer.PdfSharp/Adapters/GradientBrushAdapter.cs
@@ -0,0 +1,46 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+using TheArtOfDev.HtmlRenderer.Adapters;
+using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+
+namespace TheArtOfDev.HtmlRenderer.PdfSharp.Adapters
+{
+    /// <summary>
+    /// A multi-stop linear gradient "brush" for the PdfSharp backend. Unlike <see cref="BrushAdapter"/>,
+    /// this does not wrap a real <c>PdfSharp.Drawing.XBrush</c> - <c>XLinearGradientBrush</c> in the
+    /// PDFsharp 1.50 package this project depends on only supports 2 colors, no stop list. Instead this
+    /// just carries the gradient line and stops; <see cref="GraphicsAdapter"/>'s <c>DrawPath</c>/
+    /// <c>DrawRectangle</c> special-case this type and paint it as a series of adjacent 2-color
+    /// <c>XLinearGradientBrush</c> bands, one per consecutive stop pair - each band is a real 2-color
+    /// linear gradient by definition, so the composite is an exact piecewise-linear rendering, not an
+    /// approximation.
+    /// </summary>
+    internal sealed class GradientBrushAdapter : RBrush
+    {
+        public GradientBrushAdapter(RPoint p1, RPoint p2, (RColor Color, double Position)[] stops)
+        {
+            P1 = p1;
+            P2 = p2;
+            Stops = stops;
+        }
+
+        public RPoint P1 { get; }
+
+        public RPoint P2 { get; }
+
+        public (RColor Color, double Position)[] Stops { get; }
+
+        public override void Dispose()
+        { }
+    }
+}
diff --git a/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsAdapter.cs b/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsAdapter.cs
index c6d406c58..76ede5ea1 100644
--- a/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsAdapter.cs
+++ b/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsAdapter.cs
@@ -155,6 +155,14 @@ public override void DrawRectangle(RPen pen, double x, double y, double width, d
 
         public override void DrawRectangle(RBrush brush, double x, double y, double width, double height)
         {
+            if (brush is GradientBrushAdapter gradient)
+            {
+                var rectPath = new XGraphicsPath();
+                rectPath.AddRectangle(x, y, width, height);
+                FillGradient(gradient, rectPath);
+                return;
+            }
+
             var xBrush = ((BrushAdapter)brush).Brush;
             var xTextureBrush = xBrush as XTextureBrush;
             if (xTextureBrush != null)
@@ -188,6 +196,12 @@ public override void DrawPath(RPen pen, RGraphicsPath path)
 
         public override void DrawPath(RBrush brush, RGraphicsPath path)
         {
+            if (brush is GradientBrushAdapter gradient)
+            {
+                FillGradient(gradient, ((GraphicsPathAdapter)path).GraphicsPath);
+                return;
+            }
+
             _g.DrawPath((XBrush)((BrushAdapter)brush).Brush, ((GraphicsPathAdapter)path).GraphicsPath);
         }
 
@@ -199,6 +213,64 @@ public override void DrawPolygon(RBrush brush, RPoint[] points)
             }
         }
 
+        /// <summary>
+        /// Paints a multi-stop linear gradient by clipping to <paramref name="targetPath"/> and drawing
+        /// one real 2-color <see cref="XLinearGradientBrush"/> band per consecutive stop pair, each
+        /// spanning the full perpendicular extent needed to cover the target - see
+        /// <see cref="GradientBrushAdapter"/> for why this backend needs banding instead of a single brush.
+        /// </summary>
+        private void FillGradient(GradientBrushAdapter gradient, XGraphicsPath targetPath)
+        {
+            var stops = gradient.Stops;
+            if (stops.Length == 0)
+                return;
+
+            _g.Save();
+            _g.IntersectClip(targetPath);
+
+            double dx = gradient.P2.X - gradient.P1.X;
+            double dy = gradient.P2.Y - gradient.P1.Y;
+            double len = Math.Sqrt(dx * dx + dy * dy);
+
+            if (stops.Length == 1 || len < 1e-6)
+            {
+                // Degenerate gradient line (single stop, or a zero-size box) - just flat-fill with the
+                // last color, matching what a real linear gradient converges to in that case.
+                var flatBrush = new XSolidBrush(Utils.Convert(stops[stops.Length - 1].Color));
+                _g.DrawRectangle(flatBrush, -1e5, -1e5, 2e5, 2e5);
+                _g.Restore();
+                _g.DrawRectangle(XBrushes.White, 0, 0, 0.1, 0.1);
+                return;
+            }
+
+            double ux = dx / len, uy = dy / len;
+            double perpX = -uy, perpY = ux;
+            double perpHalf = Math.Max(len, 1.0) * 4.0;
+
+            for (int i = 0; i < stops.Length - 1; i++)
+            {
+                double t1 = stops[i].Position, t2 = stops[i + 1].Position;
+                var bp1 = new XPoint(gradient.P1.X + ux * len * t1, gradient.P1.Y + uy * len * t1);
+                var bp2 = new XPoint(gradient.P1.X + ux * len * t2, gradient.P1.Y + uy * len * t2);
+
+                var band = new[]
+                {
+                    new XPoint(bp1.X - perpX * perpHalf, bp1.Y - perpY * perpHalf),
+                    new XPoint(bp1.X + perpX * perpHalf, bp1.Y + perpY * perpHalf),
+                    new XPoint(bp2.X + perpX * perpHalf, bp2.Y + perpY * perpHalf),
+                    new XPoint(bp2.X - perpX * perpHalf, bp2.Y - perpY * perpHalf),
+                };
+
+                var bandBrush = new XLinearGradientBrush(bp1, bp2, Utils.Convert(stops[i].Color), Utils.Convert(stops[i + 1].Color));
+                _g.DrawPolygon(bandBrush, band, XFillMode.Winding);
+            }
+
+            _g.Restore();
+
+            // handle bug in PdfSharp that keeps the brush color for next string draw
+            _g.DrawRectangle(XBrushes.White, 0, 0, 0.1, 0.1);
+        }
+
         #endregion
     }
 }
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsPathAdapter.cs b/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsPathAdapter.cs
index 48290543c..9e057d8e9 100644
--- a/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsPathAdapter.cs
+++ b/Source/HtmlRenderer.PdfSharp/Adapters/GraphicsPathAdapter.cs
@@ -51,11 +51,11 @@ public override void LineTo(double x, double y)
             _lastPoint = new RPoint(x, y);
         }
 
-        public override void ArcTo(double x, double y, double size, Corner corner)
+        public override void ArcTo(double x, double y, double radiusX, double radiusY, Corner corner)
         {
-            float left = (float)(Math.Min(x, _lastPoint.X) - (corner == Corner.TopRight || corner == Corner.BottomRight ? size : 0));
-            float top = (float)(Math.Min(y, _lastPoint.Y) - (corner == Corner.BottomLeft || corner == Corner.BottomRight ? size : 0));
-            _graphicsPath.AddArc(left, top, (float)size * 2, (float)size * 2, GetStartAngle(corner), 90);
+            float left = (float)(Math.Min(x, _lastPoint.X) - (corner == Corner.TopRight || corner == Corner.BottomRight ? radiusX : 0));
+            float top = (float)(Math.Min(y, _lastPoint.Y) - (corner == Corner.BottomLeft || corner == Corner.BottomRight ? radiusY : 0));
+            _graphicsPath.AddArc(left, top, (float)radiusX * 2, (float)radiusY * 2, GetStartAngle(corner), 90);
             _lastPoint = new RPoint(x, y);
         }
 
diff --git a/Source/HtmlRenderer.PdfSharp/Adapters/PdfSharpAdapter.cs b/Source/HtmlRenderer.PdfSharp/Adapters/PdfSharpAdapter.cs
index 4e74601bc..001392f6c 100644
--- a/Source/HtmlRenderer.PdfSharp/Adapters/PdfSharpAdapter.cs
+++ b/Source/HtmlRenderer.PdfSharp/Adapters/PdfSharpAdapter.cs
@@ -13,9 +13,13 @@
 using PdfSharp.Drawing;
 using PdfSharp.Pdf;
 using System;
+using System.Collections.Generic;
 using System.IO;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+using TheArtOfDev.HtmlRenderer.Core.Network;
 using TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution;
 using TheArtOfDev.HtmlRenderer.PdfSharp.Utilities;
 
@@ -59,6 +63,19 @@ private PdfSharpAdapter()
             }
         }
 
+        /// <summary>
+        /// Also recognizes a family registered via <see cref="AddFontFace"/> - those live entirely in
+        /// <see cref="FontResolver"/>, invisible to the shared <c>FontsHandler</c> the base implementation
+        /// checks (see <see cref="AddFontFace"/>'s own doc comment for why). Without this override,
+        /// <see cref="Core.Parse.CssParser.ParseFontFamily"/> would never see an <c>@font-face</c>-only
+        /// family as "existing" and would silently substitute <see cref="Core.Utils.CssConstants.DefaultFont"/>
+        /// for it before layout ever gets a chance to resolve the real face.
+        /// </summary>
+        public override bool IsFontExists(string font)
+        {
+            return base.IsFontExists(font) || _fontResolver.HasFamily(font);
+        }
+
         /// <summary>
         /// Singleton instance of global adapter.
         /// </summary>
@@ -75,6 +92,22 @@ internal FontResolver FontResolver
             get { return _fontResolver; }
         }
 
+        /// <summary>
+        /// Paged output, so @media print applies and @media screen does not.
+        /// </summary>
+        public override string DefaultMediaType
+        {
+            get { return "print"; }
+        }
+
+        /// <summary>
+        /// A PDF has no system theme to follow, so prefers-color-scheme always reports light.
+        /// </summary>
+        public override RColorScheme SystemColorScheme
+        {
+            get { return RColorScheme.Light; }
+        }
+
         protected override RColor GetColorInt(string colorName)
         {
             try
@@ -123,18 +156,9 @@ protected override RBrush CreateSolidBrush(RColor color)
             return new BrushAdapter(solidBrush);
         }
 
-        protected override RBrush CreateLinearGradientBrush(RRect rect, RColor color1, RColor color2, double angle)
+        protected override RBrush CreateLinearGradientBrush(RPoint p1, RPoint p2, (RColor Color, double Position)[] stops)
         {
-            XLinearGradientMode mode;
-            if (angle < 45)
-                mode = XLinearGradientMode.ForwardDiagonal;
-            else if (angle < 90)
-                mode = XLinearGradientMode.Vertical;
-            else if (angle < 135)
-                mode = XLinearGradientMode.BackwardDiagonal;
-            else
-                mode = XLinearGradientMode.Horizontal;
-            return new BrushAdapter(new XLinearGradientBrush(Utils.Convert(rect), Utils.Convert(color1), Utils.Convert(color2), mode));
+            return new GradientBrushAdapter(p1, p2, stops);
         }
 
         protected override RImage ConvertImageInt(object image)
@@ -160,5 +184,80 @@ protected override RFont CreateFontInt(RFontFamily family, double size, RFontSty
             var xFont = new XFont(((FontFamilyAdapter)family).FontFamily.Name, size, fontStyle, new XPdfFontOptions(PdfFontEncoding.Unicode));
             return new FontAdapter(xFont);
         }
+
+        /// <summary>
+        /// Never called: this backend overrides <see cref="AddFontFace"/> directly (see its own doc
+        /// comment) rather than routing through the base's <c>LoadFontFaceFontInt</c>-based path.
+        /// </summary>
+        protected override RFontFamily LoadFontFaceFontInt(byte[] fontBytes, string filePath)
+        {
+            throw new NotSupportedException("PdfSharpAdapter overrides AddFontFace directly and never calls LoadFontFaceFontInt.");
+        }
+
+        /// <summary>
+        /// Bypasses the base <see cref="RAdapter.AddFontFace"/>/shared <c>FontsHandler</c> registry
+        /// entirely: PDFsharp's <see cref="IFontResolver"/> needs raw font bytes for PDF embedding, which
+        /// <see cref="FontResolver.AddFont(Stream,string,int?,bool?,int?,IReadOnlyList{CodepointRange})"/>
+        /// already stores and matches against directly - no platform font-family handle is involved.
+        /// </summary>
+        public override async Task<bool> AddFontFace(string familyName, RUri uri, int weight, bool isItalic, int stretch, IReadOnlyList<CodepointRange> ranges)
+        {
+            var networkResponse = await GetResourceStream(uri).ConfigureAwait(false);
+            if (networkResponse?.ResourceStream == null)
+            {
+                return false;
+            }
+
+            try
+            {
+                using (networkResponse.ResourceStream)
+                {
+                    _fontResolver.AddFont(networkResponse.ResourceStream, familyName, weight, isItalic, stretch, ranges);
+                }
+                return true;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        /// <summary>Bypasses the shared registry, for the same reason as <see cref="AddFontFace"/> - see its doc comment.</summary>
+        public override bool AddFontFaceFromLocalFamily(string familyName, string localFamilyName, int weight, bool isItalic, int stretch, IReadOnlyList<CodepointRange> ranges)
+        {
+            return _fontResolver.AddLocalFontFamily(familyName, localFamilyName, weight, isItalic, stretch, ranges);
+        }
+
+        /// <summary>
+        /// Bypasses the shared registry, for the same reason as <see cref="AddFontFace"/> - see its doc
+        /// comment. PDFsharp's own <see cref="XFont(string,double,XFontStyle,XPdfFontOptions)"/>
+        /// construction only ever resolves by (family name, bold, italic) internally - there is no public
+        /// PDFsharp API surface to hand it an already-chosen numeric weight/stretch/face directly - so a
+        /// numeric <paramref name="weight"/> can only steer face selection as far as PDFsharp's own
+        /// bold/not-bold threshold allows; <paramref name="codepoint"/>, which that 2-bool resolution can't
+        /// express at all, is still honored precisely by consulting the richer
+        /// <see cref="FontResolver.ResolveTypeface(string,int,bool,int,int?)"/> overload up front purely to
+        /// preserve the "codepoint-scoped miss returns null" contract.
+        /// </summary>
+        public override RFont GetFont(string family, double size, RFontStyle style, int weight, int stretch, int? codepoint)
+        {
+            var isItalic = (style & RFontStyle.Italic) != 0;
+
+            if (codepoint.HasValue)
+            {
+                var info = _fontResolver.ResolveTypeface(family, weight, isItalic, stretch, codepoint);
+                if (info == null)
+                {
+                    return null;
+                }
+            }
+
+            var isBold = weight >= 600;
+            var residualStyle = (style & (RFontStyle.Underline | RFontStyle.Strikeout))
+                                 | (isBold ? RFontStyle.Bold : RFontStyle.Regular)
+                                 | (isItalic ? RFontStyle.Italic : RFontStyle.Regular);
+
+            return CreateFontInt(family, size, residualStyle);
+        }
     }
 }
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/DirectoryFontDiscovery.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/DirectoryFontDiscovery.cs
deleted file mode 100644
index c36b2292a..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/DirectoryFontDiscovery.cs
+++ /dev/null
@@ -1,67 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
-using System.Linq;
-using System.Runtime.InteropServices;
-using TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Parsing;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Discovery
-{
-    internal static class DirectoryFontDiscovery
-    {
-        public static List<FontInfo> DiscoverFontFilesFromDirectories(List<string> customFontDirectories)
-        {
-            var fontDirectories = new List<string>();
-
-            // Add platform-specific directories
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                fontDirectories.Add(Environment.GetFolderPath(Environment.SpecialFolder.Fonts));
-            }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
-            {
-                fontDirectories.AddRange(new[]
-                {
-                    "/usr/share/fonts",
-                    "/usr/local/share/fonts",
-                    Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".fonts"),
-                    Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".local/share/fonts")
-                });
-            }
-
-            // Add custom directories
-            fontDirectories.AddRange(customFontDirectories);
-
-            return DiscoverFontFilesInDirectories(fontDirectories);
-        }
-
-        public static List<FontInfo> DiscoverFontFilesInDirectories(List<string> directories)
-        {
-            var fontInfos = new List<FontInfo>();
-            
-            foreach (var directory in directories)
-            {
-                if (!Directory.Exists(directory))
-                {
-                    continue;
-                }
-
-                try
-                {
-                    fontInfos.AddRange(FontDiscoveryService.SupportedFontExtensions.SelectMany(e => Directory.GetFiles(directory, $"*{e}", SearchOption.AllDirectories))
-                        .Select(f => new FontInfo
-                        {
-                            Name = Path.GetFileNameWithoutExtension(f),
-                            FilePath = f
-                        }));
-                }
-                catch
-                {
-                    // Silently continue on directory access errors
-                }
-            }
-
-            return fontInfos;
-        }
-    }
-}
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/FontDiscoveryService.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/FontDiscoveryService.cs
deleted file mode 100644
index 81b793cc8..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/FontDiscoveryService.cs
+++ /dev/null
@@ -1,46 +0,0 @@
-using System.Collections.Generic;
-using System.Runtime.InteropServices;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Discovery
-{
-    internal class FontDiscoveryService
-    {
-        private readonly List<string> _customFontDirectories = new List<string>();
-    
-        public static string[] SupportedFontExtensions { get; } = new[] { ".ttf", ".otf" };
-
-        public List<FontInfo> DiscoverFontInfos()
-        {
-            var fontInfos = new List<FontInfo>();
-            
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-            {
-                fontInfos = WindowsFontDiscovery.DiscoverFontInfos();
-            }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
-            {
-                fontInfos = LinuxFontDiscovery.DiscoverFontFiles();
-            }
-            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
-            {
-                fontInfos = MacOsFontDiscovery.DiscoverFontFiles();
-            }
-
-            // Always use directory scan as fallback
-            fontInfos.AddRange(DirectoryFontDiscovery.DiscoverFontFilesFromDirectories(_customFontDirectories));
-            
-            return fontInfos;
-        }
-
-        public void RegisterCustomFontDirectory(string fontDirectory)
-        {
-            if (_customFontDirectories.Contains(fontDirectory))
-            {
-                return;
-            }
-        
-            _customFontDirectories.Add(fontDirectory);
-        }
-    }
-}
-
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/LinuxFontDiscovery.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/LinuxFontDiscovery.cs
deleted file mode 100644
index 9bfee68eb..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/LinuxFontDiscovery.cs
+++ /dev/null
@@ -1,129 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.IO;
-using System.Linq;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Discovery
-{
-    internal static class LinuxFontDiscovery
-    {
-        public static List<FontInfo> DiscoverFontFiles()
-        {
-            var fontInfos = new List<FontInfo>();
-            
-            if (!IsFontConfigAvailable())
-            {
-                return fontInfos;
-            }
-
-            try
-            {
-                var startInfo = new ProcessStartInfo
-                {
-                    FileName = "fc-list",
-                    Arguments = ":",
-                    RedirectStandardOutput = true,
-                    RedirectStandardError = true,
-                    UseShellExecute = false,
-                    CreateNoWindow = true
-                };
-
-                using (var process = Process.Start(startInfo))
-                {
-                    if (process == null)
-                    {
-                        return fontInfos;
-                    }
-
-                    var output = process.StandardOutput.ReadToEnd();
-                    process.WaitForExit();
-
-                    if (process.ExitCode != 0 || string.IsNullOrWhiteSpace(output))
-                    {
-                        return fontInfos;
-                    }
-
-                    var lines = output.Split(new[] { '\n' }, StringSplitOptions.RemoveEmptyEntries);
-                    foreach (var line in lines)
-                    {
-                        var fontFamilies = DiscoverFontFile(line);
-                        
-                        if (fontFamilies.Count > 0)
-                        {
-                            fontInfos.AddRange(fontFamilies);
-                        }
-                    }
-                }
-            }
-            catch
-            {
-                // Silently continue on errors
-            }
-
-            return fontInfos;
-        }
-
-        private static bool IsFontConfigAvailable()
-        {
-            try
-            {
-                var startInfo = new ProcessStartInfo
-                {
-                    FileName = "which",
-                    Arguments = "fc-list",
-                    RedirectStandardOutput = true,
-                    RedirectStandardError = true,
-                    UseShellExecute = false,
-                    CreateNoWindow = true
-                };
-
-                using (var process = Process.Start(startInfo))
-                {
-                    if (process == null)
-                    {
-                        return false;
-                    }
-
-                    process.WaitForExit();
-                    return process.ExitCode == 0;
-                }
-            }
-            catch
-            {
-                return false;
-            }
-        }
-
-        private static List<FontInfo> DiscoverFontFile(string line)
-        {
-            var fonts = new List<FontInfo>();
-            
-            // Parse fc-list output: "path: family1,family2:style=style"
-            var parts = line.Split(new[] { ':' }, 2, StringSplitOptions.None);
-            if (parts.Length < 2)
-            {
-                return fonts;
-            }
-
-            var fontFilePath = parts[0].Trim();
-            var families = parts[1].Trim().Split(',');
-
-            if (!File.Exists(fontFilePath) || 
-                !FontDiscoveryService.SupportedFontExtensions.Any(e => fontFilePath.EndsWith(e, StringComparison.InvariantCultureIgnoreCase)))
-            {
-                return fonts;
-            }
-
-            foreach (var family in families)
-            {
-                var familyName = family.Trim();
-                if (!string.IsNullOrEmpty(familyName) && File.Exists(fontFilePath))
-                {
-                    fonts.Add(new FontInfo { Name = familyName, FilePath = fontFilePath });
-                }
-            }
-            return fonts;
-        }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/MacOsFontDiscovery.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/MacOsFontDiscovery.cs
deleted file mode 100644
index aae467b64..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/MacOsFontDiscovery.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.IO;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Discovery
-{
-    internal static class MacOsFontDiscovery
-    {
-        public static List<FontInfo> DiscoverFontFiles()
-        {
-            var fontDirectories = new List<string>
-            {
-                "/System/Library/Fonts",
-                "/Library/Fonts",
-                Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "Library/Fonts")
-            };
-
-            return DirectoryFontDiscovery.DiscoverFontFilesInDirectories(fontDirectories);
-        }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/WindowsFontDiscovery.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/WindowsFontDiscovery.cs
deleted file mode 100644
index 7885b6a54..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/Discovery/WindowsFontDiscovery.cs
+++ /dev/null
@@ -1,76 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
-using System.IO;
-using System.Linq;
-using Microsoft.Win32;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Discovery
-{
-    [SuppressMessage("Interoperability", "CA1416:Validate platform compatibility", Justification = "Platform switching in calling class")]
-    internal static class WindowsFontDiscovery
-    {
-        public static List<FontInfo> DiscoverFontInfos()
-        {
-            var fontInfos = new List<FontInfo>();
-            try
-            {
-                using (var machineRegistryKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts", false))
-                using (var userRegistryKey = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts", false))
-                {
-                    foreach (var registryKey in new[] { machineRegistryKey, userRegistryKey })
-                    {
-                        if (registryKey == null)
-                        {
-                            continue;
-                        }
-
-                        foreach (var fontName in registryKey.GetValueNames())
-                        {
-                            var fontFilePath = registryKey.GetValue(fontName)?.ToString();
-                    
-                            var fontFile = DiscoverFontFile(fontFilePath);
-
-                            if (fontFile != null)
-                            {
-                                fontInfos.Add(new FontInfo
-                                {
-                                    Name = fontName,
-                                    FilePath = fontFile
-                                });
-                            }
-                        }
-                    }
-                }
-            }
-            catch
-            {
-                // Silently continue on errors
-            }
-            
-            return fontInfos;
-        }
-
-        private static string DiscoverFontFile(string fontFilePath)
-        {
-            if (fontFilePath == null ||
-                !FontDiscoveryService.SupportedFontExtensions.Any(e => fontFilePath.EndsWith(e, StringComparison.InvariantCultureIgnoreCase)))
-            {
-                return null;
-            }
-
-            // If the path is not absolute, the font is in the Windows Fonts folder
-            if (!Path.IsPathRooted(fontFilePath))
-            {
-                fontFilePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Fonts), fontFilePath);
-            }
-
-            if (!File.Exists(fontFilePath))
-            {
-                return null;
-            }
-
-            return fontFilePath;
-        }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/FontAttributes.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/FontAttributes.cs
deleted file mode 100644
index c1c2ccfb4..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/FontAttributes.cs
+++ /dev/null
@@ -1,42 +0,0 @@
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
-{
-    public enum FontWeight
-    {
-        Thin = 100,
-        ExtraLight = 200,
-        Light = 300,
-        Normal = 400,
-        Medium = 500,
-        SemiBold = 600,
-        Bold = 700,
-        ExtraBold = 800,
-        Black = 900,
-    }
-
-    public enum FontWidth
-    {
-        UltraCondensed = 50,
-        ExtraCondensed = 62,
-        Condensed = 75,
-        SemiCondensed = 87,
-        Medium = 100,
-        SemiExpanded = 112,
-        Expanded = 125,
-        ExtraExpanded = 150,
-        UltraExpanded = 200,
-    }
-
-    public enum FontStyle
-    {
-        Normal,
-        Italic,
-        Oblique,
-    }
-
-    public class FontAttributes
-    {   
-        public FontWeight Weight { get; set; } = FontWeight.Normal;
-        public FontStyle Style { get; set; } = FontStyle.Normal;
-        public FontWidth Width { get; set; } = FontWidth.Medium;
-    }
-}
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/FontFamilyModel.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/FontFamilyModel.cs
new file mode 100644
index 000000000..f8af02288
--- /dev/null
+++ b/Source/HtmlRenderer.PdfSharp/FontResolution/FontFamilyModel.cs
@@ -0,0 +1,51 @@
+using System.Collections.Generic;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+using TheArtOfDev.HtmlRenderer.Core.Utils;
+
+namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
+{
+    /// <summary>
+    /// One registered face of a <see cref="FontFamilyModel"/>: its CSS Fonts Level 4 matching axes
+    /// (numeric weight, italic, stretch), the codepoint <see cref="CodepointRange"/>s it is restricted to
+    /// (from an <c>@font-face</c> <c>unicode-range</c> descriptor) or null when it has none - a face with
+    /// no explicit ranges is treated as covering everything (matching the same, deliberately simpler,
+    /// scope as the shared <c>Core.Handlers.FontsHandler</c> face registry - see its own doc comments for
+    /// why cmap-based coverage extraction isn't ported here: this codebase resolves one font per box, not
+    /// per glyph, so there is no per-glyph precision to exploit) - and the sniffed description
+    /// <see cref="FontResolver.ResolveTypeface(string,int,bool,int,int?)"/> hands back once this face is
+    /// chosen; <see cref="TtfFontDescription.FontNameInvariantCulture"/> doubles as this face's storage
+    /// key into <see cref="FontResolver.GetFont"/>.
+    /// </summary>
+    /// <remarks>Ported from PeachPDF's <c>Fonts\FontFamilyModel.cs</c>.</remarks>
+    internal sealed class FontFaceEntry
+    {
+        public FontFaceEntry(int weight, bool italic, int stretch, IReadOnlyList<CodepointRange> explicitRanges, TtfFontDescription description)
+        {
+            Weight = weight;
+            Italic = italic;
+            Stretch = stretch;
+            ExplicitRanges = explicitRanges;
+            Description = description;
+        }
+
+        public int Weight { get; }
+        public bool Italic { get; }
+        public int Stretch { get; }
+        public IReadOnlyList<CodepointRange> ExplicitRanges { get; }
+        public TtfFontDescription Description { get; }
+    }
+
+    /// <summary>One CSS font-family: its registered faces. Ported from PeachPDF's <c>Fonts\FontFamilyModel.cs</c>.</summary>
+    internal sealed class FontFamilyModel
+    {
+        public string Name { get; set; }
+
+        /// <summary>
+        /// Every registered face for this family - a list, not a dictionary keyed by (weight,italic,
+        /// stretch), because two faces can legitimately share the same matching axes yet differ by
+        /// <c>unicode-range</c> (e.g. a Latin subset and a Cyrillic subset of one webfont family, both
+        /// regular weight).
+        /// </summary>
+        public List<FontFaceEntry> Faces { get; } = new List<FontFaceEntry>();
+    }
+}
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/FontInfo.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/FontInfo.cs
deleted file mode 100644
index cceb0ae97..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/FontInfo.cs
+++ /dev/null
@@ -1,8 +0,0 @@
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
-{
-    public class FontInfo
-    {
-        public string Name { get; set; }
-        public string FilePath { get; set; }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/FontMetadata.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/FontMetadata.cs
deleted file mode 100644
index d452b9f0e..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/FontMetadata.cs
+++ /dev/null
@@ -1,18 +0,0 @@
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
-{
-    public class FontMetadata
-    {
-        public string FilePath { get; set; }
-    
-        public string Family { get; set; }
-        public string Subfamily { get; set; }
-    
-        public string PreferredFamily { get; set; }
-        public string PreferredSubfamily { get; set; }
-    
-        public string FullName { get; set; }
-        public string PostScriptName { get; set; }
-    
-        public FontAttributes Attributes { get; set; }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/FontNameResolver.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/FontNameResolver.cs
deleted file mode 100644
index 7faced10b..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/FontNameResolver.cs
+++ /dev/null
@@ -1,165 +0,0 @@
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
-{
-    public static class FontNameResolver
-    {
-        public static List<string> ResolveFontNames(string fontName, FontAttributes fontAttributes, FontResolveStrategy resolveStrategy)
-        {
-            var fontNames = new List<string>();
-            
-            if (resolveStrategy == FontResolveStrategy.Strict)
-            {
-                fontNames.Add(StylizeFontNameStrict(fontName, fontAttributes));
-            }
-            else
-            {
-                fontNames.AddRange(StylizeFontNameClosest(fontName, fontAttributes));
-            }
-
-            return fontNames;
-        }
-
-        public static string StylizeFontNameFamily(FontMetadata metadata)
-        {
-            if (metadata.Family is null || metadata.Attributes is null)
-            {
-                return string.Empty;
-            }
-        
-            return BuildStylizedFontName(metadata.Family, MatchWeightStrict(metadata.Attributes.Weight), MatchStyleStrict(metadata.Attributes.Style));
-        }
-
-        public static string StylizeFontNamePreferredFamily(FontMetadata metadata)
-        {
-            if (metadata.PreferredFamily is null || metadata.PreferredSubfamily is null)
-            {
-                return string.Empty;
-            }
-        
-            return string.IsNullOrEmpty(metadata.PreferredSubfamily)
-                ? metadata.PreferredFamily
-                : $"{metadata.PreferredFamily} {metadata.PreferredSubfamily}";
-        }
-
-        public static string StylizeFontNameStrict(string fontName, FontAttributes fontAttributes)
-        {
-            return BuildStylizedFontName(fontName, MatchWeightStrict(fontAttributes.Weight), MatchStyleStrict(fontAttributes.Style));
-        }
-
-        private static string[] StylizeFontNameClosest(string fontName, FontAttributes fontAttributes)
-        {
-            var fontNames = new List<string>
-            {
-                StylizeFontNameStrict(fontName, fontAttributes),
-                BuildStylizedFontName(fontName, MatchWeightStrict(fontAttributes.Weight), MatchStyleObliqueAndItalic(fontAttributes.Style)),
-                BuildStylizedFontName(fontName, MatchWeightMiddle(fontAttributes.Weight), MatchStyleStrict(fontAttributes.Style)),
-                BuildStylizedFontName(fontName, MatchWeightMiddle(fontAttributes.Weight), MatchStyleObliqueAndItalic(fontAttributes.Style)),
-                BuildStylizedFontName(fontName, MatchWeightOutward(fontAttributes.Weight), MatchStyleStrict(fontAttributes.Style)),
-                BuildStylizedFontName(fontName, MatchWeightOutward(fontAttributes.Weight), MatchStyleObliqueAndItalic(fontAttributes.Style)),
-                fontName
-            };
-
-            return fontNames.Distinct().Where(x => !string.IsNullOrEmpty(x)).ToArray();
-        }
-    
-        private static string MatchStyleStrict(FontStyle fontStyle)
-        {
-            if (fontStyle == FontStyle.Oblique || fontStyle == FontStyle.Italic)
-            {
-                return fontStyle.ToString();
-            }
-            
-            return string.Empty;
-        }
-    
-        private static string MatchStyleObliqueAndItalic(FontStyle fontStyle)
-        {
-            if (fontStyle == FontStyle.Oblique || fontStyle == FontStyle.Italic)
-            {
-                return nameof(FontStyle.Italic);
-            }
-
-            return string.Empty;
-        }
-
-        private static string MatchWeightStrict(FontWeight fontWeight)
-        {
-            if (fontWeight == FontWeight.Normal)
-            {
-                return string.Empty;
-            }
-            
-            return fontWeight.ToString();
-        }
-
-        private static string MatchWeightMiddle(FontWeight fontWeight)
-        {
-            if (fontWeight == FontWeight.Light)
-            {
-                return nameof(FontWeight.Light);
-            }
-
-            if (fontWeight == FontWeight.Medium)
-            {
-                return nameof(FontWeight.Medium);
-            }
-
-            if (fontWeight < FontWeight.Light)
-            {
-                return $"{fontWeight + 100}";
-            }
-
-            if (fontWeight < FontWeight.Medium)
-            {
-                return $"{fontWeight - 100}";
-            }
-            
-            return string.Empty;
-        }
-
-        private static string MatchWeightOutward(FontWeight fontWeight)
-        {
-            if (fontWeight == FontWeight.Thin)
-            {
-                return nameof(FontWeight.Thin);
-            }
-            
-            if (fontWeight == FontWeight.Black)
-            {
-                return nameof(FontWeight.Black);
-            }
-            
-            if (fontWeight < FontWeight.Normal)
-            {
-                return $"{fontWeight - 100}";
-            }
-
-            if (fontWeight > FontWeight.Normal)
-            {
-                return $"{fontWeight + 100}";
-            }
-
-            return string.Empty;
-        }
-
-        private static string BuildStylizedFontName(string fontName, string fontWeight, string fontStyle)
-        {
-            var stylizedFontName = new StringBuilder(fontName);
-
-            if (!string.IsNullOrEmpty(fontWeight))
-            {
-                stylizedFontName.Append($" {fontWeight}");
-            }
-
-            if (!string.IsNullOrEmpty(fontStyle))
-            {
-                stylizedFontName.Append($" {fontStyle}");
-            }
-
-            return stylizedFontName.ToString();
-        }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/FontResolveStrategy.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/FontResolveStrategy.cs
deleted file mode 100644
index ac7d9c126..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/FontResolveStrategy.cs
+++ /dev/null
@@ -1,8 +0,0 @@
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
-{
-    public enum FontResolveStrategy
-    {
-        Strict,
-        Closest
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/FontResolver.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/FontResolver.cs
index 189acc045..45187f3a5 100644
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/FontResolver.cs
+++ b/Source/HtmlRenderer.PdfSharp/FontResolution/FontResolver.cs
@@ -1,152 +1,602 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
+using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.InteropServices;
 using PdfSharp.Fonts;
-using TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Discovery;
-using TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Parsing;
+using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
 {
-    public class FontResolver : IFontResolver
-    {   
-        private readonly FontDiscoveryService _fontDiscoveryService = new FontDiscoveryService();
-        private readonly Dictionary<string, FontMetadata> _fontCache = new Dictionary<string, FontMetadata>();
-        
-        private List<FontMetadata> _fontMetadataCache = new List<FontMetadata>();
-        
-        public static string FallbackFont => "Tuffy";
-        public FontResolveStrategy ResolveStrategy { get; set; } = FontResolveStrategy.Strict;
-        
-        public FontResolverInfo ResolveTypeface(string familyName, bool bold, bool italic)
-        {
-            if (_fontMetadataCache.Count == 0)
-            {
-                DiscoverFonts();
-            }
-
-            var fontAttributes = new FontAttributes
-            {
-                Style = italic ? FontStyle.Italic : FontStyle.Normal,
-                Weight = bold ? FontWeight.Bold : FontWeight.Normal
-            };
-            
-            var fontNames = FontNameResolver.ResolveFontNames(familyName, fontAttributes, ResolveStrategy);
-            
-            foreach (var name in fontNames)
-            {
-                foreach (var metadata in _fontMetadataCache)
-                {
-                    var stylizedPreferredFamilyName = FontNameResolver.StylizeFontNamePreferredFamily(metadata);
-                    var stylizedFamilyName = FontNameResolver.StylizeFontNameFamily(metadata);
+    /// <summary>
+    /// PDFsharp <see cref="IFontResolver"/> implementation backing the PdfSharp backend's font handling -
+    /// OS font discovery plus CSS Fonts Level 4 §5 nearest-match (slant→stretch→weight) face selection,
+    /// ported from PeachPDF's <c>Fonts\FontResolver.cs</c>. Unlike WinForms/WPF (which register an
+    /// <c>@font-face</c> face as an opaque platform font-family handle and let the OS/UI framework do
+    /// matching), PDFsharp's <see cref="IFontResolver"/> contract needs raw font bytes at PDF-generation
+    /// time for embedding, so this type does its own matching entirely and is called directly by
+    /// <c>Adapters.PdfSharpAdapter</c>'s <c>AddFontFace</c>/<c>GetFont</c> overrides, bypassing the shared
+    /// <c>Core.Handlers.FontsHandler</c> registry other backends use.
+    /// </summary>
+    /// <remarks>
+    /// Two deliberate scope departures from PeachPDF's own resolver, both already established for this
+    /// port's shared <c>Core.Handlers.FontsHandler</c> (see its own doc comments):
+    /// <list type="bullet">
+    /// <item>No cmap-coverage extraction fallback for <c>unicode-range</c>-less faces - a face with no
+    /// explicit <c>unicode-range</c> is simply treated as covering everything. This codebase resolves one
+    /// font per box (not per glyph/run), so there's no per-glyph precision for cmap coverage to buy.</item>
+    /// <item>No per-<c>FontResolver</c>-instance glyph-typeface/descriptor caching. PeachPDF supports many
+    /// concurrent <c>PdfGenerator</c>s each with their own <c>FontResolver</c>, so it isolates their custom
+    /// font caches from each other. This backend's <c>PdfSharpAdapter</c> (and this resolver with it) is a
+    /// single process-wide singleton via <see cref="Register"/>, matching this project's pre-existing
+    /// architecture - there's only ever one instance, so nothing to isolate.</item>
+    /// </list>
+    /// System font discovery itself is also adapted, not verbatim: no Android/iOS branches (this project's
+    /// <c>netstandard2.0;net8.0</c> target framework list has no mobile leg to run them on), and Linux
+    /// discovery shells out to the <c>fc-list</c> CLI rather than P/Invoking <c>libfontconfig.so.1</c>
+    /// directly (see <see cref="LinuxSystemFontResolver"/>'s own doc comment for why).
+    /// </remarks>
+    public sealed class FontResolver : IFontResolver
+    {
+        public const string FallbackFont = "Tuffy";
 
-                    if (stylizedPreferredFamilyName == name || stylizedFamilyName == name)
-                    {
-                        if (!_fontCache.ContainsKey(name))
-                        {
-                            _fontCache[name] = metadata;
-                        }
+        private static readonly string[] FontExtensions = { "*.ttf", "*.otf" };
 
-                        return new FontResolverInfo(name);
-                    }
-                }
+        private static readonly Dictionary<string, string> _systemFontPaths;
+        private static readonly Dictionary<string, FontFamilyModel> _systemFamilies;
+
+        private readonly Dictionary<string, byte[]> _customFonts = new Dictionary<string, byte[]>(StringComparer.Ordinal);
+        private readonly Dictionary<string, FontFamilyModel> _installedFonts;
+        private readonly List<string> _customFontDirectories = new List<string>();
+
+        /// <summary>
+        /// When true, a family/codepoint that can't be resolved returns null instead of falling back to
+        /// the embedded Tuffy font - lets a caller detect "nothing matched" instead of silently
+        /// substituting a visually different fallback face.
+        /// </summary>
+        public bool NullIfFontNotFound { get; set; }
+
+        static FontResolver()
+        {
+            var supportedFonts = DiscoverSupportedFonts();
+            var parsed = ParseSystemFonts(supportedFonts);
+            _systemFontPaths = parsed.Paths;
+            _systemFamilies = parsed.Families;
+        }
+
+        public FontResolver()
+        {
+            _installedFonts = new Dictionary<string, FontFamilyModel>(_systemFamilies, StringComparer.Ordinal);
+        }
+
+        /// <summary>Registers a new <see cref="FontResolver"/> instance as PDFsharp's process-wide global resolver.</summary>
+        public static FontResolver Register()
+        {
+            var fontResolver = new FontResolver();
+            GlobalFontSettings.FontResolver = fontResolver;
+            return fontResolver;
+        }
+
+        #region OS font discovery
+
+        private static string[] GetFontFiles(string dir)
+        {
+            if (!Directory.Exists(dir))
+                return Array.Empty<string>();
+
+            try
+            {
+                return FontExtensions
+                    .SelectMany(pattern => Directory.GetFiles(dir, pattern, SearchOption.AllDirectories))
+                    .ToArray();
+            }
+            catch (UnauthorizedAccessException)
+            {
+                // Some directories may exist but be unreadable depending on OS/permission configuration -
+                // treat that the same as "no fonts here" rather than failing discovery entirely.
+                return Array.Empty<string>();
             }
-            
-            // Return fallback if no matching font is found
-            var stylizedFallbackFontName = FontNameResolver.StylizeFontNameStrict(FallbackFont, fontAttributes);
-            return new FontResolverInfo(stylizedFallbackFontName);
         }
 
-        public byte[] GetFont(string faceName)
+        internal static string[] DiscoverSupportedFonts()
         {
-            if (_fontCache.TryGetValue(faceName, out var font))
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
             {
-                if (File.Exists(font.FilePath))
-                {
-                    return File.ReadAllBytes(font.FilePath);
-                }
+                var homeDir = Environment.GetEnvironmentVariable("HOME");
+                var candidateDirs = new List<string> { "/System/Library/Fonts", "/Library/Fonts" };
+                if (!string.IsNullOrEmpty(homeDir))
+                    candidateDirs.Add(Path.Combine(homeDir, "Library", "Fonts"));
+
+                return candidateDirs.SelectMany(GetFontFiles).Distinct(StringComparer.OrdinalIgnoreCase).ToArray();
             }
 
-            if (!faceName.StartsWith(FallbackFont))
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
             {
-                return null;
+                return LinuxSystemFontResolver.Resolve();
             }
 
-            // Try to load embedded fallback font
-            var assembly = Assembly.GetExecutingAssembly();
-        
-            var resourceName = assembly.GetManifestResourceNames()
-                .FirstOrDefault(r => r.EndsWith($"{faceName}.ttf", StringComparison.OrdinalIgnoreCase));
-            if (resourceName == null)
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
-                return null;
+                var fontDir = Environment.ExpandEnvironmentVariables(@"%SystemRoot%\Fonts");
+                var fontPaths = new List<string>(GetFontFiles(fontDir));
+
+                // Covers per-user-installed fonts (Windows 10+ lets a non-admin install fonts for just
+                // their own account), which the machine-wide Fonts folder above doesn't.
+                var appdataFontDir = Environment.ExpandEnvironmentVariables(@"%LOCALAPPDATA%\Microsoft\Windows\Fonts");
+                fontPaths.AddRange(GetFontFiles(appdataFontDir));
+
+                return fontPaths.ToArray();
             }
 
-            using (var stream = assembly.GetManifestResourceStream(resourceName))
+            // No system font discovery on this platform - start with nothing and rely on fonts registered
+            // via AddFont/RegisterCustomFontDirectory.
+            return Array.Empty<string>();
+        }
+
+        private static (Dictionary<string, string> Paths, Dictionary<string, FontFamilyModel> Families) ParseSystemFonts(string[] supportedFonts)
+        {
+            var fontPaths = new Dictionary<string, string>(StringComparer.Ordinal);
+            var descriptions = new List<TtfFontDescription>();
+
+            foreach (var fontPathFile in supportedFonts)
             {
-                if (stream == null)
+                try
                 {
-                    return null;
+                    var description = TtfFontDescription.LoadDescription(fontPathFile);
+                    descriptions.Add(description);
+
+                    if (!fontPaths.ContainsKey(description.FontNameInvariantCulture))
+                        fontPaths.Add(description.FontNameInvariantCulture, fontPathFile);
                 }
+                catch (Exception e)
+                {
+                    Debug.WriteLine(e);
+                }
+            }
 
-                using (var memoryStream = new MemoryStream())
+            var families = new Dictionary<string, FontFamilyModel>(StringComparer.Ordinal);
+
+            foreach (var familyGroup in descriptions.GroupBy(d => d.FontFamilyInvariantCulture))
+            {
+                try
                 {
-                    stream.CopyTo(memoryStream);
-                    return memoryStream.ToArray();
+                    var familyName = familyGroup.Key;
+                    var family = DeserializeFontFamily(familyName, familyGroup);
+                    families[familyName.ToLowerInvariant()] = family;
+                }
+                catch (Exception e)
+                {
+                    Debug.WriteLine(e);
                 }
             }
+
+            return (fontPaths, families);
+        }
+
+        private static FontFamilyModel DeserializeFontFamily(string fontFamilyName, IEnumerable<TtfFontDescription> descriptions)
+        {
+            var family = new FontFamilyModel { Name = fontFamilyName };
+
+            foreach (var description in descriptions)
+            {
+                var isItalic = (description.Style & RFontStyle.Italic) != 0;
+                // System fonts declare no explicit unicode-range - their effective coverage is
+                // "everything" (see this type's own doc comment). Keep the first face seen per
+                // (weight, italic, stretch).
+                if (!family.Faces.Any(f => f.Weight == description.Weight && f.Italic == isItalic && f.Stretch == description.Stretch))
+                    family.Faces.Add(new FontFaceEntry(description.Weight, isItalic, description.Stretch, null, description));
+            }
+
+            return family;
+        }
+
+        #endregion
+
+        #region Registration (@font-face src: url()/local(), custom directories)
+
+        /// <summary>Registers a font under <paramref name="fontFamilyName"/>, using the values sniffed from the file itself.</summary>
+        public void AddFont(Stream stream, string fontFamilyName)
+        {
+            AddFont(stream, fontFamilyName, null, null, null, null);
+        }
+
+        /// <summary>
+        /// Registers a font under <paramref name="fontFamilyName"/>, optionally overriding the face's own
+        /// sniffed weight/style/stretch with the values an <c>@font-face</c> rule declared for it - those
+        /// descriptors are authoritative for how that specific resource participates in matching,
+        /// independent of what the file's own internal tables say. Null means "use the value sniffed from
+        /// the file itself". <paramref name="unicodeRanges"/> restricts which codepoints this face is used
+        /// for; null means "covers whatever is asked of it" (see this type's own doc comment).
+        /// </summary>
+        public void AddFont(Stream stream, string fontFamilyName, int? weightOverride, bool? isItalicOverride, int? stretchOverride, IReadOnlyList<CodepointRange> unicodeRanges)
+        {
+            var memoryStream = new MemoryStream();
+            stream.CopyTo(memoryStream);
+            var fontBytes = memoryStream.ToArray();
+            memoryStream.Seek(0, SeekOrigin.Begin);
+
+            var description = TtfFontDescription.LoadDescription(memoryStream);
+
+            var weight = weightOverride ?? description.Weight;
+            var isItalic = isItalicOverride ?? (description.Style & RFontStyle.Italic) != 0;
+            var stretch = stretchOverride ?? description.Stretch;
+
+            // The face name is the identity under which the bytes are stored and later fetched (GetFont)
+            // for embedding - normally the font's own internal name. But two DIFFERENT fonts can share one
+            // internal name (a common webfont-subset pattern, e.g. every "Roboto" subset file reports
+            // "Roboto"); those must not collide in _customFonts (the second would overwrite the first's
+            // bytes), so disambiguate with a content checksum when that happens.
+            var internalName = description.FontNameInvariantCulture;
+            var faceName = internalName;
+            if (_customFonts.TryGetValue(internalName, out var existingBytes) && !ByteArraysEqual(existingBytes, fontBytes))
+            {
+                faceName = internalName + "#" + ComputeChecksum(fontBytes).ToString("x", CultureInfo.InvariantCulture);
+            }
+
+            var faceDescription = new TtfFontDescription(description.FontFamilyInvariantCulture, faceName, description.Style, weight, stretch);
+
+            RegisterFace(fontFamilyName, new FontFaceEntry(weight, isItalic, stretch, unicodeRanges, faceDescription));
+            _customFonts[faceName] = fontBytes;
         }
 
+        /// <summary>
+        /// Satisfies an <c>@font-face</c> <c>src: local(...)</c> candidate: finds the nearest face already
+        /// registered under <paramref name="localFamilyName"/> (a system font or an earlier registration)
+        /// for the given axes, and registers that same face's bytes as a face of
+        /// <paramref name="familyName"/> too - reusing the OS font's embedded bytes, not copying them.
+        /// </summary>
+        /// <returns>true if a local family by that name was found and registered, false otherwise (the caller tries the next <c>src</c> candidate)</returns>
+        public bool AddLocalFontFamily(string familyName, string localFamilyName, int? weightOverride, bool? isItalicOverride, int? stretchOverride, IReadOnlyList<CodepointRange> ranges)
+        {
+            if (!_installedFonts.TryGetValue(localFamilyName.ToLowerInvariant(), out var localFamily) || localFamily.Faces.Count == 0)
+                return false;
+
+            var weight = weightOverride ?? TtfFontDescription.DefaultWeight;
+            var isItalic = isItalicOverride ?? false;
+            var stretch = stretchOverride ?? TtfFontDescription.DefaultStretch;
+
+            if (!TryFindNearestFace(localFamily, weight, isItalic, stretch, null, out var sourceFace))
+                return false;
+
+            var entry = new FontFaceEntry(
+                weightOverride ?? sourceFace.Weight,
+                isItalicOverride ?? sourceFace.Italic,
+                stretchOverride ?? sourceFace.Stretch,
+                ranges,
+                sourceFace.Description);
+
+            RegisterFace(familyName, entry);
+            return true;
+        }
+
+        /// <summary>
+        /// Registers <paramref name="fontDirectory"/> to be scanned for TTF/OTF files, each registered
+        /// under its own sniffed family name (unlike <see cref="AddFont(Stream,string)"/>, which requires
+        /// the caller to already know the family name up front).
+        /// </summary>
         public void RegisterCustomFontDirectory(string fontDirectory)
         {
-            _fontDiscoveryService.RegisterCustomFontDirectory(fontDirectory);
-            
-            // Invalidate the cache to trigger discovery
-            _fontMetadataCache.Clear();
+            if (_customFontDirectories.Contains(fontDirectory, StringComparer.OrdinalIgnoreCase))
+                return;
+
+            _customFontDirectories.Add(fontDirectory);
+
+            foreach (var path in GetFontFiles(fontDirectory))
+            {
+                try
+                {
+                    var description = TtfFontDescription.LoadDescription(path);
+                    using (var stream = File.OpenRead(path))
+                    {
+                        AddFont(stream, description.FontFamilyInvariantCulture);
+                    }
+                }
+                catch
+                {
+                    // Not every *.ttf/*.otf found in a directory scan is necessarily a valid/readable font
+                    // file - skip it and keep discovering the rest.
+                }
+            }
         }
 
+        /// <summary>Every family name currently registered (system-discovered, plus any added via <see cref="AddFont(Stream,string)"/>/<see cref="RegisterCustomFontDirectory"/>).</summary>
         public List<string> DiscoverFontFamilies()
         {
-            if (_fontMetadataCache.Count == 0)
+            return _installedFonts.Values.Select(f => f.Name).ToList();
+        }
+
+        /// <summary>
+        /// Replaces any existing same-slot face (same weight/italic/stretch/unicode-range - a
+        /// re-registration) while letting a same-axes face with a different range set coexist (the
+        /// unicode-range subset case), then adds <paramref name="entry"/>. Clones the family before
+        /// mutating: <paramref name="familyName"/> may currently resolve to the shared static
+        /// <c>_systemFamilies</c> snapshot (or an already-private clone from a prior call), and this must
+        /// never write into state shared across instances.
+        /// </summary>
+        private void RegisterFace(string familyName, FontFaceEntry entry)
+        {
+            var key = familyName.ToLowerInvariant();
+            _installedFonts.TryGetValue(key, out var existingFamily);
+
+            var clonedFamily = new FontFamilyModel { Name = existingFamily?.Name ?? familyName };
+            if (existingFamily != null)
+            {
+                foreach (var face in existingFamily.Faces)
+                {
+                    if (!IsSameFaceSlot(face, entry.Weight, entry.Italic, entry.Stretch, entry.ExplicitRanges))
+                        clonedFamily.Faces.Add(face);
+                }
+            }
+
+            clonedFamily.Faces.Add(entry);
+            _installedFonts[key] = clonedFamily;
+        }
+
+        private static bool IsSameFaceSlot(FontFaceEntry entry, int weight, bool isItalic, int stretch, IReadOnlyList<CodepointRange> ranges)
+        {
+            return entry.Weight == weight && entry.Italic == isItalic && entry.Stretch == stretch && RangesEqual(entry.ExplicitRanges, ranges);
+        }
+
+        private static bool RangesEqual(IReadOnlyList<CodepointRange> a, IReadOnlyList<CodepointRange> b)
+        {
+            if (a == null || b == null)
+                return a == null && b == null;
+            if (a.Count != b.Count)
+                return false;
+            for (var i = 0; i < a.Count; i++)
             {
-                DiscoverFonts();
+                if (a[i].Start != b[i].Start || a[i].End != b[i].End)
+                    return false;
             }
-            
-            var fontFamilies = new List<string>();
-            
-            foreach (var metadata in _fontMetadataCache)
+            return true;
+        }
+
+        private static bool ByteArraysEqual(byte[] a, byte[] b)
+        {
+            if (a.Length != b.Length)
+                return false;
+            for (var i = 0; i < a.Length; i++)
             {
-                var stylizedPreferredFamilyName = FontNameResolver.StylizeFontNamePreferredFamily(metadata);
-                var stylizedFamilyName = FontNameResolver.StylizeFontNameFamily(metadata);
+                if (a[i] != b[i])
+                    return false;
+            }
+            return true;
+        }
 
-                if (!string.IsNullOrEmpty(stylizedPreferredFamilyName))
+        // A cheap, non-cryptographic content hash - only used to disambiguate two different font files
+        // that happen to report the same internal name (see AddFont), not for any security purpose.
+        private static uint ComputeChecksum(byte[] bytes)
+        {
+            unchecked
+            {
+                const uint fnvPrime = 16777619;
+                var hash = 2166136261;
+                foreach (var b in bytes)
                 {
-                    fontFamilies.Add(stylizedFamilyName);
+                    hash ^= b;
+                    hash *= fnvPrime;
                 }
-                
-                fontFamilies.Add(stylizedFamilyName);
+                return hash;
             }
-            
-            return fontFamilies;
         }
-        
-        public static FontResolver Register()
+
+        #endregion
+
+        #region IFontResolver
+
+        public byte[] GetFont(string faceName)
         {
-            var fontResolver = new FontResolver();
-            GlobalFontSettings.FontResolver = fontResolver;
-            return fontResolver;
+            if (_customFonts.TryGetValue(faceName, out var fontBytes))
+                return fontBytes;
+
+            if (_systemFontPaths.TryGetValue(faceName, out var fontPath) && File.Exists(fontPath))
+                return File.ReadAllBytes(fontPath);
+
+            if (faceName != null && faceName.StartsWith(FallbackFont, StringComparison.Ordinal))
+            {
+                var embedded = LoadEmbeddedFallbackFont(faceName);
+                if (embedded != null)
+                    return embedded;
+            }
+
+            throw new ArgumentOutOfRangeException(nameof(faceName), faceName, "Unknown font face name.");
         }
 
-        private void DiscoverFonts()
+        public bool HasFont(string faceName)
         {
-            var fontInfos = _fontDiscoveryService.DiscoverFontInfos();
+            return _customFonts.ContainsKey(faceName) || _systemFontPaths.ContainsKey(faceName);
+        }
 
-            _fontMetadataCache = fontInfos.Select(fontInfo => fontInfo.FilePath)
-                .Distinct()
-                .Select(FontParser.ExtractFontMetadata)
-                .Where(fontMetadata => fontMetadata != null)
-                .ToList();
+        /// <summary>
+        /// Whether <paramref name="familyName"/> is registered - a system-discovered family, or one
+        /// registered via <see cref="AddFont(Stream,string,int?,bool?,int?,IReadOnlyList{CodepointRange})"/>/
+        /// <see cref="AddLocalFontFamily"/>. Used by <see cref="Adapters.PdfSharpAdapter.IsFontExists"/> so
+        /// <c>@font-face</c>-only families (registered here, not in the shared <c>FontsHandler</c> - see
+        /// this type's own doc comment) are still recognized by <see cref="Core.Parse.CssParser.ParseFontFamily"/>.
+        /// </summary>
+        public bool HasFamily(string familyName)
+        {
+            return !string.IsNullOrEmpty(familyName) && _installedFonts.ContainsKey(familyName.ToLowerInvariant());
         }
+
+        /// <summary>Whether any face of <paramref name="familyName"/> declares an explicit <c>unicode-range</c>.</summary>
+        public bool HasExplicitRanges(string familyName)
+        {
+            return _installedFonts.TryGetValue(familyName.ToLowerInvariant(), out var family)
+                   && family.Faces.Any(f => f.ExplicitRanges != null);
+        }
+
+        public FontResolverInfo ResolveTypeface(string familyName, bool isBold, bool isItalic) =>
+            ResolveTypeface(familyName, isBold ? 700 : 400, isItalic);
+
+        public FontResolverInfo ResolveTypeface(string familyName, int weight, bool isItalic) =>
+            ResolveTypeface(familyName, weight, isItalic, TtfFontDescription.DefaultStretch);
+
+        public FontResolverInfo ResolveTypeface(string familyName, int weight, bool isItalic, int stretch) =>
+            ResolveTypeface(familyName, weight, isItalic, stretch, null);
+
+        /// <summary>
+        /// Resolves a face for <paramref name="familyName"/> at the requested axes, optionally restricted
+        /// to faces whose <c>unicode-range</c> covers <paramref name="codepoint"/>. A codepoint-scoped
+        /// request that finds no covering face returns null, so per-codepoint matching can move on to the
+        /// next family instead of substituting a face that cannot render the character. A codepoint-less
+        /// request keeps the previous behavior (no coverage filter, plus a fallback rather than null/throw).
+        /// </summary>
+        public FontResolverInfo ResolveTypeface(string familyName, int weight, bool isItalic, int stretch, int? codepoint)
+        {
+            if (!string.IsNullOrEmpty(familyName) && _installedFonts.TryGetValue(familyName.ToLowerInvariant(), out var family))
+            {
+                if (TryFindNearestFace(family, weight, isItalic, stretch, codepoint, out var face))
+                {
+                    // The chosen face may be a compromise (nearest-weight/slant match, not exact) - decide
+                    // whether the gap is large enough that faux-bold/italic synthesis should kick in.
+                    // Threshold mirrors the common UA convention that weights >=600 read as "bold".
+                    var mustSimulateBold = weight >= 600 && face.Weight < 600;
+                    var mustSimulateItalic = isItalic && !face.Italic;
+                    return new FontResolverInfo(face.Description.FontNameInvariantCulture, mustSimulateBold, mustSimulateItalic);
+                }
+            }
+
+            // A codepoint-scoped miss must not substitute an arbitrary non-covering face - report it so
+            // the caller tries the next family (and ultimately the box default).
+            if (codepoint.HasValue)
+                return null;
+
+            if (NullIfFontNotFound)
+                return null;
+
+            return new FontResolverInfo(StylizeTuffyFaceName(weight, isItalic));
+        }
+
+        /// <summary>
+        /// CSS Fonts Level 4 §5 face matching. When <paramref name="codepoint"/> is supplied, only faces
+        /// whose <c>unicode-range</c> includes it (or which declare none at all - see this type's own doc
+        /// comment) are candidates; among equally-good matches the last-declared wins (CSS cascade order
+        /// for overlapping ranges). Otherwise every face is a candidate. Within the candidates it narrows
+        /// italic/slant first, then stretch, then weight; an exact axis match short-circuits.
+        /// </summary>
+        private static bool TryFindNearestFace(FontFamilyModel family, int weight, bool isItalic, int stretch, int? codepoint, out FontFaceEntry face)
+        {
+            face = null;
+
+            var covering = codepoint.HasValue
+                ? family.Faces.Where(f => FaceCovers(f, codepoint.Value)).ToList()
+                : family.Faces;
+
+            if (covering.Count == 0)
+                return false;
+
+            var exact = covering.Where(f => f.Weight == weight && f.Italic == isItalic && f.Stretch == stretch).ToList();
+            if (exact.Count > 0)
+            {
+                face = exact[exact.Count - 1];
+                return true;
+            }
+
+            var sameSlant = covering.Where(f => f.Italic == isItalic).ToList();
+            var candidates = sameSlant.Count > 0 ? sameSlant : covering;
+
+            var availableStretches = candidates.Select(f => f.Stretch).Distinct().ToList();
+            var chosenStretch = PickNearestStretch(availableStretches, stretch);
+            var stretchCandidates = candidates.Where(f => f.Stretch == chosenStretch).ToList();
+
+            var availableWeights = stretchCandidates.Select(f => f.Weight).Distinct().ToList();
+            var chosenWeight = PickNearestWeight(availableWeights, weight);
+
+            face = stretchCandidates.Last(f => f.Weight == chosenWeight);
+            return true;
+        }
+
+        private static bool FaceCovers(FontFaceEntry entry, int codepoint) =>
+            entry.ExplicitRanges == null || UnicodeRangeParser.Covers(entry.ExplicitRanges, codepoint);
+
+        /// <summary>
+        /// CSS Fonts Level 4 §5.2's nearest-stretch search order: a target at or narrower than normal (5)
+        /// searches narrower first (down to 1), then wider; a target wider than normal searches wider
+        /// first (up to 9), then narrower. <paramref name="availableStretches"/> must be non-empty.
+        /// </summary>
+        private static int PickNearestStretch(List<int> availableStretches, int target)
+        {
+            if (availableStretches.Contains(target))
+                return target;
+
+            var candidates = target <= TtfFontDescription.DefaultStretch
+                ? availableStretches.Where(s => s < target).OrderByDescending(s => s)
+                    .Concat(availableStretches.Where(s => s > target).OrderBy(s => s))
+                : availableStretches.Where(s => s > target).OrderBy(s => s)
+                    .Concat(availableStretches.Where(s => s < target).OrderByDescending(s => s));
+
+            return candidates.First();
+        }
+
+        /// <summary>
+        /// CSS Fonts Level 4 §5.2's nearest-weight search order (the standard browser algorithm): a target
+        /// in [400,500] searches upward to 500 first, then below the target, then above 500; a target
+        /// below 400 searches downward first, then upward; a target above 500 searches upward first, then
+        /// downward. <paramref name="availableWeights"/> must be non-empty and is assumed to NOT already
+        /// contain an exact match for <paramref name="target"/> (the caller checks that separately, since
+        /// an exact match also has to match the requested italic-ness, which this purely-numeric helper
+        /// doesn't know about).
+        /// </summary>
+        private static int PickNearestWeight(List<int> availableWeights, int target)
+        {
+            IEnumerable<int> candidates;
+            if (target >= 400 && target <= 500)
+            {
+                candidates = availableWeights.Where(w => w >= target && w <= 500).OrderBy(w => w)
+                    .Concat(availableWeights.Where(w => w < target).OrderByDescending(w => w))
+                    .Concat(availableWeights.Where(w => w > 500).OrderBy(w => w));
+            }
+            else if (target < 400)
+            {
+                candidates = availableWeights.Where(w => w < target).OrderByDescending(w => w)
+                    .Concat(availableWeights.Where(w => w > target).OrderBy(w => w));
+            }
+            else
+            {
+                candidates = availableWeights.Where(w => w > target).OrderBy(w => w)
+                    .Concat(availableWeights.Where(w => w < target).OrderByDescending(w => w));
+            }
+
+            return candidates.First();
+        }
+
+        private static string StylizeTuffyFaceName(int weight, bool isItalic)
+        {
+            var isBold = weight >= 600;
+            if (isBold && isItalic) return "Tuffy Bold Italic";
+            if (isBold) return "Tuffy Bold";
+            if (isItalic) return "Tuffy Italic";
+            return FallbackFont;
+        }
+
+        private static byte[] LoadEmbeddedFallbackFont(string faceName)
+        {
+            var assembly = Assembly.GetExecutingAssembly();
+
+            var resourceName = assembly.GetManifestResourceNames()
+                .FirstOrDefault(r => r.EndsWith(faceName + ".ttf", StringComparison.OrdinalIgnoreCase));
+            if (resourceName == null)
+                return null;
+
+            using (var stream = assembly.GetManifestResourceStream(resourceName))
+            {
+                if (stream == null)
+                    return null;
+
+                using (var memoryStream = new MemoryStream())
+                {
+                    stream.CopyTo(memoryStream);
+                    return memoryStream.ToArray();
+                }
+            }
+        }
+
+        #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/LinuxSystemFontResolver.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/LinuxSystemFontResolver.cs
new file mode 100644
index 000000000..d5e12ba03
--- /dev/null
+++ b/Source/HtmlRenderer.PdfSharp/FontResolution/LinuxSystemFontResolver.cs
@@ -0,0 +1,140 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.Linq;
+using System.Text.RegularExpressions;
+
+namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution
+{
+    /// <summary>
+    /// Linux system font-file discovery, used by <see cref="FontResolver.DiscoverSupportedFonts"/>.
+    /// </summary>
+    /// <remarks>
+    /// Adapted, not verbatim, from PeachPDF's <c>Fonts\LinuxSystemFontResolver.cs</c>: PeachPDF
+    /// P/Invokes <c>libfontconfig.so.1</c> directly via source-generated <c>[LibraryImport]</c> bindings,
+    /// which need .NET 7+ and don't exist on this project's <c>netstandard2.0</c> target framework.
+    /// Shelling out to the <c>fc-list</c> CLI - fontconfig's own command-line front end, present wherever
+    /// <c>libfontconfig</c> itself is - returns the identical font-file listing with no native interop and
+    /// no TFM split; this project's own pre-existing Linux discovery already took this approach, so it's
+    /// kept here rather than replaced. When <c>fc-list</c> isn't available (or fails), falls back to
+    /// scanning <c>fonts.conf</c>'s declared directories plus the conventional well-known ones directly -
+    /// matching PeachPDF's own fallback behavior.
+    /// </remarks>
+    internal static class LinuxSystemFontResolver
+    {
+        public static string[] Resolve()
+        {
+            try
+            {
+                var files = ResolveViaFontConfig();
+                if (files.Length > 0)
+                    return files;
+            }
+            catch (Exception e)
+            {
+                Debug.WriteLine(e);
+            }
+
+            return ResolveFallback();
+        }
+
+        private static string[] ResolveViaFontConfig()
+        {
+            var startInfo = new ProcessStartInfo
+            {
+                FileName = "fc-list",
+                Arguments = ": file",
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false,
+                CreateNoWindow = true
+            };
+
+            using (var process = Process.Start(startInfo))
+            {
+                if (process == null)
+                    return Array.Empty<string>();
+
+                var output = process.StandardOutput.ReadToEnd();
+                process.WaitForExit();
+
+                if (process.ExitCode != 0 || string.IsNullOrWhiteSpace(output))
+                    return Array.Empty<string>();
+
+                // Each line looks like: "/path/to/font.ttf: file"
+                return output
+                    .Split(new[] { '\n' }, StringSplitOptions.RemoveEmptyEntries)
+                    .Select(line => line.Split(':')[0].Trim())
+                    .Where(IsSupportedFontFile)
+                    .Where(File.Exists)
+                    .Distinct(StringComparer.OrdinalIgnoreCase)
+                    .ToArray();
+            }
+        }
+
+        private static bool IsSupportedFontFile(string path) =>
+            path.EndsWith(".ttf", StringComparison.OrdinalIgnoreCase) ||
+            path.EndsWith(".otf", StringComparison.OrdinalIgnoreCase);
+
+        private static string[] ResolveFallback()
+        {
+            var fontFiles = new List<string>();
+
+            foreach (var path in GetSearchPaths().Distinct(StringComparer.OrdinalIgnoreCase))
+            {
+                if (!Directory.Exists(path))
+                    continue;
+
+                try
+                {
+                    fontFiles.AddRange(Directory.EnumerateFiles(path, "*.ttf", SearchOption.AllDirectories));
+                    fontFiles.AddRange(Directory.EnumerateFiles(path, "*.otf", SearchOption.AllDirectories));
+                }
+                catch (Exception e)
+                {
+                    Debug.WriteLine(e);
+                }
+            }
+
+            return fontFiles.ToArray();
+        }
+
+        private static IEnumerable<string> GetSearchPaths()
+        {
+            var dirs = new List<string>();
+
+            try
+            {
+                var confDirRegex = new Regex("<dir>(?<dir>.*)</dir>");
+                if (File.Exists("/etc/fonts/fonts.conf"))
+                {
+                    foreach (var line in File.ReadLines("/etc/fonts/fonts.conf"))
+                    {
+                        var match = confDirRegex.Match(line);
+                        if (!match.Success)
+                            continue;
+
+                        var path = match.Groups["dir"].Value.Trim();
+                        if (path.StartsWith("~"))
+                            path = Environment.GetEnvironmentVariable("HOME") + path.Substring(1);
+
+                        dirs.Add(path);
+                    }
+                }
+            }
+            catch (Exception e)
+            {
+                Debug.WriteLine(e);
+            }
+
+            dirs.Add("/usr/share/fonts");
+            dirs.Add("/usr/local/share/fonts");
+            var home = Environment.GetEnvironmentVariable("HOME");
+            if (!string.IsNullOrEmpty(home))
+                dirs.Add(Path.Combine(home, ".fonts"));
+
+            return dirs;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/Parsing/BinaryParser.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/Parsing/BinaryParser.cs
deleted file mode 100644
index b67434a40..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/Parsing/BinaryParser.cs
+++ /dev/null
@@ -1,69 +0,0 @@
-using System;
-using System.Buffers;
-using System.Text;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Parsing
-{
-    internal static class BinaryParser
-    {
-        public static ushort ReadUint16BigEndian(Span<byte> data, int offset)
-        {
-            if (offset + 1 >= data.Length)
-            {
-                return 0;
-            }
-        
-            return (ushort)((data[offset] << 8) | data[offset + 1]);
-        }
-
-        public static uint ReadUint32BigEndian(Span<byte> data, int offset)
-        {
-            if (offset + 3 >= data.Length)
-            {
-                return 0;
-            }
-        
-            return ((uint)data[offset] << 24) | ((uint)data[offset + 1] << 16) |
-                   ((uint)data[offset + 2] << 8) | data[offset + 3];
-        }
-
-        public static string ReadAsciiString(Span<byte> data, int offset, int length)
-        {
-            return Encoding.ASCII.GetString(data.Slice(offset, length).ToArray());
-        }
-
-        public static string ReadAsciiString(Span<byte> data)
-        {
-            return ReadAsciiString(data, 0, data.Length);
-        }
-
-        public static string ReadUtf16StringBigEndian(Span<byte> data)
-        {
-            var chars = ArrayPool<char>.Shared.Rent(data.Length);
-
-            try
-            {
-                var index = 0;
-            
-                for (var i = 0; i < data.Length - 1; i += 2)
-                {
-                    var c = (char)((data[i] << 8) | data[i + 1]);
-                
-                    if (c == '\0')
-                    {
-                        continue;
-                    }
-                
-                    chars[index] = c;
-                    ++index;
-                }
-
-                return new string(chars, 0, index);
-            }
-            finally
-            {
-                ArrayPool<char>.Shared.Return(chars);
-            }
-        }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer.PdfSharp/FontResolution/Parsing/FontParser.cs b/Source/HtmlRenderer.PdfSharp/FontResolution/Parsing/FontParser.cs
deleted file mode 100644
index db01ae555..000000000
--- a/Source/HtmlRenderer.PdfSharp/FontResolution/Parsing/FontParser.cs
+++ /dev/null
@@ -1,467 +0,0 @@
-using System;
-using System.Buffers;
-using System.Collections.Generic;
-using System.IO;
-
-namespace TheArtOfDev.HtmlRenderer.PdfSharp.FontResolution.Parsing
-{
-    internal static class FontParser
-    {
-        public static FontMetadata ExtractFontMetadata(string fontFilePath)
-        {
-            try
-            {
-                using (var fs = new FileStream(fontFilePath, FileMode.Open, FileAccess.Read))
-                {
-                    if (fs.Length > int.MaxValue)
-                    {
-                        return null;
-                    }
-
-                    var pooledBytes = ArrayPool<byte>.Shared.Rent((int)fs.Length);
-
-                    try
-                    {
-                        var bytesRead = fs.Read(pooledBytes, 0, (int)fs.Length);
-                        var bytes = pooledBytes.AsSpan(0, bytesRead); // Fixed size span view
-
-                        var metadata = ParseFontMetadata(bytes);
-                        if (metadata != null)
-                        {
-                            metadata.FilePath = fontFilePath;
-                        }
-                        return metadata;
-                    }
-                    finally
-                    {
-                        ArrayPool<byte>.Shared.Return(pooledBytes);
-                    }
-                }
-            }
-            catch
-            {
-                return null;
-            }
-        }
-
-        private static FontMetadata ParseFontMetadata(Span<byte> bytes)
-        {
-            // Read the font header (big-endian)
-            var scalarType = BinaryParser.ReadUint32BigEndian(bytes, 0);
-
-            // Verify it's a valid TTF/OTF file
-            if (scalarType != 0x00010000 && // TrueType version 1.0
-                scalarType != 0x74727565 && // "true" - TrueType
-                scalarType != 0x4F54544F) // "OTTO" - OpenType with CFF outline
-            {
-                return null;
-            }
-
-            var tableCount = BinaryParser.ReadUint16BigEndian(bytes, 4);
-
-            // Find the "name" and "os/2" tables
-            long nameTableOffset = -1;
-            uint? os2TableOffset = null;
-            var tableRecordOffset = 12;
-
-            for (var i = 0; i < tableCount; i++)
-            {
-                var tag = BinaryParser.ReadAsciiString(bytes, tableRecordOffset, 4);
-                var offset = BinaryParser.ReadUint32BigEndian(bytes, tableRecordOffset + 8);
-
-                if (tag == "name")
-                {
-                    nameTableOffset = offset;
-                }
-                else if (tag == "OS/2")
-                {
-                    os2TableOffset = offset;
-                }
-
-                tableRecordOffset += 16;
-            }
-
-            if (nameTableOffset == -1)
-            {
-                return null;
-            }
-
-            var metadata = new FontMetadata();
-
-            ParseNameTable(bytes, nameTableOffset, metadata);
-
-            // Extract OS/2 table data if available for more accurate weight/width/style info
-            var hasOs2Data = ParseOs2Table(bytes, os2TableOffset, metadata);
-
-            // Parse style from subfamily if not already set from OS/2
-            if (!hasOs2Data)
-            {
-                ParseStyleFromSubfamily(metadata, metadata.Subfamily);
-            }
-
-            // Return metadata if we at least have a family name
-            return !string.IsNullOrEmpty(metadata.Family) ? metadata : null;
-        }
-
-        private static void ParseNameTable(Span<byte> bytes, long nameTableOffset, FontMetadata metadata)
-        {
-            var nameTablePos = (int)nameTableOffset;
-            var count = BinaryParser.ReadUint16BigEndian(bytes, nameTablePos + 2);
-            var stringDataOffset = BinaryParser.ReadUint16BigEndian(bytes, nameTablePos + 4);
-
-            // Track which values have been set with English entries
-            var hasEnglishValue = new HashSet<int>();
-
-            // First pass: Look for English entries
-            var nameRecordOffset = nameTablePos + 6;
-            for (var i = 0; i < count; i++, nameRecordOffset += 12)
-            {
-                var platformId = BinaryParser.ReadUint16BigEndian(bytes, nameRecordOffset);
-                var encodingId = BinaryParser.ReadUint16BigEndian(bytes, nameRecordOffset + 2);
-                var languageId = BinaryParser.ReadUint16BigEndian(bytes, nameRecordOffset + 4);
-                var nameId = BinaryParser.ReadUint16BigEndian(bytes, nameRecordOffset + 6);
-                var length = BinaryParser.ReadUint16BigEndian(bytes, nameRecordOffset + 8);
-                var offset = BinaryParser.ReadUint16BigEndian(bytes, nameRecordOffset + 10);
-
-                // Filter for English language entries:
-                // Platform 3 (Windows): languageID 0x0409 (1033) = US English
-                // Platform 1 (Macintosh): languageID 0 = English
-                var isEnglish = (platformId == 3 && languageId == 0x0409) ||
-                                (platformId == 1 && languageId == 0);
-
-                if ((platformId != 3 && platformId != 1) || !IsRelevantNameId(nameId))
-                {
-                    continue;
-                }
-            
-                var stringPos = (int)nameTableOffset + stringDataOffset + offset;
-
-                if (stringPos + length > bytes.Length)
-                {
-                    continue;
-                }
-            
-                var nameBytes = bytes.Slice(stringPos, length);
-
-                var decodedString = DecodeNameTableString(nameBytes, platformId, encodingId);
-
-                if (string.IsNullOrEmpty(decodedString) || decodedString == null)
-                {
-                    continue;
-                }
-            
-                // If English, set the value and mark as having English
-                if (isEnglish)
-                {
-                    if (SetMetadataValue(metadata, nameId, decodedString))
-                    {
-                        hasEnglishValue.Add(nameId);
-                    }
-                }
-                // If not English but we haven't found an English entry yet, use it as fallback
-                else if (!hasEnglishValue.Contains(nameId))
-                {
-                    SetMetadataValue(metadata, nameId, decodedString);
-                }
-            }
-        }
-
-        private static bool IsRelevantNameId(ushort nameId)
-        {
-            return nameId is 1 || nameId is 2 || nameId is 4 || nameId is 6 || nameId is 16 || nameId is 17;
-        }
-
-        private static bool SetMetadataValue(FontMetadata metadata, ushort nameId, string value)
-        {
-            switch (nameId)
-            {
-                case 1: // Legacy Family name
-                    if (metadata.Family == null)
-                    {
-                        metadata.Family = value;
-                        return true;
-                    }
-                    return false;
-                case 2: // Legacy Subfamily
-                    if (metadata.Subfamily == null)
-                    {
-                        metadata.Subfamily = value;
-                        ParseStyleFromSubfamily(metadata, value);
-                        return true;
-                    }
-                    return false;
-                case 4: // Full font name
-                    if (metadata.FullName == null)
-                    {
-                        metadata.FullName = value;
-                        return true;
-                    }
-                    return false;
-                case 6: // PostScript name
-                    if (metadata.PostScriptName == null)
-                    {
-                        metadata.PostScriptName = value;
-                        return true;
-                    }
-                    return false;
-                case 16: // Preferred Family (Typographic Family)
-                    if (metadata.PreferredFamily == null)
-                    {
-                        metadata.PreferredFamily = value;
-                        return true;
-                    }
-                    return false;
-                case 17: // Preferred Subfamily (Typographic Subfamily)
-                    if (metadata.PreferredSubfamily == null)
-                    {
-                        metadata.PreferredSubfamily = value;
-                        return true;
-                    }
-                    return false;
-                default:
-                    return false;
-            }
-        }
-
-        private static void ParseStyleFromSubfamily(FontMetadata metadata, string subfamily)
-        {
-            if (subfamily is null)
-            {
-                return;
-            }
-        
-            var lower = subfamily.ToLowerInvariant();
-
-            // Parse weight, width, and style
-            var weight = ParseWeight(lower);
-            var width = ParseWidth(lower);
-            var style = ParseStyle(lower);
-
-            // Update metadata with parsed attributes (note: FontAttributes order is Weight, Style, Width)
-            metadata.Attributes = new FontAttributes
-            { 
-                Weight = weight,
-                Style = style,
-                Width = width
-            };
-        }
-
-        private static FontStyle ParseStyle(string lowerSubfamily)
-        {
-            if (lowerSubfamily.Contains("oblique"))
-            {
-                return FontStyle.Oblique;
-            }
-            
-            if (lowerSubfamily.Contains("italic"))
-            {
-                return FontStyle.Italic;
-            }
-            
-            return FontStyle.Normal;
-        }
-
-        private static FontWeight ParseWeight(string lowerSubfamily)
-        {
-            // Map weight keywords to enum values
-            if (lowerSubfamily.Contains("thin") || lowerSubfamily.Contains("hairline"))
-            {
-                return FontWeight.Thin;
-            }
-            
-            if (lowerSubfamily.Contains("extralight") || lowerSubfamily.Contains("ultra light"))
-            {
-                return FontWeight.ExtraLight;
-            }
-            
-            if (lowerSubfamily.Contains("light"))
-            {
-                return FontWeight.Light;
-            }
-            
-            if (lowerSubfamily.Contains("medium"))
-            {
-                return FontWeight.Medium;
-            }
-            
-            if (lowerSubfamily.Contains("semibold") || lowerSubfamily.Contains("demibold"))
-            {
-                return FontWeight.SemiBold;
-            }
-            
-            if (lowerSubfamily.Contains("extrabold") || lowerSubfamily.Contains("ultra bold"))
-            {
-                return FontWeight.ExtraBold;
-            }
-            
-            if (lowerSubfamily.Contains("bold"))
-            {
-                return FontWeight.Bold;
-            }
-            
-            if (lowerSubfamily.Contains("black") || lowerSubfamily.Contains("heavy"))
-            {
-                return FontWeight.Black;
-            }
-            
-            return FontWeight.Normal;
-        }
-
-        private static FontWidth ParseWidth(string lowerSubfamily)
-        {
-            if (lowerSubfamily.Contains("ultracondensed") || lowerSubfamily.Contains("ultra condensed"))
-            {
-                return FontWidth.UltraCondensed;
-            }
-            
-            if (lowerSubfamily.Contains("extracondensed") || lowerSubfamily.Contains("extra condensed"))
-            {
-                return FontWidth.ExtraCondensed;
-            }
-            
-            if (lowerSubfamily.Contains("condensed"))
-            {
-                return FontWidth.Condensed;
-            }
-            
-            if (lowerSubfamily.Contains("semicondensed"))
-            {
-                return FontWidth.SemiCondensed;
-            }
-            
-            if (lowerSubfamily.Contains("semiexpanded"))
-            {
-                return FontWidth.SemiExpanded;
-            }
-            
-            if (lowerSubfamily.Contains("extraexpanded") || lowerSubfamily.Contains("extra expanded"))
-            {
-                return FontWidth.ExtraExpanded;
-            }
-            
-            if (lowerSubfamily.Contains("ultraexpanded") || lowerSubfamily.Contains("ultra expanded"))
-            {
-                return FontWidth.UltraExpanded;
-            }
-            
-            if (lowerSubfamily.Contains("expanded"))
-            {
-                return FontWidth.Expanded;
-            }
-            
-            return FontWidth.Medium;
-        }
-
-        private static bool ParseOs2Table(Span<byte> bytes, uint? os2TableOffset, FontMetadata metadata)
-        {
-            if (!os2TableOffset.HasValue)
-            {
-                return false;
-            }
-        
-            var offset = (int)os2TableOffset.Value;
-        
-            try
-            {
-                // OS/2 table structure (v0+):
-                // Offset 4: usWeightClass (USHORT) - font weight (100-900)
-                // Offset 6: usWidthClass (USHORT) - font width (1-9)
-                // Offset 8: fsType (USHORT) - embedding permissions
-                // Offset 62: fsSelection (USHORT) - contains style bits
-            
-                // Check if we have enough bytes for OS/2 table
-                if (offset + 64 > bytes.Length)
-                {
-                    return false;
-                }
-
-                // Read usWeightClass (offset 4 in OS/2)
-                var usWeightClass = BinaryParser.ReadUint16BigEndian(bytes, offset + 4);
-                var weight = FontWeight.Normal;
-                if (usWeightClass >= 100 && usWeightClass <= 900)
-                {
-                    weight = (FontWeight)usWeightClass;
-                }
-
-                // Read usWidthClass (offset 6 in OS/2)
-                var usWidthClass = BinaryParser.ReadUint16BigEndian(bytes, offset + 6);
-                var width = FontWidth.Medium;
-                if (usWidthClass >= 1 && usWidthClass <= 9)
-                {
-                    width = WidthClassToEnum(usWidthClass);
-                }
-
-                // Read fsSelection for style bits (offset 62 in OS/2)
-                var fsSelection = BinaryParser.ReadUint16BigEndian(bytes, offset + 62);
-            
-                // Bit 9: Oblique, Bit 6: Regular, Bit 0: Italic
-                var style = ((fsSelection & 0x0200) != 0) ? FontStyle.Oblique :
-                    ((fsSelection & 0x0001) != 0) ? FontStyle.Italic :
-                    FontStyle.Normal;
-
-                // Update attributes with extracted OS/2 data (note: FontAttributes order is Weight, Style, Width)
-                metadata.Attributes = new FontAttributes
-                { 
-                    Weight = weight,
-                    Style = style,
-                    Width = width
-                };
-                return true;    
-            }
-            catch
-            {
-                // Silently continue if OS/2 parsing fails
-                return false;
-            }
-        }
-
-        private static FontWidth WidthClassToEnum(int widthClass)
-        {
-            switch (widthClass)
-            {
-                case 1: return FontWidth.UltraCondensed;
-                case 2: return FontWidth.ExtraCondensed;
-                case 3: return FontWidth.Condensed;
-                case 4: return FontWidth.SemiCondensed;
-                case 5: return FontWidth.Medium;
-                case 6: return FontWidth.SemiExpanded;
-                case 7: return FontWidth.Expanded;
-                case 8: return FontWidth.ExtraExpanded;
-                case 9: return FontWidth.UltraExpanded;
-                default: return FontWidth.Medium;
-            }
-        }
-
-        private static string DecodeNameTableString(Span<byte> data, ushort platformId, ushort encodingId)
-        {
-            try
-            {
-                // Windows platform
-                if (platformId == 3)
-                {
-                    if (encodingId == 1)
-                    {
-                        return BinaryParser.ReadUtf16StringBigEndian(data);
-                    }
-
-                    return null;
-                }
-                
-                // Macintosh platform
-                if (platformId == 1)
-                {
-                    if (encodingId == 0)
-                    {
-                        return BinaryParser.ReadAsciiString(data).TrimEnd('\0');
-                    }
-                }
-
-                return null;
-            }
-            catch
-            {
-                return null;
-            }
-        }
-    }
-}
diff --git a/Source/HtmlRenderer.PdfSharp/HtmlContainer.cs b/Source/HtmlRenderer.PdfSharp/HtmlContainer.cs
index 9339fd562..6861a23eb 100644
--- a/Source/HtmlRenderer.PdfSharp/HtmlContainer.cs
+++ b/Source/HtmlRenderer.PdfSharp/HtmlContainer.cs
@@ -13,6 +13,7 @@
 using PdfSharp.Drawing;
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
@@ -256,9 +257,9 @@ public string SelectedHtml
         /// </summary>
         /// <param name="htmlSource">the html to init with, init empty if not given</param>
         /// <param name="baseCssData">optional: the stylesheet to init with, init default if not given</param>
-        public void SetHtml(string htmlSource, CssData baseCssData = null)
+        public Task SetHtml(string htmlSource, CssData baseCssData = null)
         {
-            _htmlContainerInt.SetHtml(htmlSource, baseCssData);
+            return _htmlContainerInt.SetHtml(htmlSource, baseCssData);
         }
 
         /// <summary>
diff --git a/Source/HtmlRenderer.PdfSharp/PdfGenerator.cs b/Source/HtmlRenderer.PdfSharp/PdfGenerator.cs
index 99e9b56ed..a78ea5259 100644
--- a/Source/HtmlRenderer.PdfSharp/PdfGenerator.cs
+++ b/Source/HtmlRenderer.PdfSharp/PdfGenerator.cs
@@ -14,6 +14,7 @@
 using PdfSharp.Drawing;
 using PdfSharp.Pdf;
 using System;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Core;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
@@ -77,9 +78,13 @@ public static void RegisterCustomFontDirectory(string fontDirectory)
         /// <param name="stylesheet">the stylesheet source to parse</param>
         /// <param name="combineWithDefault">true - combine the parsed CSS data with default CSS data, false - return only the parsed CSS data</param>
         /// <returns>the parsed CSS data</returns>
-        public static CssData ParseStyleSheet(string stylesheet, bool combineWithDefault = true)
+        public static Task<CssData> ParseStyleSheet(string stylesheet, bool combineWithDefault = true)
         {
-            return CssData.Parse(PdfSharpAdapter.Instance, stylesheet, combineWithDefault);
+            // CssData.Parse -> CssParser.ParseStyleSheet is not itself async yet (its @import resolution
+            // bridges into the async resource-loading pipeline synchronously for now - it's also called
+            // directly from several UI controls' public API, out of scope for this conversion) - wrapped
+            // in Task.FromResult here so this method's own shape matches the rest of this async-only API.
+            return Task.FromResult(CssData.Parse(PdfSharpAdapter.Instance, stylesheet, combineWithDefault));
         }
 
         /// <summary>
@@ -92,12 +97,12 @@ public static CssData ParseStyleSheet(string stylesheet, bool combineWithDefault
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the HTML</returns>
-        public static PdfDocument GeneratePdf(string html, PageSize pageSize, int margin = 20, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
+        public static async Task<PdfDocument> GeneratePdf(string html, PageSize pageSize, int margin = 20, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             var config = new PdfGenerateConfig();
             config.PageSize = pageSize;
             config.SetMargins(margin);
-            return GeneratePdf(html, config, cssData, stylesheetLoad, imageLoad);
+            return await GeneratePdf(html, config, cssData, stylesheetLoad, imageLoad).ConfigureAwait(false);
         }
 
         /// <summary>
@@ -109,13 +114,13 @@ public static PdfDocument GeneratePdf(string html, PageSize pageSize, int margin
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the HTML</returns>
-        public static PdfDocument GeneratePdf(string html, PdfGenerateConfig config, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
+        public static async Task<PdfDocument> GeneratePdf(string html, PdfGenerateConfig config, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             // create PDF document to render the HTML into
             var document = new PdfDocument();
 
             // add rendered PDF pages to document
-            AddPdfPages(document, html, config, cssData, stylesheetLoad, imageLoad);
+            await AddPdfPages(document, html, config, cssData, stylesheetLoad, imageLoad).ConfigureAwait(false);
 
             return document;
         }
@@ -131,12 +136,12 @@ public static PdfDocument GeneratePdf(string html, PdfGenerateConfig config, Css
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the HTML</returns>
-        public static void AddPdfPages(PdfDocument document, string html, PageSize pageSize, int margin = 20, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
+        public static Task AddPdfPages(PdfDocument document, string html, PageSize pageSize, int margin = 20, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             var config = new PdfGenerateConfig();
             config.PageSize = pageSize;
             config.SetMargins(margin);
-            AddPdfPages(document, html, config, cssData, stylesheetLoad, imageLoad);
+            return AddPdfPages(document, html, config, cssData, stylesheetLoad, imageLoad);
         }
 
         /// <summary>
@@ -149,7 +154,7 @@ public static void AddPdfPages(PdfDocument document, string html, PageSize pageS
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the HTML</returns>
-        public static void AddPdfPages(PdfDocument document, string html, PdfGenerateConfig config, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
+        public static async Task AddPdfPages(PdfDocument document, string html, PdfGenerateConfig config, CssData cssData = null, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             XSize orgPageSize;
             // get the size of each page to layout the HTML in
@@ -177,7 +182,7 @@ public static void AddPdfPages(PdfDocument document, string html, PdfGenerateCon
 
                     container.Location = new XPoint(config.MarginLeft, config.MarginTop);
                     container.MaxSize = new XSize(pageSize.Width, 0);
-                    container.SetHtml(html, cssData);
+                    await container.SetHtml(html, cssData).ConfigureAwait(false);
                     container.PageSize = pageSize;
                     container.MarginBottom = config.MarginBottom;
                     container.MarginLeft = config.MarginLeft;
diff --git a/Source/HtmlRenderer.WPF/Adapters/GraphicsPathAdapter.cs b/Source/HtmlRenderer.WPF/Adapters/GraphicsPathAdapter.cs
index a6ffb66bb..af19357b4 100644
--- a/Source/HtmlRenderer.WPF/Adapters/GraphicsPathAdapter.cs
+++ b/Source/HtmlRenderer.WPF/Adapters/GraphicsPathAdapter.cs
@@ -46,9 +46,9 @@ public override void LineTo(double x, double y)
             _geometryContext.LineTo(new Point(x, y), true, true);
         }
 
-        public override void ArcTo(double x, double y, double size, Corner corner)
+        public override void ArcTo(double x, double y, double radiusX, double radiusY, Corner corner)
         {
-            _geometryContext.ArcTo(new Point(x, y), new Size(size, size), 0, false, SweepDirection.Clockwise, true, true);
+            _geometryContext.ArcTo(new Point(x, y), new Size(radiusX, radiusY), 0, false, SweepDirection.Clockwise, true, true);
         }
 
         /// <summary>
diff --git a/Source/HtmlRenderer.WPF/Adapters/WpfAdapter.cs b/Source/HtmlRenderer.WPF/Adapters/WpfAdapter.cs
index 3ea88d9c4..d0fda838e 100644
--- a/Source/HtmlRenderer.WPF/Adapters/WpfAdapter.cs
+++ b/Source/HtmlRenderer.WPF/Adapters/WpfAdapter.cs
@@ -13,12 +13,15 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
+using System.Net.Http;
 using System.Reflection;
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.Network;
 using TheArtOfDev.HtmlRenderer.WPF.Utilities;
 using Microsoft.Win32;
 
@@ -31,6 +34,20 @@ internal sealed class WpfAdapter : RAdapter
     {
         #region Fields and Consts
 
+        // One HttpClient shared for the adapter's (process) lifetime, not one per request - `new
+        // HttpClient()` per call is a well-documented anti-pattern that exhausts sockets under load and
+        // never observes DNS changes.
+        //
+        // Declared BEFORE _instance deliberately: C# runs static field initializers in textual
+        // declaration order, and _instance's own initializer (`new WpfAdapter()`) runs the instance
+        // constructor immediately, which reads _sharedHttpClient on its very first line. If this field
+        // were declared after _instance, that read would observe _sharedHttpClient's still-default value
+        // (null - its own initializer hasn't run yet) and permanently capture a null HttpClient into
+        // NetworkLoader, since HttpClientNetworkLoader takes it as a constructor parameter, not a live
+        // reference to this field. (Confirmed by a real crash with this exact ordering, in the sibling
+        // WinFormsAdapter.)
+        private static readonly HttpClient _sharedHttpClient = new HttpClient();
+
         /// <summary>
         /// Singleton instance of global adapter.
         /// </summary>
@@ -39,7 +56,20 @@ internal sealed class WpfAdapter : RAdapter
         /// <summary>
         /// List of valid predefined color names in lower-case
         /// </summary>
-        private static readonly List<string> ValidColorNamesLc; 
+        private static readonly List<string> ValidColorNamesLc;
+
+        // Backs LoadFontFaceFontInt's temp-file registration (see its own doc comment for why a real file
+        // is necessary - WPF's font-loading APIs are documented as file-URI-only, with no supported
+        // memory-only path) - one directory per process, cleaned up by the OS's normal temp-file
+        // housekeeping, not by this process.
+        private static readonly string _fontFaceTempDirectory = CreateFontFaceTempDirectory();
+
+        private static string CreateFontFaceTempDirectory()
+        {
+            var dir = Path.Combine(Path.GetTempPath(), "HtmlRenderer.FontFace." + Guid.NewGuid().ToString("N"));
+            Directory.CreateDirectory(dir);
+            return dir;
+        }
 
         #endregion
 
@@ -58,6 +88,14 @@ static WpfAdapter()
         /// </summary>
         private WpfAdapter()
         {
+            // Unlike the PdfSharp backend (which keeps the base RAdapter.NetworkLoader default of
+            // DataUriNetworkLoader-only - safer for unattended/server-side PDF generation, matching
+            // PeachPDF's own default), WPF is an interactive UI backend where fetching a real http(s):
+            // image or stylesheet out of the box is the expected behavior. data:/file: URIs still resolve
+            // the same way regardless (RAdapter.GetResourceStream intercepts both before ever consulting
+            // NetworkLoader), so only http(s): actually reaches this loader in practice.
+            NetworkLoader = new HttpClientNetworkLoader(_sharedHttpClient, (Uri)null);
+
             AddFontFamilyMapping("monospace", "Courier New");
             AddFontFamilyMapping("Helvetica", "Arial");
 
@@ -71,6 +109,19 @@ private WpfAdapter()
 	            {
 	            }
             }
+
+            SystemEvents.UserPreferenceChanged += (sender, e) =>
+            {
+                if (e.Category != UserPreferenceCategory.General) return;
+
+                // The General category covers far more than the theme, so re-read and only report a
+                // change if the scheme really moved - otherwise every unrelated preference change
+                // would force a re-cascade and repaint.
+                var previous = _colorScheme;
+                _colorScheme = null;
+                if (previous.HasValue && previous.Value != SystemColorScheme)
+                    OnColorSchemeChanged();
+            };
         }
 
         /// <summary>
@@ -81,6 +132,27 @@ public static WpfAdapter Instance
             get { return _instance; }
         }
 
+        /// <summary>
+        /// Rendering onto a Windows surface, so the document should follow the user's app theme.
+        /// Cached and invalidated on a system preference change rather than read per query.
+        /// </summary>
+        public override RColorScheme SystemColorScheme
+        {
+            get
+            {
+                if (SystemColorSchemeOverride.HasValue)
+                    return SystemColorSchemeOverride.Value;
+                if (!_colorScheme.HasValue)
+                    _colorScheme = WindowsTheme.GetAppsColorScheme();
+                return _colorScheme.Value;
+            }
+        }
+
+        /// <summary>
+        /// Cached app theme; null when it needs to be re-read.
+        /// </summary>
+        private RColorScheme? _colorScheme;
+
         protected override RColor GetColorInt(string colorName)
         {
             // check if color name is valid to avoid ColorConverter throwing an exception
@@ -102,14 +174,19 @@ protected override RBrush CreateSolidBrush(RColor color)
             return new BrushAdapter(solidBrush);
         }
 
-        protected override RBrush CreateLinearGradientBrush(RRect rect, RColor color1, RColor color2, double angle)
+        protected override RBrush CreateLinearGradientBrush(RPoint p1, RPoint p2, (RColor Color, double Position)[] stops)
         {
-            var startColor = angle <= 180 ? Utils.Convert(color1) : Utils.Convert(color2);
-            var endColor = angle <= 180 ? Utils.Convert(color2) : Utils.Convert(color1);
-            angle = angle <= 180 ? angle : angle - 180;
-            double x = angle < 135 ? Math.Max((angle - 45) / 90, 0) : 1;
-            double y = angle <= 45 ? Math.Max(0.5 - angle / 90, 0) : angle > 135 ? Math.Abs(1.5 - angle / 90) : 0;
-            return new BrushAdapter(new LinearGradientBrush(startColor, endColor, new Point(x, y), new Point(1 - x, 1 - y)));
+            var gradientStops = new GradientStopCollection(stops.Length);
+            foreach (var stop in stops)
+                gradientStops.Add(new GradientStop(Utils.Convert(stop.Color), stop.Position));
+
+            var brush = new LinearGradientBrush(gradientStops, 0)
+            {
+                MappingMode = BrushMappingMode.Absolute,
+                StartPoint = Utils.Convert(p1),
+                EndPoint = Utils.Convert(p2)
+            };
+            return new BrushAdapter(brush);
         }
 
         protected override RImage ConvertImageInt(object image)
@@ -140,6 +217,47 @@ protected override RFont CreateFontInt(RFontFamily family, double size, RFontSty
             return new FontAdapter(new Typeface(((FontFamilyAdapter)family).FontFamily, GetFontStyle(style), GetFontWidth(style), FontStretches.Normal), size);
         }
 
+        /// <summary>
+        /// Loads one <c>@font-face</c> face's bytes as a WPF <see cref="System.Windows.Media.FontFamily"/>
+        /// via a temp file and <see cref="Fonts.GetFontFamilies(Uri)"/> - WPF's own documented way to load
+        /// a font from an arbitrary location.
+        /// </summary>
+        /// <remarks>
+        /// Two earlier approaches were tried and rejected first: the Win32 <c>AddFontMemResourceEx</c> API
+        /// registers with GDI, but WPF's text stack (DirectWrite-based) never consults GDI's per-process
+        /// font table, so registered faces were silently invisible to WPF. A fully in-memory
+        /// <see cref="System.Net.WebRequest"/>-scheme trick (serving the bytes from a
+        /// <see cref="MemoryStream"/> for a synthetic URI, the same mechanism that historically let WPF/XBAP
+        /// apps reference fonts over plain <c>http://</c>) was also tried and confirmed NOT to work: WPF's
+        /// own source documents <c>Fonts.GetFontFamilies</c>'s location parameter as "must be an absolute
+        /// file URI or path" - empirically, both the eager folder-scan API and the lazy
+        /// <c>new FontFamily(baseUri, "./file#Name")</c> reference came back empty against the synthetic
+        /// scheme even though the handler correctly served the bytes. There is no supported WPF API for
+        /// loading a font from memory alone, so - like WinForms' own <c>PrivateFontCollection.AddFontFile</c>
+        /// path, for its own different reason (GDI+'s <c>AddMemoryFont</c> being unreliable, not a
+        /// fundamental API gap) - this writes to a real, never-deleted temp file.
+        /// </remarks>
+        /// <remarks>
+        /// Each face gets its OWN, never-reused temp subdirectory - not one shared directory for every
+        /// face. WPF's font-family folder enumeration caches its scan per directory and does not notice
+        /// files added to that directory after the first scan (confirmed empirically: with a single shared
+        /// directory, every face after the first one silently resolved back to the first face's glyphs,
+        /// because <see cref="Fonts.GetFontFamilies(Uri)"/>'s first call had already cached "what's in this
+        /// folder" before the later faces' files existed). A fresh, single-file directory per face sidesteps
+        /// that cache entirely.
+        /// </remarks>
+        protected override RFontFamily LoadFontFaceFontInt(byte[] fontBytes, string filePath)
+        {
+            var faceDirectory = Path.Combine(_fontFaceTempDirectory, Guid.NewGuid().ToString("N"));
+            Directory.CreateDirectory(faceDirectory);
+            var tempFilePath = Path.Combine(faceDirectory, "face.ttf");
+            File.WriteAllBytes(tempFilePath, fontBytes);
+
+            var family = Fonts.GetFontFamilies(new Uri(tempFilePath)).FirstOrDefault();
+
+            return family != null ? new FontFamilyAdapter(family) : null;
+        }
+
         protected override object GetClipboardDataObjectInt(string html, string plainText)
         {
             return ClipboardHelper.CreateDataObject(html, plainText);
diff --git a/Source/HtmlRenderer.WPF/HtmlContainer.cs b/Source/HtmlRenderer.WPF/HtmlContainer.cs
index d7d37d5be..1177465d4 100644
--- a/Source/HtmlRenderer.WPF/HtmlContainer.cs
+++ b/Source/HtmlRenderer.WPF/HtmlContainer.cs
@@ -12,6 +12,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
@@ -271,9 +272,9 @@ public void ClearSelection()
         /// </summary>
         /// <param name="htmlSource">the html to init with, init empty if not given</param>
         /// <param name="baseCssData">optional: the stylesheet to init with, init default if not given</param>
-        public void SetHtml(string htmlSource, CssData baseCssData = null)
+        public Task SetHtml(string htmlSource, CssData baseCssData = null)
         {
-            _htmlContainerInt.SetHtml(htmlSource, baseCssData);
+            return _htmlContainerInt.SetHtml(htmlSource, baseCssData);
         }
 
         /// <summary>
diff --git a/Source/HtmlRenderer.WPF/HtmlControl.cs b/Source/HtmlRenderer.WPF/HtmlControl.cs
index be4e241fd..ca52940bd 100644
--- a/Source/HtmlRenderer.WPF/HtmlControl.cs
+++ b/Source/HtmlRenderer.WPF/HtmlControl.cs
@@ -12,6 +12,8 @@
 
 using System;
 using System.ComponentModel;
+using System.Threading;
+using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
@@ -70,6 +72,14 @@ public class HtmlControl : Control
         /// </summary>
         protected Point _lastScrollOffset;
 
+        /// <summary>
+        /// Tracks the in-flight <see cref="SetTextAsync"/> call, if any, so a newer call can supersede an
+        /// older one still awaiting <see cref="HtmlContainer.SetHtml"/> - the stale call's post-await side
+        /// effects (invalidate/error reporting) are skipped once it resumes, checked by reference equality
+        /// against this field.
+        /// </summary>
+        private CancellationTokenSource _pendingLoad;
+
         #endregion
 
 
@@ -462,6 +472,48 @@ protected virtual void InvokeMouseMove()
             _htmlContainer.HandleMouseMove(this, Mouse.GetPosition(this));
         }
 
+        /// <summary>
+        /// Sets the html of this control and awaits the async load - the real entry point behind the
+        /// <see cref="TextProperty"/>/<see cref="BaseStylesheetProperty"/> dependency-property callbacks,
+        /// for callers that want to await completion or cancel an in-flight load.
+        /// </summary>
+        /// <remarks>
+        /// A new call before a previous one finishes supersedes it: the previous call's
+        /// <see cref="HtmlContainer.SetHtml"/> keeps running (it has no mid-flight cancellation point of
+        /// its own) but its post-completion side effects - invalidate, error reporting - are discarded
+        /// once it resumes, so only the newest call's results ever reach the control.
+        /// </remarks>
+        /// <param name="html">the html to set</param>
+        /// <param name="cancellationToken">optional: cancel this specific call without affecting others</param>
+        public async Task SetTextAsync(string html, CancellationToken cancellationToken = default)
+        {
+            var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+            _pendingLoad?.Cancel();
+            _pendingLoad = cts;
+
+            try
+            {
+                await _htmlContainer.SetHtml(html, _baseCssData);
+            }
+            catch (Exception ex)
+            {
+                if (cts == _pendingLoad)
+                {
+                    OnRenderError(new HtmlRenderErrorEventArgs(HtmlRenderErrorType.General, "Failed to set html", ex));
+                }
+                return;
+            }
+
+            if (cts != _pendingLoad || cts.IsCancellationRequested)
+            {
+                return;
+            }
+
+            InvalidateMeasure();
+            InvalidateVisual();
+            InvokeMouseMove();
+        }
+
         /// <summary>
         /// Handle when dependency property value changes to update the underline HtmlContainer with the new value.
         /// </summary>
@@ -487,15 +539,12 @@ private static void OnDependencyProperty_valueChanged(DependencyObject dependenc
                 {
                     var baseCssData = HtmlRender.ParseStyleSheet((string)e.NewValue);
                     control._baseCssData = baseCssData;
-                    htmlContainer.SetHtml(control.Text, baseCssData);
+                    _ = control.SetTextAsync(control.Text);
                 }
                 else if (e.Property == TextProperty)
                 {
                     htmlContainer.ScrollOffset = new Point(0, 0);
-                    htmlContainer.SetHtml((string)e.NewValue, control._baseCssData);
-                    control.InvalidateMeasure();
-                    control.InvalidateVisual();
-                    control.InvokeMouseMove();
+                    _ = control.SetTextAsync((string)e.NewValue);
                 }
             }
         }
diff --git a/Source/HtmlRenderer.WPF/HtmlRender.cs b/Source/HtmlRenderer.WPF/HtmlRender.cs
index d9e6c65ad..76eac2606 100644
--- a/Source/HtmlRenderer.WPF/HtmlRender.cs
+++ b/Source/HtmlRenderer.WPF/HtmlRender.cs
@@ -6,11 +6,12 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
 using System;
+using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
@@ -34,9 +35,9 @@ namespace TheArtOfDev.HtmlRenderer.WPF
     /// See https://codeplexarchive.org/ProjectTab/Wiki/HtmlRenderer/Documentation/Image%20generation <br/>
     /// Because of GDI text rendering issue with alpha channel clear type text rendering rendering to image requires special handling.<br/>
     /// <u>Solid color background -</u> generate an image where the background is filled with solid color and all the html is rendered on top
-    /// of the background color, GDI text rendering will be used. (RenderToImage method where the first argument is html string)<br/>
-    /// <u>Image background -</u> render html on top of existing image with whatever currently exist but it cannot have transparent pixels, 
-    /// GDI text rendering will be used. (RenderToImage method where the first argument is Image object)<br/>
+    /// of the background color, GDI text rendering will be used. (RenderToImageAsync method where the first argument is html string)<br/>
+    /// <u>Image background -</u> render html on top of existing image with whatever currently exist but it cannot have transparent pixels,
+    /// GDI text rendering will be used. (RenderToImageAsync method where the first argument is Image object)<br/>
     /// <u>Transparent background -</u> render html to empty image using GDI+ text rendering, the generated image can be transparent.
     /// </para>
     /// <para>
@@ -54,7 +55,7 @@ namespace TheArtOfDev.HtmlRenderer.WPF
     /// Allows to overwrite the loaded image by providing the image object manually, or different source (file or URL) to load from.<br/>
     /// Example: image 'src' can be non-valid string that is interpreted in the overwrite delegate by custom logic to resource image object<br/>
     /// Example: image 'src' in the html is relative - the overwrite intercepts the load and provide full source URL to load the image from<br/>
-    /// Example: image download requires authentication - the overwrite intercepts the load, downloads the image to disk using custom code and provide 
+    /// Example: image download requires authentication - the overwrite intercepts the load, downloads the image to disk using custom code and provide
     /// file path to load the image from.<br/>
     /// If no alternative data is provided the original source will be used.<br/>
     /// Note: Cannot use asynchronous scheme overwrite scheme.<br/>
@@ -63,14 +64,14 @@ namespace TheArtOfDev.HtmlRenderer.WPF
     /// <example>
     /// <para>
     /// <b>Simple rendering</b><br/>
-    /// HtmlRender.Render(g, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
-    /// HtmlRender.Render(g, "<![CDATA[<div>Hello <b>World</b></div>]]>", 10, 10, 500, CssData.Parse("body {font-size: 20px}")");<br/>
+    /// await HtmlRender.RenderAsync(g, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
+    /// await HtmlRender.RenderAsync(g, "<![CDATA[<div>Hello <b>World</b></div>]]>", 10, 10, 500, CssData.Parse("body {font-size: 20px}")");<br/>
     /// </para>
     /// <para>
     /// <b>Image rendering</b><br/>
-    /// HtmlRender.RenderToImage("<![CDATA[<div>Hello <b>World</b></div>]]>", new Size(600,400));<br/>
-    /// HtmlRender.RenderToImage("<![CDATA[<div>Hello <b>World</b></div>]]>", 600);<br/>
-    /// HtmlRender.RenderToImage(existingImage, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
+    /// await HtmlRender.RenderToImageAsync("<![CDATA[<div>Hello <b>World</b></div>]]>", new Size(600,400));<br/>
+    /// await HtmlRender.RenderToImageAsync("<![CDATA[<div>Hello <b>World</b></div>]]>", 600);<br/>
+    /// await HtmlRender.RenderToImageAsync(existingImage, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
     /// </para>
     /// </example>
     public static class HtmlRender
@@ -93,7 +94,7 @@ public static void AddFontFamily(FontFamily fontFamily)
 
         /// <summary>
         /// Adds a font mapping from <paramref name="fromFamily"/> to <paramref name="toFamily"/> iff the <paramref name="fromFamily"/> is not found.<br/>
-        /// When the <paramref name="fromFamily"/> font is used in rendered html and is not found in existing 
+        /// When the <paramref name="fromFamily"/> font is used in rendered html and is not found in existing
         /// fonts (installed or added) it will be replaced by <paramref name="toFamily"/>.<br/>
         /// </summary>
         /// <remarks>
@@ -111,7 +112,7 @@ public static void AddFontFamilyMapping(string fromFamily, string toFamily)
 
         /// <summary>
         /// Parse the given stylesheet to <see cref="CssData"/> object.<br/>
-        /// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the 
+        /// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the
         /// default css data (as defined by W3), merged if class name already exists. If false only the data in the given stylesheet is returned.
         /// </summary>
         /// <seealso cref="http://www.w3.org/TR/CSS21/sample.html"/>
@@ -134,7 +135,7 @@ public static CssData ParseStyleSheet(string stylesheet, bool combineWithDefault
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the size required for the html</returns>
-        public static Size Measure(string html, double maxWidth = 0, CssData cssData = null,
+        public static async Task<Size> MeasureAsync(string html, double maxWidth = 0, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             Size actualSize = Size.Empty;
@@ -151,7 +152,7 @@ public static Size Measure(string html, double maxWidth = 0, CssData cssData = n
                     if (imageLoad != null)
                         container.ImageLoad += imageLoad;
 
-                    container.SetHtml(html, cssData);
+                    await container.SetHtml(html, cssData).ConfigureAwait(false);
                     container.PerformLayout();
 
                     actualSize = container.ActualSize;
@@ -162,7 +163,7 @@ public static Size Measure(string html, double maxWidth = 0, CssData cssData = n
 
         /// <summary>
         /// Renders the specified HTML source on the specified location and max width restriction.<br/>
-        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// Returned is the actual width and height of the rendered html.<br/>
         /// </summary>
@@ -175,7 +176,7 @@ public static Size Measure(string html, double maxWidth = 0, CssData cssData = n
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        public static Size Render(DrawingContext g, string html, double left = 0, double top = 0, double maxWidth = 0, CssData cssData = null,
+        public static Task<Size> RenderAsync(DrawingContext g, string html, double left = 0, double top = 0, double maxWidth = 0, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
@@ -184,7 +185,7 @@ public static Size Render(DrawingContext g, string html, double left = 0, double
 
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
-        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize"/>.Height is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -198,7 +199,7 @@ public static Size Render(DrawingContext g, string html, double left = 0, double
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        public static Size Render(DrawingContext g, string html, Point location, Size maxSize, CssData cssData = null,
+        public static Task<Size> RenderAsync(DrawingContext g, string html, Point location, Size maxSize, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
@@ -215,7 +216,7 @@ public static Size Render(DrawingContext g, string html, Point location, Size ma
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
-        public static BitmapFrame RenderToImage(string html, Size size, CssData cssData = null,
+        public static async Task<BitmapFrame> RenderToImageAsync(string html, Size size, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             var renderTarget = new RenderTargetBitmap((int)size.Width, (int)size.Height, 96, 96, PixelFormats.Pbgra32);
@@ -226,7 +227,7 @@ public static BitmapFrame RenderToImage(string html, Size size, CssData cssData
                 DrawingVisual drawingVisual = new DrawingVisual();
                 using (DrawingContext g = drawingVisual.RenderOpen())
                 {
-                    RenderHtml(g, html, new Point(), size, cssData, stylesheetLoad, imageLoad);
+                    await RenderHtml(g, html, new Point(), size, cssData, stylesheetLoad, imageLoad).ConfigureAwait(false);
                 }
 
                 // render visual into target bitmap
@@ -238,7 +239,7 @@ public static BitmapFrame RenderToImage(string html, Size size, CssData cssData
 
         /// <summary>
         /// Renders the specified HTML into a new image of unknown size that will be determined by max width/height and HTML layout.<br/>
-        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxHeight"/> is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -255,15 +256,15 @@ public static BitmapFrame RenderToImage(string html, Size size, CssData cssData
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
-        public static BitmapFrame RenderToImage(string html, int maxWidth = 0, int maxHeight = 0, Color backgroundColor = new Color(), CssData cssData = null,
+        public static Task<BitmapFrame> RenderToImageAsync(string html, int maxWidth = 0, int maxHeight = 0, Color backgroundColor = new Color(), CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
-            return RenderToImage(html, Size.Empty, new Size(maxWidth, maxHeight), backgroundColor, cssData, stylesheetLoad, imageLoad);
+            return RenderToImageAsync(html, Size.Empty, new Size(maxWidth, maxHeight), backgroundColor, cssData, stylesheetLoad, imageLoad);
         }
 
         /// <summary>
         /// Renders the specified HTML into a new image of unknown size that will be determined by min/max width/height and HTML layout.<br/>
-        /// If <paramref name="maxSize.Width"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize.Width"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize.Height"/> is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -281,7 +282,7 @@ public static BitmapFrame RenderToImage(string html, Size size, CssData cssData
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
-        public static BitmapFrame RenderToImage(string html, Size minSize, Size maxSize, Color backgroundColor = new Color(), CssData cssData = null,
+        public static async Task<BitmapFrame> RenderToImageAsync(string html, Size minSize, Size maxSize, Color backgroundColor = new Color(), CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             RenderTargetBitmap renderTarget;
@@ -296,7 +297,7 @@ public static BitmapFrame RenderToImage(string html, Size size, CssData cssData
                         container.StylesheetLoad += stylesheetLoad;
                     if (imageLoad != null)
                         container.ImageLoad += imageLoad;
-                    container.SetHtml(html, cssData);
+                    await container.SetHtml(html, cssData).ConfigureAwait(false);
 
                     var finalSize = MeasureHtmlByRestrictions(container, minSize, maxSize);
                     container.MaxSize = finalSize;
@@ -346,7 +347,7 @@ private static Size MeasureHtmlByRestrictions(HtmlContainer htmlContainer, Size
 
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
-        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize"/>.Height is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -361,12 +362,12 @@ private static Size MeasureHtmlByRestrictions(HtmlContainer htmlContainer, Size
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        private static Size RenderClip(DrawingContext g, string html, Point location, Size maxSize, CssData cssData, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
+        private static async Task<Size> RenderClip(DrawingContext g, string html, Point location, Size maxSize, CssData cssData, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
         {
             if (maxSize.Height > 0)
                 g.PushClip(new RectangleGeometry(new Rect(location, maxSize)));
 
-            var actualSize = RenderHtml(g, html, location, maxSize, cssData, stylesheetLoad, imageLoad);
+            var actualSize = await RenderHtml(g, html, location, maxSize, cssData, stylesheetLoad, imageLoad).ConfigureAwait(false);
 
             if (maxSize.Height > 0)
                 g.Pop();
@@ -376,7 +377,7 @@ private static Size RenderClip(DrawingContext g, string html, Point location, Si
 
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
-        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize"/>.Height is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -390,7 +391,7 @@ private static Size RenderClip(DrawingContext g, string html, Point location, Si
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        private static Size RenderHtml(DrawingContext g, string html, Point location, Size maxSize, CssData cssData, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
+        private static async Task<Size> RenderHtml(DrawingContext g, string html, Point location, Size maxSize, CssData cssData, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
         {
             Size actualSize = Size.Empty;
 
@@ -408,7 +409,7 @@ private static Size RenderHtml(DrawingContext g, string html, Point location, Si
                     if (imageLoad != null)
                         container.ImageLoad += imageLoad;
 
-                    container.SetHtml(html, cssData);
+                    await container.SetHtml(html, cssData).ConfigureAwait(false);
                     container.PerformLayout();
                     container.PerformPaint(g, new Rect(0, 0, double.MaxValue, double.MaxValue));
 
@@ -421,4 +422,4 @@ private static Size RenderHtml(DrawingContext g, string html, Point location, Si
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer.WPF/Utilities/WindowsTheme.cs b/Source/HtmlRenderer.WPF/Utilities/WindowsTheme.cs
new file mode 100644
index 000000000..b46984f8d
--- /dev/null
+++ b/Source/HtmlRenderer.WPF/Utilities/WindowsTheme.cs
@@ -0,0 +1,54 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+using Microsoft.Win32;
+using TheArtOfDev.HtmlRenderer.Adapters;
+
+namespace TheArtOfDev.HtmlRenderer.WPF.Utilities
+{
+    /// <summary>
+    /// Reads the Windows app theme, which is what <c>prefers-color-scheme</c> reports for on-screen
+    /// rendering.
+    /// </summary>
+    internal static class WindowsTheme
+    {
+        private const string PersonalizeKey = @"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize";
+        private const string AppsUseLightTheme = "AppsUseLightTheme";
+
+        /// <summary>
+        /// The user's app theme, or <see cref="RColorScheme.Light"/> when it cannot be determined -
+        /// light is the Windows default and the safer assumption for a document that declares no dark
+        /// styling of its own.
+        /// </summary>
+        public static RColorScheme GetAppsColorScheme()
+        {
+            try
+            {
+                using (var key = Registry.CurrentUser.OpenSubKey(PersonalizeKey))
+                {
+                    if (key != null)
+                    {
+                        var value = key.GetValue(AppsUseLightTheme);
+                        if (value is int)
+                            return (int)value == 0 ? RColorScheme.Dark : RColorScheme.Light;
+                    }
+                }
+            }
+            catch
+            {
+                // A locked-down or missing key just means "no preference expressed".
+            }
+
+            return RColorScheme.Light;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer.WinForms/Adapters/GraphicsPathAdapter.cs b/Source/HtmlRenderer.WinForms/Adapters/GraphicsPathAdapter.cs
index 6c4bbd061..d3a7b3f2c 100644
--- a/Source/HtmlRenderer.WinForms/Adapters/GraphicsPathAdapter.cs
+++ b/Source/HtmlRenderer.WinForms/Adapters/GraphicsPathAdapter.cs
@@ -51,11 +51,11 @@ public override void LineTo(double x, double y)
             _lastPoint = new RPoint(x, y);
         }
 
-        public override void ArcTo(double x, double y, double size, Corner corner)
+        public override void ArcTo(double x, double y, double radiusX, double radiusY, Corner corner)
         {
-            float left = (float)(Math.Min(x, _lastPoint.X) - (corner == Corner.TopRight || corner == Corner.BottomRight ? size : 0));
-            float top = (float)(Math.Min(y, _lastPoint.Y) - (corner == Corner.BottomLeft || corner == Corner.BottomRight ? size : 0));
-            _graphicsPath.AddArc(left, top, (float)size * 2, (float)size * 2, GetStartAngle(corner), 90);
+            float left = (float)(Math.Min(x, _lastPoint.X) - (corner == Corner.TopRight || corner == Corner.BottomRight ? radiusX : 0));
+            float top = (float)(Math.Min(y, _lastPoint.Y) - (corner == Corner.BottomLeft || corner == Corner.BottomRight ? radiusY : 0));
+            _graphicsPath.AddArc(left, top, (float)radiusX * 2, (float)radiusY * 2, GetStartAngle(corner), 90);
             _lastPoint = new RPoint(x, y);
         }
 
diff --git a/Source/HtmlRenderer.WinForms/Adapters/WinFormsAdapter.cs b/Source/HtmlRenderer.WinForms/Adapters/WinFormsAdapter.cs
index 16bc83db8..384f93983 100644
--- a/Source/HtmlRenderer.WinForms/Adapters/WinFormsAdapter.cs
+++ b/Source/HtmlRenderer.WinForms/Adapters/WinFormsAdapter.cs
@@ -10,12 +10,17 @@
 // - Sun Tsu,
 // "The Art of War"
 
+using System;
 using System.Drawing;
 using System.Drawing.Drawing2D;
+using System.Drawing.Text;
 using System.IO;
+using System.Net.Http;
 using System.Windows.Forms;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Adapters;
+using TheArtOfDev.HtmlRenderer.Core.Network;
+using TheArtOfDev.HtmlRenderer.Core.Utils;
 using TheArtOfDev.HtmlRenderer.WinForms.Utilities;
 
 namespace TheArtOfDev.HtmlRenderer.WinForms.Adapters
@@ -27,11 +32,40 @@ internal sealed class WinFormsAdapter : RAdapter
     {
         #region Fields and Consts
 
+        // One HttpClient shared for the adapter's (process) lifetime, not one per request - `new
+        // HttpClient()` per call is a well-documented anti-pattern that exhausts sockets under load and
+        // never observes DNS changes.
+        //
+        // Declared BEFORE _instance deliberately: C# runs static field initializers in textual
+        // declaration order, and _instance's own initializer (`new WinFormsAdapter()`) runs the instance
+        // constructor immediately, which reads _sharedHttpClient on its very first line. If this field
+        // were declared after _instance, that read would observe _sharedHttpClient's still-default value
+        // (null - its own initializer hasn't run yet) and permanently capture a null HttpClient into
+        // NetworkLoader, since HttpClientNetworkLoader takes it as a constructor parameter, not a live
+        // reference to this field. (Confirmed by a real crash with this exact ordering.)
+        private static readonly HttpClient _sharedHttpClient = new HttpClient();
+
         /// <summary>
         /// Singleton instance of global adapter.
         /// </summary>
         private static readonly WinFormsAdapter _instance = new WinFormsAdapter();
 
+        // Adapter-level PrivateFontCollection for @font-face-loaded faces - one collection shared for the
+        // adapter's (process) lifetime, growing by one family per LoadFontFaceFontInt call.
+        private readonly PrivateFontCollection _fontFaceCollection = new PrivateFontCollection();
+
+        // Backs LoadFontFaceFontInt's temp-file registration (see its own doc comment for why a temp file
+        // is used instead of PrivateFontCollection.AddMemoryFont) - one directory per process, cleaned up
+        // by the OS's normal temp-file housekeeping, not by this process.
+        private static readonly string _fontFaceTempDirectory = CreateFontFaceTempDirectory();
+
+        private static string CreateFontFaceTempDirectory()
+        {
+            var dir = Path.Combine(Path.GetTempPath(), "HtmlRenderer.FontFace." + Guid.NewGuid().ToString("N"));
+            Directory.CreateDirectory(dir);
+            return dir;
+        }
+
         #endregion
 
 
@@ -40,6 +74,14 @@ internal sealed class WinFormsAdapter : RAdapter
         /// </summary>
         private WinFormsAdapter()
         {
+            // Unlike the PdfSharp backend (which keeps the base RAdapter.NetworkLoader default of
+            // DataUriNetworkLoader-only - safer for unattended/server-side PDF generation, matching
+            // PeachPDF's own default), WinForms is an interactive UI backend where fetching a real
+            // http(s): image or stylesheet out of the box is the expected behavior. data:/file: URIs
+            // still resolve the same way regardless (RAdapter.GetResourceStream intercepts both before
+            // ever consulting NetworkLoader), so only http(s): actually reaches this loader in practice.
+            NetworkLoader = new HttpClientNetworkLoader(_sharedHttpClient, (Uri)null);
+
             AddFontFamilyMapping("monospace", "Courier New");
             AddFontFamilyMapping("Helvetica", "Arial");
 
@@ -47,6 +89,19 @@ private WinFormsAdapter()
             {
                 AddFontFamily(new FontFamilyAdapter(family));
             }
+
+            Microsoft.Win32.SystemEvents.UserPreferenceChanged += (sender, e) =>
+            {
+                if (e.Category != Microsoft.Win32.UserPreferenceCategory.General) return;
+
+                // The General category covers far more than the theme, so re-read and only report a
+                // change if the scheme really moved - otherwise every unrelated preference change
+                // would force a re-cascade and repaint.
+                var previous = _colorScheme;
+                _colorScheme = null;
+                if (previous.HasValue && previous.Value != SystemColorScheme)
+                    OnColorSchemeChanged();
+            };
         }
 
         /// <summary>
@@ -57,6 +112,28 @@ public static WinFormsAdapter Instance
             get { return _instance; }
         }
 
+        /// <summary>
+        /// Rendering onto a Windows control, so the document should follow the user's app theme.
+        /// Cached and invalidated on a system preference change rather than read per query.
+        /// </summary>
+        public override RColorScheme SystemColorScheme
+        {
+            get
+            {
+                if (SystemColorSchemeOverride.HasValue)
+                    return SystemColorSchemeOverride.Value;
+                if (!_colorScheme.HasValue)
+                    _colorScheme = WindowsTheme.GetAppsColorScheme();
+                return _colorScheme.Value;
+            }
+        }
+
+        /// <summary>
+        /// Cached app theme; null when it needs to be re-read.
+        /// </summary>
+        private RColorScheme? _colorScheme;
+
+
         protected override RColor GetColorInt(string colorName)
         {
             var color = Color.FromName(colorName);
@@ -83,9 +160,32 @@ protected override RBrush CreateSolidBrush(RColor color)
             return new BrushAdapter(solidBrush, false);
         }
 
-        protected override RBrush CreateLinearGradientBrush(RRect rect, RColor color1, RColor color2, double angle)
+        protected override RBrush CreateLinearGradientBrush(RPoint p1, RPoint p2, (RColor Color, double Position)[] stops)
         {
-            return new BrushAdapter(new LinearGradientBrush(Utils.Convert(rect), Utils.Convert(color1), Utils.Convert(color2), (float)angle), true);
+            var brush = new LinearGradientBrush(Utils.Convert(p1), Utils.Convert(p2), Color.Black, Color.Black);
+
+            var colors = new Color[stops.Length];
+            var positions = new float[stops.Length];
+            for (int i = 0; i < stops.Length; i++)
+            {
+                colors[i] = Utils.Convert(stops[i].Color);
+                var pos = (float)Math.Min(Math.Max(stops[i].Position, 0.0), 1.0);
+                // GDI+ requires strictly increasing positions - nudge any duplicate up by an epsilon.
+                positions[i] = i > 0 && pos <= positions[i - 1] ? positions[i - 1] + 0.0001f : pos;
+            }
+            // GDI+ requires the first/last position to be exactly 0/1 - forcing them here (rather than
+            // requiring the caller to pre-normalize) also matches spec behavior for a gradient whose
+            // outermost stops aren't at the very ends: the outermost color simply extends flat to the edge.
+            positions[0] = 0f;
+            positions[positions.Length - 1] = 1f;
+
+            brush.InterpolationColors = new ColorBlend
+            {
+                Colors = colors,
+                Positions = positions
+            };
+
+            return new BrushAdapter(brush, true);
         }
 
         protected override RImage ConvertImageInt(object image)
@@ -110,6 +210,67 @@ protected override RFont CreateFontInt(RFontFamily family, double size, RFontSty
             return new FontAdapter(new Font(((FontFamilyAdapter)family).FontFamily, (float)size, fontStyle));
         }
 
+        /// <summary>
+        /// Loads one <c>@font-face</c> face's bytes into the adapter's <see cref="PrivateFontCollection"/>
+        /// via <see cref="PrivateFontCollection.AddFontFile"/> - through a temp file, matching this
+        /// adapter's own pre-existing <c>DemoForm.LoadCustomFonts</c> pattern (that path is untouched,
+        /// this is a new, separate mechanism specific to <c>@font-face</c>).
+        /// </summary>
+        /// <remarks>
+        /// Deliberately NOT <see cref="PrivateFontCollection.AddMemoryFont"/>, despite it needing no temp
+        /// file: empirically (a throwaway repro project registering a dozen distinct families into one
+        /// <see cref="PrivateFontCollection"/>), <c>AddMemoryFont</c> is unreliable on this target
+        /// framework - <see cref="PrivateFontCollection.Families"/> permanently fails to reflect several of
+        /// the added families (not a timing race: polling for up to 300ms after the call never finds them
+        /// either), while the identical sequence of files through <c>AddFontFile</c> succeeds 100% of the
+        /// time across repeated runs. This is a known-flaky area of GDI+'s <c>AddMemoryFont</c> P/Invoke
+        /// path, not a bug in this port. The temp file is deliberately never deleted: GDI+ keeps it
+        /// memory-mapped for as long as this process-lifetime singleton's <see cref="PrivateFontCollection"/>
+        /// references it, and the OS's own temp-directory housekeeping reclaims it afterward - the same
+        /// "small, bounded, process-lifetime" rationale the removed <c>AddMemoryFont</c>/<c>AllocHGlobal</c>
+        /// approach relied on.
+        /// <para>
+        /// The returned <see cref="FontFamilyAdapter"/> is found by sniffing the font's own internal
+        /// family name via <see cref="TtfFontDescription"/> and matching it against
+        /// <see cref="PrivateFontCollection.Families"/> - not by comparing <c>Families.Length</c> before
+        /// and after, nor by taking the array's last entry. Two bugs made that approach unreliable: (1)
+        /// <c>Families</c> groups every face by family name (the whole point of
+        /// <see cref="PrivateFontCollection"/> - it lets <see cref="Font"/> pick the right face via
+        /// <see cref="FontStyle"/> automatically), so registering a second face of an *already-registered*
+        /// family (e.g. this face set's own Bold after its Regular) never changes the count at all; and
+        /// (2) even when the count does change, <c>Families</c> is returned in a GDI-defined (effectively
+        /// alphabetical) order, not insertion order, so "the last entry" is often a completely unrelated,
+        /// alphabetically-later family, not the one just added.
+        /// </para>
+        /// </remarks>
+        protected override RFontFamily LoadFontFaceFontInt(byte[] fontBytes, string filePath)
+        {
+            string familyName;
+            using (var stream = new MemoryStream(fontBytes))
+            {
+                familyName = TtfFontDescription.LoadDescription(stream).FontFamilyInvariantCulture;
+            }
+
+            if (string.IsNullOrEmpty(familyName))
+            {
+                return null;
+            }
+
+            var tempFilePath = Path.Combine(_fontFaceTempDirectory, Guid.NewGuid().ToString("N") + ".ttf");
+            File.WriteAllBytes(tempFilePath, fontBytes);
+            _fontFaceCollection.AddFontFile(tempFilePath);
+
+            foreach (var family in _fontFaceCollection.Families)
+            {
+                if (string.Equals(family.Name, familyName, StringComparison.OrdinalIgnoreCase))
+                {
+                    return new FontFamilyAdapter(family);
+                }
+            }
+
+            return null;
+        }
+
         protected override object GetClipboardDataObjectInt(string html, string plainText)
         {
             return ClipboardHelper.CreateDataObject(html, plainText);
diff --git a/Source/HtmlRenderer.WinForms/HtmlContainer.cs b/Source/HtmlRenderer.WinForms/HtmlContainer.cs
index 5bc7c5cd0..af7fc9040 100644
--- a/Source/HtmlRenderer.WinForms/HtmlContainer.cs
+++ b/Source/HtmlRenderer.WinForms/HtmlContainer.cs
@@ -14,6 +14,7 @@
 using System.Collections.Generic;
 using System.Drawing;
 using System.Drawing.Text;
+using System.Threading.Tasks;
 using System.Windows.Forms;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core;
@@ -312,9 +313,9 @@ public void ClearSelection()
         /// </summary>
         /// <param name="htmlSource">the html to init with, init empty if not given</param>
         /// <param name="baseCssData">optional: the stylesheet to init with, init default if not given</param>
-        public void SetHtml(string htmlSource, CssData baseCssData = null)
+        public Task SetHtml(string htmlSource, CssData baseCssData = null)
         {
-            _htmlContainerInt.SetHtml(htmlSource, baseCssData);
+            return _htmlContainerInt.SetHtml(htmlSource, baseCssData);
         }
 
         /// <summary>
diff --git a/Source/HtmlRenderer.WinForms/HtmlLabel.cs b/Source/HtmlRenderer.WinForms/HtmlLabel.cs
index 283ef7360..254566541 100644
--- a/Source/HtmlRenderer.WinForms/HtmlLabel.cs
+++ b/Source/HtmlRenderer.WinForms/HtmlLabel.cs
@@ -15,6 +15,8 @@
 using System.Diagnostics;
 using System.Drawing;
 using System.Drawing.Text;
+using System.Threading;
+using System.Threading.Tasks;
 using System.Windows.Forms;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core;
@@ -112,6 +114,14 @@ public class HtmlLabel : Control
         /// </summary>
         protected TextRenderingHint _textRenderingHint = TextRenderingHint.SystemDefault;
 
+        /// <summary>
+        /// Tracks the in-flight <see cref="SetTextAsync"/> call, if any, so a newer call can supersede an
+        /// older one still awaiting <see cref="HtmlContainer.SetHtml"/> - the stale call's post-await side
+        /// effects (layout/invalidate/error reporting) are skipped once it resumes, checked by reference
+        /// equality against this field.
+        /// </summary>
+        private CancellationTokenSource _pendingLoad;
+
         #endregion
 
 
@@ -304,7 +314,7 @@ public virtual string BaseStylesheet
             {
                 _baseRawCssData = value;
                 _baseCssData = HtmlRender.ParseStyleSheet(value);
-                _htmlContainer.SetHtml(_text, _baseCssData);
+                _ = SetTextAsync(_text);
             }
         }
 
@@ -397,11 +407,50 @@ public override string Text
                 base.Text = value;
                 if (!IsDisposed)
                 {
-                    _htmlContainer.SetHtml(_text, _baseCssData);
-                    PerformLayout();
-                    Invalidate();
+                    _ = SetTextAsync(_text);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Sets the html of this control and awaits the async load - the real entry point behind the
+        /// <see cref="Text"/>/<see cref="BaseStylesheet"/> property setters, for callers that want to
+        /// await completion or cancel an in-flight load.
+        /// </summary>
+        /// <remarks>
+        /// A new call before a previous one finishes supersedes it: the previous call's
+        /// <see cref="HtmlContainer.SetHtml"/> keeps running (it has no mid-flight cancellation point of
+        /// its own) but its post-completion side effects - layout, invalidate, error reporting - are
+        /// discarded once it resumes, so only the newest call's results ever reach the control.
+        /// </remarks>
+        /// <param name="html">the html to set</param>
+        /// <param name="cancellationToken">optional: cancel this specific call without affecting others</param>
+        public async Task SetTextAsync(string html, CancellationToken cancellationToken = default)
+        {
+            var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+            _pendingLoad?.Cancel();
+            _pendingLoad = cts;
+
+            try
+            {
+                await _htmlContainer.SetHtml(html, _baseCssData);
+            }
+            catch (Exception ex)
+            {
+                if (cts == _pendingLoad)
+                {
+                    OnRenderError(this, new HtmlRenderErrorEventArgs(HtmlRenderErrorType.General, "Failed to set html", ex));
                 }
+                return;
+            }
+
+            if (cts != _pendingLoad || cts.IsCancellationRequested || IsDisposed)
+            {
+                return;
             }
+
+            PerformLayout();
+            Invalidate();
         }
 
         /// <summary>
@@ -677,6 +726,7 @@ protected override void WndProc(ref Message m)
         /// </summary>
         protected override void Dispose(bool disposing)
         {
+            _pendingLoad?.Cancel();
             if (_htmlContainer != null)
             {
                 _htmlContainer.LoadComplete -= OnLoadComplete;
diff --git a/Source/HtmlRenderer.WinForms/HtmlPanel.cs b/Source/HtmlRenderer.WinForms/HtmlPanel.cs
index a2f061874..9d150fd19 100644
--- a/Source/HtmlRenderer.WinForms/HtmlPanel.cs
+++ b/Source/HtmlRenderer.WinForms/HtmlPanel.cs
@@ -15,6 +15,8 @@
 using System.Diagnostics;
 using System.Drawing;
 using System.Drawing.Text;
+using System.Threading;
+using System.Threading.Tasks;
 using System.Windows.Forms;
 using TheArtOfDev.HtmlRenderer.Core;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
@@ -104,6 +106,14 @@ public class HtmlPanel : ScrollableControl
         /// </summary>
         protected Point _lastScrollOffset;
 
+        /// <summary>
+        /// Tracks the in-flight <see cref="SetTextAsync"/> call, if any, so a newer call can supersede an
+        /// older one still awaiting <see cref="HtmlContainer.SetHtml"/> - the stale call's post-await side
+        /// effects (layout/invalidate/error reporting) are skipped once it resumes, checked by reference
+        /// equality against this field.
+        /// </summary>
+        private CancellationTokenSource _pendingLoad;
+
         #endregion
 
 
@@ -312,7 +322,7 @@ public virtual string BaseStylesheet
             {
                 _baseRawCssData = value;
                 _baseCssData = HtmlRender.ParseStyleSheet(value);
-                _htmlContainer.SetHtml(_text, _baseCssData);
+                _ = SetTextAsync(_text);
             }
         }
 
@@ -342,12 +352,53 @@ public override string Text
                 if (!IsDisposed)
                 {
                     VerticalScroll.Value = VerticalScroll.Minimum;
-                    _htmlContainer.SetHtml(_text, _baseCssData);
-                    PerformLayout();
-                    Invalidate();
-                    InvokeMouseMove();
+                    _ = SetTextAsync(_text);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Sets the html of this control and awaits the async load - the real entry point behind the
+        /// <see cref="Text"/>/<see cref="BaseStylesheet"/> property setters, for callers that want to
+        /// await completion or cancel an in-flight load.
+        /// </summary>
+        /// <remarks>
+        /// A new call before a previous one finishes supersedes it: the previous call's
+        /// <see cref="HtmlContainer.SetHtml"/> keeps running (it has no mid-flight cancellation point of
+        /// its own) but its post-completion side effects - layout, invalidate, error reporting - are
+        /// discarded once it resumes, so only the newest call's results ever reach the control.
+        /// </remarks>
+        /// <param name="html">the html to set</param>
+        /// <param name="cancellationToken">optional: cancel this specific call without affecting others</param>
+        public async Task SetTextAsync(string html, CancellationToken cancellationToken = default)
+        {
+            var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+            _pendingLoad?.Cancel();
+            _pendingLoad = cts;
+
+            try
+            {
+                await _htmlContainer.SetHtml(html, _baseCssData);
+            }
+            catch (Exception ex)
+            {
+                if (cts == _pendingLoad)
+                {
+                    OnRenderError(this, new HtmlRenderErrorEventArgs(HtmlRenderErrorType.General, "Failed to set html", ex));
                 }
+                return;
+            }
+
+            // Superseded by a newer SetTextAsync/Text/BaseStylesheet call while this one was awaiting -
+            // that call's own results are what the control should reflect, not this stale one's.
+            if (cts != _pendingLoad || cts.IsCancellationRequested || IsDisposed)
+            {
+                return;
             }
+
+            PerformLayout();
+            Invalidate();
+            InvokeMouseMove();
         }
 
         /// <summary>
@@ -764,6 +815,7 @@ protected override void WndProc(ref Message m)
         /// </summary>
         protected override void Dispose(bool disposing)
         {
+            _pendingLoad?.Cancel();
             if (_htmlContainer != null)
             {
                 _htmlContainer.LoadComplete -= OnLoadComplete;
diff --git a/Source/HtmlRenderer.WinForms/HtmlRender.cs b/Source/HtmlRenderer.WinForms/HtmlRender.cs
index ca0f44532..cd15e2f47 100644
--- a/Source/HtmlRenderer.WinForms/HtmlRender.cs
+++ b/Source/HtmlRenderer.WinForms/HtmlRender.cs
@@ -6,7 +6,7 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
@@ -15,6 +15,7 @@
 using System.Drawing.Drawing2D;
 using System.Drawing.Imaging;
 using System.Drawing.Text;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Core;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
@@ -31,8 +32,8 @@ namespace TheArtOfDev.HtmlRenderer.WinForms
     /// <remarks>
     /// <para>
     /// <b>GDI vs. GDI+ text rendering</b><br/>
-    /// Windows supports two text rendering technologies: GDI and GDI+.<br/> 
-    /// GDI is older, has better performance and looks better on standard monitors but doesn't support alpha channel for transparency.<br/> 
+    /// Windows supports two text rendering technologies: GDI and GDI+.<br/>
+    /// GDI is older, has better performance and looks better on standard monitors but doesn't support alpha channel for transparency.<br/>
     /// GDI+ is newer, device independent so work better for printers but is slower and looks worse on monitors.<br/>
     /// HtmlRender supports both GDI and GDI+ text rendering to accommodate different needs, GDI+ text rendering methods have "GdiPlus" suffix
     /// in their name where GDI do not.<br/>
@@ -42,12 +43,12 @@ namespace TheArtOfDev.HtmlRenderer.WinForms
     /// See https://codeplexarchive.org/ProjectTab/Wiki/HtmlRenderer/Documentation/Image%20generation <br/>
     /// Because of GDI text rendering issue with alpha channel clear type text rendering rendering to image requires special handling.<br/>
     /// <u>Solid color background -</u> generate an image where the background is filled with solid color and all the html is rendered on top
-    /// of the background color, GDI text rendering will be used. (RenderToImage method where the first argument is html string)<br/>
-    /// <u>Image background -</u> render html on top of existing image with whatever currently exist but it cannot have transparent pixels, 
-    /// GDI text rendering will be used. (RenderToImage method where the first argument is Image object)<br/>
+    /// of the background color, GDI text rendering will be used. (RenderToImageAsync method where the first argument is html string)<br/>
+    /// <u>Image background -</u> render html on top of existing image with whatever currently exist but it cannot have transparent pixels,
+    /// GDI text rendering will be used. (RenderToImageAsync method where the first argument is Image object)<br/>
     /// <u>Transparent background -</u> render html to empty image using GDI+ text rendering, the generated image can be transparent.
     /// Text rendering can be controlled using <see cref="TextRenderingHint"/>, note that <see cref="TextRenderingHint.ClearTypeGridFit"/>
-    /// doesn't render well on transparent background. (RenderToImageGdiPlus method)<br/>
+    /// doesn't render well on transparent background. (RenderToImageGdiPlusAsync method)<br/>
     /// </para>
     /// <para>
     /// <b>Overwrite stylesheet resolution</b><br/>
@@ -64,7 +65,7 @@ namespace TheArtOfDev.HtmlRenderer.WinForms
     /// Allows to overwrite the loaded image by providing the image object manually, or different source (file or URL) to load from.<br/>
     /// Example: image 'src' can be non-valid string that is interpreted in the overwrite delegate by custom logic to resource image object<br/>
     /// Example: image 'src' in the html is relative - the overwrite intercepts the load and provide full source URL to load the image from<br/>
-    /// Example: image download requires authentication - the overwrite intercepts the load, downloads the image to disk using custom code and provide 
+    /// Example: image download requires authentication - the overwrite intercepts the load, downloads the image to disk using custom code and provide
     /// file path to load the image from.<br/>
     /// If no alternative data is provided the original source will be used.<br/>
     /// Note: Cannot use asynchronous scheme overwrite scheme.<br/>
@@ -73,14 +74,14 @@ namespace TheArtOfDev.HtmlRenderer.WinForms
     /// <example>
     /// <para>
     /// <b>Simple rendering</b><br/>
-    /// HtmlRender.Render(g, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
-    /// HtmlRender.Render(g, "<![CDATA[<div>Hello <b>World</b></div>]]>", 10, 10, 500, CssData.Parse("body {font-size: 20px}")");<br/>
+    /// await HtmlRender.RenderAsync(g, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
+    /// await HtmlRender.RenderAsync(g, "<![CDATA[<div>Hello <b>World</b></div>]]>", 10, 10, 500, CssData.Parse("body {font-size: 20px}")");<br/>
     /// </para>
     /// <para>
     /// <b>Image rendering</b><br/>
-    /// HtmlRender.RenderToImage("<![CDATA[<div>Hello <b>World</b></div>]]>", new Size(600,400));<br/>
-    /// HtmlRender.RenderToImage("<![CDATA[<div>Hello <b>World</b></div>]]>", 600);<br/>
-    /// HtmlRender.RenderToImage(existingImage, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
+    /// await HtmlRender.RenderToImageAsync("<![CDATA[<div>Hello <b>World</b></div>]]>", new Size(600,400));<br/>
+    /// await HtmlRender.RenderToImageAsync("<![CDATA[<div>Hello <b>World</b></div>]]>", 600);<br/>
+    /// await HtmlRender.RenderToImageAsync(existingImage, "<![CDATA[<div>Hello <b>World</b></div>]]>");<br/>
     /// </para>
     /// </example>
     public static class HtmlRender
@@ -104,7 +105,7 @@ public static void AddFontFamily(FontFamily fontFamily)
 
         /// <summary>
         /// Adds a font mapping from <paramref name="fromFamily"/> to <paramref name="toFamily"/> iff the <paramref name="fromFamily"/> is not found.<br/>
-        /// When the <paramref name="fromFamily"/> font is used in rendered html and is not found in existing 
+        /// When the <paramref name="fromFamily"/> font is used in rendered html and is not found in existing
         /// fonts (installed or added) it will be replaced by <paramref name="toFamily"/>.<br/>
         /// </summary>
         /// <remarks>
@@ -122,7 +123,7 @@ public static void AddFontFamilyMapping(string fromFamily, string toFamily)
 
         /// <summary>
         /// Parse the given stylesheet to <see cref="CssData"/> object.<br/>
-        /// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the 
+        /// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the
         /// default css data (as defined by W3), merged if class name already exists. If false only the data in the given stylesheet is returned.
         /// </summary>
         /// <seealso cref="http://www.w3.org/TR/CSS21/sample.html"/>
@@ -147,7 +148,7 @@ public static CssData ParseStyleSheet(string stylesheet, bool combineWithDefault
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the size required for the html</returns>
-        public static SizeF Measure(Graphics g, string html, float maxWidth = 0, CssData cssData = null,
+        public static Task<SizeF> MeasureAsync(Graphics g, string html, float maxWidth = 0, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
@@ -167,7 +168,7 @@ public static SizeF Measure(Graphics g, string html, float maxWidth = 0, CssData
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the size required for the html</returns>
-        public static SizeF MeasureGdiPlus(Graphics g, string html, float maxWidth = 0, CssData cssData = null,
+        public static Task<SizeF> MeasureGdiPlusAsync(Graphics g, string html, float maxWidth = 0, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
@@ -177,7 +178,7 @@ public static SizeF MeasureGdiPlus(Graphics g, string html, float maxWidth = 0,
         /// <summary>
         /// Renders the specified HTML source on the specified location and max width restriction.<br/>
         /// Use GDI text rendering, note <see cref="Graphics.TextRenderingHint"/> has no effect.<br/>
-        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// Returned is the actual width and height of the rendered html.<br/>
         /// </summary>
@@ -190,7 +191,7 @@ public static SizeF MeasureGdiPlus(Graphics g, string html, float maxWidth = 0,
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        public static SizeF Render(Graphics g, string html, float left = 0, float top = 0, float maxWidth = 0, CssData cssData = null,
+        public static Task<SizeF> RenderAsync(Graphics g, string html, float left = 0, float top = 0, float maxWidth = 0, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
@@ -200,7 +201,7 @@ public static SizeF Render(Graphics g, string html, float left = 0, float top =
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
         /// Use GDI text rendering, note <see cref="Graphics.TextRenderingHint"/> has no effect.<br/>
-        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize"/>.Height is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -214,7 +215,7 @@ public static SizeF Render(Graphics g, string html, float left = 0, float top =
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        public static SizeF Render(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData = null,
+        public static Task<SizeF> RenderAsync(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
@@ -224,7 +225,7 @@ public static SizeF Render(Graphics g, string html, PointF location, SizeF maxSi
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
         /// Use GDI+ text rending, use <see cref="Graphics.TextRenderingHint"/> to control text rendering.<br/>
-        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// Returned is the actual width and height of the rendered html.<br/>
         /// </summary>
@@ -237,7 +238,7 @@ public static SizeF Render(Graphics g, string html, PointF location, SizeF maxSi
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        public static SizeF RenderGdiPlus(Graphics g, string html, float left = 0, float top = 0, float maxWidth = 0, CssData cssData = null,
+        public static Task<SizeF> RenderGdiPlusAsync(Graphics g, string html, float left = 0, float top = 0, float maxWidth = 0, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
@@ -247,7 +248,7 @@ public static SizeF RenderGdiPlus(Graphics g, string html, float left = 0, float
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
         /// Use GDI+ text rending, use <see cref="Graphics.TextRenderingHint"/> to control text rendering.<br/>
-        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize"/>.Height is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -261,14 +262,14 @@ public static SizeF RenderGdiPlus(Graphics g, string html, float left = 0, float
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        public static SizeF RenderGdiPlus(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData = null,
+        public static Task<SizeF> RenderGdiPlusAsync(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(g, "g");
             return RenderClip(g, html, location, maxSize, cssData, true, stylesheetLoad, imageLoad);
         }
 
-        public static Metafile RenderToMetafile(string html, float left = 0, float top = 0, float maxWidth = 0, CssData cssData = null,
+        public static async Task<Metafile> RenderToMetafileAsync(string html, float left = 0, float top = 0, float maxWidth = 0, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             Metafile image;
@@ -280,7 +281,7 @@ public static Metafile RenderToMetafile(string html, float left = 0, float top =
 
                 using (var g = Graphics.FromImage(image))
                 {
-                    Render(g, html, left, top, maxWidth, cssData, stylesheetLoad, imageLoad);
+                    await RenderAsync(g, html, left, top, maxWidth, cssData, stylesheetLoad, imageLoad).ConfigureAwait(false);
                 }
             }
             finally
@@ -303,12 +304,12 @@ public static Metafile RenderToMetafile(string html, float left = 0, float top =
         /// <param name="cssData">optional: the style to use for html rendering (default - use W3 default style)</param>
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
-        public static void RenderToImage(Image image, string html, PointF location = new PointF(), CssData cssData = null,
+        public static Task RenderToImageAsync(Image image, string html, PointF location = new PointF(), CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(image, "image");
             var maxSize = new SizeF(image.Size.Width - location.X, image.Size.Height - location.Y);
-            RenderToImage(image, html, location, maxSize, cssData, stylesheetLoad, imageLoad);
+            return RenderToImageAsync(image, html, location, maxSize, cssData, stylesheetLoad, imageLoad);
         }
 
         /// <summary>
@@ -324,7 +325,7 @@ public static Metafile RenderToMetafile(string html, float left = 0, float top =
         /// <param name="cssData">optional: the style to use for html rendering (default - use W3 default style)</param>
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
-        public static void RenderToImage(Image image, string html, PointF location, SizeF maxSize, CssData cssData = null,
+        public static async Task RenderToImageAsync(Image image, string html, PointF location, SizeF maxSize, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             ArgChecker.AssertArgNotNull(image, "image");
@@ -343,7 +344,7 @@ public static void RenderToImage(Image image, string html, PointF location, Size
                         memoryGraphics.DrawImageUnscaled(image, 0, 0);
 
                         // render HTML into the memory buffer
-                        RenderHtml(memoryGraphics, html, location, maxSize, cssData, false, stylesheetLoad, imageLoad);
+                        await RenderHtml(memoryGraphics, html, location, maxSize, cssData, false, stylesheetLoad, imageLoad).ConfigureAwait(false);
                     }
 
                     // copy from memory buffer to image
@@ -372,7 +373,7 @@ public static void RenderToImage(Image image, string html, PointF location, Size
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
         /// <exception cref="ArgumentOutOfRangeException">if <paramref name="backgroundColor"/> is <see cref="Color.Transparent"/></exception>.
-        public static Image RenderToImage(string html, Size size, Color backgroundColor = new Color(), CssData cssData = null,
+        public static async Task<Image> RenderToImageAsync(string html, Size size, Color backgroundColor = new Color(), CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             if (backgroundColor == Color.Transparent)
@@ -394,7 +395,7 @@ public static void RenderToImage(Image image, string html, PointF location, Size
                         memoryGraphics.Clear(backgroundColor != Color.Empty ? backgroundColor : Color.White);
 
                         // render HTML into the memory buffer
-                        RenderHtml(memoryGraphics, html, PointF.Empty, size, cssData, true, stylesheetLoad, imageLoad);
+                        await RenderHtml(memoryGraphics, html, PointF.Empty, size, cssData, true, stylesheetLoad, imageLoad).ConfigureAwait(false);
                     }
 
                     // copy from memory buffer to image
@@ -411,7 +412,7 @@ public static void RenderToImage(Image image, string html, PointF location, Size
 
         /// <summary>
         /// Renders the specified HTML into a new image of unknown size that will be determined by max width/height and HTML layout.<br/>
-        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxHeight"/> is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -429,15 +430,15 @@ public static void RenderToImage(Image image, string html, PointF location, Size
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
         /// <exception cref="ArgumentOutOfRangeException">if <paramref name="backgroundColor"/> is <see cref="Color.Transparent"/></exception>.
-        public static Image RenderToImage(string html, int maxWidth = 0, int maxHeight = 0, Color backgroundColor = new Color(), CssData cssData = null,
+        public static Task<Image> RenderToImageAsync(string html, int maxWidth = 0, int maxHeight = 0, Color backgroundColor = new Color(), CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
-            return RenderToImage(html, Size.Empty, new Size(maxWidth, maxHeight), backgroundColor, cssData, stylesheetLoad, imageLoad);
+            return RenderToImageAsync(html, Size.Empty, new Size(maxWidth, maxHeight), backgroundColor, cssData, stylesheetLoad, imageLoad);
         }
 
         /// <summary>
         /// Renders the specified HTML into a new image of unknown size that will be determined by min/max width/height and HTML layout.<br/>
-        /// If <paramref name="maxSize.Width"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize.Width"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize.Height"/> is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -456,7 +457,7 @@ public static void RenderToImage(Image image, string html, PointF location, Size
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
         /// <exception cref="ArgumentOutOfRangeException">if <paramref name="backgroundColor"/> is <see cref="Color.Transparent"/></exception>.
-        public static Image RenderToImage(string html, Size minSize, Size maxSize, Color backgroundColor = new Color(), CssData cssData = null,
+        public static async Task<Image> RenderToImageAsync(string html, Size minSize, Size maxSize, Color backgroundColor = new Color(), CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             if (backgroundColor == Color.Transparent)
@@ -474,7 +475,7 @@ public static void RenderToImage(Image image, string html, PointF location, Size
                     container.StylesheetLoad += stylesheetLoad;
                 if (imageLoad != null)
                     container.ImageLoad += imageLoad;
-                container.SetHtml(html, cssData);
+                await container.SetHtml(html, cssData).ConfigureAwait(false);
 
                 var finalSize = MeasureHtmlByRestrictions(container, minSize, maxSize);
                 container.MaxSize = finalSize;
@@ -520,7 +521,7 @@ public static void RenderToImage(Image image, string html, PointF location, Size
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
-        public static Image RenderToImageGdiPlus(string html, Size size, TextRenderingHint textRenderingHint = TextRenderingHint.AntiAlias, CssData cssData = null,
+        public static async Task<Image> RenderToImageGdiPlusAsync(string html, Size size, TextRenderingHint textRenderingHint = TextRenderingHint.AntiAlias, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             var image = new Bitmap(size.Width, size.Height, PixelFormat.Format32bppArgb);
@@ -528,7 +529,7 @@ public static Image RenderToImageGdiPlus(string html, Size size, TextRenderingHi
             using (var g = Graphics.FromImage(image))
             {
                 g.TextRenderingHint = textRenderingHint;
-                RenderHtml(g, html, PointF.Empty, size, cssData, true, stylesheetLoad, imageLoad);
+                await RenderHtml(g, html, PointF.Empty, size, cssData, true, stylesheetLoad, imageLoad).ConfigureAwait(false);
             }
 
             return image;
@@ -536,7 +537,7 @@ public static Image RenderToImageGdiPlus(string html, Size size, TextRenderingHi
 
         /// <summary>
         /// Renders the specified HTML into a new image of unknown size that will be determined by max width/height and HTML layout.<br/>
-        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxWidth"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxHeight"/> is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -552,15 +553,15 @@ public static Image RenderToImageGdiPlus(string html, Size size, TextRenderingHi
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
-        public static Image RenderToImageGdiPlus(string html, int maxWidth = 0, int maxHeight = 0, TextRenderingHint textRenderingHint = TextRenderingHint.AntiAlias, CssData cssData = null,
+        public static Task<Image> RenderToImageGdiPlusAsync(string html, int maxWidth = 0, int maxHeight = 0, TextRenderingHint textRenderingHint = TextRenderingHint.AntiAlias, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
-            return RenderToImageGdiPlus(html, Size.Empty, new Size(maxWidth, maxHeight), textRenderingHint, cssData, stylesheetLoad, imageLoad);
+            return RenderToImageGdiPlusAsync(html, Size.Empty, new Size(maxWidth, maxHeight), textRenderingHint, cssData, stylesheetLoad, imageLoad);
         }
 
         /// <summary>
         /// Renders the specified HTML into a new image of unknown size that will be determined by min/max width/height and HTML layout.<br/>
-        /// If <paramref name="maxSize.Width"/> is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize.Width"/> is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize.Height"/> is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -577,7 +578,7 @@ public static Image RenderToImageGdiPlus(string html, int maxWidth = 0, int maxH
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the generated image of the html</returns>
-        public static Image RenderToImageGdiPlus(string html, Size minSize, Size maxSize, TextRenderingHint textRenderingHint = TextRenderingHint.AntiAlias, CssData cssData = null,
+        public static async Task<Image> RenderToImageGdiPlusAsync(string html, Size minSize, Size maxSize, TextRenderingHint textRenderingHint = TextRenderingHint.AntiAlias, CssData cssData = null,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad = null, EventHandler<HtmlImageLoadEventArgs> imageLoad = null)
         {
             if (string.IsNullOrEmpty(html))
@@ -593,7 +594,7 @@ public static Image RenderToImageGdiPlus(string html, Size minSize, Size maxSize
                     container.StylesheetLoad += stylesheetLoad;
                 if (imageLoad != null)
                     container.ImageLoad += imageLoad;
-                container.SetHtml(html, cssData);
+                await container.SetHtml(html, cssData).ConfigureAwait(false);
 
                 var finalSize = MeasureHtmlByRestrictions(container, minSize, maxSize);
                 container.MaxSize = finalSize;
@@ -626,7 +627,7 @@ public static Image RenderToImageGdiPlus(string html, Size minSize, Size maxSize
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the size required for the html</returns>
-        private static SizeF Measure(Graphics g, string html, float maxWidth, CssData cssData, bool useGdiPlusTextRendering,
+        private static async Task<SizeF> Measure(Graphics g, string html, float maxWidth, CssData cssData, bool useGdiPlusTextRendering,
             EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
         {
             SizeF actualSize = SizeF.Empty;
@@ -644,7 +645,7 @@ private static SizeF Measure(Graphics g, string html, float maxWidth, CssData cs
                     if (imageLoad != null)
                         container.ImageLoad += imageLoad;
 
-                    container.SetHtml(html, cssData);
+                    await container.SetHtml(html, cssData).ConfigureAwait(false);
                     container.PerformLayout(g);
 
                     actualSize = container.ActualSize;
@@ -675,7 +676,7 @@ private static Size MeasureHtmlByRestrictions(HtmlContainer htmlContainer, Size
 
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
-        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize"/>.Height is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -691,7 +692,7 @@ private static Size MeasureHtmlByRestrictions(HtmlContainer htmlContainer, Size
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        private static SizeF RenderClip(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData, bool useGdiPlusTextRendering, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
+        private static async Task<SizeF> RenderClip(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData, bool useGdiPlusTextRendering, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
         {
             Region prevClip = null;
             if (maxSize.Height > 0)
@@ -700,7 +701,7 @@ private static SizeF RenderClip(Graphics g, string html, PointF location, SizeF
                 g.SetClip(new RectangleF(location, maxSize));
             }
 
-            var actualSize = RenderHtml(g, html, location, maxSize, cssData, useGdiPlusTextRendering, stylesheetLoad, imageLoad);
+            var actualSize = await RenderHtml(g, html, location, maxSize, cssData, useGdiPlusTextRendering, stylesheetLoad, imageLoad).ConfigureAwait(false);
 
             if (prevClip != null)
             {
@@ -712,7 +713,7 @@ private static SizeF RenderClip(Graphics g, string html, PointF location, SizeF
 
         /// <summary>
         /// Renders the specified HTML source on the specified location and max size restriction.<br/>
-        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line 
+        /// If <paramref name="maxSize"/>.Width is zero the html will use all the required width, otherwise it will perform line
         /// wrap as specified in the html<br/>
         /// If <paramref name="maxSize"/>.Height is zero the html will use all the required height, otherwise it will clip at the
         /// given max height not rendering the html below it.<br/>
@@ -727,7 +728,7 @@ private static SizeF RenderClip(Graphics g, string html, PointF location, SizeF
         /// <param name="stylesheetLoad">optional: can be used to overwrite stylesheet resolution logic</param>
         /// <param name="imageLoad">optional: can be used to overwrite image resolution logic</param>
         /// <returns>the actual size of the rendered html</returns>
-        private static SizeF RenderHtml(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData, bool useGdiPlusTextRendering, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
+        private static async Task<SizeF> RenderHtml(Graphics g, string html, PointF location, SizeF maxSize, CssData cssData, bool useGdiPlusTextRendering, EventHandler<HtmlStylesheetLoadEventArgs> stylesheetLoad, EventHandler<HtmlImageLoadEventArgs> imageLoad)
         {
             SizeF actualSize = SizeF.Empty;
 
@@ -746,7 +747,7 @@ private static SizeF RenderHtml(Graphics g, string html, PointF location, SizeF
                     if (imageLoad != null)
                         container.ImageLoad += imageLoad;
 
-                    container.SetHtml(html, cssData);
+                    await container.SetHtml(html, cssData).ConfigureAwait(false);
                     container.PerformLayout(g);
                     container.PerformPaint(g);
 
@@ -774,4 +775,4 @@ private static void CopyBufferToImage(IntPtr memoryHdc, Image image)
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer.WinForms/HtmlToolTip.cs b/Source/HtmlRenderer.WinForms/HtmlToolTip.cs
index 2a82209bd..9b6bb1eb8 100644
--- a/Source/HtmlRenderer.WinForms/HtmlToolTip.cs
+++ b/Source/HtmlRenderer.WinForms/HtmlToolTip.cs
@@ -241,7 +241,11 @@ protected virtual void OnToolTipPopup(PopupEventArgs e)
             //Create fragment container
             var cssClass = string.IsNullOrEmpty(_tooltipCssClass) ? null : string.Format(" class=\"{0}\"", _tooltipCssClass);
             var toolipHtml = string.Format("<div{0}>{1}</div>", cssClass, GetToolTip(e.AssociatedControl));
-            _htmlContainer.SetHtml(toolipHtml, _baseCssData);
+            // Bridges into the async HtmlContainer.SetHtml from this synchronous event handler.
+            // Deliberately, permanently blocking: WinForms' ToolTip.Popup is a synchronous framework
+            // callback with no async variant - e.ToolTipSize must be set before this method returns or
+            // the tooltip won't position correctly, so there is no way to make this fire-and-forget.
+            _htmlContainer.SetHtml(toolipHtml, _baseCssData).GetAwaiter().GetResult();
             _htmlContainer.MaxSize = MaximumSize;
 
             //Measure size of the container
diff --git a/Source/HtmlRenderer.WinForms/Utilities/WindowsTheme.cs b/Source/HtmlRenderer.WinForms/Utilities/WindowsTheme.cs
new file mode 100644
index 000000000..e3892153c
--- /dev/null
+++ b/Source/HtmlRenderer.WinForms/Utilities/WindowsTheme.cs
@@ -0,0 +1,54 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+using Microsoft.Win32;
+using TheArtOfDev.HtmlRenderer.Adapters;
+
+namespace TheArtOfDev.HtmlRenderer.WinForms.Utilities
+{
+    /// <summary>
+    /// Reads the Windows app theme, which is what <c>prefers-color-scheme</c> reports for on-screen
+    /// rendering.
+    /// </summary>
+    internal static class WindowsTheme
+    {
+        private const string PersonalizeKey = @"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize";
+        private const string AppsUseLightTheme = "AppsUseLightTheme";
+
+        /// <summary>
+        /// The user's app theme, or <see cref="RColorScheme.Light"/> when it cannot be determined -
+        /// light is the Windows default and the safer assumption for a document that declares no dark
+        /// styling of its own.
+        /// </summary>
+        public static RColorScheme GetAppsColorScheme()
+        {
+            try
+            {
+                using (var key = Registry.CurrentUser.OpenSubKey(PersonalizeKey))
+                {
+                    if (key != null)
+                    {
+                        var value = key.GetValue(AppsUseLightTheme);
+                        if (value is int)
+                            return (int)value == 0 ? RColorScheme.Dark : RColorScheme.Light;
+                    }
+                }
+            }
+            catch
+            {
+                // A locked-down or missing key just means "no preference expressed".
+            }
+
+            return RColorScheme.Light;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Adapters/RAdapter.cs b/Source/HtmlRenderer/Adapters/RAdapter.cs
index 6b13459c1..6632f6942 100644
--- a/Source/HtmlRenderer/Adapters/RAdapter.cs
+++ b/Source/HtmlRenderer/Adapters/RAdapter.cs
@@ -14,10 +14,13 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Handlers;
+using TheArtOfDev.HtmlRenderer.Core.Network;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Adapters
@@ -54,6 +57,16 @@ public abstract class RAdapter
         /// </summary>
         private readonly FontsHandler _fontsHandler;
 
+        /// <summary>
+        /// Dedup cache for <see cref="AddFontFace"/>, keyed by the resolved resource's absolute URI - since
+        /// the orchestrator re-runs <c>@font-face</c> registration on every <c>SetHtml</c> and this adapter
+        /// is a process-wide singleton, re-registering the same face's bytes with the platform text engine
+        /// on every call would leak native font handles (WinForms' <c>PrivateFontCollection.AddMemoryFont</c>/
+        /// WPF's <c>AddFontMemResourceEx</c> both register a *new* resource each call, even for identical
+        /// bytes - neither is idempotent).
+        /// </summary>
+        private readonly Dictionary<string, RFontFamily> _fontFaceCache = new Dictionary<string, RFontFamily>();
+
         /// <summary>
         /// default CSS parsed data singleton
         /// </summary>
@@ -80,12 +93,158 @@ protected RAdapter()
             _fontsHandler = new FontsHandler(this);
         }
 
+        /// <summary>
+        /// The CSS media type this adapter renders for, used to evaluate <c>@media</c> queries -
+        /// <c>"screen"</c> for on-screen adapters (the default), <c>"print"</c> for paged output.
+        /// </summary>
+        public virtual string DefaultMediaType
+        {
+            get { return "screen"; }
+        }
+
+        /// <summary>
+        /// The colour scheme the rendering surface presents, answering the <c>prefers-color-scheme</c>
+        /// media feature. Defaults to <see cref="RColorScheme.Light"/>; an adapter that renders onto a
+        /// themed surface should report the system setting instead, and raise
+        /// <see cref="ColorSchemeChanged"/> when it changes.
+        /// </summary>
+        public virtual RColorScheme SystemColorScheme
+        {
+            get { return RColorScheme.Light; }
+        }
+
+        /// <summary>
+        /// Test-only seam: when set, an adapter that would otherwise report a live system theme (WinForms/
+        /// WPF) returns this value from <see cref="SystemColorScheme"/> instead of querying the OS. Image-
+        /// regression tests render against a fixed baseline and must not depend on the host machine's own
+        /// theme setting - without this, a CI runner whose theme differs from whatever machine captured the
+        /// baseline fails a <c>prefers-color-scheme</c> sample for reasons unrelated to any real rendering
+        /// regression. Production code must never set this.
+        /// </summary>
+        internal static RColorScheme? SystemColorSchemeOverride { get; set; }
+
+        /// <summary>
+        /// Raised when <see cref="SystemColorScheme"/> has changed, so anything rendered against it can
+        /// re-evaluate its <c>prefers-color-scheme</c> rules and repaint. Never raised by an adapter
+        /// whose scheme is fixed.
+        /// </summary>
+        /// <remarks>
+        /// Handlers are held for the lifetime of the adapter, which is typically a process-wide
+        /// singleton, so a subscriber must unsubscribe when it is disposed.
+        /// </remarks>
+        public event EventHandler ColorSchemeChanged;
+
+        /// <summary>
+        /// Raises <see cref="ColorSchemeChanged"/>. For adapters that track a system theme.
+        /// </summary>
+        protected void OnColorSchemeChanged()
+        {
+            var handler = ColorSchemeChanged;
+            if (handler != null)
+                handler(this, EventArgs.Empty);
+        }
+
+        /// <summary>
+        /// Controls how the root HTML document and every external resource it references (stylesheets,
+        /// images, <c>@font-face</c> fonts) is loaded. Defaults to <see cref="DataUriNetworkLoader"/>,
+        /// which only resolves <c>data:</c> URIs — set this to a <see cref="FileUriNetworkLoader"/> or
+        /// <see cref="HttpClientNetworkLoader"/> (or a custom <see cref="Network.RNetworkLoader"/>) to
+        /// enable loading from local files or over HTTP(S).
+        /// </summary>
+        public RNetworkLoader NetworkLoader { get; set; } = new DataUriNetworkLoader();
+
+        /// <summary>
+        /// Whether <c>file:</c> resource requests are honored. Checked ahead of, and independently from,
+        /// whether <see cref="NetworkLoader"/> happens to be a <see cref="FileUriNetworkLoader"/> — a
+        /// <c>false</c> value refuses local file access even then. Defaults to <c>true</c>.
+        /// </summary>
+        public bool AllowLocalFileAccess { get; set; } = true;
+
+        // Serves file: URIs (and supplies the default working-directory base URI) whenever the configured
+        // NetworkLoader isn't itself a FileUriNetworkLoader - mirroring how data: URIs are always handled
+        // internally regardless of which loader is configured. Lazily created so its
+        // Directory.GetCurrentDirectory() snapshot isn't taken until a file: resource (or the fallback base
+        // URI) is actually needed.
+        private FileUriNetworkLoader _internalFileLoader;
+        private FileUriNetworkLoader InternalFileLoader => _internalFileLoader ?? (_internalFileLoader = new FileUriNetworkLoader());
+
+        // Serves embedded: URIs unconditionally, the same way data:/file: are always handled internally
+        // regardless of which loader is configured - stateless (the target assembly is named in the URI
+        // itself, see EmbeddedResourceNetworkLoader), so a single shared instance needs no lazy init.
+        private static readonly EmbeddedResourceNetworkLoader InternalEmbeddedResourceLoader = new EmbeddedResourceNetworkLoader();
+
+        /// <summary>
+        /// The document's base URL, used to resolve relative <c>href</c>/<c>src</c>/CSS <c>url()</c>
+        /// references that have no closer <c>&lt;base href&gt;</c> element to resolve against. Sourced from
+        /// <see cref="NetworkLoader"/>'s own base URI when it has one; otherwise (e.g. the default
+        /// <see cref="DataUriNetworkLoader"/>, which has none) falls back to the current working directory
+        /// as a <c>file:</c> URI when local file access is allowed, or <c>null</c> when it is not.
+        /// </summary>
+        public RUri BaseUri => NetworkLoader.BaseUri ?? (AllowLocalFileAccess ? InternalFileLoader.BaseUri : null);
+
+        /// <summary>
+        /// Resolve an external resource (a stylesheet, image, or <c>@font-face</c> font) referenced by the
+        /// document, dispatching by URI scheme: <c>data:</c>, <c>file:</c>, and <c>embedded:</c> always
+        /// resolve internally (<c>file:</c> refused outright when <see cref="AllowLocalFileAccess"/> is
+        /// <c>false</c>), every other scheme goes to the configured <see cref="NetworkLoader"/>.
+        /// </summary>
+        /// <param name="uri">the resource URI, already resolved to absolute against <see cref="BaseUri"/> or a <c>&lt;base href&gt;</c> element</param>
+        /// <returns>the resolved resource, or null if it could not be resolved</returns>
+        public Task<RNetworkResponse> GetResourceStream(RUri uri)
+        {
+            // BaseUri is normally never null, so every reference resolves to an absolute URI and loaders
+            // only ever see those - RUri.Scheme throws on a relative URI, and neither DataUriNetworkLoader
+            // nor HttpClientNetworkLoader checks. Denying local file access is what makes BaseUri nullable,
+            // so a relative reference can now survive resolution; answer "unresolved" for it here rather
+            // than handing a loader a URI it cannot inspect.
+            if (!uri.IsAbsoluteUri)
+            {
+                return Task.FromResult<RNetworkResponse>(null);
+            }
+
+            if (uri.Scheme == "data")
+            {
+                var dataLoader = NetworkLoader as DataUriNetworkLoader ?? new DataUriNetworkLoader();
+                return dataLoader.GetResourceStream(uri);
+            }
+
+            if (uri.Scheme == "file")
+            {
+                // Checked ahead of the configured loader, so a deny holds even when that loader is itself a
+                // FileUriNetworkLoader - the two settings contradict each other, and refusing is the safe read.
+                if (!AllowLocalFileAccess)
+                {
+                    return Task.FromResult<RNetworkResponse>(null);
+                }
+
+                var fileLoader = NetworkLoader as FileUriNetworkLoader ?? InternalFileLoader;
+                return fileLoader.GetResourceStream(uri);
+            }
+
+            if (uri.Scheme == EmbeddedResourceNetworkLoader.Scheme)
+            {
+                var embeddedLoader = NetworkLoader as EmbeddedResourceNetworkLoader ?? InternalEmbeddedResourceLoader;
+                return embeddedLoader.GetResourceStream(uri);
+            }
+
+            return NetworkLoader.GetResourceStream(uri);
+        }
+
         /// <summary>
         /// Get the default CSS stylesheet data.
         /// </summary>
         public CssData DefaultCssData
         {
-            get { return _defaultCssData ?? (_defaultCssData = CssData.Parse(this, CssDefaults.DefaultStyleSheet, false)); }
+            get
+            {
+                if (_defaultCssData == null)
+                {
+                    _defaultCssData = CssData.Parse(this, CssDefaults.DefaultStyleSheet, false);
+                    foreach (var stylesheet in _defaultCssData.Stylesheets)
+                        stylesheet.IsUserAgent = true;
+                }
+                return _defaultCssData;
+            }
         }
 
         /// <summary>
@@ -130,16 +289,15 @@ public RBrush GetSolidBrush(RColor color)
         }
 
         /// <summary>
-        /// Get linear gradient color brush from <paramref name="color1"/> to <paramref name="color2"/>.
+        /// Get a multi-stop linear gradient brush along the line from <paramref name="p1"/> to <paramref name="p2"/>.
         /// </summary>
-        /// <param name="rect">the rectangle to get the brush for</param>
-        /// <param name="color1">the start color of the gradient</param>
-        /// <param name="color2">the end color of the gradient</param>
-        /// <param name="angle">the angle to move the gradient from start color to end color in the rectangle</param>
+        /// <param name="p1">the gradient line's start point</param>
+        /// <param name="p2">the gradient line's end point</param>
+        /// <param name="stops">color stops, each with a position in [0,1] along the gradient line</param>
         /// <returns>linear gradient color brush instance</returns>
-        public RBrush GetLinearGradientBrush(RRect rect, RColor color1, RColor color2, double angle)
+        public RBrush GetLinearGradientBrush(RPoint p1, RPoint p2, (RColor Color, double Position)[] stops)
         {
-            return CreateLinearGradientBrush(rect, color1, color2, angle);
+            return CreateLinearGradientBrush(p1, p2, stops);
         }
 
         /// <summary>
@@ -164,11 +322,20 @@ public RImage ImageFromStream(Stream memoryStream)
         }
 
         /// <summary>
-        /// Check if the given font exists in the system by font family name.
+        /// Check if the given font exists in the system by font family name. Consulted by
+        /// <see cref="Core.Parse.CssParser.ParseFontFamily"/> to decide whether a <c>font-family</c>
+        /// candidate should be kept as-is or the next fallback (ultimately <see cref="Core.Utils.CssConstants.DefaultFont"/>)
+        /// tried instead - so this must recognize a family the moment it's usable, including one
+        /// registered via <see cref="AddFontFace"/>, not just <see cref="AddFontFamily"/>/system fonts.
         /// </summary>
         /// <param name="font">the font name to check</param>
         /// <returns>true - font exists by given family name, false - otherwise</returns>
-        public bool IsFontExists(string font)
+        /// <remarks>
+        /// Virtual so the PdfSharp backend can override it - its <c>@font-face</c> registrations live
+        /// entirely in its own <c>FontResolver</c> (see <see cref="AddFontFace"/>'s doc comment for why),
+        /// invisible to the shared <c>FontsHandler</c> this base implementation checks.
+        /// </remarks>
+        public virtual bool IsFontExists(string font)
         {
             return _fontsHandler.IsFontExists(font);
         }
@@ -194,6 +361,91 @@ public void AddFontFamilyMapping(string fromFamily, string toFamily)
             _fontsHandler.AddFontFamilyMapping(fromFamily, toFamily);
         }
 
+        /// <summary>
+        /// Loads one <c>@font-face</c> <c>src: url(...)</c> candidate and registers it as a face of
+        /// <paramref name="familyName"/> for CSS Fonts Level 4 matching. Resolves the resource through
+        /// <see cref="GetResourceStream"/> - the same funnel used for images/stylesheets, so this supports
+        /// <c>file:</c>/<c>data:</c>/<c>http(s):</c> uniformly - loads the platform-specific face via
+        /// <see cref="LoadFontFaceFontInt"/>, and registers it with <see cref="FontsHandler.AddFontFace"/>.
+        /// </summary>
+        /// <param name="familyName">the CSS family name declared by the <c>@font-face</c> rule</param>
+        /// <param name="uri">the resolved, absolute <c>src</c> URI to fetch (already resolved against the document base/a stylesheet's own location by the caller)</param>
+        /// <param name="weight">CSS Fonts Level 4 numeric weight (1-1000) this face matches for</param>
+        /// <param name="isItalic">whether this face matches an italic/oblique request</param>
+        /// <param name="stretch">CSS Fonts Level 3 stretch (1-9) this face matches for</param>
+        /// <param name="ranges">the face's <c>unicode-range</c> restriction, or null for "covers whatever is asked of it"</param>
+        /// <returns>true if the face was loaded and registered, false if the resource could not be resolved/loaded (the caller tries the next <c>src</c> candidate)</returns>
+        /// <remarks>
+        /// Virtual so the PdfSharp backend can override it to bypass <see cref="FontsHandler"/>'s shared
+        /// registry entirely and register directly with its own <c>FontResolver</c> instead - PDFsharp
+        /// needs raw font bytes at PDF-generation time for embedding (via its own richer
+        /// <c>IFontResolver</c>-based CSS-Fonts-L4 matching), unlike WinForms/WPF, which just need an
+        /// opaque platform font-family handle. See the base implementation's own doc comment for the
+        /// shared-registry path this overrides.
+        /// </remarks>
+        public virtual async Task<bool> AddFontFace(string familyName, RUri uri, int weight, bool isItalic, int stretch, IReadOnlyList<CodepointRange> ranges)
+        {
+            RFontFamily fontFamily;
+            if (!_fontFaceCache.TryGetValue(uri.AbsoluteUri, out fontFamily))
+            {
+                var networkResponse = await GetResourceStream(uri).ConfigureAwait(false);
+                if (networkResponse == null || networkResponse.ResourceStream == null)
+                {
+                    return false;
+                }
+
+                byte[] fontBytes;
+                using (var memoryStream = new MemoryStream())
+                {
+                    using (networkResponse.ResourceStream)
+                    {
+                        networkResponse.ResourceStream.CopyTo(memoryStream);
+                    }
+                    fontBytes = memoryStream.ToArray();
+                }
+
+                try
+                {
+                    fontFamily = LoadFontFaceFontInt(fontBytes, uri.AbsoluteUri);
+                }
+                catch
+                {
+                    return false;
+                }
+
+                if (fontFamily == null)
+                {
+                    return false;
+                }
+
+                _fontFaceCache[uri.AbsoluteUri] = fontFamily;
+            }
+
+            _fontsHandler.AddFontFace(familyName, fontFamily, weight, isItalic, stretch, ranges);
+            return true;
+        }
+
+        /// <summary>
+        /// Satisfies an <c>@font-face</c> <c>src: local(...)</c> candidate: rather than fetching a resource
+        /// at all, this looks for a family already registered under <paramref name="localFamilyName"/> (a
+        /// system font, or an earlier <see cref="AddFontFamily"/>/<see cref="AddFontFace"/> registration)
+        /// and, if found, registers *that same* <see cref="RFontFamily"/> as a face of
+        /// <paramref name="familyName"/> too.
+        /// </summary>
+        /// <returns>true if a local family by that name was found and registered, false otherwise (the caller tries the next <c>src</c> candidate)</returns>
+        /// <remarks>Virtual for the same reason as <see cref="AddFontFace"/> - see its doc comment.</remarks>
+        public virtual bool AddFontFaceFromLocalFamily(string familyName, string localFamilyName, int weight, bool isItalic, int stretch, IReadOnlyList<CodepointRange> ranges)
+        {
+            var localFamily = _fontsHandler.TryGetExistingFamily(localFamilyName);
+            if (localFamily == null)
+            {
+                return false;
+            }
+
+            _fontsHandler.AddFontFace(familyName, localFamily, weight, isItalic, stretch, ranges);
+            return true;
+        }
+
         /// <summary>
         /// Get font instance by given font family name, size and style.
         /// </summary>
@@ -206,6 +458,28 @@ public RFont GetFont(string family, double size, RFontStyle style)
             return _fontsHandler.GetCachedFont(family, size, style);
         }
 
+        /// <summary>
+        /// Get font instance by given font family name, size, style, and CSS Fonts Level 4 numeric
+        /// weight/stretch - matches against any <c>@font-face</c> faces registered for <paramref name="family"/>
+        /// (see <see cref="FontsHandler.GetCachedFont(string,double,RFontStyle,int,int,int?)"/>), falling
+        /// back to the legacy family-name lookup when none are registered.
+        /// </summary>
+        /// <param name="family">the font family name</param>
+        /// <param name="size">font size</param>
+        /// <param name="style">font style (Italic/Underline/Strikeout are honored regardless of which face is chosen; Bold is superseded by <paramref name="weight"/>)</param>
+        /// <param name="weight">CSS Fonts Level 4 numeric weight (1-1000)</param>
+        /// <param name="stretch">CSS Fonts Level 3 stretch (1-9)</param>
+        /// <param name="codepoint">the box's first non-whitespace character's codepoint, for <c>unicode-range</c> face disambiguation, or null to skip it</param>
+        /// <returns>font instance, or null when <paramref name="codepoint"/> is given and no registered face covers it</returns>
+        /// <remarks>
+        /// Virtual so the PdfSharp backend can override it to bypass <see cref="FontsHandler"/>'s shared
+        /// registry entirely, for the same reason as <see cref="AddFontFace"/> - see its doc comment.
+        /// </remarks>
+        public virtual RFont GetFont(string family, double size, RFontStyle style, int weight, int stretch, int? codepoint)
+        {
+            return _fontsHandler.GetCachedFont(family, size, style, weight, stretch, codepoint);
+        }
+
         /// <summary>
         /// Get image to be used while HTML image is loading.
         /// </summary>
@@ -351,14 +625,13 @@ internal RFont CreateFont(RFontFamily family, double size, RFontStyle style)
         protected abstract RBrush CreateSolidBrush(RColor color);
 
         /// <summary>
-        /// Get linear gradient color brush from <paramref name="color1"/> to <paramref name="color2"/>.
+        /// Get a multi-stop linear gradient brush along the line from <paramref name="p1"/> to <paramref name="p2"/>.
         /// </summary>
-        /// <param name="rect">the rectangle to get the brush for</param>
-        /// <param name="color1">the start color of the gradient</param>
-        /// <param name="color2">the end color of the gradient</param>
-        /// <param name="angle">the angle to move the gradient from start color to end color in the rectangle</param>
+        /// <param name="p1">the gradient line's start point</param>
+        /// <param name="p2">the gradient line's end point</param>
+        /// <param name="stops">color stops, each with a position in [0,1] along the gradient line</param>
         /// <returns>linear gradient color brush instance</returns>
-        protected abstract RBrush CreateLinearGradientBrush(RRect rect, RColor color1, RColor color2, double angle);
+        protected abstract RBrush CreateLinearGradientBrush(RPoint p1, RPoint p2, (RColor Color, double Position)[] stops);
 
         /// <summary>
         /// Convert image object returned from <see cref="HtmlImageLoadEventArgs"/> to <see cref="RImage"/>.
@@ -393,6 +666,19 @@ internal RFont CreateFont(RFontFamily family, double size, RFontStyle style)
         /// <returns>font instance</returns>
         protected abstract RFont CreateFontInt(RFontFamily family, double size, RFontStyle style);
 
+        /// <summary>
+        /// Registers <paramref name="fontBytes"/> (a loaded <c>@font-face</c> <c>src</c> candidate's raw
+        /// font file bytes) with the platform text engine and returns an opaque <see cref="RFontFamily"/>
+        /// handle for it - one file's bytes in, one face's family handle out (a WinForms/WPF
+        /// implementation registers with the OS/GDI text engine and returns a handle to that one face;
+        /// this is not called for backends - like PdfSharp - that override <see cref="AddFontFace"/> to
+        /// bypass this entirely).
+        /// </summary>
+        /// <param name="fontBytes">the font file's raw bytes (TTF/OTF)</param>
+        /// <param name="filePath">the resolved source this was loaded from, for diagnostics/error messages only</param>
+        /// <returns>the registered face's family handle, or null if the bytes could not be loaded as a font (the caller tries the next <c>src</c> candidate)</returns>
+        protected abstract RFontFamily LoadFontFaceFontInt(byte[] fontBytes, string filePath);
+
         /// <summary>
         /// Get data object for the given html and plain text data.<br />
         /// The data object can be used for clipboard or drag-drop operation.
diff --git a/Source/HtmlRenderer/Adapters/RColorScheme.cs b/Source/HtmlRenderer/Adapters/RColorScheme.cs
new file mode 100644
index 000000000..b4fd68303
--- /dev/null
+++ b/Source/HtmlRenderer/Adapters/RColorScheme.cs
@@ -0,0 +1,32 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+namespace TheArtOfDev.HtmlRenderer.Adapters
+{
+    /// <summary>
+    /// The colour scheme the rendering surface presents, as reported by the platform adapter and
+    /// queried by the <c>prefers-color-scheme</c> media feature (Media Queries 5 §5.1).
+    /// </summary>
+    public enum RColorScheme
+    {
+        /// <summary>
+        /// A light surface - dark content on a light background. The default for any adapter that has
+        /// no system theme to follow.
+        /// </summary>
+        Light,
+
+        /// <summary>
+        /// A dark surface - light content on a dark background.
+        /// </summary>
+        Dark
+    }
+}
diff --git a/Source/HtmlRenderer/Adapters/RGraphics.cs b/Source/HtmlRenderer/Adapters/RGraphics.cs
index af54f2ae4..22ba0df77 100644
--- a/Source/HtmlRenderer/Adapters/RGraphics.cs
+++ b/Source/HtmlRenderer/Adapters/RGraphics.cs
@@ -76,16 +76,15 @@ public RBrush GetSolidBrush(RColor color)
         }
 
         /// <summary>
-        /// Get linear gradient color brush from <paramref name="color1"/> to <paramref name="color2"/>.
+        /// Get a multi-stop linear gradient brush along the line from <paramref name="p1"/> to <paramref name="p2"/>.
         /// </summary>
-        /// <param name="rect">the rectangle to get the brush for</param>
-        /// <param name="color1">the start color of the gradient</param>
-        /// <param name="color2">the end color of the gradient</param>
-        /// <param name="angle">the angle to move the gradient from start color to end color in the rectangle</param>
+        /// <param name="p1">the gradient line's start point</param>
+        /// <param name="p2">the gradient line's end point</param>
+        /// <param name="stops">color stops, each with a position in [0,1] along the gradient line</param>
         /// <returns>linear gradient color brush instance</returns>
-        public RBrush GetLinearGradientBrush(RRect rect, RColor color1, RColor color2, double angle)
+        public RBrush GetLinearGradientBrush(RPoint p1, RPoint p2, (RColor Color, double Position)[] stops)
         {
-            return _adapter.GetLinearGradientBrush(rect, color1, color2, angle);
+            return _adapter.GetLinearGradientBrush(p1, p2, stops);
         }
 
         /// <summary>
diff --git a/Source/HtmlRenderer/Adapters/RGraphicsPath.cs b/Source/HtmlRenderer/Adapters/RGraphicsPath.cs
index 21c86bc1a..474781a5e 100644
--- a/Source/HtmlRenderer/Adapters/RGraphicsPath.cs
+++ b/Source/HtmlRenderer/Adapters/RGraphicsPath.cs
@@ -30,10 +30,19 @@ public abstract class RGraphicsPath : IDisposable
         public abstract void LineTo(double x, double y);
         
         /// <summary>
-        /// Add circular arc of the given size to the given point from the last point.
+        /// Add an elliptical arc with independent horizontal (X) and vertical (Y) radii to the given
+        /// point from the last point - supports elliptical border-radius corners.
         /// </summary>
-        public abstract void ArcTo(double x, double y, double size, Corner corner);
-        
+        public abstract void ArcTo(double x, double y, double radiusX, double radiusY, Corner corner);
+
+        /// <summary>
+        /// Add a circular arc of the given size to the given point from the last point.
+        /// </summary>
+        public void ArcTo(double x, double y, double size, Corner corner)
+        {
+            ArcTo(x, y, size, size, corner);
+        }
+
         /// <summary>
         /// Release path resources.
         /// </summary>
diff --git a/Source/HtmlRenderer/Core/CssData.cs b/Source/HtmlRenderer/Core/CssData.cs
index f0e4a8106..d7ae1ca52 100644
--- a/Source/HtmlRenderer/Core/CssData.cs
+++ b/Source/HtmlRenderer/Core/CssData.cs
@@ -6,54 +6,51 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using TheArtOfDev.HtmlRenderer.Adapters;
-using TheArtOfDev.HtmlRenderer.Core.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+using TheArtOfDev.HtmlRenderer.Core.Dom;
 using TheArtOfDev.HtmlRenderer.Core.Parse;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core
 {
     /// <summary>
-    /// Holds parsed stylesheet css blocks arranged by media and classes.<br/>
-    /// <seealso cref="CssBlock"/>
+    /// Holds parsed stylesheets (UA default + author + inline), and provides origin-aware,
+    /// specificity-ordered selector matching against the box tree.<br/>
     /// </summary>
     /// <remarks>
-    /// To learn more about CSS blocks visit CSS spec: http://www.w3.org/TR/CSS21/syndata.html#block
+    /// Derived from the same ExCSS lineage as the vendored CSS-OM (originally Tyler Brinks' ExCSS),
+    /// adapted to HTML-Renderer's CssBox/HtmlTag shape. One deliberate omission from the source: the
+    /// <c>::marker</c> pseudo-element box-synthesis path is removed - <c>::before</c>/<c>::after</c>
+    /// synthesis is kept, but this codebase has no <c>CssBox.IsMarkerPseudoElement</c> concept and no
+    /// consumer for it (list markers are painted procedurally, not via a synthesized box).
     /// </remarks>
     public sealed class CssData
     {
-        #region Fields and Consts
-
-        /// <summary>
-        /// used to return empty array
-        /// </summary>
-        private static readonly List<CssBlock> _emptyArray = new List<CssBlock>();
-
         /// <summary>
-        /// dictionary of media type to dictionary of css class name to the cssBlocks collection with all the data.
+        /// The parsed stylesheets that make up this CssData, in the order they were added (UA default
+        /// first, then author/`&lt;link&gt;`/`&lt;style&gt;` stylesheets in document order). Each carries its own
+        /// <see cref="Stylesheet.IsUserAgent"/> flag so origin-aware cascade phases can be resolved.
         /// </summary>
-        private readonly Dictionary<string, Dictionary<string, List<CssBlock>>> _mediaBlocks = new Dictionary<string, Dictionary<string, List<CssBlock>>>(StringComparer.InvariantCultureIgnoreCase);
-
-        #endregion
-
+        internal List<Stylesheet> Stylesheets { get; } = new List<Stylesheet>();
 
         /// <summary>
         /// Init.
         /// </summary>
         internal CssData()
         {
-            _mediaBlocks.Add("all", new Dictionary<string, List<CssBlock>>(StringComparer.InvariantCultureIgnoreCase));
         }
 
         /// <summary>
         /// Parse the given stylesheet to <see cref="CssData"/> object.<br/>
-        /// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the 
+        /// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the
         /// default css data (as defined by W3), merged if class name already exists. If false only the data in the given stylesheet is returned.
         /// </summary>
         /// <seealso cref="http://www.w3.org/TR/CSS21/sample.html"/>
@@ -63,152 +60,966 @@ internal CssData()
         /// <returns>the parsed css data</returns>
         public static CssData Parse(RAdapter adapter, string stylesheet, bool combineWithDefault = true)
         {
-            CssParser parser = new CssParser(adapter);
+            var parser = new CssParser(adapter);
             return parser.ParseStyleSheet(stylesheet, combineWithDefault);
         }
 
         /// <summary>
-        /// dictionary of media type to dictionary of css class name to the cssBlocks collection with all the data
+        /// Combine this CSS data's stylesheets with <paramref name="other"/>'s.
+        /// </summary>
+        /// <param name="other">the CSS data to combine with</param>
+        public void Combine(CssData other)
+        {
+            ArgChecker.AssertArgNotNull(other, "other");
+            Stylesheets.AddRange(other.Stylesheets);
+        }
+
+        /// <summary>
+        /// Create a shallow copy of this css data - the returned instance has its own <see cref="Stylesheets"/>
+        /// list (so appending a new stylesheet to the clone doesn't affect the original), but the
+        /// <see cref="Stylesheet"/> instances themselves are shared (they're never mutated after parsing).
         /// </summary>
-        internal IDictionary<string, Dictionary<string, List<CssBlock>>> MediaBlocks
+        /// <returns>cloned object</returns>
+        public CssData Clone()
+        {
+            var clone = new CssData();
+            clone.Stylesheets.AddRange(Stylesheets);
+            return clone;
+        }
+
+        // --- Rule index -----------------------------------------------------------------------
+        //
+        // Matching every stylesheet rule against every CssBox in the document (the naive approach)
+        // is O(rules x boxes) and dominates cascade cost on large documents. Real browser engines
+        // avoid this by bucketing rules by the "subject" simple selector (the one that must match the
+        // box itself, e.g. the tag/class/id) so a box only needs to test the handful of rules that
+        // could plausibly match it, instead of the whole stylesheet. DoesSelectorMatch remains the
+        // source of truth for whether a rule actually matches - the index only narrows the candidates.
+        //
+        // Built lazily, once, the first time this CssData's rules are queried. Safe because by the
+        // time CascadeApplyStyles starts querying rules for the box tree, DomParser has already
+        // finished building/cloning CssData from <style>/<link> tags, so Stylesheets doesn't change
+        // during the walk.
+        private enum SelectorBucketKind { Tag, Class, Id, Universal }
+
+        // DocumentOrder is assigned while walking stylesheets (recursing into @media blocks in
+        // place) so that, regardless of which bucket a rule is later retrieved through, the true
+        // source order - including across the plain-rule/@media boundary - can be reconstructed
+        // for specificity tie-breaking (see GetStyleRulesByOrigin). EnclosingMedia carries the
+        // chain of @media conditions (outermost first) a rule was nested under, so media matching
+        // doesn't need a separate unindexed scan.
+        private readonly struct IndexedRule
         {
-            get { return _mediaBlocks; }
+            public IndexedRule(IStyleRule rule, bool isUserAgent, int documentOrder, MediaList[] enclosingMedia)
+            {
+                Rule = rule;
+                IsUserAgent = isUserAgent;
+                DocumentOrder = documentOrder;
+                EnclosingMedia = enclosingMedia;
+            }
+
+            public IStyleRule Rule { get; }
+            public bool IsUserAgent { get; }
+            public int DocumentOrder { get; }
+            public MediaList[] EnclosingMedia { get; }
         }
 
+        private List<MediaList[]> _mediaConditions;
+        private Dictionary<string, List<IndexedRule>> _tagIndex;
+        private Dictionary<string, List<IndexedRule>> _classIndex;
+        private Dictionary<string, List<IndexedRule>> _idIndex;
+        private List<IndexedRule> _universalRules;
+
         /// <summary>
-        /// Check if there are css blocks for the given class selector.
+        /// The distinct <c>@media</c> chains any indexed rule is nested under. Small (one entry per
+        /// distinct <c>@media</c> block), and only used to test whether a change of device would change
+        /// which rules apply - see <see cref="MediaOutcomeChanged"/>.
         /// </summary>
-        /// <param name="className">the class selector to check for css blocks by</param>
-        /// <param name="media">optional: the css media type (default - all)</param>
-        /// <returns>true - has css blocks for the class, false - otherwise</returns>
-        public bool ContainsCssBlock(string className, string media = "all")
+        private static List<MediaList[]> CollectMediaConditions(
+            Dictionary<string, List<IndexedRule>> tagIndex,
+            Dictionary<string, List<IndexedRule>> classIndex,
+            Dictionary<string, List<IndexedRule>> idIndex,
+            List<IndexedRule> universal)
         {
-            Dictionary<string, List<CssBlock>> mid;
-            return _mediaBlocks.TryGetValue(media, out mid) && mid.ContainsKey(className);
+            var conditions = new List<MediaList[]>();
+
+            Action<IEnumerable<IndexedRule>> collect = rules =>
+            {
+                foreach (var indexed in rules)
+                {
+                    if (indexed.EnclosingMedia == null) continue;
+                    if (conditions.Contains(indexed.EnclosingMedia)) continue;   // reference compare: one array per block
+                    conditions.Add(indexed.EnclosingMedia);
+                }
+            };
+
+            foreach (var bucket in tagIndex.Values) collect(bucket);
+            foreach (var bucket in classIndex.Values) collect(bucket);
+            foreach (var bucket in idIndex.Values) collect(bucket);
+            collect(universal);
+
+            return conditions;
         }
 
         /// <summary>
-        /// Get collection of css blocks for the requested class selector.<br/>
-        /// the <paramref name="className"/> can be: class name, html element name, html element and 
-        /// class name (elm.class), hash tag with element id (#id).<br/>
-        /// returned all the blocks that word on the requested class selector, it can contain simple
-        /// selector or hierarchy selector.
+        /// Whether moving from <paramref name="before"/> to <paramref name="after"/> changes the outcome
+        /// of any <c>@media</c> condition in these stylesheets - i.e. whether the cascade needs to be
+        /// re-run. False for a resize that doesn't cross any breakpoint, and for documents with no
+        /// viewport-dependent <c>@media</c> at all (the common case), so the caller can skip the work.
         /// </summary>
-        /// <param name="className">the class selector to get css blocks by</param>
-        /// <param name="media">optional: the css media type (default - all)</param>
-        /// <returns>collection of css blocks, empty collection if no blocks exists (never null)</returns>
-        public IEnumerable<CssBlock> GetCssBlock(string className, string media = "all")
+        internal bool MediaOutcomeChanged(MediaQueryContext before, MediaQueryContext after)
         {
-            List<CssBlock> block = null;
-            Dictionary<string, List<CssBlock>> mid;
-            if (_mediaBlocks.TryGetValue(media, out mid))
+            EnsureIndex();
+
+            foreach (var condition in _mediaConditions)
             {
-                mid.TryGetValue(className, out block);
+                if (MediaQueryMatcher.Matches(condition, before) != MediaQueryMatcher.Matches(condition, after))
+                    return true;
             }
-            return block ?? _emptyArray;
+
+            return false;
         }
 
         /// <summary>
-        /// Add the given css block to the css data, merging to existing block if required.
+        /// Every rule in a rule list, in document order, descending into <c>@layer</c>, <c>@media</c>,
+        /// <c>@container</c>, and (when its condition evaluates true) <c>@supports</c> blocks - matching
+        /// PeachPDF's own <c>CssData.FlattenRules</c> exactly (full descent, not the narrower
+        /// style-rule-only/no-@supports-or-@container predecessor this replaces). Callers that only want
+        /// style rules (the common case - e.g. scanning for a rule by selector rather than matching
+        /// against a box, since <see cref="Stylesheet.StyleRules"/> only sees the top level) filter with
+        /// <c>.OfType&lt;IStyleRule&gt;()</c>, matching PeachPDF's own call-site pattern of filtering the
+        /// general enumerator per use rather than a dedicated pre-filtered helper. CSS-Nesting child rules
+        /// are reached because <see cref="IStyleRule"/> is itself yielded before recursing.
         /// </summary>
-        /// <remarks>
-        /// If there is no css blocks for the same class it will be added to data collection.<br/>
-        /// If there is already css blocks for the same class it will check for each existing block
-        /// if the hierarchical selectors match (or not exists). if do the two css blocks will be merged into
-        /// one where the new block properties overwrite existing if needed. if the new block doesn't mach any
-        /// existing it will be added either to the beginning of the list if it has no  hierarchical selectors or at the end.<br/>
-        /// Css block without hierarchical selectors must be added to the beginning of the list so more specific block
-        /// can overwrite it when the style is applied.
-        /// </remarks>
-        /// <param name="media">the media type to add the CSS to</param>
-        /// <param name="cssBlock">the css block to add</param>
-        public void AddCssBlock(string media, CssBlock cssBlock)
+        internal static IEnumerable<IRule> FlattenRules(IEnumerable<IRule> rules)
         {
-            Dictionary<string, List<CssBlock>> mid;
-            if (!_mediaBlocks.TryGetValue(media, out mid))
+            foreach (var rule in rules)
             {
-                mid = new Dictionary<string, List<CssBlock>>(StringComparer.InvariantCultureIgnoreCase);
-                _mediaBlocks.Add(media, mid);
+                yield return rule;
+
+                if (rule is IStyleRule styleRule)
+                {
+                    foreach (var nested in FlattenRules(styleRule.NestedRules))
+                        yield return nested;
+                }
+                else if (rule is ILayerRule layerRule)
+                {
+                    foreach (var nested in FlattenRules(layerRule.Rules))
+                        yield return nested;
+                }
+                else if (rule is IMediaRule mediaRule)
+                {
+                    foreach (var nested in FlattenRules(mediaRule.Rules))
+                        yield return nested;
+                }
+                else if (rule is IContainerRule containerRule)
+                {
+                    foreach (var nested in FlattenRules(containerRule.Rules))
+                        yield return nested;
+                }
+                else if (rule is ISupportsRule supportsRule)
+                {
+                    if (supportsRule.Condition.Check())
+                    {
+                        foreach (var nested in FlattenRules(supportsRule.Rules))
+                            yield return nested;
+                    }
+                }
             }
+        }
+
+        private void EnsureIndex()
+        {
+            if (_universalRules != null) return;
 
-            if (!mid.ContainsKey(cssBlock.Class))
+            var tagIndex = new Dictionary<string, List<IndexedRule>>(StringComparer.InvariantCultureIgnoreCase);
+            var classIndex = new Dictionary<string, List<IndexedRule>>(StringComparer.InvariantCultureIgnoreCase);
+            var idIndex = new Dictionary<string, List<IndexedRule>>(StringComparer.InvariantCultureIgnoreCase);
+            var universal = new List<IndexedRule>();
+            var keys = new List<(SelectorBucketKind Kind, string Key)>();
+            var order = 0;
+
+            foreach (var stylesheet in Stylesheets)
             {
-                var list = new List<CssBlock>();
-                list.Add(cssBlock);
-                mid[cssBlock.Class] = list;
+                IndexRules(stylesheet.Rules, stylesheet.IsUserAgent, null, tagIndex, classIndex, idIndex, universal, keys, ref order);
             }
-            else
+
+            _tagIndex = tagIndex;
+            _classIndex = classIndex;
+            _idIndex = idIndex;
+            _mediaConditions = CollectMediaConditions(tagIndex, classIndex, idIndex, universal);
+            _universalRules = universal;
+        }
+
+        /// <summary>
+        /// Walks a rule list in true document order, recursing into <c>@media</c> blocks, <c>@layer</c>
+        /// blocks and CSS-Nesting child rules (any nesting depth) in place, and buckets every style rule
+        /// found - assigning each an ever-increasing <see cref="IndexedRule.DocumentOrder"/> and recording
+        /// the chain of enclosing media conditions it's nested under, if any.
+        /// </summary>
+        private static void IndexRules(
+            IEnumerable<IRule> rules,
+            bool isUserAgent,
+            MediaList[] enclosingMedia,
+            Dictionary<string, List<IndexedRule>> tagIndex,
+            Dictionary<string, List<IndexedRule>> classIndex,
+            Dictionary<string, List<IndexedRule>> idIndex,
+            List<IndexedRule> universal,
+            List<(SelectorBucketKind Kind, string Key)> keys,
+            ref int order)
+        {
+            foreach (var rule in rules)
             {
-                bool merged = false;
-                var list = mid[cssBlock.Class];
-                foreach (var block in list)
+                if (rule is IStyleRule styleRule)
                 {
-                    if (block.EqualsSelector(cssBlock))
+                    var indexedRule = new IndexedRule(styleRule, isUserAgent, order++, enclosingMedia);
+
+                    keys.Clear();
+                    CollectIndexKeys(styleRule.Selector, keys);
+
+                    foreach (var (kind, key) in keys)
                     {
-                        merged = true;
-                        block.Merge(cssBlock);
-                        break;
+                        Dictionary<string, List<IndexedRule>> bucket;
+                        switch (kind)
+                        {
+                            case SelectorBucketKind.Tag: bucket = tagIndex; break;
+                            case SelectorBucketKind.Class: bucket = classIndex; break;
+                            case SelectorBucketKind.Id: bucket = idIndex; break;
+                            default: bucket = null; break;
+                        }
+
+                        if (bucket == null)
+                        {
+                            universal.Add(indexedRule);
+                        }
+                        else
+                        {
+                            List<IndexedRule> list;
+                            if (!bucket.TryGetValue(key, out list))
+                                bucket[key] = list = new List<IndexedRule>();
+                            list.Add(indexedRule);
+                        }
                     }
+
+                    // CSS Nesting: a nested rule lives in its parent's NestedRules, deliberately not in
+                    // Children, so it is invisible to Stylesheet.Rules and would otherwise never be
+                    // indexed. Its selector was already resolved against the parent at parse time, so it
+                    // indexes like any other rule - under the same media context, and with a document
+                    // order that continues from the parent so it tie-breaks after it.
+                    if (styleRule.NestedRules.Count > 0)
+                    {
+                        IndexRules(styleRule.NestedRules, isUserAgent, enclosingMedia, tagIndex, classIndex, idIndex, universal, keys, ref order);
+                    }
+                }
+                else if (rule is IMediaRule mediaRule)
+                {
+                    MediaList[] nestedMedia = enclosingMedia == null
+                        ? new[] { mediaRule.Media }
+                        : enclosingMedia.Concat(new[] { mediaRule.Media }).ToArray();
+                    IndexRules(mediaRule.Rules, isUserAgent, nestedMedia, tagIndex, classIndex, idIndex, universal, keys, ref order);
                 }
+                else if (rule is ILayerRule layerRule)
+                {
+                    // @layer's contents are indexed as ordinary, unlayered rules: they apply, ordered by
+                    // source position and specificity. Layer precedence, !important layer reversal and
+                    // revert-layer are deliberately not implemented - that needs a layer-banded cascade,
+                    // which is separate work. Without this branch the block would fall through and every
+                    // rule inside a layer would silently stop applying.
+                    IndexRules(layerRule.Rules, isUserAgent, enclosingMedia, tagIndex, classIndex, idIndex, universal, keys, ref order);
+                }
+                // Everything else (@layer statements, @property, @font-palette-values, @supports,
+                // @container, ...) contributes no style rules to the cascade, so falling through is the
+                // correct handling rather than an oversight.
+            }
+        }
 
-                if (!merged)
+        /// <summary>
+        /// Determines which bucket(s) a rule's selector should be indexed under, based on the simple
+        /// selector that must match the box itself (for <see cref="ComplexSelector"/>, that's its
+        /// rightmost/subject selector - see the reversal in <see cref="DoesSelectorMatch(ComplexSelector, CssBox)"/>).
+        /// A <see cref="ListSelector"/> (comma-separated) contributes one key per alternative, since
+        /// matching any alternative matches the rule.
+        /// </summary>
+        private static void CollectIndexKeys(ISelector selector, List<(SelectorBucketKind Kind, string Key)> keys)
+        {
+            if (selector is ListSelector listSelector)
+            {
+                foreach (var sub in listSelector)
+                    CollectIndexKeys(sub, keys);
+            }
+            else if (selector is ComplexSelector complexSelector)
+            {
+                var last = complexSelector.LastOrDefault().Selector;
+                if (last != null)
+                    CollectIndexKeys(last, keys);
+                else
+                    keys.Add((SelectorBucketKind.Universal, string.Empty));
+            }
+            else if (selector is CompoundSelector compoundSelector)
+            {
+                // Pseudo-element and :first-child subjects need the box's own HtmlTag/ParentBox
+                // re-derived at match time (see DoesSelectorMatch), including for synthesized
+                // pseudo-element boxes whose HtmlTag is null - the tag/class/id index can't
+                // safely represent that, so fall back to a full scan for these.
+                if (compoundSelector.Any(s => s is PseudoElementSelector || s is FirstChildSelector))
+                {
+                    keys.Add((SelectorBucketKind.Universal, string.Empty));
+                    return;
+                }
+
+                IdSelector id = null;
+                ClassSelector cls = null;
+                TypeSelector type = null;
+
+                foreach (var member in compoundSelector)
                 {
-                    // general block must be first
-                    if (cssBlock.Selectors == null)
-                        list.Insert(0, cssBlock);
-                    else
-                        list.Add(cssBlock);
+                    if (member is IdSelector idSel) id = id ?? idSel;
+                    else if (member is ClassSelector clsSel) cls = cls ?? clsSel;
+                    else if (member is TypeSelector typeSel) type = type ?? typeSel;
                 }
+
+                if (id != null) keys.Add((SelectorBucketKind.Id, id.Id));
+                else if (cls != null) keys.Add((SelectorBucketKind.Class, cls.Class));
+                else if (type != null) keys.Add((SelectorBucketKind.Tag, type.Name));
+                else keys.Add((SelectorBucketKind.Universal, string.Empty));
+            }
+            else if (selector is TypeSelector typeSelector)
+            {
+                keys.Add((SelectorBucketKind.Tag, typeSelector.Name));
+            }
+            else if (selector is ClassSelector classSelector)
+            {
+                keys.Add((SelectorBucketKind.Class, classSelector.Class));
+            }
+            else if (selector is IdSelector idSelector)
+            {
+                keys.Add((SelectorBucketKind.Id, idSelector.Id));
+            }
+            else
+            {
+                // AllSelector, bare pseudo-class/element/attribute selectors, etc.
+                keys.Add((SelectorBucketKind.Universal, string.Empty));
             }
         }
 
         /// <summary>
-        /// Combine this CSS data blocks with <paramref name="other"/> CSS blocks for each media.<br/>
-        /// Merge blocks if exists in both.
+        /// All style rules (any origin) matching <paramref name="box"/> under <paramref name="media"/>,
+        /// ordered by specificity then document order.
         /// </summary>
-        /// <param name="other">the CSS data to combine with</param>
-        public void Combine(CssData other)
+        internal IEnumerable<IStyleRule> GetStyleRules(MediaQueryContext media, CssBox box)
         {
-            ArgChecker.AssertArgNotNull(other, "other");
+            return GetStyleRulesByOrigin(media, box, null);
+        }
+
+        /// <summary>
+        /// Only the user-agent (default stylesheet) rules matching <paramref name="box"/>.
+        /// </summary>
+        internal IEnumerable<IStyleRule> GetUserAgentStyleRules(MediaQueryContext media, CssBox box)
+        {
+            return GetStyleRulesByOrigin(media, box, true);
+        }
+
+        /// <summary>
+        /// Only the author (non-default) rules matching <paramref name="box"/>.
+        /// </summary>
+        internal IEnumerable<IStyleRule> GetAuthorStyleRules(MediaQueryContext media, CssBox box)
+        {
+            return GetStyleRulesByOrigin(media, box, false);
+        }
+
+        private IEnumerable<IStyleRule> GetStyleRulesByOrigin(MediaQueryContext media, CssBox box, bool? userAgentOnly)
+        {
+            EnsureIndex();
+
+            // Rules matched via the index below can, in rare cases (a comma-separated selector list
+            // whose alternatives land in different buckets, e.g. "div, .foo" matching a <div class="foo">),
+            // be reachable through more than one bucket. Dedup so callers never see the same rule twice.
+            HashSet<IStyleRule> seen = null;
+            var matched = new List<IndexedRule>();
 
-            // for each media block
-            foreach (var mediaBlock in other.MediaBlocks)
+            Action<IndexedRule> collect = indexed =>
             {
-                // for each css class in the media block
-                foreach (var bla in mediaBlock.Value)
+                if (userAgentOnly.HasValue && indexed.IsUserAgent != userAgentOnly.Value) return;
+                if (!MediaQueryMatcher.Matches(indexed.EnclosingMedia, media)) return;
+                if (!DoesSelectorMatch(indexed.Rule.Selector, box)) return;
+                seen = seen ?? new HashSet<IStyleRule>();
+                if (!seen.Add(indexed.Rule)) return;
+                matched.Add(indexed);
+            };
+
+            foreach (var indexed in _universalRules)
+                collect(indexed);
+
+            if (box.HtmlTag != null)
+            {
+                List<IndexedRule> tagRules;
+                if (_tagIndex.TryGetValue(box.HtmlTag.Name, out tagRules))
+                {
+                    foreach (var indexed in tagRules)
+                        collect(indexed);
+                }
+
+                if (box.HtmlTag.Attributes != null)
                 {
-                    // for each css block of the css class
-                    foreach (var cssBlock in bla.Value)
+                    string classAttr;
+                    if (box.HtmlTag.Attributes.TryGetValue("class", out classAttr) && classAttr.Length > 0)
                     {
-                        // combine with this
-                        AddCssBlock(mediaBlock.Key, cssBlock);
+                        foreach (var className in classAttr.Split(' '))
+                        {
+                            if (className.Length == 0) continue;
+                            List<IndexedRule> classRules;
+                            if (_classIndex.TryGetValue(className, out classRules))
+                                foreach (var indexed in classRules)
+                                    collect(indexed);
+                        }
+                    }
+
+                    string idAttr;
+                    List<IndexedRule> idRules;
+                    if (box.HtmlTag.Attributes.TryGetValue("id", out idAttr) && idAttr.Length > 0
+                        && _idIndex.TryGetValue(idAttr, out idRules))
+                    {
+                        foreach (var indexed in idRules)
+                            collect(indexed);
                     }
                 }
             }
+
+            // Stable sort by specificity, tie-broken by DocumentOrder (true source order, including
+            // across the plain-rule/@media boundary, assigned once up front by IndexRules) - equal-
+            // specificity rules keep true document order for correct source-order tiebreaking.
+            return matched
+                .OrderBy(indexed => GetMatchedSpecificity(indexed.Rule.Selector, box))
+                .ThenBy(indexed => indexed.DocumentOrder)
+                .Select(indexed => indexed.Rule);
         }
 
         /// <summary>
-        /// Create deep copy of the css data with cloned css blocks.
+        /// The effective specificity of a matched rule's selector for cascade-ordering purposes,
+        /// relative to a specific matched box. This deliberately differs from calling
+        /// <c>selector.Specificity</c> directly for a top-level <see cref="ListSelector"/> (comma-
+        /// separated rule selector, e.g. "h1, h2 {}"): per spec a selector list used as a whole
+        /// rule's selector is cascade-equivalent to separate rules, so the specificity that governs
+        /// THIS box's cascade is whichever one alternative actually matched it - not every
+        /// alternative's static max (which is what <see cref="ListSelector.Specificity"/> reports,
+        /// correctly, for its OTHER use as an argument to :is()/:not()/:has()).
         /// </summary>
-        /// <returns>cloned object</returns>
-        public CssData Clone()
+        private static Priority GetMatchedSpecificity(ISelector selector, CssBox box)
         {
-            var clone = new CssData();
-            foreach (var mid in _mediaBlocks)
+            var list = selector as ListSelector;
+            if (list != null)
+            {
+                return list
+                    .Where(s => DoesSelectorMatch(s, box))
+                    .Select(s => s.Specificity)
+                    .DefaultIfEmpty(Priority.Zero)
+                    .Max();
+            }
+
+            return selector.Specificity;
+        }
+
+        private static bool DoesSelectorMatch(ISelector selector, CssBox box)
+        {
+            if (selector is AllSelector) return true;
+            if (selector is ListSelector listSelector) return DoesSelectorMatch(listSelector, box);
+            if (selector is TypeSelector typeSelector) return DoesSelectorMatch(typeSelector, box);
+            if (selector is ComplexSelector complexSelector) return DoesSelectorMatch(complexSelector, box);
+            if (selector is CompoundSelector compoundSelector) return DoesSelectorMatch(compoundSelector, box);
+            if (selector is PseudoElementSelector pseudoElementSelector) return DoesSelectorMatch(pseudoElementSelector, box);
+            if (selector is PseudoClassSelector pseudoClassSelector) return DoesSelectorMatch(pseudoClassSelector, box);
+            if (selector is AttrMatchSelector attrMatchSelector) return DoesSelectorMatch(attrMatchSelector, box);
+            if (selector is ClassSelector classSelector) return DoesSelectorMatch(classSelector, box);
+            if (selector is IdSelector idSelector) return DoesSelectorMatch(idSelector, box);
+            if (selector is AttrAvailableSelector attrAvailableSelector) return DoesSelectorMatch(attrAvailableSelector, box);
+            if (selector is AttrContainsSelector attrContainsSelector) return DoesSelectorMatch(attrContainsSelector, box);
+            if (selector is AttrListSelector attrListSelector) return DoesSelectorMatch(attrListSelector, box);
+            if (selector is AttrBeginsSelector attrBeginsSelector) return DoesSelectorMatch(attrBeginsSelector, box);
+            if (selector is AttrEndsSelector attrEndsSelector) return DoesSelectorMatch(attrEndsSelector, box);
+            if (selector is AttrHyphenSelector attrHyphenSelector) return DoesSelectorMatch(attrHyphenSelector, box);
+            if (selector is ChildSelector childSelector) return DoesSelectorMatch(childSelector, box);
+            if (selector is OnlyChildSelector onlyChildSelector) return DoesSelectorMatch(onlyChildSelector, box);
+            if (selector is OnlyOfTypeSelector onlyOfTypeSelector) return DoesSelectorMatch(onlyOfTypeSelector, box);
+            if (selector is NotSelector notSelector) return DoesSelectorMatch(notSelector, box);
+            if (selector is MatchesSelector matchesSelector) return DoesSelectorMatch(matchesSelector, box);
+            if (selector is HasSelector hasSelector) return DoesSelectorMatch(hasSelector, box);
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(ListSelector listSelector, CssBox box)
+        {
+            return listSelector.Any(selector => DoesSelectorMatch(selector, box));
+        }
+
+        private static bool DoesSelectorMatch(CompoundSelector compoundSelector, CssBox box)
+        {
+            if (box == null)
+            {
+                return false;
+            }
+
+            var lastSelector = compoundSelector.Last();
+
+            // Structural pseudo-classes (ChildSelector subtypes, OnlyChildSelector, OnlyOfTypeSelector)
+            // are matched against `box` itself here, same as every other compound member - their own
+            // DoesSelectorMatch overload re-derives sibling scope from `box` as needed, so no special
+            // handling is required for them beyond the plain path below.
+            var pseudoElementSelector = lastSelector as PseudoElementSelector;
+            if (pseudoElementSelector == null)
+                return compoundSelector.All(selector => DoesSelectorMatch(selector, box));
+
+            var referenceBox = box.IsPseudoElement ? box.ParentBox : box;
+
+            var isMatchWithoutPseudoElement = compoundSelector
+                .Where(x => !(x is PseudoElementSelector))
+                .All(selector => DoesSelectorMatch(selector, referenceBox));
+
+            if (!isMatchWithoutPseudoElement) return false;
+
+            if (box.IsPseudoElement)
+            {
+                return DoesSelectorMatch(pseudoElementSelector, box);
+            }
+
+            // Only ::before/::after synthesize a box here - ::marker is intentionally not ported
+            // (no CssBox.IsMarkerPseudoElement concept in this codebase; list markers are painted
+            // procedurally, not via a synthesized box - see PaintListStyleShapeMarker and friends).
+            if (pseudoElementSelector.Name == CssConstants.Before && !box.Boxes.Any(b => b.IsBeforePseudoElement))
+            {
+                var beforePseudoBox = new CssBox(box, null);
+                beforePseudoBox.IsBeforePseudoElement = true;
+
+                beforePseudoBox.InheritStyle(box);
+                box.Boxes.Remove(beforePseudoBox);
+                box.Boxes.Insert(0, beforePseudoBox);
+            }
+            else if (pseudoElementSelector.Name == CssConstants.After && !box.Boxes.Any(b => b.IsAfterPseudoElement))
+            {
+                var afterPseudoBox = new CssBox(box, null);
+                afterPseudoBox.IsAfterPseudoElement = true;
+
+                afterPseudoBox.InheritStyle(box);
+                box.Boxes.Remove(afterPseudoBox);
+                box.Boxes.Add(afterPseudoBox);
+            }
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(TypeSelector typeSelector, CssBox box)
+        {
+            return box != null && box.HtmlTag != null && typeSelector.Name.Equals(box.HtmlTag.Name, StringComparison.InvariantCultureIgnoreCase);
+        }
+
+        private static bool DoesSelectorMatch(ClassSelector classSelector, CssBox box)
+        {
+            string classNames;
+            if (box != null && box.HtmlTag != null && box.HtmlTag.Attributes != null && box.HtmlTag.Attributes.TryGetValue("class", out classNames))
+            {
+                return classNames.Split(' ').Any(className =>
+                    className.Equals(classSelector.Class, StringComparison.InvariantCultureIgnoreCase));
+            }
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(IdSelector idSelector, CssBox box)
+        {
+            string id;
+            if (box != null && box.HtmlTag != null && box.HtmlTag.Attributes != null && box.HtmlTag.Attributes.TryGetValue("id", out id))
+            {
+                return id.Equals(idSelector.Id, StringComparison.InvariantCultureIgnoreCase);
+            }
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(AttrAvailableSelector attrAvailableSelector, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null || box.HtmlTag.Attributes == null)
+            {
+                return false;
+            }
+
+            foreach (var attribute in box.HtmlTag.Attributes)
             {
-                var cloneMid = new Dictionary<string, List<CssBlock>>(StringComparer.InvariantCultureIgnoreCase);
-                foreach (var blocks in mid.Value)
+                if (attribute.Key.Equals(attrAvailableSelector.Attribute, StringComparison.InvariantCultureIgnoreCase))
                 {
-                    var cloneList = new List<CssBlock>();
-                    foreach (var cssBlock in blocks.Value)
-                    {
-                        cloneList.Add(cssBlock.Clone());
-                    }
-                    cloneMid[blocks.Key] = cloneList;
+                    return true;
                 }
-                clone._mediaBlocks[mid.Key] = cloneMid;
             }
-            return clone;
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(AttrMatchSelector attrMatchSelector, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null || box.HtmlTag.Attributes == null)
+            {
+                return false;
+            }
+
+            foreach (var attribute in box.HtmlTag.Attributes)
+            {
+                if (attribute.Key.Equals(attrMatchSelector.Attribute, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    return attribute.Value.Equals(attrMatchSelector.Value, StringComparison.InvariantCultureIgnoreCase);
+                }
+            }
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(AttrListSelector attrListSelector, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null || box.HtmlTag.Attributes == null)
+            {
+                return false;
+            }
+
+            foreach (var attribute in box.HtmlTag.Attributes)
+            {
+                if (attribute.Key.Equals(attrListSelector.Attribute, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    var attributeValues = attribute.Value.Split(' ').Where(x => x.Length > 0).ToArray();
+
+                    return attributeValues.Any(value => value.Equals(attrListSelector.Value, StringComparison.InvariantCultureIgnoreCase));
+                }
+            }
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(AttrContainsSelector attrContainsSelector, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null || box.HtmlTag.Attributes == null)
+            {
+                return false;
+            }
+
+            foreach (var attribute in box.HtmlTag.Attributes)
+            {
+                if (attribute.Key.Equals(attrContainsSelector.Attribute, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    return attribute.Value.IndexOf(attrContainsSelector.Value, StringComparison.InvariantCultureIgnoreCase) >= 0;
+                }
+            }
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(AttrBeginsSelector s, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null || box.HtmlTag.Attributes == null) return false;
+            foreach (var attr in box.HtmlTag.Attributes)
+                if (attr.Key.Equals(s.Attribute, StringComparison.InvariantCultureIgnoreCase))
+                    return attr.Value.StartsWith(s.Value, StringComparison.InvariantCultureIgnoreCase);
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(AttrEndsSelector s, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null || box.HtmlTag.Attributes == null) return false;
+            foreach (var attr in box.HtmlTag.Attributes)
+                if (attr.Key.Equals(s.Attribute, StringComparison.InvariantCultureIgnoreCase))
+                    return attr.Value.EndsWith(s.Value, StringComparison.InvariantCultureIgnoreCase);
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(AttrHyphenSelector s, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null || box.HtmlTag.Attributes == null) return false;
+            foreach (var attr in box.HtmlTag.Attributes)
+                if (attr.Key.Equals(s.Attribute, StringComparison.InvariantCultureIgnoreCase))
+                    return attr.Value.Equals(s.Value, StringComparison.InvariantCultureIgnoreCase)
+                        || attr.Value.StartsWith(s.Value + "-", StringComparison.InvariantCultureIgnoreCase);
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(PseudoClassSelector pseudoClassSelector, CssBox box)
+        {
+            if (box == null) return false;
+
+            // ":hover" is matched structurally (ignoring live mouse-hover state, which this engine
+            // doesn't track at cascade time) so DomParser.AssignCssBlock can intercept the match and
+            // divert it to HtmlContainerInt.AddHoverBox instead of applying it - preserving the
+            // "matched but inert" behavior this engine has always had for :hover (see DomParser).
+            if (pseudoClassSelector.Class == "hover") return true;
+
+            // ":root" always matches the document's <html> element - this engine has no separate
+            // CssBox.IsRoot flag, so match on tag name directly (correct for any HTML document).
+            if (pseudoClassSelector.Class == "root")
+                return box.HtmlTag != null && box.HtmlTag.Name.Equals("html", StringComparison.InvariantCultureIgnoreCase);
+
+            return pseudoClassSelector.Class == "link" && box.IsClickable;
+        }
+
+        private static bool DoesSelectorMatch(PseudoElementSelector pseudoElementSelector, CssBox box)
+        {
+            if (box == null)
+            {
+                return false;
+            }
+
+            if (pseudoElementSelector.Name == CssConstants.Before) return box.IsBeforePseudoElement;
+            if (pseudoElementSelector.Name == CssConstants.After) return box.IsAfterPseudoElement;
+            return false;
+        }
+
+        /// <summary>
+        /// Matches the six structural "An+B" pseudo-classes (:nth-child, :nth-last-child,
+        /// :nth-of-type, :nth-last-of-type, :nth-column, :nth-last-column - including their bare-ident
+        /// forms like :first-child, wired to Step=0/Offset=1 by PseudoClassSelectorFactory).
+        /// Each variant differs only in (a) which sibling scope to count within and (b) whether to
+        /// count from the start or the end; the actual "does this position satisfy An+B" test is
+        /// shared via <see cref="MatchesAnPlusB"/>.
+        /// </summary>
+        private static bool DoesSelectorMatch(ChildSelector childSelector, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null)
+            {
+                return false;
+            }
+
+            if (childSelector is FirstColumnSelector || childSelector is LastColumnSelector)
+            {
+                return DoesColumnSelectorMatch(childSelector, box, childSelector is LastColumnSelector);
+            }
+
+            var parentBox = DomUtils.GetNearestParentElementBox(box);
+            if (parentBox == null)
+            {
+                return false;
+            }
+
+            IEnumerable<CssBox> siblingBoxes = parentBox.Boxes.Where(b => b.HtmlTag != null);
+
+            var sameTypeOnly = childSelector is FirstTypeSelector || childSelector is LastTypeSelector;
+            if (sameTypeOnly)
+            {
+                siblingBoxes = siblingBoxes.Where(b =>
+                    b.HtmlTag.Name.Equals(box.HtmlTag.Name, StringComparison.InvariantCultureIgnoreCase));
+            }
+
+            // CSS4 "of <selector>" extension (:nth-child(An+B of S)/:nth-last-child(An+B of S)).
+            // Kind defaults to AllSelector (matches unconditionally) whenever no "of" clause was
+            // written, and the parser only ever allows a non-default Kind on FirstChildSelector/
+            // LastChildSelector - so this filter is always a no-op for the four other subtypes.
+            // Applying it unconditionally is simpler than special-casing which subtypes can have it.
+            siblingBoxes = siblingBoxes.Where(b => DoesSelectorMatch(childSelector.Kind, b));
+
+            var siblings = siblingBoxes.ToList();
+            var index = siblings.IndexOf(box);
+            if (index < 0)
+            {
+                return false;
+            }
+
+            var fromEndPosition = childSelector is LastChildSelector || childSelector is LastTypeSelector;
+            var position = fromEndPosition ? siblings.Count - index : index + 1;
+
+            return MatchesAnPlusB(position, childSelector.Step, childSelector.Offset);
+        }
+
+        /// <summary>
+        /// Matches :nth-column()/:nth-last-column() against the cell's occupied column position(s)
+        /// within its own row. Only accounts for colspan of preceding cells in the SAME row.
+        /// A colspan-N cell occupies N columns; per spec this matches if ANY occupied column position
+        /// satisfies the An+B formula, not just the cell's starting column.
+        /// </summary>
+        private static bool DoesColumnSelectorMatch(ChildSelector childSelector, CssBox box, bool fromEnd)
+        {
+            var row = box.ParentBox;
+            if (row == null)
+            {
+                return false;
+            }
+
+            var cellsInRow = row.Boxes.Where(b => b.HtmlTag != null).ToList();
+            var columnIndex = 0;
+            var totalColumns = 0;
+            var found = false;
+
+            foreach (var cell in cellsInRow)
+            {
+                if (cell == box)
+                {
+                    columnIndex = totalColumns;
+                    found = true;
+                }
+
+                totalColumns += GetColSpan(cell);
+            }
+
+            if (!found)
+            {
+                return false;
+            }
+
+            var boxSpan = GetColSpan(box);
+            for (var column = columnIndex; column < columnIndex + boxSpan; column++)
+            {
+                var position = fromEnd ? totalColumns - column : column + 1;
+                if (MatchesAnPlusB(position, childSelector.Step, childSelector.Offset))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Reads a box's "colspan" HTML attribute (default 1 if absent/invalid). Deliberately
+        /// duplicated from <see cref="Dom.CssLayoutEngineTable"/>'s private equivalent rather than
+        /// shared - this runs at cascade time, before the layout-phase state that method's column
+        /// bookkeeping otherwise depends on exists.
+        /// </summary>
+        private static int GetColSpan(CssBox box)
+        {
+            var value = box.GetAttribute("colspan", "1");
+            int colSpan;
+            return !int.TryParse(value, out colSpan) || colSpan < 1 ? 1 : colSpan;
+        }
+
+        /// <summary>
+        /// The standard CSS "An+B" existence test: does there exist a non-negative integer n such that
+        /// position == step*n + offset? position is always the 1-based index within whatever sibling
+        /// scope the caller has already resolved.
+        /// </summary>
+        private static bool MatchesAnPlusB(int position, int step, int offset)
+        {
+            if (step == 0)
+            {
+                return position == offset;
+            }
+
+            var diff = position - offset;
+            return diff % step == 0 && (step > 0 ? diff >= 0 : diff <= 0);
+        }
+
+        private static bool DoesSelectorMatch(OnlyChildSelector _, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null)
+            {
+                return false;
+            }
+
+            var parentBox = DomUtils.GetNearestParentElementBox(box);
+            return parentBox != null && parentBox.Boxes.Count(b => b.HtmlTag != null) == 1;
+        }
+
+        private static bool DoesSelectorMatch(OnlyOfTypeSelector _, CssBox box)
+        {
+            if (box == null || box.HtmlTag == null)
+            {
+                return false;
+            }
+
+            var parentBox = DomUtils.GetNearestParentElementBox(box);
+            if (parentBox == null)
+            {
+                return false;
+            }
+
+            return parentBox.Boxes.Count(b =>
+                b.HtmlTag != null &&
+                b.HtmlTag.Name.Equals(box.HtmlTag.Name, StringComparison.InvariantCultureIgnoreCase)) == 1;
+        }
+
+        private static bool DoesSelectorMatch(NotSelector notSelector, CssBox box)
+        {
+            return box != null && !DoesSelectorMatch(notSelector.Inner, box);
+        }
+
+        private static bool DoesSelectorMatch(MatchesSelector matchesSelector, CssBox box)
+        {
+            return DoesSelectorMatch(matchesSelector.Inner, box);
+        }
+
+        private static bool DoesSelectorMatch(HasSelector hasSelector, CssBox box)
+        {
+            return box != null && HasDescendantMatch(box, hasSelector.Inner);
+        }
+
+        /// <summary>
+        /// Recursively searches box's descendants (at any depth) for one matching inner, short-
+        /// circuiting on the first hit. Backs :has()'s default (descendant) relative-selector form;
+        /// leading-combinator forms (":has(&gt; x)"/"+"/"~") aren't supported.
+        /// </summary>
+        private static bool HasDescendantMatch(CssBox box, ISelector inner)
+        {
+            foreach (var child in box.Boxes)
+            {
+                if (DoesSelectorMatch(inner, child)) return true;
+                if (HasDescendantMatch(child, inner)) return true;
+            }
+
+            return false;
+        }
+
+        private static bool DoesSelectorMatch(ComplexSelector complexSelector, CssBox box)
+        {
+            var selectorsInReverse = complexSelector.Reverse().ToList();
+
+            var isLowestItem = true;
+            var currentRef = box;
+
+            foreach (var selector in selectorsInReverse)
+            {
+                if (selector.Selector == null) return false;
+
+                if (isLowestItem)
+                {
+                    if (!DoesSelectorMatch(selector.Selector, currentRef)) return false;
+                    isLowestItem = false;
+                    continue;
+                }
+
+                if (currentRef == null) return false;
+
+                if (selector.Delimiter == ">")
+                {
+                    currentRef = currentRef.ParentBox;
+                    if (!DoesSelectorMatch(selector.Selector, currentRef)) return false;
+                }
+                else if (selector.Delimiter == " " || selector.Delimiter == null)
+                {
+                    currentRef = currentRef.ParentBox;
+                    while (currentRef != null && !DoesSelectorMatch(selector.Selector, currentRef))
+                        currentRef = currentRef.ParentBox;
+                    if (currentRef == null) return false;
+                }
+                else if (selector.Delimiter == "+")
+                {
+                    var parent = currentRef.ParentBox;
+                    if (parent == null) return false;
+                    var siblings = parent.Boxes.Where(b => b.HtmlTag != null).ToList();
+                    var idx = siblings.IndexOf(currentRef);
+                    if (idx <= 0) return false;
+                    currentRef = siblings[idx - 1];
+                    if (!DoesSelectorMatch(selector.Selector, currentRef)) return false;
+                }
+                else if (selector.Delimiter == "~")
+                {
+                    var parent = currentRef.ParentBox;
+                    if (parent == null) return false;
+                    var siblings = parent.Boxes.Where(b => b.HtmlTag != null).ToList();
+                    var idx = siblings.IndexOf(currentRef);
+                    if (idx <= 0) return false;
+                    CssBox match = null;
+                    for (var i = idx - 1; i >= 0; i--)
+                        if (DoesSelectorMatch(selector.Selector, siblings[i])) { match = siblings[i]; break; }
+                    if (match == null) return false;
+                    currentRef = match;
+                }
+                else
+                {
+                    return false;
+                }
+            }
+
+            return true;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer/Core/CssDefaults.cs b/Source/HtmlRenderer/Core/CssDefaults.cs
index bb313c223..fa143788a 100644
--- a/Source/HtmlRenderer/Core/CssDefaults.cs
+++ b/Source/HtmlRenderer/Core/CssDefaults.cs
@@ -119,10 +119,122 @@ @media print {
         /*This is the background of the HtmlToolTip*/
         .htmltooltip {
             border:solid 1px #767676;
-            background-color:white;
-            background-gradient:#E4E5F0;
-            padding: 8px; 
+            background-color:#E4E5F0;
+            padding: 8px;
             Font: 9pt Tahoma;
         }";
+
+        /// <summary>
+        /// The initial value of every property this engine recognizes (<see cref="Utils.CssUtils"/>'s exact
+        /// whitelist), used to resolve the <c>initial</c>/<c>unset</c>/<c>revert</c>/<c>revert-layer</c>
+        /// CSS-wide keywords in the six-phase cascade (<see cref="Parse.DomParser"/>). Deliberately matches
+        /// this engine's own existing field defaults (<see cref="Dom.CssBoxProperties"/>'s private field
+        /// initializers) rather than the CSS spec's initial values where the two differ (e.g. this engine's
+        /// border-color default is "black", not the spec's "currentcolor"; text-align/text-decoration/
+        /// list-style-image default to an empty string here, not "left"/"none"/"none") - so resolving
+        /// "initial" produces exactly what an unstyled box already looks like today, not a new value.
+        /// </summary>
+        internal static readonly System.Collections.Generic.Dictionary<string, string> InitialValues =
+            new System.Collections.Generic.Dictionary<string, string>(System.StringComparer.OrdinalIgnoreCase)
+        {
+            { "background-color", "transparent" },
+            { "background-image", "none" },
+            { "background-position", "0% 0%" },
+            { "background-repeat", "repeat" },
+            { "border-top-width", "medium" },
+            { "border-right-width", "medium" },
+            { "border-bottom-width", "medium" },
+            { "border-left-width", "medium" },
+            { "border-top-color", "black" },
+            { "border-right-color", "black" },
+            { "border-bottom-color", "black" },
+            { "border-left-color", "black" },
+            { "border-top-style", "none" },
+            { "border-right-style", "none" },
+            { "border-bottom-style", "none" },
+            { "border-left-style", "none" },
+            { "border-spacing", "0" },
+            { "border-collapse", "separate" },
+            { "color", "black" },
+            { "content", "normal" },
+            { "border-top-left-radius", "0 0" },
+            { "border-top-right-radius", "0 0" },
+            { "border-bottom-right-radius", "0 0" },
+            { "border-bottom-left-radius", "0 0" },
+            { "empty-cells", "show" },
+            { "direction", "ltr" },
+            { "display", "inline" },
+            { "font-size", "medium" },
+            { "font-style", "normal" },
+            { "font-variant", "normal" },
+            { "font-weight", "normal" },
+            { "font-stretch", "normal" },
+            { "float", "none" },
+            { "clear", "none" },
+            { "box-sizing", "content-box" },
+            { "height", "auto" },
+            { "min-height", "0" },
+            { "max-height", "none" },
+            { "margin-bottom", "0" },
+            { "margin-left", "0" },
+            { "margin-right", "0" },
+            { "margin-top", "0" },
+            { "left", "auto" },
+            { "line-height", "normal" },
+            { "list-style-type", "disc" },
+            { "list-style-image", "" },
+            { "list-style-position", "outside" },
+            { "list-style", "" },
+            { "overflow", "visible" },
+            { "padding-left", "0" },
+            { "padding-bottom", "0" },
+            { "padding-right", "0" },
+            { "padding-top", "0" },
+            { "page-break-inside", "auto" },
+            { "text-align", "" },
+            { "text-decoration-line", "" },
+            { "text-indent", "0" },
+            { "top", "auto" },
+            { "position", "static" },
+            { "vertical-align", "baseline" },
+            { "width", "auto" },
+            { "max-width", "none" },
+            { "word-spacing", "normal" },
+            { "word-break", "normal" },
+            { "visibility", "visible" },
+            { "white-space", "normal" },
+        };
+
+        /// <summary>
+        /// Properties inherited from parent to child during cascade - kept exactly in sync with the set
+        /// <see cref="Dom.CssBoxProperties.InheritStyle"/> already (independently) copies, since this is
+        /// used only to decide whether the <c>unset</c> keyword should behave like <c>inherit</c> or
+        /// <c>initial</c> for a given property, and the two must agree for "unset" to make sense.
+        /// </summary>
+        internal static readonly System.Collections.Generic.HashSet<string> InheritedProperties =
+            new System.Collections.Generic.HashSet<string>(System.StringComparer.OrdinalIgnoreCase)
+        {
+            "border-spacing", "border-collapse",
+            "color",
+            "empty-cells",
+            "white-space",
+            "visibility",
+            "text-indent", "text-align",
+            "font-family", "font-size", "font-style", "font-variant", "font-weight", "font-stretch",
+            "list-style-image", "list-style-position", "list-style-type", "list-style",
+            "line-height",
+            "word-break",
+            "direction",
+        };
+
+        /// <summary>
+        /// Returns the initial value for the given property name, or null if this engine doesn't
+        /// recognize the property at all.
+        /// </summary>
+        internal static string GetInitialValue(string propertyName)
+        {
+            string value;
+            return InitialValues.TryGetValue(propertyName, out value) ? value : null;
+        }
     }
 }
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/AspectRatioGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/AspectRatioGrammar.cs
new file mode 100644
index 000000000..2570eafff
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/AspectRatioGrammar.cs
@@ -0,0 +1,111 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The shared grammar for the <c>aspect-ratio</c> value (<c>[ auto || &lt;ratio&gt; ]</c>, where
+    /// <c>&lt;ratio&gt; = &lt;number [0,∞]&gt; [ / &lt;number [0,∞]&gt; ]?</c>). Used by both Layer A (to
+    /// validate/accept-or-reject at parse time) and Layer B (to compute the used ratio during layout), so the
+    /// grammar is defined once — the <see cref="BasicShapeGrammar"/> precedent.
+    /// </summary>
+    internal static class AspectRatioGrammar
+    {
+        /// <summary>
+        /// Validates the token stream as an <c>aspect-ratio</c> value. Returns false for anything that is not a
+        /// valid value. On success, <paramref name="ratio"/> is the used width/height ratio, or null when there
+        /// is no usable ratio (a bare <c>auto</c>, or a ratio with a zero term — both of which mean "no
+        /// preferred aspect ratio" for a non-replaced box).
+        /// </summary>
+        internal static bool TryParse(IReadOnlyList<Token> tokens, out double? ratio) =>
+            TryParse(tokens, out ratio, out _);
+
+        /// <summary>
+        /// Validates the token stream as an <c>aspect-ratio</c> value, additionally reporting whether the
+        /// <c>auto</c> keyword was present (<c>[ auto || &lt;ratio&gt; ]</c>). <paramref name="hasAuto"/> lets a
+        /// replaced element prefer its natural aspect ratio and fall back to the specified <c>&lt;ratio&gt;</c>
+        /// (CSS Box Sizing 4 §5): <c>auto &lt;ratio&gt;</c> ⇒ <c>hasAuto=true</c> with a usable
+        /// <paramref name="ratio"/>; a bare <c>&lt;ratio&gt;</c> ⇒ <c>hasAuto=false</c> (the ratio always
+        /// overrides); a bare <c>auto</c> ⇒ <c>hasAuto=true</c> with a null <paramref name="ratio"/>.
+        /// </summary>
+        internal static bool TryParse(IReadOnlyList<Token> tokens, out double? ratio, out bool hasAuto)
+        {
+            ratio = null;
+            hasAuto = false;
+
+            Token[] toks = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            if (toks.Length == 0) return false;
+
+            var i = 0;
+
+            if (IsAuto(toks[i])) { hasAuto = true; i++; }
+
+            if (i == toks.Length) return hasAuto; // bare `auto`
+
+            // <ratio> = <number> [ / <number> ]?
+            if (!TryRatioCore(toks, ref i, out ratio)) return false;
+
+            // An optional trailing `auto` (the `||` allows either order: `<ratio> auto`).
+            if (i < toks.Length && !hasAuto && IsAuto(toks[i])) { hasAuto = true; i++; }
+
+            if (i != toks.Length) return false; // trailing junk
+
+            return true;
+        }
+
+        /// <summary>
+        /// Validates a bare <c>&lt;ratio&gt;</c> value (<c>&lt;number [0,∞]&gt; [ / &lt;number [0,∞]&gt; ]?</c>),
+        /// with no <c>auto</c> — the CSS Values 4 <c>&lt;ratio&gt;</c> data type, as used by the <c>@property</c>
+        /// <c>syntax: "&lt;ratio&gt;"</c> matcher. Distinct from <see cref="TryParse(IReadOnlyList{Token}, out double?)"/>, whose <c>aspect-ratio</c>
+        /// grammar additionally permits <c>auto</c>. On success <paramref name="ratio"/> is the used width/height
+        /// ratio, or null when a term is zero.
+        /// </summary>
+        internal static bool TryParseRatio(IReadOnlyList<Token> tokens, out double? ratio)
+        {
+            ratio = null;
+
+            Token[] toks = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            var i = 0;
+            if (!TryRatioCore(toks, ref i, out ratio)) return false;
+            return i == toks.Length; // no trailing junk (and, since we never consume `auto`, no `auto`)
+        }
+
+        private static bool TryRatioCore(Token[] toks, ref int i, out double? ratio)
+        {
+            ratio = null;
+
+            // <number> [ / <number> ]?
+            if (i >= toks.Length || !TryNonNegativeNumber(toks[i], out var width)) return false;
+            double height = 1;
+            i++;
+
+            if (i < toks.Length && IsSlash(toks[i]))
+            {
+                i++;
+                if (i >= toks.Length || !TryNonNegativeNumber(toks[i], out height)) return false;
+                i++;
+            }
+
+            // A zero term degenerates to "no preferred aspect ratio".
+            ratio = width <= 0 || height <= 0 ? (double?)null : width / height;
+            return true;
+        }
+
+        private static bool IsAuto(Token token) => token.Type == TokenType.Ident && token.Data.Isi(Keywords.Auto);
+
+        private static bool IsSlash(Token token) => token.Type == TokenType.Delim && token.Data == "/";
+
+        private static bool TryNonNegativeNumber(Token token, out double value)
+        {
+            if (token is NumberToken number && number.Value >= 0f)
+            {
+                value = number.Value;
+                return true;
+            }
+
+            value = 0;
+            return false;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/BackgroundPositionGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/BackgroundPositionGrammar.cs
new file mode 100644
index 000000000..b9b05f2ac
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/BackgroundPositionGrammar.cs
@@ -0,0 +1,189 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Shared grammar for the CSS <c>background-position</c> value (the 1/2/3/4-token forms,
+    /// including the edge-relative offset syntax, e.g. "right 20px bottom 10px"). Used by both
+    /// <see cref="Converters.PointConverter"/> (CSS-OM grammar validation/serialization) and
+    /// the render-time background-layer resolution (pixel-offset arithmetic) so
+    /// there is one parser for this grammar, not two independent re-implementations - mirroring how
+    /// CalcParser is shared between CalcValueConverter and CssValueParser rather than re-parsed twice.
+    /// </summary>
+    internal static class BackgroundPositionGrammar
+    {
+        internal enum AxisKeyword { None, Left, Right, Top, Bottom, Center }
+
+        internal readonly struct Component
+        {
+            public AxisKeyword Keyword { get; }
+
+            /// <summary>The length/percentage/calc() token for this component, or null when there is
+            /// none (a keyword-only component, or the implicit "center" filled in for a 1-token value).</summary>
+            public Token Offset { get; }
+
+            public Component(AxisKeyword keyword, Token offset)
+            {
+                Keyword = keyword;
+                Offset = offset;
+            }
+        }
+
+        internal sealed class ParsedPosition
+        {
+            public Component X { get; }
+            public Component Y { get; }
+
+            /// <summary>The 1-2 authored components in original left-to-right order, needed to
+            /// re-serialize in the exact order/form the author wrote (CSS round-trips verbatim).</summary>
+            public IReadOnlyList<Component> AuthoredOrder { get; }
+
+            public ParsedPosition(Component x, Component y, IReadOnlyList<Component> authoredOrder)
+            {
+                X = x;
+                Y = y;
+                AuthoredOrder = authoredOrder;
+            }
+        }
+
+        internal static ParsedPosition TryParse(IReadOnlyList<Token> tokens)
+        {
+            switch (tokens.Count)
+            {
+                case 1:
+                    return ParseSingle(tokens[0]);
+                case 2:
+                    return ParseDouble(tokens[0], tokens[1]);
+                case 3:
+                    return ParseTriple(tokens[0], tokens[1], tokens[2]);
+                case 4:
+                    return ParseQuadruple(tokens[0], tokens[1], tokens[2], tokens[3]);
+                default:
+                    return null;
+            }
+        }
+
+        private static ParsedPosition ParseSingle(Token token)
+        {
+            var keyword = KeywordOf(token);
+            if (keyword == AxisKeyword.None)
+            {
+                if (!IsLengthOrPercent(token)) return null;
+
+                var bare = new Component(AxisKeyword.None, token);
+                var center = new Component(AxisKeyword.Center, null);
+                return new ParsedPosition(bare, center, new[] { bare });
+            }
+
+            if (IsVerticalOnly(keyword))
+            {
+                var y = new Component(keyword, null);
+                var x = new Component(AxisKeyword.Center, null);
+                return new ParsedPosition(x, y, new[] { y });
+            }
+
+            var xComp = new Component(keyword, null);
+            var yComp = new Component(AxisKeyword.Center, null);
+            return new ParsedPosition(xComp, yComp, new[] { xComp });
+        }
+
+        private static ParsedPosition ParseDouble(Token t0, Token t1)
+        {
+            // "h then v" (horizontal-ish first): left/right/center/bare-length, then top/bottom/center/bare-length.
+            if (IsHSlotValid(t0) && IsVSlotValid(t1))
+            {
+                var x = ToComponent(t0);
+                var y = ToComponent(t1);
+                return new ParsedPosition(x, y, new[] { x, y });
+            }
+
+            // "v then h" (vertical-ish first, e.g. "bottom center", "top left").
+            if (IsVSlotValid(t0) && IsHSlotValid(t1))
+            {
+                var y = ToComponent(t0);
+                var x = ToComponent(t1);
+                return new ParsedPosition(x, y, new[] { y, x });
+            }
+
+            return null;
+        }
+
+        private static ParsedPosition ParseTriple(Token t0, Token t1, Token t2)
+        {
+            // hi, vi, offset (offset applies to the vertical group): e.g. "right bottom 20px".
+            if (IsEdgeKeywordSlot(t0, horizontal: true) && IsEdgeKeywordSlot(t1, horizontal: false) && IsLengthOrPercent(t2))
+            {
+                var x = new Component(KeywordOf(t0), null);
+                var y = new Component(KeywordOf(t1), t2);
+                return new ParsedPosition(x, y, new[] { x, y });
+            }
+
+            // hi, offset, vi (offset applies to the horizontal group): e.g. "right 20px bottom".
+            if (IsEdgeKeywordSlot(t0, horizontal: true) && IsLengthOrPercent(t1) && IsEdgeKeywordSlot(t2, horizontal: false))
+            {
+                var x = new Component(KeywordOf(t0), t1);
+                var y = new Component(KeywordOf(t2), null);
+                return new ParsedPosition(x, y, new[] { x, y });
+            }
+
+            return null;
+        }
+
+        private static ParsedPosition ParseQuadruple(Token t0, Token t1, Token t2, Token t3)
+        {
+            // hi, offset, vi, offset: e.g. "right 20px bottom 10px".
+            if (IsEdgeKeywordSlot(t0, horizontal: true) && IsLengthOrPercent(t1) &&
+                IsEdgeKeywordSlot(t2, horizontal: false) && IsLengthOrPercent(t3))
+            {
+                var x = new Component(KeywordOf(t0), t1);
+                var y = new Component(KeywordOf(t2), t3);
+                return new ParsedPosition(x, y, new[] { x, y });
+            }
+
+            return null;
+        }
+
+        private static Component ToComponent(Token token) =>
+            new Component(KeywordOf(token), KeywordOf(token) == AxisKeyword.None ? token : null);
+
+        private static AxisKeyword KeywordOf(Token token)
+        {
+            if (token.Type != TokenType.Ident) return AxisKeyword.None;
+            if (token.Data.Isi(Keywords.Left)) return AxisKeyword.Left;
+            if (token.Data.Isi(Keywords.Right)) return AxisKeyword.Right;
+            if (token.Data.Isi(Keywords.Top)) return AxisKeyword.Top;
+            if (token.Data.Isi(Keywords.Bottom)) return AxisKeyword.Bottom;
+            if (token.Data.Isi(Keywords.Center)) return AxisKeyword.Center;
+            return AxisKeyword.None;
+        }
+
+        private static bool IsHorizontalOnly(AxisKeyword k) => k == AxisKeyword.Left || k == AxisKeyword.Right;
+        private static bool IsVerticalOnly(AxisKeyword k) => k == AxisKeyword.Top || k == AxisKeyword.Bottom;
+
+        private static bool IsLengthOrPercent(Token token) =>
+            Converters.LengthOrPercentConverter.Convert(new[] { token }) != null;
+
+        /// <summary>Valid for the 2-value "h" slot: left/right/center keywords, or a bare length/percent - not top/bottom.</summary>
+        private static bool IsHSlotValid(Token token)
+        {
+            var k = KeywordOf(token);
+            return k != AxisKeyword.None ? !IsVerticalOnly(k) : IsLengthOrPercent(token);
+        }
+
+        /// <summary>Valid for the 2-value "v" slot: top/bottom/center keywords, or a bare length/percent - not left/right.</summary>
+        private static bool IsVSlotValid(Token token)
+        {
+            var k = KeywordOf(token);
+            return k != AxisKeyword.None ? !IsHorizontalOnly(k) : IsLengthOrPercent(token);
+        }
+
+        /// <summary>Valid for the 3/4-value "hi"/"vi" edge-keyword slots: keyword only, no bare-length fallback.</summary>
+        private static bool IsEdgeKeywordSlot(Token token, bool horizontal)
+        {
+            var k = KeywordOf(token);
+            if (k == AxisKeyword.Center) return true;
+            if (k == AxisKeyword.None) return false;
+            return horizontal ? IsHorizontalOnly(k) : IsVerticalOnly(k);
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/BackgroundSizeGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/BackgroundSizeGrammar.cs
new file mode 100644
index 000000000..99bf73e5d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/BackgroundSizeGrammar.cs
@@ -0,0 +1,88 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Shared grammar for the CSS <c>background-size</c> value (<c>auto</c>, <c>cover</c>,
+    /// <c>contain</c>, or a 1-2 token length/percentage/auto form). Used by both
+    /// <see cref="Converters.BackgroundSizeConverter"/> (CSS-OM grammar validation/serialization)
+    /// and the render-time background-layer resolution (size resolution), so there
+    /// is one parser for this grammar, not two.
+    /// </summary>
+    internal static class BackgroundSizeGrammar
+    {
+        internal readonly struct Component
+        {
+            public bool IsAuto { get; }
+
+            /// <summary>The length/percentage/calc() token for this component, null when <see cref="IsAuto"/>.</summary>
+            public Token Value { get; }
+
+            public Component(bool isAuto, Token value)
+            {
+                IsAuto = isAuto;
+                Value = value;
+            }
+        }
+
+        internal sealed class ParsedSize
+        {
+            public bool IsCover { get; }
+            public bool IsContain { get; }
+            public Component Width { get; }
+            public Component Height { get; }
+
+            /// <summary>False for the 1-token auto/length/percent form (height defaults to auto for
+            /// resolution purposes, but must NOT be re-serialized - "2em" stays "2em", not "2em auto").</summary>
+            public bool HasExplicitHeight { get; }
+
+            private ParsedSize(bool isCover, bool isContain, Component width, Component height, bool hasExplicitHeight)
+            {
+                IsCover = isCover;
+                IsContain = isContain;
+                Width = width;
+                Height = height;
+                HasExplicitHeight = hasExplicitHeight;
+            }
+
+            public static ParsedSize Cover() => new ParsedSize(true, false, default, default, false);
+            public static ParsedSize Contain() => new ParsedSize(false, true, default, default, false);
+            public static ParsedSize SingleValue(Component width) => new ParsedSize(false, false, width, AutoComponent, false);
+            public static ParsedSize TwoValue(Component width, Component height) => new ParsedSize(false, false, width, height, true);
+        }
+
+        private static readonly Component AutoComponent = new Component(true, null);
+
+        internal static ParsedSize TryParse(IReadOnlyList<Token> tokens)
+        {
+            if (tokens.Count == 1)
+            {
+                var t = tokens[0];
+                if (IsKeyword(t, Keywords.Cover)) return ParsedSize.Cover();
+                if (IsKeyword(t, Keywords.Contain)) return ParsedSize.Contain();
+
+                var w = ToComponent(t);
+                return w is null ? null : ParsedSize.SingleValue(w.Value);
+            }
+
+            if (tokens.Count == 2)
+            {
+                var w = ToComponent(tokens[0]);
+                var h = ToComponent(tokens[1]);
+                return w is null || h is null ? null : ParsedSize.TwoValue(w.Value, h.Value);
+            }
+
+            return null;
+        }
+
+        private static Component? ToComponent(Token token)
+        {
+            if (IsKeyword(token, Keywords.Auto)) return AutoComponent;
+            if (Converters.LengthOrPercentConverter.Convert(new[] { token }) != null) return new Component(false, token);
+            return null;
+        }
+
+        private static bool IsKeyword(Token token, string keyword) =>
+            token.Type == TokenType.Ident && token.Data.Isi(keyword);
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/BasicShapeGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/BasicShapeGrammar.cs
new file mode 100644
index 000000000..b234ccd70
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/BasicShapeGrammar.cs
@@ -0,0 +1,401 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Shared, layer-agnostic grammar for the CSS <c>&lt;basic-shape&gt;</c> function values used by
+    /// <c>clip-path</c> (CSS Masking Level 1 / CSS Shapes Level 1): <c>polygon()</c>, <c>inset()</c>,
+    /// <c>circle()</c> and <c>ellipse()</c>. Like <see cref="BackgroundPositionGrammar"/> /
+    /// <see cref="BackgroundSizeGrammar"/>, it validates the grammar and captures the value's structure
+    /// as <b>raw component strings / enums</b> (never resolved numbers), so both Layer A (the CSS-OM
+    /// converter, which only needs to accept/reject and preserve the authored text) and Layer B (the
+    /// render-time resolver in <c>TheArtOfDev.HtmlRenderer.Core</c>, which resolves each component against the
+    /// element's reference box) share a single parser rather than re-implementing the grammar twice.
+    /// </summary>
+    internal static class BasicShapeGrammar
+    {
+        internal enum BasicShapeKind { Polygon, Inset, Circle, Ellipse }
+
+        internal enum FillRule { Nonzero, Evenodd }
+
+        internal enum ShapeRadiusKind { LengthPercentage, ClosestSide, FarthestSide }
+
+        /// <summary>A <c>&lt;shape-radius&gt;</c>: either an explicit length-percentage (component string
+        /// in <see cref="Length"/>) or one of the <c>closest-side</c>/<c>farthest-side</c> keywords.</summary>
+        internal readonly struct ShapeRadius
+        {
+            public ShapeRadiusKind Kind { get; }
+
+            /// <summary>The length-percentage component string when <see cref="Kind"/> is
+            /// <see cref="ShapeRadiusKind.LengthPercentage"/>; otherwise null.</summary>
+            public string Length { get; }
+
+            private ShapeRadius(ShapeRadiusKind kind, string length)
+            {
+                Kind = kind;
+                Length = length;
+            }
+
+            public static readonly ShapeRadius ClosestSide = new ShapeRadius(ShapeRadiusKind.ClosestSide, null);
+            public static readonly ShapeRadius FarthestSide = new ShapeRadius(ShapeRadiusKind.FarthestSide, null);
+            public static ShapeRadius FromLength(string length) => new ShapeRadius(ShapeRadiusKind.LengthPercentage, length);
+        }
+
+        /// <summary>A single <c>&lt;length-percentage&gt; &lt;length-percentage&gt;</c> polygon vertex,
+        /// stored as the two authored component strings.</summary>
+        internal readonly struct Point
+        {
+            public string X { get; }
+            public string Y { get; }
+
+            public Point(string x, string y)
+            {
+                X = x;
+                Y = y;
+            }
+        }
+
+        internal sealed class ParsedBasicShape
+        {
+            public BasicShapeKind Kind { get; private set; }
+
+            // --- polygon() ---
+            public FillRule PolygonFillRule { get; private set; }
+            public IReadOnlyList<Point> PolygonPoints { get; private set; }
+
+            // --- inset() ---
+            /// <summary>The four inset offsets in [top, right, bottom, left] order (CSS shorthand-filled),
+            /// each an authored length-percentage component string.</summary>
+            public IReadOnlyList<string> InsetEdges { get; private set; }
+
+            /// <summary>Whether an <c>inset(... round &lt;border-radius&gt;)</c> corner radius was present.
+            /// The radius itself is captured in <see cref="InsetRoundRadius"/> but not rendered - inset is
+            /// drawn as a rectangle (see the resolver / docs).</summary>
+            public bool InsetHasRound { get; private set; }
+            public IReadOnlyList<Token> InsetRoundRadius { get; private set; }
+
+            // --- circle() / ellipse() ---
+            /// <summary>circle: the single radius. ellipse: the x-radius.</summary>
+            public ShapeRadius RadiusX { get; private set; }
+            /// <summary>ellipse: the y-radius. Unused for circle.</summary>
+            public ShapeRadius RadiusY { get; private set; }
+            /// <summary>Center x as an authored length-percentage component string (position keywords
+            /// already resolved to <c>0%</c>/<c>50%</c>/<c>100%</c>). Default <c>50%</c>.</summary>
+            public string CenterX { get; private set; }
+            /// <summary>Center y, same convention as <see cref="CenterX"/>.</summary>
+            public string CenterY { get; private set; }
+
+            internal static ParsedBasicShape Polygon(FillRule fillRule, IReadOnlyList<Point> points) => new ParsedBasicShape
+            {
+                Kind = BasicShapeKind.Polygon,
+                PolygonFillRule = fillRule,
+                PolygonPoints = points,
+            };
+
+            internal static ParsedBasicShape Inset(IReadOnlyList<string> edges, bool hasRound, IReadOnlyList<Token> roundRadius) => new ParsedBasicShape
+            {
+                Kind = BasicShapeKind.Inset,
+                InsetEdges = edges,
+                InsetHasRound = hasRound,
+                InsetRoundRadius = roundRadius,
+            };
+
+            internal static ParsedBasicShape Circle(ShapeRadius radius, string centerX, string centerY) => new ParsedBasicShape
+            {
+                Kind = BasicShapeKind.Circle,
+                RadiusX = radius,
+                CenterX = centerX,
+                CenterY = centerY,
+            };
+
+            internal static ParsedBasicShape Ellipse(ShapeRadius radiusX, ShapeRadius radiusY, string centerX, string centerY) => new ParsedBasicShape
+            {
+                Kind = BasicShapeKind.Ellipse,
+                RadiusX = radiusX,
+                RadiusY = radiusY,
+                CenterX = centerX,
+                CenterY = centerY,
+            };
+        }
+
+        /// <summary>
+        /// Parses a <c>clip-path</c> value's tokens into a <see cref="ParsedBasicShape"/>, or returns
+        /// null when the value is not a valid basic shape - <b>including the literal <c>none</c></b>,
+        /// which callers treat as "no clip". (Layer A therefore accepts <c>none</c> separately, since a
+        /// null result here can't distinguish <c>none</c> from an invalid value.)
+        /// </summary>
+        internal static ParsedBasicShape TryParse(IReadOnlyList<Token> tokens)
+        {
+            var significant = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            if (significant.Length != 1) return null;
+            var function = significant[0] as FunctionToken;
+            if (function == null) return null;
+
+            var args = function.ArgumentTokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            if (function.Data.Isi(FunctionNames.Polygon)) return ParsePolygon(args);
+            if (function.Data.Isi(FunctionNames.Inset)) return ParseInset(args);
+            if (function.Data.Isi(FunctionNames.Circle)) return ParseCircle(args);
+            if (function.Data.Isi(FunctionNames.Ellipse)) return ParseEllipse(args);
+
+            return null;
+        }
+
+        private static ParsedBasicShape ParsePolygon(IReadOnlyList<Token> args)
+        {
+            var groups = SplitByComma(args);
+            if (groups.Count == 0) return null;
+
+            var fillRule = FillRule.Nonzero;
+            var firstGroup = 0;
+
+            // An optional leading fill-rule ident is its own comma-separated group: "polygon(evenodd, x y, ...)".
+            if (groups[0].Count == 1 && TryFillRule(groups[0][0], out var parsedRule))
+            {
+                fillRule = parsedRule;
+                firstGroup = 1;
+            }
+
+            var points = new List<Point>();
+
+            for (var i = firstGroup; i < groups.Count; i++)
+            {
+                var group = groups[i];
+                if (group.Count != 2) return null;
+                if (!IsLengthPercentage(group[0]) || !IsLengthPercentage(group[1])) return null;
+                points.Add(new Point(group[0].ToValue(), group[1].ToValue()));
+            }
+
+            return points.Count == 0 ? null : ParsedBasicShape.Polygon(fillRule, points);
+        }
+
+        private static ParsedBasicShape ParseInset(IReadOnlyList<Token> args)
+        {
+            if (args.Count == 0) return null;
+
+            var roundIndex = -1;
+            for (var i = 0; i < args.Count; i++)
+            {
+                if (args[i].Type == TokenType.Ident && args[i].Data.Isi(Keywords.Round))
+                {
+                    roundIndex = i;
+                    break;
+                }
+            }
+
+            var lengthTokens = roundIndex >= 0 ? args.Take(roundIndex).ToArray() : args.ToArray();
+            Token[] roundTokens = roundIndex >= 0 ? args.Skip(roundIndex + 1).ToArray() : new Token[0];
+
+            if (lengthTokens.Length < 1 || lengthTokens.Length > 4) return null;
+            if (lengthTokens.Any(t => !IsLengthPercentage(t))) return null;
+
+            // "round" with no radius following it is malformed.
+            if (roundIndex >= 0 && roundTokens.Length == 0) return null;
+
+            var values = lengthTokens.Select(t => t.ToValue()).ToArray();
+            var (top, right, bottom, left) = ExpandBox(values);
+
+            return ParsedBasicShape.Inset(new[] { top, right, bottom, left }, roundIndex >= 0, roundTokens);
+        }
+
+        private static ParsedBasicShape ParseCircle(IReadOnlyList<Token> args)
+        {
+            if (!SplitAtKeyword(args, Keywords.At, out var radiusTokens, out var hasAt, out var positionTokens))
+                return null;
+
+            ShapeRadius radius;
+            switch (radiusTokens.Count)
+            {
+                case 0:
+                    radius = ShapeRadius.ClosestSide;
+                    break;
+                case 1:
+                    if (!TryShapeRadius(radiusTokens[0], out radius)) return null;
+                    break;
+                default:
+                    return null;
+            }
+
+            if (!ResolveCenter(hasAt, positionTokens, out var centerX, out var centerY)) return null;
+
+            return ParsedBasicShape.Circle(radius, centerX, centerY);
+        }
+
+        private static ParsedBasicShape ParseEllipse(IReadOnlyList<Token> args)
+        {
+            if (!SplitAtKeyword(args, Keywords.At, out var radiusTokens, out var hasAt, out var positionTokens))
+                return null;
+
+            ShapeRadius rx, ry;
+            switch (radiusTokens.Count)
+            {
+                case 0:
+                    rx = ShapeRadius.ClosestSide;
+                    ry = ShapeRadius.ClosestSide;
+                    break;
+                case 2:
+                    if (!TryShapeRadius(radiusTokens[0], out rx)) return null;
+                    if (!TryShapeRadius(radiusTokens[1], out ry)) return null;
+                    break;
+                default:
+                    return null;
+            }
+
+            if (!ResolveCenter(hasAt, positionTokens, out var centerX, out var centerY)) return null;
+
+            return ParsedBasicShape.Ellipse(rx, ry, centerX, centerY);
+        }
+
+        /// <summary>Resolves the optional <c>at &lt;position&gt;</c> tail (via the shared
+        /// <see cref="BackgroundPositionGrammar"/>) to center-x/center-y component strings; defaults to
+        /// <c>50% 50%</c> when absent.</summary>
+        private static bool ResolveCenter(bool hasAt, IReadOnlyList<Token> positionTokens, out string centerX, out string centerY)
+        {
+            centerX = "50%";
+            centerY = "50%";
+
+            if (!hasAt) return true;
+
+            var parsed = BackgroundPositionGrammar.TryParse(positionTokens);
+            if (parsed is null) return false;
+
+            centerX = ComponentToLength(parsed.X, horizontal: true);
+            centerY = ComponentToLength(parsed.Y, horizontal: false);
+            return true;
+        }
+
+        private static string ComponentToLength(BackgroundPositionGrammar.Component c, bool horizontal)
+        {
+            switch (c.Keyword)
+            {
+                case BackgroundPositionGrammar.AxisKeyword.Center:
+                    return "50%";
+                case BackgroundPositionGrammar.AxisKeyword.Left:
+                case BackgroundPositionGrammar.AxisKeyword.Top:
+                    // "left"/"top" == 0% edge; "left 20px" == 20px in from that edge.
+                    return c.Offset != null ? c.Offset.ToValue() : "0%";
+                case BackgroundPositionGrammar.AxisKeyword.Right:
+                case BackgroundPositionGrammar.AxisKeyword.Bottom:
+                    // "right"/"bottom" == 100% edge; "right 20px" == 20px in from the far edge.
+                    return c.Offset != null ? $"calc(100% - {c.Offset.ToValue()})" : "100%";
+                default: // a bare length-percentage
+                    return c.Offset.ToValue();
+            }
+        }
+
+        /// <summary>Splits tokens at the first standalone ident equal to <paramref name="keyword"/>
+        /// (e.g. <c>at</c>). Fails if the keyword appears with nothing after it.</summary>
+        private static bool SplitAtKeyword(IReadOnlyList<Token> tokens, string keyword,
+            out IReadOnlyList<Token> before, out bool found, out IReadOnlyList<Token> after)
+        {
+            for (var i = 0; i < tokens.Count; i++)
+            {
+                if (tokens[i].Type == TokenType.Ident && tokens[i].Data.Isi(keyword))
+                {
+                    before = tokens.Take(i).ToArray();
+                    after = tokens.Skip(i + 1).ToArray();
+                    found = true;
+                    return after.Count > 0;
+                }
+            }
+
+            before = tokens.ToArray();
+            after = new Token[0];
+            found = false;
+            return true;
+        }
+
+        private static List<List<Token>> SplitByComma(IReadOnlyList<Token> tokens)
+        {
+            var groups = new List<List<Token>>();
+            var current = new List<Token>();
+
+            foreach (var token in tokens)
+            {
+                if (token.Type == TokenType.Comma)
+                {
+                    groups.Add(current);
+                    current = new List<Token>();
+                }
+                else
+                {
+                    current.Add(token);
+                }
+            }
+
+            groups.Add(current);
+
+            // A trailing/leading/doubled comma yields an empty group, which is always malformed here.
+            return groups.Any(g => g.Count == 0) && tokens.Count > 0 ? new List<List<Token>>() : groups;
+        }
+
+        private static (string top, string right, string bottom, string left) ExpandBox(IReadOnlyList<string> values)
+        {
+            switch (values.Count)
+            {
+                case 1: return (values[0], values[0], values[0], values[0]);
+                case 2: return (values[0], values[1], values[0], values[1]);
+                case 3: return (values[0], values[1], values[2], values[1]);
+                default: return (values[0], values[1], values[2], values[3]);
+            }
+        }
+
+        private static bool TryFillRule(Token token, out FillRule fillRule)
+        {
+            if (token.Type == TokenType.Ident)
+            {
+                if (token.Data.Isi(Keywords.Nonzero)) { fillRule = FillRule.Nonzero; return true; }
+                if (token.Data.Isi(Keywords.Evenodd)) { fillRule = FillRule.Evenodd; return true; }
+            }
+
+            fillRule = FillRule.Nonzero;
+            return false;
+        }
+
+        private static bool TryShapeRadius(Token token, out ShapeRadius radius)
+        {
+            if (token.Type == TokenType.Ident)
+            {
+                if (token.Data.Isi(Keywords.ClosestSide)) { radius = ShapeRadius.ClosestSide; return true; }
+                if (token.Data.Isi(Keywords.FarthestSide)) { radius = ShapeRadius.FarthestSide; return true; }
+                radius = default;
+                return false;
+            }
+
+            if (IsLengthPercentage(token))
+            {
+                // A <shape-radius> is a non-negative <length-percentage> (CSS Shapes 1 §3.2); a negative
+                // radius makes the whole clip-path value invalid.
+                var unitToken = token as UnitToken;
+                var numberToken = token as NumberToken;
+                if ((unitToken != null && unitToken.Value < 0f) || (numberToken != null && numberToken.Value < 0f))
+                {
+                    radius = default(ShapeRadius);
+                    return false;
+                }
+
+                radius = ShapeRadius.FromLength(token.ToValue());
+                return true;
+            }
+
+            radius = default;
+            return false;
+        }
+
+        private static bool IsLengthPercentage(Token token)
+        {
+            if (token.Type == TokenType.Dimension || token.Type == TokenType.Percentage) return true;
+            // A calc()-family function computes to a <length-percentage> at used-value time. The render-time
+            // resolver (CssClipPathResolver → CssValueParser.ParseLength) evaluates it, and the token's
+            // ToValue() reconstructs the full "calc(…)" text, so accept it here rather than invalidating the
+            // whole shape (this is what lets a Charts.css area/line polygon vertex be a calc() expression).
+            var function = token as FunctionToken;
+            if (function != null && CalcParser.IsCalcFamily(function.Data)) return true;
+            // Unitless zero is a valid length.
+            var number = token as NumberToken;
+            return number != null && number.Value == 0f;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/BoxShadowGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/BoxShadowGrammar.cs
new file mode 100644
index 000000000..fcee98a0e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/BoxShadowGrammar.cs
@@ -0,0 +1,222 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Shared, layer-agnostic grammar for the CSS <c>box-shadow</c> value (CSS Backgrounds &amp; Borders
+    /// Level 3 §5): a comma-separated list of shadow layers, each
+    /// <c>[ inset? &amp;&amp; &lt;length&gt;{2,4} &amp;&amp; &lt;color&gt;? ]</c>. Like
+    /// <see cref="BasicShapeGrammar"/> / <see cref="AspectRatioGrammar"/>, it validates the grammar and
+    /// captures each layer's structure as <b>raw component strings</b> (never resolved numbers), so both
+    /// Layer A (the CSS-OM converter, which only needs to accept/reject and preserve the authored text)
+    /// and Layer B (the paint-time resolver in <c>TheArtOfDev.HtmlRenderer.Core</c>, which resolves each length
+    /// against the box's own font/size) share a single parser rather than re-implementing the grammar.
+    /// </summary>
+    internal static class BoxShadowGrammar
+    {
+        /// <summary>
+        /// A single parsed shadow layer. Lengths and the color are kept as the authored component strings -
+        /// box-shadow lengths may be font-relative (<c>em</c>/<c>rem</c>), so only Layer B can resolve them.
+        /// <see cref="Blur"/> defaults to <c>"0"</c> and <see cref="Spread"/> to <c>"0"</c> when the author
+        /// omitted them; <see cref="Color"/> is null when omitted, meaning "use the element's own color"
+        /// (currentColor) at paint time.
+        /// </summary>
+        internal sealed class ShadowLayer
+        {
+            public bool Inset { get; set; }
+            public string OffsetX { get; set; }
+            public string OffsetY { get; set; }
+            public string Blur { get; set; }
+            public string Spread { get; set; }
+            public string Color { get; set; }
+        }
+
+        // The one color grammar (named/hex/rgb()/rgba()/hsl()/currentColor/transparent), reused so box-shadow
+        // never re-implements color parsing - matches the CLAUDE.md "one grammar per value" rule.
+        private static readonly IValueConverter ColorValidator = Converters.ColorConverter.WithCurrentColor();
+
+        /// <summary>
+        /// Parses a <c>box-shadow</c> value's tokens into an ordered list of <see cref="ShadowLayer"/>s
+        /// (first-declared first), or returns null when the value is not a valid box-shadow. The literal
+        /// keyword <c>none</c> returns an <b>empty list</b> (no shadows), distinct from a null (invalid)
+        /// result.
+        /// </summary>
+        internal static List<ShadowLayer> TryParse(IReadOnlyList<Token> tokens)
+        {
+            var significant = NormalizeHexColorTokens(tokens.Where(t => t.Type != TokenType.Whitespace).ToArray());
+
+            if (significant.Count == 0) return null;
+
+            if (significant.Count == 1 && significant[0].Type == TokenType.Ident && significant[0].Data.Isi(Keywords.None))
+                return new List<ShadowLayer>();
+
+            var layers = new List<ShadowLayer>();
+
+            foreach (var group in SplitByComma(significant))
+            {
+                if (group.Count == 0) return null; // leading/trailing/doubled comma
+
+                var layer = ParseLayer(group);
+                if (layer is null) return null;
+
+                layers.Add(layer);
+            }
+
+            return layers;
+        }
+
+        private static ShadowLayer ParseLayer(IReadOnlyList<Token> group)
+        {
+            var insetSeen = false;
+            var lengths = new List<Token>();
+            var colorTokens = new List<Token>();
+            var lengthsClosed = false; // set once a non-length token appears after lengths have begun
+
+            foreach (var token in group)
+            {
+                if (IsInset(token))
+                {
+                    if (insetSeen) return null;          // "inset" at most once
+                    insetSeen = true;
+                    if (lengths.Count > 0) lengthsClosed = true;
+                }
+                else if (IsLength(token))
+                {
+                    if (lengthsClosed) return null;      // <length>{2,4} must be one contiguous run
+                    lengths.Add(token);
+                }
+                else
+                {
+                    if (lengths.Count > 0) lengthsClosed = true;
+                    colorTokens.Add(token);
+                }
+            }
+
+            // Two to four lengths: offset-x, offset-y, [blur], [spread].
+            if (lengths.Count < 2 || lengths.Count > 4) return null;
+
+            // Blur radius (the third length) must be non-negative.
+            if (lengths.Count >= 3 && LengthValue(lengths[2]) < 0) return null;
+
+            // Any color present must be a single valid <color>.
+            string color = null;
+            if (colorTokens.Count > 0)
+            {
+                if (!IsValidColor(colorTokens)) return null;
+                color = string.Concat(colorTokens.Select(t => t.ToValue()));
+            }
+
+            return new ShadowLayer
+            {
+                Inset = insetSeen,
+                OffsetX = lengths[0].ToValue(),
+                OffsetY = lengths[1].ToValue(),
+                Blur = lengths.Count >= 3 ? lengths[2].ToValue() : "0",
+                Spread = lengths.Count >= 4 ? lengths[3].ToValue() : "0",
+                Color = color,
+            };
+        }
+
+        /// <summary>
+        /// Validates the color component. The full color grammar (named/rgb()/rgba()/hsl()/currentColor)
+        /// is checked via the shared <see cref="ColorValidator"/>, but a hex color is special-cased: the
+        /// raw <c>CssValueParser.GetCssTokens</c> tokenizer Layer B feeds this grammar produces a bare
+        /// <see cref="TokenType.Hash"/> token for <c>#fff</c> (only the in-declaration-value tokenizer path
+        /// yields a <see cref="ColorToken"/> the converter understands), so accept a well-formed hex token
+        /// directly - otherwise a hex shadow color accepted by Layer A would be dropped at paint time.
+        /// </summary>
+        private static bool IsValidColor(IReadOnlyList<Token> colorTokens)
+        {
+            if (colorTokens.Count == 1 && colorTokens[0].Type == TokenType.Hash)
+                return IsHexColor(colorTokens[0].Data);
+
+            return ColorValidator.Convert(colorTokens) != null;
+        }
+
+        private static bool IsHexColor(string data)
+        {
+            var length = data.Length;
+            return (length == 3 || length == 4 || length == 6 || length == 8) && data.All(Uri.IsHexDigit);
+        }
+
+        /// <summary>
+        /// Merges a <c>#</c> delimiter followed by a number/dimension back into one hex-color token. The
+        /// <c>CssValueParser.GetCssTokens</c> tokenizer Layer B feeds this grammar is not in "value" mode,
+        /// so a <b>digit-leading</b> hex color (<c>#08f</c>, <c>#000</c>) is split into a bare
+        /// <see cref="TokenType.Delim"/> <c>#</c> plus a <see cref="TokenType.Number"/>/<see cref="TokenType.Dimension"/>
+        /// (e.g. <c>08f</c> becomes a dimension "08" + unit "f"), whereas a letter-leading hex (<c>#c00</c>)
+        /// becomes a single <see cref="TokenType.Hash"/> token. Without this, a digit-leading hex shadow color
+        /// accepted by Layer A (whose value-mode tokenizer yields a proper color token) would fail to re-parse
+        /// at paint time and the shadow would silently vanish.
+        /// </summary>
+        private static List<Token> NormalizeHexColorTokens(IReadOnlyList<Token> tokens)
+        {
+            var result = new List<Token>(tokens.Count);
+
+            for (var i = 0; i < tokens.Count; i++)
+            {
+                var token = tokens[i];
+
+                if (token.Type == TokenType.Delim && token.Data == "#" && i + 1 < tokens.Count
+                    && (tokens[i + 1].Type == TokenType.Number || tokens[i + 1].Type == TokenType.Dimension)
+                    && IsHexColor(tokens[i + 1].ToValue()))
+                {
+                    result.Add(new KeywordToken(TokenType.Hash, tokens[i + 1].ToValue(), token.Position));
+                    i++;
+                    continue;
+                }
+
+                result.Add(token);
+            }
+
+            return result;
+        }
+
+        private static bool IsInset(Token token) =>
+            token.Type == TokenType.Ident && token.Data.Isi(Keywords.Inset);
+
+        /// <summary>A box-shadow offset/blur/spread is a <c>&lt;length&gt;</c> (not a length-percentage):
+        /// a dimension, or the unitless zero. Percentages are not valid here.</summary>
+        private static bool IsLength(Token token)
+        {
+            if (token.Type == TokenType.Dimension) return true;
+            var number = token as NumberToken;
+            return number != null && number.Value == 0f;
+        }
+
+        private static float LengthValue(Token token)
+        {
+            var unit = token as UnitToken;
+            if (unit != null) return unit.Value;
+
+            var number = token as NumberToken;
+            if (number != null) return number.Value;
+
+            return 0f;
+        }
+
+        private static List<List<Token>> SplitByComma(IReadOnlyList<Token> tokens)
+        {
+            var groups = new List<List<Token>>();
+            var current = new List<Token>();
+
+            foreach (var token in tokens)
+            {
+                if (token.Type == TokenType.Comma)
+                {
+                    groups.Add(current);
+                    current = new List<Token>();
+                }
+                else
+                {
+                    current.Add(token);
+                }
+            }
+
+            groups.Add(current);
+            return groups;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcCategory.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcCategory.cs
new file mode 100644
index 000000000..ddf28cfd8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcCategory.cs
@@ -0,0 +1,37 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The CSS calc() type-checking category a (sub-)expression resolves to. Flags so that
+    /// "Length | Percentage" can represent the combined &lt;length-percentage&gt; type once a
+    /// length and a percentage have been added/subtracted together.
+    /// </summary>
+    [Flags]
+    internal enum CalcCategory
+    {
+        Number = 1,
+        Length = 2,
+        Percentage = 4,
+        LengthPercentage = Length | Percentage,
+
+        /// <summary>
+        /// Unlike Length/Percentage, Angle never needs layout context to resolve (deg/grad/rad/turn all
+        /// convert via fixed constants), so a valid Angle-category expression always folds fully at
+        /// Layer A parse time - see CalcSerializer.
+        /// </summary>
+        Angle = 8,
+
+        /// <summary>
+        /// &lt;time&gt; (s/ms). Like Angle, it resolves without layout context. Currently produced only by
+        /// <c>@property</c> <c>syntax: "&lt;time&gt;"</c> validation - no layout property consumes a time
+        /// calc(), so it never reaches CalcEvaluator during a render.
+        /// </summary>
+        Time = 16,
+
+        /// <summary>
+        /// &lt;resolution&gt; (dpi/dpcm/dppx). Context-free like Angle/Time; same @property-only provenance.
+        /// </summary>
+        Resolution = 32
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcEvaluator.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcEvaluator.cs
new file mode 100644
index 000000000..2ec7b8d08
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcEvaluator.cs
@@ -0,0 +1,138 @@
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The layout-time context needed to resolve relative units within a calc-family expression: how
+    /// many pixels 1em/1rem are, and what 100% means for this particular call site (e.g. containing-block
+    /// width for <c>width</c>, parent font-size for <c>font-size</c>'s em-relative resolution).
+    /// </summary>
+    internal readonly struct CalcContext
+    {
+        public CalcContext(double hundredPercent, double emFactor, double remFactor, bool fontAdjust, bool returnPoints = false)
+        {
+            HundredPercent = hundredPercent;
+            EmFactor = emFactor;
+            RemFactor = remFactor;
+            FontAdjust = fontAdjust;
+            ReturnPoints = returnPoints;
+        }
+
+        public double HundredPercent { get; }
+        public double EmFactor { get; }
+        public double RemFactor { get; }
+        public bool FontAdjust { get; }
+
+        /// <summary>
+        /// Mirrors ParseLength's returnPoints parameter: when the caller's em/rem/percent factors are
+        /// already expressed in points (as CssBoxProperties.FontSize's caller does), a bare <c>pt</c> leaf
+        /// must bypass the normal pt-&gt;px factor rather than being converted into this already-points space.
+        /// </summary>
+        public bool ReturnPoints { get; }
+    }
+
+    /// <summary>
+    /// Evaluates a validated calc-family AST to a pixel-space number. This is the one place calc()
+    /// numbers actually get computed — called only from Layer B (<c>CssValueParser.ParseLength</c>),
+    /// since only layout has the <see cref="CalcContext"/> a percentage/em/rem leaf needs to resolve.
+    /// Reuses <see cref="Length.ToPixels"/> for every leaf, so no unit-conversion arithmetic is duplicated
+    /// here. A null result signals a divide-by-zero; per the type-checker's rules every legal divisor is
+    /// a constant that Layer A already folds and rejects at validation time, so in practice this is a
+    /// defensive fallback rather than a load-bearing check.
+    /// </summary>
+    internal static class CalcEvaluator
+    {
+        public static double? Evaluate(CalcNode node, CalcContext context)
+        {
+            switch (node)
+            {
+                case NumberCalcNode number:
+                    return number.Value;
+
+                case DimensionCalcNode dimension when dimension.Unit == Length.Unit.Pt && context.ReturnPoints:
+                    return dimension.Value;
+
+                case DimensionCalcNode dimension:
+                    return new Length((float)dimension.Value, dimension.Unit)
+                        .ToPixels(context.EmFactor, context.RemFactor, context.HundredPercent, context.FontAdjust);
+
+                case PercentageCalcNode percentage:
+                    return new Length((float)percentage.Value, Length.Unit.Percent)
+                        .ToPixels(context.EmFactor, context.RemFactor, context.HundredPercent, context.FontAdjust);
+
+                case AngleCalcNode angle:
+                    // An angle leaf evaluates to radians (the canonical angle unit), so an angle-typed
+                    // calc such as `calc(1turn * 0.35)` yields 0.35 turn in radians (a Number leaf stays a
+                    // unitless scalar). Length calc()s never contain an angle leaf, so this never perturbs
+                    // length evaluation; the only current caller is conic-gradient stop-position parsing.
+                    return new Angle((float)angle.Value, angle.Unit).ToRadian();
+
+                case TimeCalcNode time:
+                    // Canonical time unit is milliseconds. No layout property evaluates a time calc() today
+                    // (these nodes only arise from @property `syntax: "<time>"` validation, which type-checks
+                    // rather than evaluates), so this case is defensive completeness paralleling the angle leaf.
+                    return new Time((float)time.Value, time.Unit).ToMilliseconds();
+
+                case ResolutionCalcNode resolution:
+                    // Canonical resolution unit is dots-per-pixel; same @property-only provenance as TimeCalcNode.
+                    return new Resolution((float)resolution.Value, resolution.Unit).ToDotsPerPixel();
+
+                case UnaryCalcNode unary:
+                {
+                    var operand = Evaluate(unary.Operand, context);
+                    if (operand is null) return null;
+                    return unary.Negative ? -operand.Value : operand.Value;
+                }
+
+                case BinaryCalcNode binary:
+                {
+                    var left = Evaluate(binary.Left, context);
+                    var right = Evaluate(binary.Right, context);
+                    if (left is null || right is null) return null;
+
+                    if (binary.Operator == '+') return left.Value + right.Value;
+                    if (binary.Operator == '-') return left.Value - right.Value;
+                    if (binary.Operator == '*') return left.Value * right.Value;
+                    if (binary.Operator == '/') return right.Value != 0d ? (double?)(left.Value / right.Value) : null;
+                    return null;
+                }
+
+                case CallCalcNode call:
+                {
+                    var values = new List<double>(call.Arguments.Count);
+                    foreach (var argument in call.Arguments)
+                    {
+                        var value = Evaluate(argument, context);
+                        if (value is null) return null;
+                        values.Add(value.Value);
+                    }
+
+                    if (call.Name.Isi(FunctionNames.Min)) return Min(values);
+                    if (call.Name.Isi(FunctionNames.Max)) return Max(values);
+                    if (call.Name.Isi(FunctionNames.Clamp) && values.Count == 3)
+                        return values[0] > values[2] ? values[2] : Math.Min(Math.Max(values[1], values[0]), values[2]);
+
+                    return null;
+                }
+
+                default:
+                    return null;
+            }
+        }
+
+        private static double Min(List<double> values)
+        {
+            var result = values[0];
+            for (var i = 1; i < values.Count; i++) if (values[i] < result) result = values[i];
+            return result;
+        }
+
+        private static double Max(List<double> values)
+        {
+            var result = values[0];
+            for (var i = 1; i < values.Count; i++) if (values[i] > result) result = values[i];
+            return result;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcNode.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcNode.cs
new file mode 100644
index 000000000..de42bde8a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcNode.cs
@@ -0,0 +1,122 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// AST node for a parsed calc()/min()/max()/clamp() expression. Shared between Layer A (the CSS
+    /// object model, which type-checks and canonicalizes it) and Layer B (layout, which evaluates it to
+    /// a pixel number using context Layer A never has, such as containing-block width or font size).
+    /// </summary>
+    internal abstract class CalcNode
+    {
+    }
+
+    internal sealed class NumberCalcNode : CalcNode
+    {
+        public NumberCalcNode(double value)
+        {
+            Value = value;
+        }
+
+        public double Value { get; }
+    }
+
+    internal sealed class DimensionCalcNode : CalcNode
+    {
+        public DimensionCalcNode(double value, Length.Unit unit)
+        {
+            Value = value;
+            Unit = unit;
+        }
+
+        public double Value { get; }
+        public Length.Unit Unit { get; }
+    }
+
+    internal sealed class PercentageCalcNode : CalcNode
+    {
+        public PercentageCalcNode(double value)
+        {
+            Value = value;
+        }
+
+        public double Value { get; }
+    }
+
+    internal sealed class AngleCalcNode : CalcNode
+    {
+        public AngleCalcNode(double value, Angle.Unit unit)
+        {
+            Value = value;
+            Unit = unit;
+        }
+
+        public double Value { get; }
+        public Angle.Unit Unit { get; }
+    }
+
+    internal sealed class TimeCalcNode : CalcNode
+    {
+        public TimeCalcNode(double value, Time.Unit unit)
+        {
+            Value = value;
+            Unit = unit;
+        }
+
+        public double Value { get; }
+        public Time.Unit Unit { get; }
+    }
+
+    internal sealed class ResolutionCalcNode : CalcNode
+    {
+        public ResolutionCalcNode(double value, Resolution.Unit unit)
+        {
+            Value = value;
+            Unit = unit;
+        }
+
+        public double Value { get; }
+        public Resolution.Unit Unit { get; }
+    }
+
+    /// <summary>A leading unary sign directly before a parenthesized group or a nested function call.</summary>
+    internal sealed class UnaryCalcNode : CalcNode
+    {
+        public UnaryCalcNode(bool negative, CalcNode operand)
+        {
+            Negative = negative;
+            Operand = operand;
+        }
+
+        public bool Negative { get; }
+        public CalcNode Operand { get; }
+    }
+
+    /// <summary>A binary <c>+</c>/<c>-</c>/<c>*</c>/<c>/</c> operation.</summary>
+    internal sealed class BinaryCalcNode : CalcNode
+    {
+        public BinaryCalcNode(char op, CalcNode left, CalcNode right)
+        {
+            Operator = op;
+            Left = left;
+            Right = right;
+        }
+
+        public char Operator { get; }
+        public CalcNode Left { get; }
+        public CalcNode Right { get; }
+    }
+
+    /// <summary>A <c>min()</c>, <c>max()</c>, or <c>clamp()</c> call over its comma-separated arguments.</summary>
+    internal sealed class CallCalcNode : CalcNode
+    {
+        public CallCalcNode(string name, IReadOnlyList<CalcNode> arguments)
+        {
+            Name = name;
+            Arguments = arguments;
+        }
+
+        public string Name { get; }
+        public IReadOnlyList<CalcNode> Arguments { get; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcParser.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcParser.cs
new file mode 100644
index 000000000..419614196
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcParser.cs
@@ -0,0 +1,252 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Recursive-descent parser for calc()/min()/max()/clamp() expressions, shared by Layer A (which
+    /// calls it during property-value conversion) and Layer B (which re-parses already-validated
+    /// canonical text at layout time — see CalcEvaluator). Grammar:
+    /// <c>&lt;calc-sum&gt; := &lt;calc-product&gt; (('+'|'-') &lt;calc-product&gt;)*</c>
+    /// <c>&lt;calc-product&gt; := &lt;calc-value&gt; (('*'|'/') &lt;calc-value&gt;)*</c>
+    /// <c>&lt;calc-value&gt; := &lt;number&gt; | &lt;dimension&gt; | &lt;percentage&gt; | '(' &lt;calc-sum&gt; ')' | &lt;nested-call&gt; | &lt;unary-sign&gt; &lt;calc-value&gt;</c>
+    /// Per spec, binary <c>+</c>/<c>-</c> require whitespace on both sides; <c>*</c>/<c>/</c> do not.
+    /// Returns <c>null</c> on any grammar violation.
+    /// </summary>
+    internal static class CalcParser
+    {
+        public static CalcNode Parse(FunctionToken function)
+        {
+            var name = function.Data;
+
+            if (name.Isi(FunctionNames.Calc))
+            {
+                var tokens = new List<Token>(function.ArgumentTokens);
+                var pos = 0;
+                var node = ParseSum(tokens, ref pos);
+                if (node is null) return null;
+
+                SkipWhitespace(tokens, ref pos);
+                return pos == tokens.Count ? node : null;
+            }
+
+            if (name.Isi(FunctionNames.Min) || name.Isi(FunctionNames.Max))
+            {
+                var args = ParseCommaSeparatedSums(function, out var groupCount);
+                return groupCount >= 1 && args != null
+                    ? new CallCalcNode(name.Isi(FunctionNames.Min) ? FunctionNames.Min : FunctionNames.Max, args)
+                    : null;
+            }
+
+            if (name.Isi(FunctionNames.Clamp))
+            {
+                var args = ParseCommaSeparatedSums(function, out var groupCount);
+                return groupCount == 3 && args != null ? new CallCalcNode(FunctionNames.Clamp, args) : null;
+            }
+
+            return null;
+        }
+
+        private static List<CalcNode> ParseCommaSeparatedSums(FunctionToken function, out int groupCount)
+        {
+            var groups = function.ArgumentTokens.ToList();
+            groupCount = groups.Count;
+
+            var args = new List<CalcNode>(groups.Count);
+            foreach (var group in groups)
+            {
+                if (group.Count == 0) return null;
+
+                var pos = 0;
+                var node = ParseSum(group, ref pos);
+                if (node is null) return null;
+
+                SkipWhitespace(group, ref pos);
+                if (pos != group.Count) return null;
+
+                args.Add(node);
+            }
+
+            return args;
+        }
+
+        private static CalcNode ParseSum(List<Token> tokens, ref int pos)
+        {
+            var left = ParseProduct(tokens, ref pos);
+            if (left is null) return null;
+
+            while (true)
+            {
+                var beforeWhitespace = pos;
+                SkipWhitespace(tokens, ref pos);
+                var sawWhitespaceBefore = pos != beforeWhitespace;
+
+                if (pos >= tokens.Count || tokens[pos].Type != TokenType.Delim ||
+                    (tokens[pos].Data != "+" && tokens[pos].Data != "-"))
+                {
+                    pos = beforeWhitespace;
+                    break;
+                }
+
+                // Binary +/- must have whitespace on both sides; without it, this can't be a valid
+                // binary operator here (an attached sign would already have been merged into the
+                // adjacent numeric token by the lexer).
+                if (!sawWhitespaceBefore) return null;
+
+                var op = tokens[pos].Data[0];
+                pos++;
+
+                var afterOp = pos;
+                SkipWhitespace(tokens, ref pos);
+                if (pos == afterOp) return null;
+
+                var right = ParseProduct(tokens, ref pos);
+                if (right is null) return null;
+
+                left = new BinaryCalcNode(op, left, right);
+            }
+
+            return left;
+        }
+
+        private static CalcNode ParseProduct(List<Token> tokens, ref int pos)
+        {
+            var left = ParseValue(tokens, ref pos);
+            if (left is null) return null;
+
+            while (true)
+            {
+                var save = pos;
+                SkipWhitespace(tokens, ref pos);
+
+                if (pos >= tokens.Count || tokens[pos].Type != TokenType.Delim ||
+                    (tokens[pos].Data != "*" && tokens[pos].Data != "/"))
+                {
+                    pos = save;
+                    break;
+                }
+
+                var op = tokens[pos].Data[0];
+                pos++;
+                SkipWhitespace(tokens, ref pos);
+
+                var right = ParseValue(tokens, ref pos);
+                if (right is null) return null;
+
+                left = new BinaryCalcNode(op, left, right);
+            }
+
+            return left;
+        }
+
+        private static CalcNode ParseValue(List<Token> tokens, ref int pos)
+        {
+            SkipWhitespace(tokens, ref pos);
+            if (pos >= tokens.Count) return null;
+
+            var token = tokens[pos];
+
+            switch (token.Type)
+            {
+                case TokenType.Number:
+                    pos++;
+                    return new NumberCalcNode(((NumberToken)token).Value);
+
+                case TokenType.Percentage:
+                    pos++;
+                    return new PercentageCalcNode(((UnitToken)token).Value);
+
+                case TokenType.Dimension:
+                {
+                    var unitToken = (UnitToken)token;
+                    var lengthUnit = Length.GetUnit(unitToken.Unit);
+                    if (IsSupportedLengthUnit(lengthUnit))
+                    {
+                        pos++;
+                        return new DimensionCalcNode(unitToken.Value, lengthUnit);
+                    }
+
+                    var angleUnit = Angle.GetUnit(unitToken.Unit);
+                    if (angleUnit != Angle.Unit.None)
+                    {
+                        pos++;
+                        return new AngleCalcNode(unitToken.Value, angleUnit);
+                    }
+
+                    var timeUnit = Time.GetUnit(unitToken.Unit);
+                    if (timeUnit != Time.Unit.None)
+                    {
+                        pos++;
+                        return new TimeCalcNode(unitToken.Value, timeUnit);
+                    }
+
+                    var resolutionUnit = Resolution.GetUnit(unitToken.Unit);
+                    if (resolutionUnit != Resolution.Unit.None)
+                    {
+                        pos++;
+                        return new ResolutionCalcNode(unitToken.Value, resolutionUnit);
+                    }
+
+                    return null;
+                }
+
+                case TokenType.RoundBracketOpen:
+                {
+                    pos++;
+                    var inner = ParseSum(tokens, ref pos);
+                    if (inner is null) return null;
+
+                    SkipWhitespace(tokens, ref pos);
+                    if (pos >= tokens.Count || tokens[pos].Type != TokenType.RoundBracketClose) return null;
+                    pos++;
+                    return inner;
+                }
+
+                case TokenType.Delim when token.Data == "+" || token.Data == "-":
+                {
+                    var negative = token.Data == "-";
+                    pos++;
+
+                    // A unary sign must be immediately followed by a parenthesized group or a nested
+                    // function call (a signed number/dimension is already a single token from the lexer).
+                    if (pos >= tokens.Count ||
+                        (tokens[pos].Type != TokenType.RoundBracketOpen && tokens[pos].Type != TokenType.Function))
+                    {
+                        return null;
+                    }
+
+                    var operand = ParseValue(tokens, ref pos);
+                    return operand is null ? null : new UnaryCalcNode(negative, operand);
+                }
+
+                case TokenType.Function:
+                {
+                    var nested = (FunctionToken)token;
+                    if (!IsCalcFamily(nested.Data)) return null;
+                    pos++;
+                    return Parse(nested);
+                }
+
+                default:
+                    return null;
+            }
+        }
+
+        private static bool IsSupportedLengthUnit(Length.Unit unit)
+        {
+            return unit == Length.Unit.Em || unit == Length.Unit.Rem || unit == Length.Unit.Ex || unit == Length.Unit.Px ||
+                unit == Length.Unit.Mm || unit == Length.Unit.Cm || unit == Length.Unit.In || unit == Length.Unit.Pt || unit == Length.Unit.Pc;
+        }
+
+        /// <summary>Whether <paramref name="name"/> is one of calc/min/max/clamp (case-insensitive).</summary>
+        public static bool IsCalcFamily(string name)
+        {
+            return name.Isi(FunctionNames.Calc) || name.Isi(FunctionNames.Min) ||
+                   name.Isi(FunctionNames.Max) || name.Isi(FunctionNames.Clamp);
+        }
+
+        private static void SkipWhitespace(List<Token> tokens, ref int pos)
+        {
+            while (pos < tokens.Count && tokens[pos].Type == TokenType.Whitespace) pos++;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcSerializer.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcSerializer.cs
new file mode 100644
index 000000000..f092a0cef
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcSerializer.cs
@@ -0,0 +1,270 @@
+using System.Collections.Generic;
+using System.Globalization;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Produces the canonical CSS text (<see cref="IPropertyValue.CssText"/>) for a validated calc-family
+    /// AST (Layer A only). A fully-numeric expression folds to a plain number; an expression built
+    /// entirely from absolute length units folds to a single pixel length; anything needing layout
+    /// context (mixed em/rem/%) is re-serialized back to normalized calc()/min()/max()/clamp() text.
+    /// </summary>
+    internal static class CalcSerializer
+    {
+        public static string Serialize(CalcNode node, CalcCategory category)
+        {
+            if (category == CalcCategory.Number)
+            {
+                var value = CalcTypeChecker.FoldNumber(node) ?? 0d;
+                return ((float)value).ToString(null, CultureInfo.InvariantCulture);
+            }
+
+            if (category == CalcCategory.Angle)
+            {
+                // Unlike Length/Percentage, Angle never needs layout context to resolve - deg/grad/rad/turn
+                // all convert via fixed constants - so a valid Angle expression always folds fully here;
+                // there's no "defer to layout" text-preserving fallback needed the way there is below.
+                var radians = FoldAngle(node) ?? 0d;
+                var degrees = radians * (180.0 / System.Math.PI);
+                return new Angle((float)degrees, Angle.Unit.Deg).ToString(null, CultureInfo.InvariantCulture);
+            }
+
+            if (TryFoldPixels(node, out var pixels))
+            {
+                return new Length((float)pixels, Length.Unit.Px).ToString(null, CultureInfo.InvariantCulture);
+            }
+
+            return SerializeExpression(node);
+        }
+
+        /// <summary>Folds an Angle-category subtree to radians; always succeeds for a validated tree.</summary>
+        private static double? FoldAngle(CalcNode node)
+        {
+            switch (node)
+            {
+                case AngleCalcNode angle:
+                    return new Angle((float)angle.Value, angle.Unit).ToRadian();
+
+                case UnaryCalcNode unary:
+                {
+                    var value = FoldAngle(unary.Operand);
+                    return value is null ? null : (double?)(unary.Negative ? -value.Value : value.Value);
+                }
+
+                case BinaryCalcNode binary when binary.Operator == '+' || binary.Operator == '-':
+                {
+                    var left = FoldAngle(binary.Left);
+                    var right = FoldAngle(binary.Right);
+                    if (left is null || right is null) return null;
+                    return binary.Operator == '+' ? left.Value + right.Value : left.Value - right.Value;
+                }
+
+                case BinaryCalcNode binary when binary.Operator == '*':
+                {
+                    var leftAngle = FoldAngle(binary.Left);
+                    if (leftAngle != null)
+                    {
+                        var scalar = CalcTypeChecker.FoldNumber(binary.Right);
+                        return scalar is null ? (double?)null : leftAngle.Value * scalar.Value;
+                    }
+
+                    var rightAngle = FoldAngle(binary.Right);
+                    if (rightAngle != null)
+                    {
+                        var scalar = CalcTypeChecker.FoldNumber(binary.Left);
+                        return scalar is null ? (double?)null : rightAngle.Value * scalar.Value;
+                    }
+
+                    return null;
+                }
+
+                case BinaryCalcNode binary when binary.Operator == '/':
+                {
+                    var left = FoldAngle(binary.Left);
+                    if (left is null) return null;
+                    var divisor = CalcTypeChecker.FoldNumber(binary.Right);
+                    return divisor is null || divisor == 0d ? (double?)null : left.Value / divisor.Value;
+                }
+
+                case CallCalcNode call:
+                {
+                    var values = new List<double>(call.Arguments.Count);
+                    foreach (var argument in call.Arguments)
+                    {
+                        var value = FoldAngle(argument);
+                        if (value is null) return null;
+                        values.Add(value.Value);
+                    }
+
+                    if (call.Name.Isi(FunctionNames.Min)) return Min(values);
+                    if (call.Name.Isi(FunctionNames.Max)) return Max(values);
+                    if (call.Name.Isi(FunctionNames.Clamp) && values.Count == 3)
+                        return values[0] > values[2] ? values[2] : System.Math.Min(System.Math.Max(values[1], values[0]), values[2]);
+
+                    return null;
+                }
+
+                default:
+                    return null;
+            }
+        }
+
+        private static string SerializeExpression(CalcNode node)
+        {
+            if (node is CallCalcNode call)
+            {
+                var args = new List<string>(call.Arguments.Count);
+                foreach (var argument in call.Arguments) args.Add(SerializeOperand(argument, false, 0));
+                return $"{call.Name}({string.Join(", ", args)})";
+            }
+
+            return $"calc({SerializeOperand(node, false, 0)})";
+        }
+
+        /// <summary>
+        /// Serializes a node as an operand of a parent with the given precedence (0 = none, 1 = sum-level
+        /// +/-, 2 = product-level */÷), adding parentheses whenever omitting them would change the
+        /// expression's meaning on re-parse (lower-precedence child under a higher-precedence parent, or
+        /// a same-precedence child on the right — since +/- and */÷ are left-associative and not, in
+        /// general, safe to flatten on the right).
+        /// </summary>
+        private static string SerializeOperand(CalcNode node, bool isRightOperand, int parentPrecedence)
+        {
+            switch (node)
+            {
+                case NumberCalcNode number:
+                    return ((float)number.Value).ToString(null, CultureInfo.InvariantCulture);
+
+                case DimensionCalcNode dimension:
+                    return new Length((float)dimension.Value, dimension.Unit).ToString(null, CultureInfo.InvariantCulture);
+
+                case PercentageCalcNode percentage:
+                    return new Length((float)percentage.Value, Length.Unit.Percent).ToString(null, CultureInfo.InvariantCulture);
+
+                // Time/Resolution leaves are only produced by @property `<time>`/`<resolution>` validation,
+                // which type-checks rather than serializes, so these arms are defensive completeness. A
+                // Time/Resolution-category Serialize() (were one ever created) folds through neither the Number
+                // nor Angle branch nor TryFoldPixels, so it reaches SerializeExpression and re-serializes to
+                // normalized calc() text using these leaf renderings.
+                case TimeCalcNode time:
+                    return new Time((float)time.Value, time.Unit).ToString(null, CultureInfo.InvariantCulture);
+
+                case ResolutionCalcNode resolution:
+                    return new Resolution((float)resolution.Value, resolution.Unit).ToString(null, CultureInfo.InvariantCulture);
+
+                case UnaryCalcNode unary:
+                {
+                    var operand = SerializeOperand(unary.Operand, false, 3);
+                    return unary.Negative ? $"-{operand}" : operand;
+                }
+
+                case CallCalcNode call:
+                    return SerializeExpression(call);
+
+                case BinaryCalcNode binary:
+                {
+                    var precedence = binary.Operator == '+' || binary.Operator == '-' ? 1 : 2;
+                    var text =
+                        $"{SerializeOperand(binary.Left, false, precedence)} {binary.Operator} {SerializeOperand(binary.Right, true, precedence)}";
+                    var needsParens = precedence < parentPrecedence || (precedence == parentPrecedence && isRightOperand);
+                    return needsParens ? $"({text})" : text;
+                }
+
+                default:
+                    return string.Empty;
+            }
+        }
+
+        private static bool TryFoldPixels(CalcNode node, out double pixels)
+        {
+            switch (node)
+            {
+                case NumberCalcNode number:
+                    pixels = number.Value;
+                    return true;
+
+                case DimensionCalcNode dimension when dimension.Unit != Length.Unit.Em && dimension.Unit != Length.Unit.Rem && dimension.Unit != Length.Unit.Ex:
+                    pixels = new Length((float)dimension.Value, dimension.Unit).ToPixels(0, 0, 0);
+                    return true;
+
+                case UnaryCalcNode unary when TryFoldPixels(unary.Operand, out var operand):
+                    pixels = unary.Negative ? -operand : operand;
+                    return true;
+
+                case BinaryCalcNode binary when TryFoldPixels(binary.Left, out var left) && TryFoldPixels(binary.Right, out var right):
+                    switch (binary.Operator)
+                    {
+                        case '+':
+                            pixels = left + right;
+                            return true;
+                        case '-':
+                            pixels = left - right;
+                            return true;
+                        case '*':
+                            pixels = left * right;
+                            return true;
+                        case '/' when right != 0d:
+                            pixels = left / right;
+                            return true;
+                        default:
+                            pixels = 0;
+                            return false;
+                    }
+
+                case CallCalcNode call:
+                {
+                    var values = new List<double>(call.Arguments.Count);
+                    foreach (var argument in call.Arguments)
+                    {
+                        if (!TryFoldPixels(argument, out var value))
+                        {
+                            pixels = 0;
+                            return false;
+                        }
+
+                        values.Add(value);
+                    }
+
+                    if (call.Name.Isi(FunctionNames.Min))
+                    {
+                        pixels = Min(values);
+                        return true;
+                    }
+
+                    if (call.Name.Isi(FunctionNames.Max))
+                    {
+                        pixels = Max(values);
+                        return true;
+                    }
+
+                    if (call.Name.Isi(FunctionNames.Clamp) && values.Count == 3)
+                    {
+                        pixels = values[0] > values[2] ? values[2] : System.Math.Min(System.Math.Max(values[1], values[0]), values[2]);
+                        return true;
+                    }
+
+                    pixels = 0;
+                    return false;
+                }
+
+                default:
+                    pixels = 0;
+                    return false;
+            }
+        }
+
+        private static double Min(List<double> values)
+        {
+            var result = values[0];
+            for (var i = 1; i < values.Count; i++) if (values[i] < result) result = values[i];
+            return result;
+        }
+
+        private static double Max(List<double> values)
+        {
+            var result = values[0];
+            for (var i = 1; i < values.Count; i++) if (values[i] > result) result = values[i];
+            return result;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcTypeChecker.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcTypeChecker.cs
new file mode 100644
index 000000000..2c7f71edd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcTypeChecker.cs
@@ -0,0 +1,156 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Implements CSS calc()'s type-checking rules over a parsed <see cref="CalcNode"/> tree (Layer A
+    /// only — Layer B's evaluator trusts that a value it's asked to evaluate already passed this check,
+    /// see CalcValueConverter/CalcEvaluator). Also folds pure-Number subtrees to concrete values, which
+    /// is what makes a constant divide-by-zero divisor detectable here rather than deferred to layout.
+    /// </summary>
+    internal static class CalcTypeChecker
+    {
+        public static CalcCategory? Check(CalcNode node)
+        {
+            switch (node)
+            {
+                case NumberCalcNode _:
+                    return CalcCategory.Number;
+
+                case DimensionCalcNode _:
+                    return CalcCategory.Length;
+
+                case PercentageCalcNode _:
+                    return CalcCategory.Percentage;
+
+                case AngleCalcNode _:
+                    return CalcCategory.Angle;
+
+                case TimeCalcNode _:
+                    return CalcCategory.Time;
+
+                case ResolutionCalcNode _:
+                    return CalcCategory.Resolution;
+
+                case UnaryCalcNode unary:
+                    return Check(unary.Operand);
+
+                case BinaryCalcNode binary when binary.Operator == '+' || binary.Operator == '-':
+                {
+                    var left = Check(binary.Left);
+                    var right = Check(binary.Right);
+                    return Combine(left, right);
+                }
+
+                case BinaryCalcNode binary when binary.Operator == '*':
+                {
+                    var left = Check(binary.Left);
+                    var right = Check(binary.Right);
+                    if (left is null || right is null) return null;
+                    if (left == CalcCategory.Number) return right;
+                    if (right == CalcCategory.Number) return left;
+                    return null;
+                }
+
+                case BinaryCalcNode binary when binary.Operator == '/':
+                {
+                    var left = Check(binary.Left);
+                    var right = Check(binary.Right);
+                    if (left is null || right != CalcCategory.Number) return null;
+
+                    // Every valid Number-category subtree is built entirely from Number leaves, so it's
+                    // always foldable here — this is what lets a constant divide-by-zero be rejected at
+                    // validation time rather than silently producing an infinity/NaN at layout time.
+                    var divisor = FoldNumber(binary.Right);
+                    return divisor == null || divisor == 0d ? null : left;
+                }
+
+                case CallCalcNode call:
+                {
+                    CalcCategory? combined = null;
+                    foreach (var argument in call.Arguments)
+                    {
+                        var category = Check(argument);
+                        if (category is null) return null;
+                        combined = combined is null ? category : Combine(combined, category);
+                        if (combined is null) return null;
+                    }
+
+                    return combined;
+                }
+
+                default:
+                    return null;
+            }
+        }
+
+        /// <summary>Folds a pure-Number subtree to a concrete value; null if it isn't purely numeric.</summary>
+        public static double? FoldNumber(CalcNode node)
+        {
+            switch (node)
+            {
+                case NumberCalcNode number:
+                    return number.Value;
+
+                case UnaryCalcNode unary:
+                {
+                    var value = FoldNumber(unary.Operand);
+                    return value is null ? null : (double?)(unary.Negative ? -value.Value : value.Value);
+                }
+
+                case BinaryCalcNode binary:
+                {
+                    var left = FoldNumber(binary.Left);
+                    var right = FoldNumber(binary.Right);
+                    if (left is null || right is null) return null;
+
+                    switch (binary.Operator)
+                    {
+                        case '+':
+                            return left.Value + right.Value;
+                        case '-':
+                            return left.Value - right.Value;
+                        case '*':
+                            return left.Value * right.Value;
+                        case '/':
+                            return right.Value != 0d ? (double?)(left.Value / right.Value) : null;
+                        default:
+                            return null;
+                    }
+                }
+
+                case CallCalcNode call:
+                {
+                    var values = new List<double>(call.Arguments.Count);
+                    foreach (var argument in call.Arguments)
+                    {
+                        var value = FoldNumber(argument);
+                        if (value is null) return null;
+                        values.Add(value.Value);
+                    }
+
+                    if (call.Name.Isi(FunctionNames.Min)) return values.Min();
+                    if (call.Name.Isi(FunctionNames.Max)) return values.Max();
+                    if (call.Name.Isi(FunctionNames.Clamp) && values.Count == 3)
+                        return values[0] > values[2] ? values[2] : Math.Max(values[0], Math.Min(values[2], values[1]));
+
+                    return null;
+                }
+
+                default:
+                    // Dimension/Percentage leaves are never purely numeric.
+                    return null;
+            }
+        }
+
+        private static CalcCategory? Combine(CalcCategory? left, CalcCategory? right)
+        {
+            if (left is null || right is null) return null;
+            if (left == CalcCategory.Number && right == CalcCategory.Number) return CalcCategory.Number;
+            if (left.Value.HasFlag(CalcCategory.Number) || right.Value.HasFlag(CalcCategory.Number)) return null;
+            return left.Value | right.Value;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcValue.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcValue.cs
new file mode 100644
index 000000000..d99ba471e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcValue.cs
@@ -0,0 +1,33 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <see cref="IPropertyValue"/> produced by <see cref="CalcValueConverter"/> for an accepted
+    /// calc()/min()/max()/clamp() declaration. Mirrors StructValueConverter's wrapper: CssText is the
+    /// canonical (possibly folded) text, Original is the raw token stream.
+    /// </summary>
+    internal sealed class CalcValue : IPropertyValue
+    {
+        public CalcValue(CalcNode node, CalcCategory category, IEnumerable<Token> tokens)
+        {
+            Node = node;
+            Category = category;
+            CssText = CalcSerializer.Serialize(node, category);
+            Original = new TokenValue(tokens);
+        }
+
+        internal CalcNode Node { get; }
+
+        internal CalcCategory Category { get; }
+
+        public string CssText { get; }
+
+        public TokenValue Original { get; }
+
+        public TokenValue ExtractFor(string name)
+        {
+            return Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Calc/CalcValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcValueConverter.cs
new file mode 100644
index 000000000..f13de2f7a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Calc/CalcValueConverter.cs
@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Accepts a calc()/min()/max()/clamp() declaration whose resolved type-checking category is within
+    /// <c>allowed</c>, composed onto the existing length/percent/number converters via
+    /// <c>.Or(...)</c> (see Converters.cs) so support cascades to every property built on them. Runs only
+    /// for non-var() declarations — var()-containing values are already routed to Converters.Any by
+    /// Property.TrySetValue, and reach this converter again (for the substituted text) via
+    /// DomParser.ApplyResolvedPropertyValue's re-parse.
+    /// </summary>
+    internal sealed class CalcValueConverter : IValueConverter
+    {
+        private readonly CalcCategory _allowed;
+
+        public CalcValueConverter(CalcCategory allowed)
+        {
+            _allowed = allowed;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            if (!(value.OnlyOrDefault() is FunctionToken function)) return null;
+            if (!CalcParser.IsCalcFamily(function.Data)) return null;
+
+            var node = CalcParser.Parse(function);
+            if (node is null) return null;
+
+            var category = CalcTypeChecker.Check(node);
+            if (category is null || (category.Value & ~_allowed) != 0) return null;
+
+            return new CalcValue(node, category.Value, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<CalcValue>();
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ColorInterpolationMethodGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/ColorInterpolationMethodGrammar.cs
new file mode 100644
index 000000000..f508d92c9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ColorInterpolationMethodGrammar.cs
@@ -0,0 +1,172 @@
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The single, shared grammar for a gradient's <c>&lt;color-interpolation-method&gt;</c> prelude
+    /// (<a href="https://drafts.csswg.org/css-images-4/#color-interpolation-method">CSS Images 4 §3.1</a>):
+    /// <code>in [ &lt;rectangular-color-space&gt; | &lt;polar-color-space&gt; &lt;hue-interpolation-method&gt;? ]</code>.
+    /// Both the CSS-OM validator (<see cref="GradientConverter"/>, which drops a malformed prelude at
+    /// parse time) and the render-time parser classify keywords through this one class, so the two
+    /// layers cannot disagree about which preludes are valid.
+    ///
+    /// Only the color spaces the interpolation math actually implements are recognized; the
+    /// wide-gamut RGB spaces <c>a98-rgb</c>/<c>prophoto-rgb</c>/<c>rec2020</c> are valid CSS but are
+    /// deliberately rejected here rather than approximated.
+    /// </summary>
+    internal static class ColorInterpolationMethodGrammar
+    {
+        private const string In = "in";
+        private const string Hue = "hue";
+
+        private static readonly HashSet<string> ColorSpaces = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+        {
+            "srgb", "srgb-linear", "display-p3", "lab", "oklab", "xyz", "xyz-d65", "xyz-d50",
+            "hsl", "hwb", "lch", "oklch",
+        };
+
+        private static readonly HashSet<string> PolarColorSpaces = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+        {
+            "hsl", "hwb", "lch", "oklch",
+        };
+
+        private static readonly HashSet<string> HueDirections = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+        {
+            "shorter", "longer", "increasing", "decreasing",
+        };
+
+        public static bool IsColorSpace(string name)
+        {
+            return name != null && ColorSpaces.Contains(name);
+        }
+
+        public static bool IsPolarColorSpace(string name)
+        {
+            return name != null && PolarColorSpaces.Contains(name);
+        }
+
+        public static bool IsHueDirection(string name)
+        {
+            return name != null && HueDirections.Contains(name);
+        }
+
+        /// <summary>
+        /// If <paramref name="group"/> (one gradient comma-group's tokens) contains an <c>in</c>
+        /// interpolation-method prelude, validates it and returns the group with the contiguous
+        /// <c>in …</c> slice removed as <paramref name="remainder"/> (for the caller to validate as the
+        /// gradient's own direction/shape/position, since the two combine with <c>||</c> in either order).
+        /// Returns <see langword="false"/> when an <c>in</c> is present but the method is malformed
+        /// (unknown/unsupported space, a hue-interpolation method on a rectangular space or without the
+        /// trailing <c>hue</c>, or <c>in</c> with nothing after it) — the caller drops the declaration.
+        /// When no <c>in</c> is present, <paramref name="hasInterpolationMethod"/> is
+        /// <see langword="false"/>, <paramref name="remainder"/> is the group unchanged, and it returns
+        /// <see langword="true"/>.
+        /// </summary>
+        public static bool TryExtractInterpolationMethod(
+            IEnumerable<Token> group, out List<Token> remainder, out bool hasInterpolationMethod)
+        {
+            var tokens = new List<Token>(group);
+
+            int inIndex = IndexOfIdent(tokens, 0, In);
+            if (inIndex < 0)
+            {
+                remainder = tokens;
+                hasInterpolationMethod = false;
+                return true;
+            }
+
+            hasInterpolationMethod = true;
+
+            // in <color-space>
+            int spaceIndex = NextNonWhitespace(tokens, inIndex + 1);
+            string spaceName;
+            if (spaceIndex < 0 || !IsIdent(tokens[spaceIndex], out spaceName) || !IsColorSpace(spaceName))
+            {
+                remainder = null;
+                return false;
+            }
+
+            int lastMethodIndex = spaceIndex;
+
+            // A hue-interpolation method (<dir> hue) is only valid after a polar space, and only complete
+            // with the trailing "hue" keyword.
+            if (IsPolarColorSpace(spaceName))
+            {
+                int dirIndex = NextNonWhitespace(tokens, spaceIndex + 1);
+                string dir;
+                if (dirIndex >= 0 && IsIdent(tokens[dirIndex], out dir) && IsHueDirection(dir))
+                {
+                    int hueIndex = NextNonWhitespace(tokens, dirIndex + 1);
+                    string hueWord;
+                    if (hueIndex < 0 || !IsIdent(tokens[hueIndex], out hueWord) ||
+                        !string.Equals(hueWord, Hue, StringComparison.OrdinalIgnoreCase))
+                    {
+                        remainder = null;
+                        return false;
+                    }
+
+                    lastMethodIndex = hueIndex;
+                }
+            }
+
+            remainder = BuildRemainder(tokens, inIndex, lastMethodIndex);
+            return true;
+        }
+
+        // The group with tokens [firstMethodIndex..lastMethodIndex] removed, then whitespace-trimmed at the
+        // edges so the leftover direction/shape validates the same as an un-prefixed group would.
+        private static List<Token> BuildRemainder(List<Token> tokens, int firstMethodIndex, int lastMethodIndex)
+        {
+            var remainder = new List<Token>(tokens.Count);
+
+            for (int i = 0; i < tokens.Count; i++)
+            {
+                if (i >= firstMethodIndex && i <= lastMethodIndex) continue;
+                remainder.Add(tokens[i]);
+            }
+
+            while (remainder.Count > 0 && remainder[0].Type == TokenType.Whitespace)
+                remainder.RemoveAt(0);
+            while (remainder.Count > 0 && remainder[remainder.Count - 1].Type == TokenType.Whitespace)
+                remainder.RemoveAt(remainder.Count - 1);
+
+            return remainder;
+        }
+
+        private static int IndexOfIdent(List<Token> tokens, int start, string data)
+        {
+            for (int i = start; i < tokens.Count; i++)
+            {
+                string value;
+                if (IsIdent(tokens[i], out value) &&
+                    string.Equals(value, data, StringComparison.OrdinalIgnoreCase))
+                    return i;
+            }
+
+            return -1;
+        }
+
+        private static int NextNonWhitespace(List<Token> tokens, int start)
+        {
+            for (int i = start; i < tokens.Count; i++)
+            {
+                if (tokens[i].Type != TokenType.Whitespace) return i;
+            }
+
+            return -1;
+        }
+
+        private static bool IsIdent(Token token, out string data)
+        {
+            if (token.Type == TokenType.Ident)
+            {
+                data = token.Data;
+                return true;
+            }
+
+            data = null;
+            return false;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Conditions/AndCondition.cs b/Source/HtmlRenderer/Core/CssEngine/Conditions/AndCondition.cs
new file mode 100644
index 000000000..ca20727ce
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Conditions/AndCondition.cs
@@ -0,0 +1,31 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine.Conditions
+{
+    internal sealed class AndCondition : StylesheetNode, IConditionFunction
+    {
+        public bool Check()
+        {
+            var conditions = Children.OfType<IConditionFunction>();
+
+            return conditions.All(condition => condition.Check());
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var conditions = Children.OfType<IConditionFunction>();
+            var first = true;
+
+            foreach (var condition in conditions)
+            {
+                if (first)
+                    first = false;
+                else
+                    writer.Write(" and ");
+
+                condition.ToCss(writer, formatter);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Conditions/DeclarationCondition.cs b/Source/HtmlRenderer/Core/CssEngine/Conditions/DeclarationCondition.cs
new file mode 100644
index 000000000..35dba9e9b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Conditions/DeclarationCondition.cs
@@ -0,0 +1,28 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DeclarationCondition : StylesheetNode, IConditionFunction
+    {
+        private readonly Property _property;
+        private readonly TokenValue _tokenValue;
+
+        public DeclarationCondition(Property property, TokenValue tokenValue)
+        {
+            _property = property;
+            _tokenValue = tokenValue;
+        }
+
+        public bool Check()
+        {
+            return _property is UnknownProperty == false &&
+                   _property.TrySetValue(_tokenValue);
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var delcaration = formatter.Declaration(_property.Name, _tokenValue.Text, _property.IsImportant);
+            writer.Write($"({delcaration})");
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Conditions/EmptyCondition.cs b/Source/HtmlRenderer/Core/CssEngine/Conditions/EmptyCondition.cs
new file mode 100644
index 000000000..20774d4af
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Conditions/EmptyCondition.cs
@@ -0,0 +1,16 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class EmptyCondition : StylesheetNode, IConditionFunction
+    {
+        public bool Check()
+        {
+            return true;
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Conditions/GroupCondition.cs b/Source/HtmlRenderer/Core/CssEngine/Conditions/GroupCondition.cs
new file mode 100644
index 000000000..a2eab5321
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Conditions/GroupCondition.cs
@@ -0,0 +1,34 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class GroupCondition : StylesheetNode, IConditionFunction
+    {
+        private IConditionFunction _content;
+
+        public IConditionFunction Content
+        {
+            get => _content ?? new EmptyCondition();
+            set
+            {
+                if (_content != null) RemoveChild(_content);
+
+                _content = value;
+
+                if (value != null) AppendChild(_content);
+            }
+        }
+
+        public bool Check()
+        {
+            return Content.Check();
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write("(");
+            Content.ToCss(writer, formatter);
+            writer.Write(")");
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Conditions/NotCondition.cs b/Source/HtmlRenderer/Core/CssEngine/Conditions/NotCondition.cs
new file mode 100644
index 000000000..d459849f5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Conditions/NotCondition.cs
@@ -0,0 +1,33 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class NotCondition : StylesheetNode, IConditionFunction
+    {
+        private IConditionFunction _content;
+
+        public IConditionFunction Content
+        {
+            get => _content ?? new EmptyCondition();
+            set
+            {
+                if (_content != null) RemoveChild(_content);
+
+                _content = value;
+
+                if (value != null) AppendChild(_content);
+            }
+        }
+
+        public bool Check()
+        {
+            return !Content.Check();
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write("not ");
+            Content.ToCss(writer, formatter);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Conditions/OrCondition.cs b/Source/HtmlRenderer/Core/CssEngine/Conditions/OrCondition.cs
new file mode 100644
index 000000000..58c458b29
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Conditions/OrCondition.cs
@@ -0,0 +1,35 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OrCondition : StylesheetNode, IConditionFunction
+    {
+        public bool Check()
+        {
+            var conditions = Children.OfType<IConditionFunction>();
+
+            return conditions.Any(condition => condition.Check());
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var conditions = Children.OfType<IConditionFunction>();
+            var first = true;
+
+            foreach (var condition in conditions)
+            {
+                if (first)
+                {
+                    first = false;
+                }
+                else
+                {
+                    writer.Write(" or ");
+                }
+
+                condition.ToCss(writer, formatter);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/CssProperty.cs b/Source/HtmlRenderer/Core/CssEngine/CssProperty.cs
new file mode 100644
index 000000000..c47b38093
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/CssProperty.cs
@@ -0,0 +1,90 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The five CSS-wide keywords (CSS Cascade &amp; Inheritance §7.3) a property value can be.</summary>
+    internal enum CssGlobalKeyword
+    {
+        Inherit,
+        Initial,
+        Unset,
+        Revert,
+        RevertLayer
+    }
+
+    /// <summary>
+    /// A typed box-side property value that carries the <b>parsed</b> value through the cascade to the box,
+    /// so a layout consumer reads the object rather than re-parsing the authored string. A value is in exactly
+    /// one of three states:
+    /// <list type="bullet">
+    /// <item>a CSS-wide keyword (<see cref="GlobalValue"/> non-null),</item>
+    /// <item><i>unresolved</i> — the authored text still contains <c>var()</c> and has not been resolved yet
+    /// (<see cref="IsUnresolved"/>; <see cref="Value"/> is default), or</item>
+    /// <item>resolved — <see cref="Value"/> holds the parsed <typeparamref name="T"/>.</item>
+    /// </list>
+    /// The authored/keyword text is retained so the string-based getter/snapshot/revert cascade path keeps
+    /// working (<see cref="ToString"/>). Grid templates (<c>T = GridTemplate</c>) are the first adopter; the
+    /// mechanism is intended to eventually back every box property.
+    /// </summary>
+    internal sealed class CssProperty<T>
+    {
+        private readonly string _cssText;
+
+        private CssProperty(CssGlobalKeyword? global, bool unresolved, T value, string cssText)
+        {
+            GlobalValue = global;
+            IsUnresolved = unresolved;
+            Value = value;
+            _cssText = cssText;
+        }
+
+        /// <summary>The CSS-wide keyword, when this value is one; otherwise null.</summary>
+        public CssGlobalKeyword? GlobalValue { get; }
+
+        public bool IsGlobalValue => GlobalValue.HasValue;
+
+        /// <summary>The authored text still contains an unresolved <c>var()</c> — <see cref="Value"/> is not
+        /// meaningful until resolution replaces this with a resolved value.</summary>
+        public bool IsUnresolved { get; }
+
+        /// <summary>The parsed value — meaningful only when the value is neither global nor unresolved.</summary>
+        public T Value { get; }
+
+        public static CssProperty<T> Global(CssGlobalKeyword keyword) =>
+            new CssProperty<T>(keyword, unresolved: false, value: default(T), CssGlobalKeywords.ToText(keyword));
+
+        public static CssProperty<T> Unresolved(string rawText) =>
+            new CssProperty<T>(global: null, unresolved: true, value: default(T), rawText);
+
+        public static CssProperty<T> FromValue(string cssText, T value) =>
+            new CssProperty<T>(global: null, unresolved: false, value, cssText);
+
+        public override string ToString() => _cssText;
+    }
+
+    /// <summary>Maps between the CSS-wide keyword string literals and <see cref="CssGlobalKeyword"/>.</summary>
+    internal static class CssGlobalKeywords
+    {
+        public static bool TryParse(string value, out CssGlobalKeyword keyword)
+        {
+            if (value.Isi(Keywords.Inherit)) { keyword = CssGlobalKeyword.Inherit; return true; }
+            if (value.Isi(Keywords.Initial)) { keyword = CssGlobalKeyword.Initial; return true; }
+            if (value.Isi(Keywords.Unset)) { keyword = CssGlobalKeyword.Unset; return true; }
+            if (value.Isi(Keywords.Revert)) { keyword = CssGlobalKeyword.Revert; return true; }
+            if (value.Isi(Keywords.RevertLayer)) { keyword = CssGlobalKeyword.RevertLayer; return true; }
+            keyword = default;
+            return false;
+        }
+
+        public static string ToText(CssGlobalKeyword keyword)
+        {
+            switch (keyword)
+            {
+                case CssGlobalKeyword.Inherit: return Keywords.Inherit;
+                case CssGlobalKeyword.Initial: return Keywords.Initial;
+                case CssGlobalKeyword.Unset: return Keywords.Unset;
+                case CssGlobalKeyword.Revert: return Keywords.Revert;
+                case CssGlobalKeyword.RevertLayer: return Keywords.RevertLayer;
+                default: return Keywords.Initial;
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/AlignContent.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AlignContent.cs
new file mode 100644
index 000000000..bbc53fe2e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AlignContent.cs
@@ -0,0 +1,18 @@
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum AlignContent : byte
+    {
+        Center,
+        Start,
+        End,
+        FlexStart,
+        FlexEnd,
+        Normal,
+        Baseline,
+        SpaceBetween,
+        SpaceAround,
+        SpaceEvenly,
+        Stretch
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/AlignItem.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AlignItem.cs
new file mode 100644
index 000000000..39328e6dc
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AlignItem.cs
@@ -0,0 +1,17 @@
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum AlignItem : byte
+    {
+        Normal,
+        Stretch,
+        Center,
+        Start,
+        End,
+        FlexStart,
+        FlexEnd,
+        SelfStart,
+        SelfEnd,
+        Baseline
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/AnimationDirection.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AnimationDirection.cs
new file mode 100644
index 000000000..ced03901f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AnimationDirection.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum AnimationDirection : byte
+    {
+        Normal,
+        Alternate,
+        Reverse,
+        AlternateReverse
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/AnimationFillStyle.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AnimationFillStyle.cs
new file mode 100644
index 000000000..55eee7828
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/AnimationFillStyle.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum AnimationFillStyle : byte
+    {
+        None,
+        Forwards,
+        Backwards,
+        Both
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/BackgroundAttachment.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BackgroundAttachment.cs
new file mode 100644
index 000000000..0284109a0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BackgroundAttachment.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum BackgroundAttachment : byte
+    {
+        Fixed,
+        Local,
+        Scroll
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/BackgroundRepeat.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BackgroundRepeat.cs
new file mode 100644
index 000000000..3b6a676e6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BackgroundRepeat.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum BackgroundRepeat : byte
+    {
+        Repeat,
+        Space,
+        Round,
+        NoRepeat
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/BlendMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BlendMode.cs
new file mode 100644
index 000000000..fa823598f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BlendMode.cs
@@ -0,0 +1,22 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum BlendMode : byte
+    {
+        Normal,
+        Multiply,
+        Screen,
+        Overlay,
+        Darken,
+        Lighten,
+        ColorDodge,
+        ColorBurn,
+        HardLight,
+        SoftLight,
+        Difference,
+        Exclusion,
+        Hue,
+        Saturation,
+        Color,
+        Luminosity
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/BorderRepeat.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BorderRepeat.cs
new file mode 100644
index 000000000..a679c49a7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BorderRepeat.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum BorderRepeat : byte
+    {
+        Stretch,
+        Repeat,
+        Round
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/BoxModel.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BoxModel.cs
new file mode 100644
index 000000000..c1590a3c0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BoxModel.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum BoxModel : byte
+    {
+        BorderBox,
+        PaddingBox,
+        ContentBox
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/BreakMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BreakMode.cs
new file mode 100644
index 000000000..dbd7ca9f4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/BreakMode.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum BreakMode : byte
+    {
+        Auto,
+        Always,
+        Avoid,
+        Left,
+        Right,
+        Page,
+        Column,
+        AvoidPage,
+        AvoidColumn,
+        AvoidRegion
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/ClearMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ClearMode.cs
new file mode 100644
index 000000000..b19a8307a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ClearMode.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum ClearMode : byte
+    {
+        None,
+        Left,
+        Right,
+        Both
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/Colors.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Colors.cs
new file mode 100644
index 000000000..5c1ccdeb7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Colors.cs
@@ -0,0 +1,205 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class Colors
+    {
+        private static readonly Dictionary<string, Color> NamedColors =
+            new Dictionary<string, Color>(StringComparer.OrdinalIgnoreCase)
+            {
+                {"aliceblue", new Color(240, 248, 255)},
+                {"antiquewhite", new Color(250, 235, 215)},
+                {"aqua", new Color(0, 255, 255)},
+                {"aquamarine", new Color(127, 255, 212)},
+                {"azure", new Color(240, 255, 255)},
+                {"beige", new Color(245, 245, 220)},
+                {"bisque", new Color(255, 228, 196)},
+                {"black", new Color(0, 0, 0)},
+                {"blanchedalmond", new Color(255, 235, 205)},
+                {"blue", new Color(0, 0, 255)},
+                {"blueviolet", new Color(138, 43, 226)},
+                {"brown", new Color(165, 42, 42)},
+                {"burlywood", new Color(222, 184, 135)},
+                {"cadetblue", new Color(95, 158, 160)},
+                {"chartreuse", new Color(127, 255, 0)},
+                {"chocolate", new Color(210, 105, 30)},
+                {"coral", new Color(255, 127, 80)},
+                {"cornflowerblue", new Color(100, 149, 237)},
+                {"cornsilk", new Color(255, 248, 220)},
+                {"crimson", new Color(220, 20, 60)},
+                {"cyan", new Color(0, 255, 255)},
+                {"darkblue", new Color(0, 0, 139)},
+                {"darkcyan", new Color(0, 139, 139)},
+                {"darkgoldenrod", new Color(184, 134, 11)},
+                {"darkgray", new Color(169, 169, 169)},
+                {"darkgreen", new Color(0, 100, 0)},
+                {"darkgrey", new Color(169, 169, 169)},
+                {"darkkhaki", new Color(189, 183, 107)},
+                {"darkmagenta", new Color(139, 0, 139)},
+                {"darkolivegreen", new Color(85, 107, 47)},
+                {"darkorange", new Color(255, 140, 0)},
+                {"darkorchid", new Color(153, 50, 204)},
+                {"darkred", new Color(139, 0, 0)},
+                {"darksalmon", new Color(233, 150, 122)},
+                {"darkseagreen", new Color(143, 188, 143)},
+                {"darkslateblue", new Color(72, 61, 139)},
+                {"darkslategray", new Color(47, 79, 79)},
+                {"darkslategrey", new Color(47, 79, 79)},
+                {"darkturquoise", new Color(0, 206, 209)},
+                {"darkviolet", new Color(148, 0, 211)},
+                {"deeppink", new Color(255, 20, 147)},
+                {"deepskyblue", new Color(0, 191, 255)},
+                {"dimgray", new Color(105, 105, 105)},
+                {"dimgrey", new Color(105, 105, 105)},
+                {"dodgerblue", new Color(30, 144, 255)},
+                {"firebrick", new Color(178, 34, 34)},
+                {"floralwhite", new Color(255, 250, 240)},
+                {"forestgreen", new Color(34, 139, 34)},
+                {"fuchsia", new Color(255, 0, 255)},
+                {"gainsboro", new Color(220, 220, 220)},
+                {"ghostwhite", new Color(248, 248, 255)},
+                {"gold", new Color(255, 215, 0)},
+                {"goldenrod", new Color(218, 165, 32)},
+                {"gray", new Color(128, 128, 128)},
+                {"green", new Color(0, 128, 0)},
+                {"greenyellow", new Color(173, 255, 47)},
+                {"grey", new Color(128, 128, 128)},
+                {"honeydew", new Color(240, 255, 240)},
+                {"hotpink", new Color(255, 105, 180)},
+                {"indianred", new Color(205, 92, 92)},
+                {"indigo", new Color(75, 0, 130)},
+                {"ivory", new Color(255, 255, 240)},
+                {"khaki", new Color(240, 230, 140)},
+                {"lavender", new Color(230, 230, 250)},
+                {"lavenderblush", new Color(255, 240, 245)},
+                {"lawngreen", new Color(124, 252, 0)},
+                {"lemonchiffon", new Color(255, 250, 205)},
+                {"lightblue", new Color(173, 216, 230)},
+                {"lightcoral", new Color(240, 128, 128)},
+                {"lightcyan", new Color(224, 255, 255)},
+                {"lightgoldenrodyellow", new Color(250, 250, 210)},
+                {"lightgray", new Color(211, 211, 211)},
+                {"lightgreen", new Color(144, 238, 144)},
+                {"lightgrey", new Color(211, 211, 211)},
+                {"lightpink", new Color(255, 182, 193)},
+                {"lightsalmon", new Color(255, 160, 122)},
+                {"lightseagreen", new Color(32, 178, 170)},
+                {"lightskyblue", new Color(135, 206, 250)},
+                {"lightslategray", new Color(119, 136, 153)},
+                {"lightslategrey", new Color(119, 136, 153)},
+                {"lightsteelblue", new Color(176, 196, 222)},
+                {"lightyellow", new Color(255, 255, 224)},
+                {"lime", new Color(0, 255, 0)},
+                {"limegreen", new Color(50, 205, 50)},
+                {"linen", new Color(250, 240, 230)},
+                {"magenta", new Color(255, 0, 255)},
+                {"maroon", new Color(128, 0, 0)},
+                {"mediumaquamarine", new Color(102, 205, 170)},
+                {"mediumblue", new Color(0, 0, 205)},
+                {"mediumorchid", new Color(186, 85, 211)},
+                {"mediumpurple", new Color(147, 112, 219)},
+                {"mediumseagreen", new Color(60, 179, 113)},
+                {"mediumslateblue", new Color(123, 104, 238)},
+                {"mediumspringgreen", new Color(0, 250, 154)},
+                {"mediumturquoise", new Color(72, 209, 204)},
+                {"mediumvioletred", new Color(199, 21, 133)},
+                {"midnightblue", new Color(25, 25, 112)},
+                {"mintcream", new Color(245, 255, 250)},
+                {"mistyrose", new Color(255, 228, 225)},
+                {"moccasin", new Color(255, 228, 181)},
+                {"navajowhite", new Color(255, 222, 173)},
+                {"navy", new Color(0, 0, 128)},
+                {"oldlace", new Color(253, 245, 230)},
+                {"olive", new Color(128, 128, 0)},
+                {"olivedrab", new Color(107, 142, 35)},
+                {"orange", new Color(255, 165, 0)},
+                {"orangered", new Color(255, 69, 0)},
+                {"orchid", new Color(218, 112, 214)},
+                {"palegoldenrod", new Color(238, 232, 170)},
+                {"palegreen", new Color(152, 251, 152)},
+                {"paleturquoise", new Color(175, 238, 238)},
+                {"palevioletred", new Color(219, 112, 147)},
+                {"papayawhip", new Color(255, 239, 213)},
+                {"peachpuff", new Color(255, 218, 185)},
+                {"peru", new Color(205, 133, 63)},
+                {"pink", new Color(255, 192, 203)},
+                {"plum", new Color(221, 160, 221)},
+                {"powderblue", new Color(176, 224, 230)},
+                {"purple", new Color(128, 0, 128)},
+                {"rebeccapurple", new Color(102, 51, 153)},
+                {"red", new Color(255, 0, 0)},
+                {"rosybrown", new Color(188, 143, 143)},
+                {"royalblue", new Color(65, 105, 225)},
+                {"saddlebrown", new Color(139, 69, 19)},
+                {"salmon", new Color(250, 128, 114)},
+                {"sandybrown", new Color(244, 164, 96)},
+                {"seagreen", new Color(46, 139, 87)},
+                {"seashell", new Color(255, 245, 238)},
+                {"sienna", new Color(160, 82, 45)},
+                {"silver", new Color(192, 192, 192)},
+                {"skyblue", new Color(135, 206, 235)},
+                {"slateblue", new Color(106, 90, 205)},
+                {"slategray", new Color(112, 128, 144)},
+                {"slategrey", new Color(112, 128, 144)},
+                {"snow", new Color(255, 250, 250)},
+                {"springgreen", new Color(0, 255, 127)},
+                {"steelblue", new Color(70, 130, 180)},
+                {"tan", new Color(210, 180, 140)},
+                {"teal", new Color(0, 128, 128)},
+                {"thistle", new Color(216, 191, 216)},
+                {"tomato", new Color(255, 99, 71)},
+                {"turquoise", new Color(64, 224, 208)},
+                {"violet", new Color(238, 130, 238)},
+                {"wheat", new Color(245, 222, 179)},
+                {"white", new Color(255, 255, 255)},
+                {"whitesmoke", new Color(245, 245, 245)},
+                {"yellow", new Color(255, 255, 0)},
+                {"yellowgreen", new Color(154, 205, 50)},
+                {"transparent", new Color(0, 0, 0, 0)},
+                {"activeborder", new Color(255, 255, 255)},
+                {"activecaption", new Color(204, 204, 204)},
+                {"appworkspace", new Color(255, 255, 255)},
+                {"background", new Color(99, 99, 206)},
+                {"buttonface", new Color(221, 221, 221)},
+                {"buttonhighlight", new Color(221, 221, 221)},
+                {"buttonshadow", new Color(136, 136, 136)},
+                {"buttontext", new Color(0, 0, 0)},
+                {"captiontext", new Color(0, 0, 0)},
+                {"graytext", new Color(128, 128, 128)},
+                {"highlight", new Color(181, 213, 255)},
+                {"highlighttext", new Color(0, 0, 0)},
+                {"inactiveborder", new Color(255, 255, 255)},
+                {"inactivecaption", new Color(255, 255, 255)},
+                {"inactivecaptiontext", new Color(127, 127, 127)},
+                {"infobackground", new Color(251, 252, 197)},
+                {"infotext", new Color(0, 0, 0)},
+                {"menu", new Color(247, 247, 247)},
+                {"menutext", new Color(0, 0, 0)},
+                {"scrollbar", new Color(255, 255, 255)},
+                {"threeddarkshadow", new Color(102, 102, 102)},
+                {"threedface", new Color(255, 255, 255)},
+                {"threedhighlight", new Color(221, 221, 221)},
+                {"threedlightshadow", new Color(192, 192, 192)},
+                {"threedshadow", new Color(136, 136, 136)},
+                {"window", new Color(255, 255, 255)},
+                {"windowframe", new Color(204, 204, 204)},
+                {"windowtext", new Color(0, 0, 0)}
+            };
+
+        public static IEnumerable<string> Names => NamedColors.Keys;
+
+        public static Color? GetColor(string name)
+        {
+            if (NamedColors.TryGetValue(name, out var color)) return color;
+
+            return null;
+        }
+
+        public static string GetName(Color color)
+        {
+            return (from pair in NamedColors where pair.Value.Equals(color) select pair.Key).FirstOrDefault();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/Combinators.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Combinators.cs
new file mode 100644
index 000000000..e023138ad
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Combinators.cs
@@ -0,0 +1,23 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class Combinators
+    {
+        // const (not static readonly) so these can be used as constant patterns in switch statements
+        // (e.g. AttributeSelectorFactory's reflection-free dispatch). String literals are interned, so
+        // reference/value equality behaviour is unchanged.
+        public const string Exactly = "=";
+        public const string Unlike = "!=";
+        public const string InList = "~=";
+        public const string InToken = "|=";
+        public const string Begins = "^=";
+        public const string Ends = "$=";
+        public const string InText = "*=";
+        public const string Column = "||";
+        public const string Pipe = "|";
+        public const string Adjacent = "+";
+        public const string Descendent = " ";
+        public const string Deep = ">>>";
+        public const string Child = ">";
+        public const string Sibling = "~";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/ContainerType.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ContainerType.cs
new file mode 100644
index 000000000..1e5a37cc7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ContainerType.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum ContainerType : byte
+    {
+        Normal,
+        Size,
+        InlineSize
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/DirectionMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/DirectionMode.cs
new file mode 100644
index 000000000..5eb2b5423
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/DirectionMode.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum DirectionMode : byte
+    {
+        Ltr,
+        Rtl
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/DisplayMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/DisplayMode.cs
new file mode 100644
index 000000000..5f2739ce8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/DisplayMode.cs
@@ -0,0 +1,25 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum DisplayMode : byte
+    {
+        None,
+        Inline,
+        Block,
+        ListItem,
+        InlineBlock,
+        InlineTable,
+        Table,
+        TableCaption,
+        TableCell,
+        TableColumn,
+        TableColumnGroup,
+        TableFooterGroup,
+        TableHeaderGroup,
+        TableRow,
+        TableRowGroup,
+        Flex,
+        InlineFlex,
+        Grid,
+        InlineGrid
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FeatureNames.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FeatureNames.cs
new file mode 100644
index 000000000..69e71400f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FeatureNames.cs
@@ -0,0 +1,55 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class FeatureNames
+    {
+        public static readonly string MinWidth = "min-width";
+        public static readonly string MinHeight = "min-height";
+        public static readonly string MinDeviceWidth = "min-device-width";
+        public static readonly string MinDeviceHeight = "min-device-height";
+        public static readonly string MinAspectRatio = "min-aspect-ratio";
+        public static readonly string MinResolution = "min-resolution";
+        public static readonly string MinColor = "min-color";
+        public static readonly string MinColorIndex = "min-color-index";
+        public static readonly string MinMonochrome = "min-monochrome";
+        public static readonly string MinDevicePixelRatio = "min-device-pixel-ratio";
+        public static readonly string MaxWidth = "max-width";
+        public static readonly string MaxHeight = "max-height";
+        public static readonly string MaxDeviceWidth = "max-device-width";
+        public static readonly string MaxDeviceHeight = "max-device-height";
+        public static readonly string MaxAspectRatio = "max-aspect-ratio";
+        public static readonly string MaxResolution = "max-resolution";
+        public static readonly string MaxColor = "max-color";
+        public static readonly string MaxColorIndex = "max-color-index";
+        public static readonly string MaxMonochrome = "max-monochrome";
+        public static readonly string MaxDevicePixelRatio = "max-device-pixel-ratio";
+        public static readonly string Width = "width";
+        public static readonly string Height = "height";
+        public static readonly string DeviceWidth = "device-width";
+        public static readonly string DeviceHeight = "device-height";
+        public static readonly string AspectRatio = "aspect-ratio";
+        public static readonly string Resolution = "resolution";
+        public static readonly string Color = "color";
+        public static readonly string ColorIndex = "color-index";
+        public static readonly string Monochrome = "monochrome";
+        public static readonly string Orientation = "orientation";
+        public static readonly string Grid = "grid";
+        public static readonly string Scan = "scan";
+        public static readonly string DevicePixelRatio = "device-pixel-ratio";
+        public static readonly string MinDeviceAspectRatio = "min-device-aspect-ratio";
+        public static readonly string MaxDeviceAspectRatio = "max-device-aspect-ratio";
+        public static readonly string DeviceAspectRatio = "device-aspect-ratio";
+        public static readonly string UpdateFrequency = "update-frequency";
+        public static readonly string Scripting = "scripting";
+        public static readonly string Pointer = "pointer";
+        public static readonly string Hover = "hover";
+        public static readonly string BlockSize = "block-size";
+        public static readonly string InlineSize = "inline-size";
+        public static readonly string PrefersColorScheme = "prefers-color-scheme";
+        public static readonly string PrefersReducedMotion = "prefers-reduced-motion";
+        public static readonly string PrefersContrast = "prefers-contrast";
+        public static readonly string PrefersReducedTransparency = "prefers-reduced-transparency";
+        public static readonly string Update = "update";
+        public static readonly string AnyHover = "any-hover";
+        public static readonly string AnyPointer = "any-pointer";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FillRule.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FillRule.cs
new file mode 100644
index 000000000..ecb83ad69
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FillRule.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FillRule : byte
+    {
+        Nonzero,
+        Evenodd
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FlexDirection.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FlexDirection.cs
new file mode 100644
index 000000000..f11e6d565
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FlexDirection.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FlexDirection : byte
+    {
+        Row,
+        RowReverse,
+        Column,
+        ColumnReverse
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FlexWrap.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FlexWrap.cs
new file mode 100644
index 000000000..e9ace9395
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FlexWrap.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FlexWrap : byte
+    {
+        NoWrap,
+        Wrap,
+        WrapReverse
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/Floating.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Floating.cs
new file mode 100644
index 000000000..6ae2fe94b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Floating.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum Floating : byte
+    {
+        None,
+        Left,
+        Right
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontSize.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontSize.cs
new file mode 100644
index 000000000..bb4981bc8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontSize.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FontSize : byte
+    {
+        Custom,
+        Tiny,
+        Little,
+        Smaller,
+        Small,
+        Medium,
+        Large,
+        Larger,
+        Big,
+        Huge
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontStretch.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontStretch.cs
new file mode 100644
index 000000000..543ab1790
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontStretch.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FontStretch : byte
+    {
+        Normal,
+        UltraCondensed,
+        ExtraCondensed,
+        Condensed,
+        SemiCondensed,
+        SemiExpanded,
+        Expanded,
+        ExtraExpanded,
+        UltraExpanded
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontStyle.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontStyle.cs
new file mode 100644
index 000000000..f49a466d6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontStyle.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FontStyle : byte
+    {
+        Normal,
+        Italic,
+        Oblique
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontVariant.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontVariant.cs
new file mode 100644
index 000000000..02f34f3d0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontVariant.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FontVariant : byte
+    {
+        Normal,
+        SmallCaps
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontWeight.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontWeight.cs
new file mode 100644
index 000000000..2f06350df
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FontWeight.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum FontWeight : byte
+    {
+        Normal,
+        Bold,
+        Bolder,
+        Lighter
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/FunctionNames.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FunctionNames.cs
new file mode 100644
index 000000000..94c802298
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/FunctionNames.cs
@@ -0,0 +1,72 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class FunctionNames
+    {
+        public static readonly string Url = "url";
+        public static readonly string UrlPrefix = "url-prefix";
+        public static readonly string Domain = "domain";
+        public static readonly string Regexp = "regexp";
+        public static readonly string Rgba = "rgba";
+        public static readonly string Rgb = "rgb";
+        public static readonly string Hsl = "hsl";
+        public static readonly string Hsla = "hsla";
+        public static readonly string Rect = "rect";
+        public static readonly string Polygon = "polygon";
+        public static readonly string Circle = "circle";
+        public static readonly string Ellipse = "ellipse";
+        public static readonly string Inset = "inset";
+        public static readonly string Repeat = "repeat";
+        public static readonly string Minmax = "minmax";
+        public static readonly string FitContent = "fit-content";
+        public static readonly string Attr = "attr";
+        public static readonly string LinearGradient = "linear-gradient";
+        public static readonly string RadialGradient = "radial-gradient";
+        public static readonly string RepeatingLinearGradient = "repeating-linear-gradient";
+        public static readonly string RepeatingRadialGradient = "repeating-radial-gradient";
+        public static readonly string Image = "image";
+        public static readonly string Counter = "counter";
+        public static readonly string Counters = "counters";
+        public static readonly string Content = "content";
+        public static readonly string Calc = "calc";
+        public static readonly string Min = "min";
+        public static readonly string Max = "max";
+        public static readonly string Clamp = "clamp";
+        public static readonly string Toggle = "toggle";
+        public static readonly string Translate = "translate";
+        public static readonly string TranslateX = "translateX";
+        public static readonly string TranslateY = "translateY";
+        public static readonly string TranslateZ = "translateZ";
+        public static readonly string Translate3d = "translate3d";
+        public static readonly string Matrix = "matrix";
+        public static readonly string Matrix3d = "matrix3d";
+        public static readonly string Rotate = "rotate";
+        public static readonly string Rotate3d = "rotate3d";
+        public static readonly string RotateX = "rotateX";
+        public static readonly string RotateY = "rotateY";
+        public static readonly string RotateZ = "rotateZ";
+        public static readonly string Skew = "skew";
+        public static readonly string SkewX = "skewX";
+        public static readonly string SkewY = "skewY";
+        public static readonly string Scale = "scale";
+        public static readonly string Scale3d = "scale3d";
+        public static readonly string ScaleX = "scaleX";
+        public static readonly string ScaleY = "scaleY";
+        public static readonly string ScaleZ = "scaleZ";
+        public static readonly string Steps = "steps";
+        public static readonly string CubicBezier = "cubic-bezier";
+        public static readonly string Perspective = "perspective";
+        public static readonly string Gray = "gray";
+        public static readonly string Hwb = "hwb";
+        public static readonly string Lab = "lab";
+        public static readonly string Oklab = "oklab";
+        public static readonly string Lch = "lch";
+        public static readonly string Oklch = "oklch";
+        public static readonly string ColorMix = "color-mix";
+        public static readonly string ConicGradient = "conic-gradient";
+        public static readonly string RepeatingConicGradient = "repeating-conic-gradient";
+        public static readonly string Var = "var";
+        public static readonly string ImageSet = "image-set";
+        public static readonly string CrossFade = "cross-fade";
+        public static readonly string Element = "element";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/HorizontalAlignment.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/HorizontalAlignment.cs
new file mode 100644
index 000000000..ad5286781
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/HorizontalAlignment.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum HorizontalAlignment : byte
+    {
+        Left,
+        Center,
+        Right,
+        Justify
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/HoverAbility.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/HoverAbility.cs
new file mode 100644
index 000000000..3bc8615ee
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/HoverAbility.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum HoverAbility : byte
+    {
+        None,
+        OnDemand,
+        Hover
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/IntrinsicSizing.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/IntrinsicSizing.cs
new file mode 100644
index 000000000..019c198b4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/IntrinsicSizing.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum IntrinsicSizing : byte
+    {
+        MaxContent,
+        MinContent,
+        FitContent,
+        Content
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/JustifyContent.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/JustifyContent.cs
new file mode 100644
index 000000000..8f5e95923
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/JustifyContent.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum JustifyContent : byte
+    {
+        Start,
+        Center,
+        SpaceBetween,
+        SpaceAround,
+        SpaceEvenly,
+        End,
+        FlexStart,
+        FlexEnd,
+        Left,
+        Right,
+        Normal,
+        Stretch
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/Keywords.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Keywords.cs
new file mode 100644
index 000000000..232ba506e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Keywords.cs
@@ -0,0 +1,326 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class Keywords
+    {
+        public static readonly string Important = "important";
+        public static readonly string Inherit = "inherit";
+        public static readonly string Initial = "initial";
+        public static readonly string None = "none";
+        public static readonly string Auto = "auto";
+        public static readonly string Manual = "manual";
+        public static readonly string From = "from";
+        public static readonly string To = "to";
+        public static readonly string Always = "always";
+        public static readonly string Avoid = "avoid";
+        public static readonly string Left = "left";
+        public static readonly string Right = "right";
+        public static readonly string Both = "both";
+        public static readonly string Forwards = "forwards";
+        public static readonly string Backwards = "backwards";
+        public static readonly string Page = "page";
+        public static readonly string Column = "column";
+        public static readonly string AvoidPage = "avoid-page";
+        public static readonly string AvoidColumn = "avoid-column";
+        public static readonly string AvoidRegion = "avoid-region";
+        public static readonly string Inset = "inset";
+        public static readonly string Outset = "outset";
+        public static readonly string Ridge = "ridge";
+        public static readonly string Groove = "groove";
+        public static readonly string Fixed = "fixed";
+        public static readonly string Local = "local";
+        public static readonly string Scroll = "scroll";
+        public static readonly string NoRepeat = "no-repeat";
+        public static readonly string Repeat = "repeat";
+        public static readonly string RepeatX = "repeat-x";
+        public static readonly string RepeatY = "repeat-y";
+        public static readonly string Round = "round";
+        public static readonly string Space = "space";
+        public static readonly string Stretch = "stretch";
+        public static readonly string Inline = "inline";
+        public static readonly string Block = "block";
+        public static readonly string InlineBlock = "inline-block";
+        public static readonly string ListItem = "list-item";
+        public static readonly string InlineTable = "inline-table";
+        public static readonly string Table = "table";
+        public static readonly string TableCaption = "table-caption";
+        public static readonly string TableCell = "table-cell";
+        public static readonly string TableColumn = "table-column";
+        public static readonly string TableColumnGroup = "table-column-group";
+        public static readonly string TableFooterGroup = "table-footer-group";
+        public static readonly string TableHeaderGroup = "table-header-group";
+        public static readonly string TableRow = "table-row";
+        public static readonly string TableRowGroup = "table-row-group";
+        public static readonly string Flex = "flex";
+        public static readonly string InlineFlex = "inline-flex";
+        public static readonly string Grid = "grid";
+        public static readonly string InlineGrid = "inline-grid";
+        public static readonly string Visible = "visible";
+        public static readonly string Hidden = "hidden";
+        public static readonly string Collapse = "collapse";
+        public static readonly string Static = "static";
+        public static readonly string Relative = "relative";
+        public static readonly string Absolute = "absolute";
+        public static readonly string Sticky = "sticky";
+        public static readonly string Serif = "serif";
+        public static readonly string SansSerif = "sans-serif";
+        public static readonly string Monospace = "monospace";
+        public static readonly string Cursive = "cursive";
+        public static readonly string Fantasy = "fantasy";
+        public static readonly string Caption = "caption";
+        public static readonly string Icon = "icon";
+        public static readonly string Menu = "menu";
+        public static readonly string MessageBox = "message-box";
+        public static readonly string SmallCaption = "small-caption";
+        public static readonly string StatusBar = "status-bar";
+        public static readonly string Normal = "normal";
+        public static readonly string Italic = "italic";
+        public static readonly string Oblique = "oblique";
+        public static readonly string UltraCondensed = "ultra-condensed";
+        public static readonly string ExtraCondensed = "extra-condensed";
+        public static readonly string Condensed = "condensed";
+        public static readonly string SemiCondensed = "semi-condensed";
+        public static readonly string SemiExpanded = "semi-expanded";
+        public static readonly string Expanded = "expanded";
+        public static readonly string ExtraExpanded = "extra-expanded";
+        public static readonly string UltraExpanded = "ultra-expanded";
+        public static readonly string Bold = "bold";
+        public static readonly string Bolder = "bolder";
+        public static readonly string Lighter = "lighter";
+        public static readonly string Center = "center";
+        public static readonly string SpaceBetween = "space-between";
+        public static readonly string SpaceAround = "space-around";
+        public static readonly string SpaceEvenly = "space-evenly";
+        public static readonly string Justify = "justify";
+        public static readonly string Underline = "underline";
+        public static readonly string Overline = "overline";
+        public static readonly string LineThrough = "line-through";
+        public static readonly string Blink = "blink";
+        public static readonly string Solid = "solid";
+        public static readonly string Double = "double";
+        public static readonly string Dotted = "dotted";
+        public static readonly string Dashed = "dashed";
+        public static readonly string Wavy = "wavy";
+        public static readonly string Capitalize = "capitalize";
+        public static readonly string Uppercase = "uppercase";
+        public static readonly string Lowercase = "lowercase";
+        public static readonly string FullWidth = "full-width";
+        public static readonly string Baseline = "baseline";
+        public static readonly string Sub = "sub";
+        public static readonly string Super = "super";
+        public static readonly string TextTop = "text-top";
+        public static readonly string TextBottom = "text-bottom";
+        public static readonly string Middle = "middle";
+        public static readonly string Top = "top";
+        public static readonly string Bottom = "bottom";
+        public static readonly string Pre = "pre";
+        public static readonly string Nowrap = "nowrap";
+        public static readonly string PreWrap = "pre-wrap";
+        public static readonly string PreLine = "pre-line";
+        public static readonly string OpenQuote = "open-quote";
+        public static readonly string NoOpenQuote = "no-open-quote";
+        public static readonly string CloseQuote = "close-quote";
+        public static readonly string NoCloseQuote = "no-close-quote";
+        public static readonly string Embed = "embed";
+        public static readonly string Isolate = "isolate";
+        public static readonly string IsolateOverride = "isolate-override";
+        public static readonly string BidirectionalOverride = "bidi-override";
+        public static readonly string Plaintext = "plaintext";
+        public static readonly string Default = "default";
+        public static readonly string ContextMenu = "context-menu";
+        public static readonly string Help = "help";
+        public static readonly string Pointer = "pointer";
+        public static readonly string Progress = "progress";
+        public static readonly string Wait = "wait";
+        public static readonly string Cell = "cell";
+        public static readonly string Crosshair = "crosshair";
+        public static readonly string Text = "text";
+        public static readonly string VerticalText = "vertical-text";
+        public static readonly string Alias = "alias";
+        public static readonly string Copy = "copy";
+        public static readonly string Move = "move";
+        public static readonly string NoDrop = "no-drop";
+        public static readonly string NotAllowed = "not-allowed";
+        public static readonly string EastResize = "e-resize";
+        public static readonly string NorthResize = "n-resize";
+        public static readonly string NorthEastResize = "ne-resize";
+        public static readonly string NorthWestResize = "nw-resize";
+        public static readonly string SouthResize = "s-resize";
+        public static readonly string SouthEastResize = "se-resize";
+        public static readonly string SouthWestResize = "sw-resize";
+        public static readonly string WestResize = "w-resize";
+        public static readonly string EastWestResize = "ew-resize";
+        public static readonly string NorthSouthResize = "ns-resize";
+        public static readonly string NorthEastSouthWestResize = "nesw-resize";
+        public static readonly string NorthWestSouthEastResize = "nwse-resize";
+        public static readonly string ColResize = "col-resize";
+        public static readonly string RowResize = "row-resize";
+        public static readonly string AllScroll = "all-scroll";
+        public static readonly string ZoomIn = "zoom-in";
+        public static readonly string ZoomOut = "zoom-out";
+        public static readonly string Grab = "grab";
+        public static readonly string Grabbing = "grabbing";
+        public static readonly string Thin = "thin";
+        public static readonly string Medium = "medium";
+        public static readonly string Thick = "thick";
+        public static readonly string Inside = "inside";
+        public static readonly string Outside = "outside";
+        public static readonly string BorderBox = "border-box";
+        public static readonly string PaddingBox = "padding-box";
+        public static readonly string ContentBox = "content-box";
+        public static readonly string Reverse = "reverse";
+        public static readonly string Alternate = "alternate";
+        public static readonly string AlternateReverse = "alternate-reverse";
+        public static readonly string Ease = "ease";
+        public static readonly string EaseIn = "ease-in";
+        public static readonly string EaseOut = "ease-out";
+        public static readonly string EaseInOut = "ease-in-out";
+        public static readonly string Linear = "linear";
+        public static readonly string StepStart = "step-start";
+        public static readonly string StepEnd = "step-end";
+        public static readonly string Disc = "disc";
+        public static readonly string Circle = "circle";
+        public static readonly string Square = "square";
+        public static readonly string Decimal = "decimal";
+        public static readonly string DecimalLeadingZero = "decimal-leading-zero";
+        public static readonly string LowerRoman = "lower-roman";
+        public static readonly string UpperRoman = "upper-roman";
+        public static readonly string LowerGreek = "lower-greek";
+        public static readonly string LowerLatin = "lower-latin";
+        public static readonly string UpperLatin = "upper-latin";
+        public static readonly string Armenian = "armenian";
+        public static readonly string Georgian = "georgian";
+        public static readonly string Hebrew = "hebrew";
+        public static readonly string LowerAlpha = "lower-alpha";
+        public static readonly string UpperAlpha = "upper-alpha";
+        public static readonly string XxSmall = "xx-small";
+        public static readonly string XSmall = "x-small";
+        public static readonly string Small = "small";
+        public static readonly string Large = "large";
+        public static readonly string XLarge = "x-large";
+        public static readonly string XxLarge = "xx-large";
+        public static readonly string Larger = "larger";
+        public static readonly string Smaller = "smaller";
+        public static readonly string And = "and";
+        public static readonly string Or = "or";
+        public static readonly string Not = "not";
+        public static readonly string Only = "only";
+        public static readonly string Show = "show";
+        public static readonly string Hide = "hide";
+        public static readonly string Invert = "invert";
+        public static readonly string Flat = "flat";
+        public static readonly string Preserve3d = "preserve-3d";
+        public static readonly string SmallCaps = "small-caps";
+        public static readonly string Slice = "slice";
+        public static readonly string Clone = "clone";
+        public static readonly string Running = "running";
+        public static readonly string Paused = "paused";
+        public static readonly string Infinite = "infinite";
+        public static readonly string Cover = "cover";
+        public static readonly string Contain = "contain";
+        public static readonly string Ltr = "ltr";
+        public static readonly string Rtl = "rtl";
+        public static readonly string All = "all";
+        public static readonly string Balance = "balance";
+        public static readonly string Separate = "separate";
+        public static readonly string Start = "start";
+        public static readonly string End = "end";
+        public static readonly string Fill = "fill";
+        public static readonly string Screen = "screen";
+        public static readonly string Print = "print";
+        public static readonly string Speech = "speech";
+        public static readonly string StyleSheet = "stylesheet";
+        public static readonly string On = "on";
+        public static readonly string Off = "off";
+        public static readonly string Of = "of";
+        public static readonly string Portrait = "portrait";
+        public static readonly string Landscape = "landscape";
+        public static readonly string Progressive = "progressive";
+        public static readonly string Interlace = "interlace";
+        public static readonly string Replace = "replace";
+        public static readonly string At = "at";
+        public static readonly string Yes = "yes";
+        public static readonly string No = "no";
+        public static readonly string Color = "color";
+        public static readonly string ColorBurn = "color-burn";
+        public static readonly string ColorDodge = "color-dodge";
+        public static readonly string Darken = "darken";
+        public static readonly string Difference = "difference";
+        public static readonly string Exclusion = "exclusion";
+        public static readonly string HardLight = "hard-light";
+        public static readonly string Hue = "hue";
+        public static readonly string Lighten = "lighten";
+        public static readonly string Luminosity = "luminosity";
+        public static readonly string Multiply = "multiply";
+        public static readonly string Overlay = "overlay";
+        public static readonly string Saturation = "saturation";
+        public static readonly string SoftLight = "soft-light";
+        public static readonly string Ellipse = "ellipse";
+        public static readonly string ClosestSide = "closest-side";
+        public static readonly string ClosestCorner = "closest-corner";
+        public static readonly string FarthestSide = "farthest-side";
+        public static readonly string FarthestCorner = "farthest-corner";
+        public static readonly string Slow = "slow";
+        public static readonly string Enabled = "enabled";
+        public static readonly string Disabled = "disabled";
+        public static readonly string InitialOnly = "initial-only";
+        public static readonly string Coarse = "coarse";
+        public static readonly string Fine = "fine";
+        public static readonly string OnDemand = "on-demand";
+        public static readonly string Hover = "hover";
+        public static readonly string Any = "any";
+        public static readonly string ScaleDown = "scale-down";
+        public static readonly string CurrentColor = "currentColor";
+        public static readonly string Public = "PUBLIC";
+        public static readonly string System = "SYSTEM";
+        public static readonly string CData = "[CDATA[";
+        public static readonly string Asterisk = "*";
+        public static readonly string Odd = "odd";
+        public static readonly string Even = "even";
+        public static readonly string Distribute = "distribute";
+        public static readonly string DistributeAllLines = "distribute-all-lines";
+        public static readonly string DistributeCenterLast = "distribute-center-last";
+        public static readonly string InterCluster = "inter-cluster";
+        public static readonly string InterIdeograph = "inter-ideograph";
+        public static readonly string InterWord = "inter-word";
+        public static readonly string Kashida = "kashida";
+        public static readonly string Newspaper = "newspaper";
+        public static readonly string Butt = "butt";
+        public static readonly string Miter = "miter";
+        public static readonly string Bevel = "bevel";
+        public static readonly string BreakAll = "break-all";
+        public static readonly string KeepAll = "keep-all";
+        public static readonly string BreakWord = "break-word";
+        public static readonly string Nonzero = "nonzero";
+        public static readonly string Evenodd = "evenodd";
+        public static readonly string Row = "row";
+        public static readonly string RowReverse = "row-reverse";
+        public static readonly string ColumnReverse = "column-reverse";
+        public static readonly string Wrap = "wrap";
+        public static readonly string WrapReverse = "wrap-reverse";
+        public static readonly string MaxContent = "max-content";
+        public static readonly string MinContent = "min-content";
+        public static readonly string FitContent = "fit-content";
+        public static readonly string AutoFill = "auto-fill";
+        public static readonly string AutoFit = "auto-fit";
+        public static readonly string AutoFlow = "auto-flow";
+        public static readonly string Subgrid = "subgrid";
+        public static readonly string Dense = "dense";
+        public static readonly string Content = "content";
+        public static readonly string Revert = "revert";
+        public static readonly string RevertLayer = "revert-layer";
+        public static readonly string Unset = "unset";
+        public static readonly string FlexStart = "flex-start";
+        public static readonly string FlexEnd = "flex-end";
+        public static readonly string Safe = "safe";
+        public static readonly string Unsafe = "unsafe";
+        public static readonly string First = "first";
+        public static readonly string Last = "last";
+        public static readonly string SelfStart = "self-start";
+        public static readonly string SelfEnd = "self-end";
+        public static readonly string Size = "size";
+        public static readonly string InlineSize = "inline-size";
+
+        // The `span` keyword of a grid-placement value (CSS Grid 1 §8.3).
+        public static readonly string Span = "span";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/LineStyle.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/LineStyle.cs
new file mode 100644
index 000000000..e51fe55a3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/LineStyle.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum LineStyle : byte
+    {
+        None,
+        Hidden,
+        Dotted,
+        Dashed,
+        Solid,
+        Double,
+        Groove,
+        Ridge,
+        Inset,
+        Outset
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/ListPosition.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ListPosition.cs
new file mode 100644
index 000000000..2e28cb801
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ListPosition.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum ListPosition : byte
+    {
+        Inside,
+        Outside
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/ListStyle.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ListStyle.cs
new file mode 100644
index 000000000..56db230ac
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ListStyle.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum ListStyle : byte
+    {
+        None,
+        Disc,
+        Circle,
+        Square,
+        Decimal,
+        DecimalLeadingZero,
+        LowerRoman,
+        UpperRoman,
+        LowerGreek,
+        LowerLatin,
+        UpperLatin,
+        Armenian,
+        Georgian,
+        Hebrew
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/ObjectFitting.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ObjectFitting.cs
new file mode 100644
index 000000000..ee61859c0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ObjectFitting.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum ObjectFitting : byte
+    {
+        None,
+        Fill,
+        Contain,
+        Cover,
+        ScaleDown
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/Overflow.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Overflow.cs
new file mode 100644
index 000000000..d04300cd4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Overflow.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum Overflow : byte
+    {
+        Auto,
+        Visible,
+        Hidden,
+        Scroll
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/OverflowWrap.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/OverflowWrap.cs
new file mode 100644
index 000000000..921c52c04
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/OverflowWrap.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum OverflowWrap : byte
+    {
+        Normal,
+        BreakWord
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/ParseError.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ParseError.cs
new file mode 100644
index 000000000..bb6a6b13a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ParseError.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum ParseError : byte
+    {
+        EOF = 0,
+        InvalidCharacter = 16, // 0x10,
+        InvalidBlockStart = 17, // 0x11,
+        InvalidToken = 18, // 0x12,
+        ColonMissing = 19, // 0x13,
+        IdentExpected = 20, // 0x14,
+        InputUnexpected = 21, // 0x15,
+        LineBreakUnexpected = 22, // 0x16,
+        UnknownAtRule = 32, // 0x20,
+        InvalidSelector = 48, // 0x30,
+        InvalidKeyframe = 49, // 0x31,
+        ValueMissing = 64, // 0x40,
+        InvalidValue = 65, // 0x41,
+        UnknownDeclarationName = 80 // 0x50
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/PlayState.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PlayState.cs
new file mode 100644
index 000000000..6cfe9a147
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PlayState.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum PlayState : byte
+    {
+        Running,
+        Paused
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/PointerAccuracy.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PointerAccuracy.cs
new file mode 100644
index 000000000..947619f9e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PointerAccuracy.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum PointerAccuracy : byte
+    {
+        None,
+        Coarse,
+        Fine
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/PositionMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PositionMode.cs
new file mode 100644
index 000000000..6a5cab131
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PositionMode.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum PositionMode : byte
+    {
+        Static,
+        Relative,
+        Absolute,
+        Fixed,
+        Sticky
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/PropertyFlags.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PropertyFlags.cs
new file mode 100644
index 000000000..b75899af7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PropertyFlags.cs
@@ -0,0 +1,15 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    [Flags]
+    internal enum PropertyFlags : byte
+    {
+        None = 0,
+        Inherited = 1,
+        Hashless = 2,
+        Unitless = 4,
+        Animatable = 8,
+        Shorthand = 16
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/PropertyNames.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PropertyNames.cs
new file mode 100644
index 000000000..518dd65fa
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PropertyNames.cs
@@ -0,0 +1,328 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class PropertyNames
+    {
+        public static readonly string AlignContent = "align-content";
+        public static readonly string AlignItems = "align-items";
+        public static readonly string AlignBaseline = "alignment-baseline";
+        public static readonly string AlignSelf = "align-self";
+        public static readonly string Accelerator = "accelerator";
+        public static readonly string Animation = "animation";
+        public static readonly string AnimationDelay = "animation-delay";
+        public static readonly string AnimationDirection = "animation-direction";
+        public static readonly string AnimationDuration = "animation-duration";
+        public static readonly string AnimationFillMode = "animation-fill-mode";
+        public static readonly string AnimationIterationCount = "animation-iteration-count";
+        public static readonly string AnimationName = "animation-name";
+        public static readonly string AnimationPlayState = "animation-play-state";
+        public static readonly string AnimationTimingFunction = "animation-timing-function";
+        public static readonly string BackgroundAttachment = "background-attachment";
+        public static readonly string BackgroundColor = "background-color";
+        public static readonly string BackgroundClip = "background-clip";
+        public static readonly string BackgroundOrigin = "background-origin";
+        public static readonly string BackgroundSize = "background-size";
+        public static readonly string BackgroundImage = "background-image";
+        public static readonly string BackgroundPosition = "background-position";
+        public static readonly string BackgroundPositionX = "background-position-x";
+        public static readonly string BackgroundPositionY = "background-position-y";
+        public static readonly string BackgroundRepeat = "background-repeat";
+        public static readonly string Background = "background";
+        public static readonly string Behavior = "behavior";
+        public static readonly string BaselineShift = "baseline-shift";
+        public static readonly string BorderColor = "border-color";
+        public static readonly string BorderSpacing = "border-spacing";
+        public static readonly string BorderCollapse = "border-collapse";
+        public static readonly string BorderStyle = "border-style";
+        public static readonly string BorderRadius = "border-radius";
+        public static readonly string BorderTopLeftRadius = "border-top-left-radius";
+        public static readonly string BorderTopRightRadius = "border-top-right-radius";
+        public static readonly string BorderBottomLeftRadius = "border-bottom-left-radius";
+        public static readonly string BorderBottomRightRadius = "border-bottom-right-radius";
+        public static readonly string BoxShadow = "box-shadow";
+        public static readonly string BoxSizing = "box-sizing";
+        public static readonly string AspectRatio = "aspect-ratio";
+        public static readonly string BoxDecorationBreak = "box-decoration-break";
+        public static readonly string BreakAfter = "break-after";
+        public static readonly string BreakBefore = "break-before";
+        public static readonly string BreakInside = "break-inside";
+        public static readonly string BackfaceVisibility = "backface-visibility";
+        public static readonly string BorderImage = "border-image";
+        public static readonly string BorderImageOutset = "border-image-outset";
+        public static readonly string BorderImageRepeat = "border-image-repeat";
+        public static readonly string BorderImageSource = "border-image-source";
+        public static readonly string BorderImageSlice = "border-image-slice";
+        public static readonly string BorderImageWidth = "border-image-width";
+        public static readonly string BorderTop = "border-top";
+        public static readonly string BorderRight = "border-right";
+        public static readonly string BorderBottom = "border-bottom";
+        public static readonly string BorderLeft = "border-left";
+        public static readonly string BorderTopColor = "border-top-color";
+        public static readonly string BorderLeftColor = "border-left-color";
+        public static readonly string BorderRightColor = "border-right-color";
+        public static readonly string BorderBottomColor = "border-bottom-color";
+        public static readonly string BorderTopStyle = "border-top-style";
+        public static readonly string BorderLeftStyle = "border-left-style";
+        public static readonly string BorderRightStyle = "border-right-style";
+        public static readonly string BorderBottomStyle = "border-bottom-style";
+        public static readonly string BorderTopWidth = "border-top-width";
+        public static readonly string BorderLeftWidth = "border-left-width";
+        public static readonly string BorderRightWidth = "border-right-width";
+        public static readonly string BorderBottomWidth = "border-bottom-width";
+        public static readonly string BorderWidth = "border-width";
+        public static readonly string Border = "border";
+        public static readonly string Bottom = "bottom";
+        public static readonly string Columns = "columns";
+        public static readonly string ColumnCount = "column-count";
+        public static readonly string ColumnFill = "column-fill";
+        public static readonly string ColumnGap = "column-gap";
+        public static readonly string ColumnRule = "column-rule";
+        public static readonly string ColumnRuleColor = "column-rule-color";
+        public static readonly string ColumnRuleStyle = "column-rule-style";
+        public static readonly string ColumnRuleWidth = "column-rule-width";
+        public static readonly string ColumnSpan = "column-span";
+        public static readonly string ColumnWidth = "column-width";
+        public static readonly string CaptionSide = "caption-side";
+        public static readonly string Clear = "clear";
+        public static readonly string Clip = "clip";
+        public static readonly string ClipLeft = "clip-left";
+        public static readonly string ClipTop = "clip-top";
+        public static readonly string ClipRight = "clip-right";
+        public static readonly string ClipBottom = "clip-bottom";
+        public static readonly string ClipPath = "clip-path";
+        public static readonly string ClipRule = "clip-rule";
+        public static readonly string Color = "color";
+        public static readonly string ColorInterpolationFilters = "color-interpolation-filters";
+        public static readonly string ContainerName = "container-name";
+        public static readonly string ContainerType = "container-type";
+        public static readonly string Content = "content";
+        public static readonly string CounterIncrement = "counter-increment";
+        public static readonly string CounterReset = "counter-reset";
+        public static readonly string Cursor = "cursor";
+        public static readonly string Direction = "direction";
+        public static readonly string Display = "display";
+        public static readonly string DominantBaseline = "dominant-baseline";
+        public static readonly string EmptyCells = "empty-cells";
+        public static readonly string EnableBackground = "enable-background";
+        public static readonly string Fill = "fill";
+        public static readonly string FillOpacity = "fill-opacity";
+        public static readonly string FillRule = "fill-rule";
+        public static readonly string Filter = "filter";
+        public static readonly string Flex = "flex";
+        public static readonly string FlexBasis = "flex-basis";
+        public static readonly string FlexDirection = "flex-direction";
+        public static readonly string FlexFlow = "flex-flow";
+        public static readonly string FlexGrow = "flex-grow";
+        public static readonly string FlexShrink = "flex-shrink";
+        public static readonly string FlexWrap = "flex-wrap";
+        public static readonly string Float = "float";
+        public static readonly string FontFamily = "font-family";
+        public static readonly string FontFeatureSettings = "font-feature-settings";
+        public static readonly string FontPalette = "font-palette";
+        public static readonly string FontSize = "font-size";
+        public static readonly string FontSizeAdjust = "font-size-adjust";
+        public static readonly string FontStyle = "font-style";
+        public static readonly string FontStretch = "font-stretch";
+        public static readonly string FontVariant = "font-variant";
+        public static readonly string FontWeight = "font-weight";
+        public static readonly string Font = "font";
+        public static readonly string Gap = "gap";
+        public static readonly string Grid = "grid";
+        public static readonly string GridTemplate = "grid-template";
+        public static readonly string GridTemplateColumns = "grid-template-columns";
+        public static readonly string GridTemplateRows = "grid-template-rows";
+        public static readonly string GridTemplateAreas = "grid-template-areas";
+        public static readonly string GridAutoColumns = "grid-auto-columns";
+        public static readonly string GridAutoRows = "grid-auto-rows";
+        public static readonly string GridAutoFlow = "grid-auto-flow";
+        public static readonly string GridColumn = "grid-column";
+        public static readonly string GridColumnStart = "grid-column-start";
+        public static readonly string GridColumnEnd = "grid-column-end";
+        public static readonly string GridRow = "grid-row";
+        public static readonly string GridRowStart = "grid-row-start";
+        public static readonly string GridRowEnd = "grid-row-end";
+        public static readonly string GridArea = "grid-area";
+        public static readonly string JustifyItems = "justify-items";
+        public static readonly string JustifySelf = "justify-self";
+        public static readonly string PlaceItems = "place-items";
+        public static readonly string PlaceContent = "place-content";
+        public static readonly string PlaceSelf = "place-self";
+        public static readonly string GlyphOrientationHorizontal = "glyph-orientation-horizontal";
+        public static readonly string GlyphOrientationVertical = "glyph-orientation-vertical";
+        public static readonly string Height = "height";
+        public static readonly string Hyphens = "hyphens";
+        public static readonly string ImeMode = "ime-mode";
+        public static readonly string JustifyContent = "justify-content";
+        public static readonly string LayoutGrid = "layout-grid";
+        public static readonly string LayoutGridChar = "layout-grid-char";
+        public static readonly string LayoutGridType = "layout-grid-type";
+        public static readonly string LayoutGridMode = "layout-grid-mode";
+        public static readonly string LayoutGridLine = "layout-grid-line";
+        public static readonly string Left = "left";
+        public static readonly string LetterSpacing = "letter-spacing";
+        public static readonly string LineHeight = "line-height";
+        public static readonly string ListStyleImage = "list-style-image";
+        public static readonly string ListStylePosition = "list-style-position";
+        public static readonly string ListStyleType = "list-style-type";
+        public static readonly string ListStyle = "list-style";
+        public static readonly string MarginRight = "margin-right";
+        public static readonly string MarginLeft = "margin-left";
+        public static readonly string MarginTop = "margin-top";
+        public static readonly string MarginBottom = "margin-bottom";
+        public static readonly string Margin = "margin";
+        public static readonly string Marker = "marker";
+        public static readonly string MarkerEnd = "marker-end";
+        public static readonly string MarkerMid = "marker-mid";
+        public static readonly string MarkerStart = "marker-start";
+        public static readonly string Mask = "mask";
+        public static readonly string MaxHeight = "max-height";
+        public static readonly string MaxWidth = "max-width";
+        public static readonly string MinHeight = "min-height";
+        public static readonly string MinWidth = "min-width";
+        public static readonly string Opacity = "opacity";
+        public static readonly string Order = "order";
+        public static readonly string Orphans = "orphans";
+        public static readonly string OutlineColor = "outline-color";
+        public static readonly string OutlineStyle = "outline-style";
+        public static readonly string OutlineWidth = "outline-width";
+        public static readonly string Outline = "outline";
+        public static readonly string Overflow = "overflow";
+        public static readonly string OverflowX = "overflow-x";
+        public static readonly string OverflowY = "overflow-y";
+        public static readonly string OverflowWrap = "overflow-wrap";
+        public static readonly string PaddingTop = "padding-top";
+        public static readonly string PaddingRight = "padding-right";
+        public static readonly string PaddingLeft = "padding-left";
+        public static readonly string PaddingBottom = "padding-bottom";
+        public static readonly string Padding = "padding";
+        public static readonly string PageBreakAfter = "page-break-after";
+        public static readonly string PageBreakBefore = "page-break-before";
+        public static readonly string PageBreakInside = "page-break-inside";
+        public static readonly string PageName = "page";
+        public static readonly string Perspective = "perspective";
+        public static readonly string PerspectiveOrigin = "perspective-origin";
+        public static readonly string PointerEvents = "pointer-events";
+        public static readonly string Position = "position";
+        public static readonly string Quotes = "quotes";
+        public static readonly string Right = "right";
+        public static readonly string RowGap = "row-gap";
+        public static readonly string RubyAlign = "ruby-align";
+        public static readonly string RubyOverhang = "ruby-overhang";
+        public static readonly string RubyPosition = "ruby-position";
+        public static readonly string Scrollbar3dLightColor = "scrollbar3d-light-color";
+        public static readonly string ScrollbarArrowColor = "scrollbar-arrow-color";
+        public static readonly string ScrollbarDarkShadowColor = "scrollbar-dark-shadow-color";
+        public static readonly string ScrollbarFaceColor = "scrollbar-face-color";
+        public static readonly string ScrollbarHighlightColor = "scrollbar-highlight-color";
+        public static readonly string ScrollbarShadowColor = "scrollbar-shadow-color";
+        public static readonly string ScrollbarTrackColor = "scrollbar-track-color";
+        public static readonly string Stroke = "stroke";
+        public static readonly string StrokeDasharray = "stroke-dasharray";
+        public static readonly string StrokeDashoffset = "stroke-dashoffset";
+        public static readonly string StrokeLinecap = "stroke-linecap";
+        public static readonly string StrokeLinejoin = "stroke-linejoin";
+        public static readonly string StrokeMiterlimit = "stroke-miterlimit";
+        public static readonly string StrokeOpacity = "stroke-opacity";
+        public static readonly string StrokeWidth = "stroke-width";
+        public static readonly string StringSet = "string-set";
+        public static readonly string TableLayout = "table-layout";
+        public static readonly string TextAlign = "text-align";
+        public static readonly string TextAlignLast = "text-align-last";
+        public static readonly string TextAnchor = "text-anchor";
+        public static readonly string TextAutospace = "text-autospace";
+        public static readonly string TextDecoration = "text-decoration";
+        public static readonly string TextDecorationColor = "text-decoration-color";
+        public static readonly string TextDecorationLine = "text-decoration-line";
+        public static readonly string TextDecorationStyle = "text-decoration-style";
+        public static readonly string TextIndent = "text-indent";
+        public static readonly string TextJustify = "text-justify";
+        public static readonly string TextOverflow = "text-overflow";
+        public static readonly string TextShadow = "text-shadow";
+        public static readonly string TextTransform = "text-transform";
+        public static readonly string TextUnderlinePosition = "text-underline-position";
+        public static readonly string Transform = "transform";
+        public static readonly string TransformOrigin = "transform-origin";
+        public static readonly string TransformStyle = "transform-style";
+        public static readonly string Transition = "transition";
+        public static readonly string TransitionDelay = "transition-delay";
+        public static readonly string TransitionDuration = "transition-duration";
+        public static readonly string TransitionTimingFunction = "transition-timing-function";
+        public static readonly string TransitionProperty = "transition-property";
+        public static readonly string Top = "top";
+        public static readonly string UnicodeBidirectional = "unicode-bidi";
+        public static readonly string VerticalAlign = "vertical-align";
+        public static readonly string Visibility = "visibility";
+        public static readonly string WhiteSpace = "white-space";
+        public static readonly string Widows = "widows";
+        public static readonly string Width = "width";
+        public static readonly string WordBreak = "word-break";
+        public static readonly string WordSpacing = "word-spacing";
+        public static readonly string WordWrap = "word-wrap";
+        public static readonly string WritingMode = "writing-mode";
+        public static readonly string ZIndex = "z-index";
+        public static readonly string Zoom = "zoom";
+        public static readonly string UnicodeRange = "unicode-range";
+        public static readonly string Src = "src";
+        // @property descriptors (CSS Properties & Values API Level 1 §3)
+        public static readonly string Syntax = "syntax";
+        public static readonly string InitialValue = "initial-value";
+        public static readonly string Inherits = "inherits";
+        public static readonly string BasePalette = "base-palette";
+        public static readonly string OverrideColors = "override-colors";
+        public static readonly string ObjectFit = "object-fit";
+        public static readonly string ObjectPosition = "object-position";
+        public static readonly string Size = "size";
+
+        // CSS Logical Properties and Values Level 1. Layout here is always LTR / horizontal-tb,
+        // so each logical property maps 1:1 to a physical one (block-start = top,
+        // block-end = bottom, inline-start = left, inline-end = right) and is registered to
+        // produce/export the existing physical longhands.
+        public static readonly string MarginBlock = "margin-block";
+        public static readonly string MarginBlockStart = "margin-block-start";
+        public static readonly string MarginBlockEnd = "margin-block-end";
+        public static readonly string MarginInline = "margin-inline";
+        public static readonly string MarginInlineStart = "margin-inline-start";
+        public static readonly string MarginInlineEnd = "margin-inline-end";
+
+        public static readonly string PaddingBlock = "padding-block";
+        public static readonly string PaddingBlockStart = "padding-block-start";
+        public static readonly string PaddingBlockEnd = "padding-block-end";
+        public static readonly string PaddingInline = "padding-inline";
+        public static readonly string PaddingInlineStart = "padding-inline-start";
+        public static readonly string PaddingInlineEnd = "padding-inline-end";
+
+        public static readonly string Inset = "inset";
+        public static readonly string InsetBlock = "inset-block";
+        public static readonly string InsetBlockStart = "inset-block-start";
+        public static readonly string InsetBlockEnd = "inset-block-end";
+        public static readonly string InsetInline = "inset-inline";
+        public static readonly string InsetInlineStart = "inset-inline-start";
+        public static readonly string InsetInlineEnd = "inset-inline-end";
+
+        public static readonly string BorderBlock = "border-block";
+        public static readonly string BorderBlockStart = "border-block-start";
+        public static readonly string BorderBlockEnd = "border-block-end";
+        public static readonly string BorderInline = "border-inline";
+        public static readonly string BorderInlineStart = "border-inline-start";
+        public static readonly string BorderInlineEnd = "border-inline-end";
+
+        public static readonly string BorderBlockWidth = "border-block-width";
+        public static readonly string BorderBlockStyle = "border-block-style";
+        public static readonly string BorderBlockColor = "border-block-color";
+        public static readonly string BorderInlineWidth = "border-inline-width";
+        public static readonly string BorderInlineStyle = "border-inline-style";
+        public static readonly string BorderInlineColor = "border-inline-color";
+
+        public static readonly string BorderBlockStartWidth = "border-block-start-width";
+        public static readonly string BorderBlockStartStyle = "border-block-start-style";
+        public static readonly string BorderBlockStartColor = "border-block-start-color";
+        public static readonly string BorderBlockEndWidth = "border-block-end-width";
+        public static readonly string BorderBlockEndStyle = "border-block-end-style";
+        public static readonly string BorderBlockEndColor = "border-block-end-color";
+        public static readonly string BorderInlineStartWidth = "border-inline-start-width";
+        public static readonly string BorderInlineStartStyle = "border-inline-start-style";
+        public static readonly string BorderInlineStartColor = "border-inline-start-color";
+        public static readonly string BorderInlineEndWidth = "border-inline-end-width";
+        public static readonly string BorderInlineEndStyle = "border-inline-end-style";
+        public static readonly string BorderInlineEndColor = "border-inline-end-color";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/PseudoClassNames.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PseudoClassNames.cs
new file mode 100644
index 000000000..e99dec18c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PseudoClassNames.cs
@@ -0,0 +1,56 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class PseudoClassNames
+    {
+        public static readonly string Root = "root";
+        public static readonly string Scope = "scope";
+        public static readonly string OnlyType = "only-of-type";
+        public static readonly string FirstOfType = "first-of-type";
+        public static readonly string LastOfType = "last-of-type";
+        public static readonly string OnlyChild = "only-child";
+        public static readonly string FirstChild = "first-child";
+        public static readonly string LastChild = "last-child";
+        public static readonly string Empty = "empty";
+        public static readonly string AnyLink = "any-link";
+        public static readonly string Link = "link";
+        public static readonly string Visited = "visited";
+        public static readonly string Active = "active";
+        public static readonly string Hover = "hover";
+        public static readonly string Focus = "focus";
+        public static readonly string FocusVisible = "focus-visible";
+        public static readonly string FocusWithin = "focus-within";
+        public static readonly string Target = "target";
+        public static readonly string Enabled = "enabled";
+        public static readonly string Disabled = "disabled";
+        public static readonly string Checked = "checked";
+        public static readonly string Unchecked = "unchecked";
+        public static readonly string Indeterminate = "indeterminate";
+        public static readonly string PlaceholderShown = "placeholder-shown";
+        public static readonly string Default = "default";
+        public static readonly string Valid = "valid";
+        public static readonly string Invalid = "invalid";
+        public static readonly string Required = "required";
+        public static readonly string InRange = "in-range";
+        public static readonly string OutOfRange = "out-of-range";
+        public static readonly string Optional = "optional";
+        public static readonly string ReadOnly = "read-only";
+        public static readonly string ReadWrite = "read-write";
+        public static readonly string Shadow = "shadow";
+        public static readonly string Dir = "dir";
+        public static readonly string Has = "has";
+        public static readonly string Matches = "matches";
+        public static readonly string Is = "is";
+        public static readonly string Where = "where";
+        public static readonly string NthChild = "nth-child";
+        public static readonly string NthLastChild = "nth-last-child";
+        public static readonly string NthOfType = "nth-of-type";
+        public static readonly string NthLastOfType = "nth-last-of-type";
+        public static readonly string NthColumn = "nth-column";
+        public static readonly string NthLastColumn = "nth-last-column";
+        public static readonly string Not = "not";
+        public static readonly string Lang = "lang";
+        public static readonly string Contains = "contains";
+        public static readonly string HostContext = "host-context";
+        public static readonly string Separator = ":";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/PseudoElementNames.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PseudoElementNames.cs
new file mode 100644
index 000000000..c78fd111f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/PseudoElementNames.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class PseudoElementNames
+    {
+        public static readonly string Before = "before";
+        public static readonly string After = "after";
+        public static readonly string Marker = "marker";
+        public static readonly string Selection = "selection";
+        public static readonly string FirstLine = "first-line";
+        public static readonly string FirstLetter = "first-letter";
+        public static readonly string Content = "content";
+        public static readonly string Separator = "::";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/QuirksMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/QuirksMode.cs
new file mode 100644
index 000000000..29af0dea3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/QuirksMode.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum QuirksMode : byte
+    {
+        Off,
+        Limited,
+        On
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/RuleNames.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/RuleNames.cs
new file mode 100644
index 000000000..6ada85658
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/RuleNames.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class RuleNames
+    {
+        public static readonly string Supports = "supports";
+        public static readonly string Charset = "charset";
+        public static readonly string Document = "document";
+        public static readonly string FontFace = "font-face";
+        public static readonly string ViewPort = "viewport";
+        public static readonly string Import = "import";
+        public static readonly string Keyframes = "keyframes";
+        public static readonly string Media = "media";
+        public static readonly string Namespace = "namespace";
+        public static readonly string Page = "page";
+        public static readonly string Container = "container";
+        public static readonly string Property = "property";
+        public static readonly string Layer = "layer";
+        public static readonly string FontPaletteValues = "font-palette-values";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/RuleType.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/RuleType.cs
new file mode 100644
index 000000000..f13b491b6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/RuleType.cs
@@ -0,0 +1,28 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum RuleType : byte
+    {
+        Unknown,
+        Style,
+        Charset,
+        Import,
+        Media,
+        FontFace,
+        Page,
+        Keyframes,
+        Keyframe,
+        MarginBox,
+        Namespace,
+        CounterStyle,
+        Supports,
+        Document,
+        FontFeatureValues,
+        Viewport,
+        RegionStyle,
+        Container,
+        Property,
+        Layer,
+        LayerStatement,
+        FontPaletteValues
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/ScriptingState.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ScriptingState.cs
new file mode 100644
index 000000000..3818d21b1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/ScriptingState.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum ScriptingState : byte
+    {
+        None,
+        InitialOnly,
+        Enabled
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/StrokeLinecap.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/StrokeLinecap.cs
new file mode 100644
index 000000000..41772164d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/StrokeLinecap.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum StrokeLinecap : byte
+    {
+        Butt,
+        Round,
+        Square
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/StrokeLinejoin.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/StrokeLinejoin.cs
new file mode 100644
index 000000000..fea9f2c52
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/StrokeLinejoin.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum StrokeLinejoin : byte
+    {
+        Miter,
+        Round,
+        Bevel
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/SystemCursor.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/SystemCursor.cs
new file mode 100644
index 000000000..b5a6e0d52
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/SystemCursor.cs
@@ -0,0 +1,42 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum SystemCursor : byte
+    {
+        Auto,
+        Default,
+        None,
+        ContextMenu,
+        Help,
+        Pointer,
+        Progress,
+        Wait,
+        Cell,
+        Crosshair,
+        Text,
+        VerticalText,
+        Alias,
+        Copy,
+        Move,
+        NoDrop,
+        NotAllowed,
+        EResize,
+        NResize,
+        NeResize,
+        NwResize,
+        SResize,
+        SeResize,
+        SwResize,
+        WResize,
+        EwResize,
+        NsResize,
+        NeswResize,
+        NwseResize,
+        ColResize,
+        RowResize,
+        AllScroll,
+        ZoomIn,
+        ZoomOut,
+        Grab,
+        Grabbing
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/SystemFont.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/SystemFont.cs
new file mode 100644
index 000000000..61f52b259
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/SystemFont.cs
@@ -0,0 +1,12 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum SystemFont : byte
+    {
+        Caption,
+        Icon,
+        Menu,
+        MessageBox,
+        SmallCaption,
+        StatusBar
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextAlignLast.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextAlignLast.cs
new file mode 100644
index 000000000..6c7a72e2e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextAlignLast.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum TextAlignLast : byte
+    {
+        Auto,
+        Start,
+        End,
+        Left,
+        Right,
+        Center,
+        Justify
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextAnchor.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextAnchor.cs
new file mode 100644
index 000000000..cc2bea7c2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextAnchor.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum TextAnchor : byte
+    {
+        Start,
+        Middle,
+        End
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextDecorationLine.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextDecorationLine.cs
new file mode 100644
index 000000000..917f0190b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextDecorationLine.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum TextDecorationLine : byte
+    {
+        Underline,
+        Overline,
+        LineThrough,
+        Blink
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextDecorationStyle.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextDecorationStyle.cs
new file mode 100644
index 000000000..65bc5b67b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextDecorationStyle.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum TextDecorationStyle : byte
+    {
+        Solid,
+        Double,
+        Dotted,
+        Dashed,
+        Wavy
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextJustify.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextJustify.cs
new file mode 100644
index 000000000..02e2de43b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextJustify.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum TextJustify : byte
+    {
+        Auto,
+        InterWord,
+        InterIdeograph,
+        InterCluster,
+        Distribute,
+        DistributeAllLines,
+        DistributeCenterLast,
+        Kashida,
+        Newspaper
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextTransform.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextTransform.cs
new file mode 100644
index 000000000..431798d95
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TextTransform.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum TextTransform : byte
+    {
+        None,
+        Capitalize,
+        Uppercase,
+        Lowercase,
+        FullWidth
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/TokenType.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TokenType.cs
new file mode 100644
index 000000000..a8dc773b3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/TokenType.cs
@@ -0,0 +1,39 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum TokenType : byte
+    {
+        String,
+        Url,
+        Color,
+        Hash,
+        Comment,
+        AtKeyword,
+        Ident,
+        Function,
+        Number,
+        Percentage,
+        Dimension,
+        Range,
+        Cdo,
+        Cdc,
+        Column,
+        Delim,
+        Match,
+        RoundBracketOpen,
+        RoundBracketClose,
+        CurlyBracketOpen,
+        CurlyBracketClose,
+        SquareBracketOpen,
+        SquareBracketClose,
+        Colon,
+        Comma,
+        Semicolon,
+        Whitespace,
+        EndOfFile,
+        GreaterThan,
+        GreaterThanOrEqual,
+        LessThan,
+        LessThanOrEqual,
+        Equal
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/UnicodeMode.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/UnicodeMode.cs
new file mode 100644
index 000000000..d79f2d1c3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/UnicodeMode.cs
@@ -0,0 +1,12 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum UnicodeMode : byte
+    {
+        Normal,
+        Embed,
+        Isolate,
+        BidirectionalOverride,
+        IsolateOverride,
+        Plaintext
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/UnitNames.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/UnitNames.cs
new file mode 100644
index 000000000..a1ad6394d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/UnitNames.cs
@@ -0,0 +1,32 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class UnitNames
+    {
+        public static readonly string Khz = "khz";
+        public static readonly string Hz = "hz";
+        public static readonly string Ms = "ms";
+        public static readonly string S = "s";
+        public static readonly string Turn = "turn";
+        public static readonly string Rad = "rad";
+        public static readonly string Grad = "grad";
+        public static readonly string Deg = "deg";
+        public static readonly string Em = "em";
+        public static readonly string Ex = "ex";
+        public static readonly string Cm = "cm";
+        public static readonly string Mm = "mm";
+        public static readonly string In = "in";
+        public static readonly string Px = "px";
+        public static readonly string Ch = "ch";
+        public static readonly string Vw = "vw";
+        public static readonly string Vh = "vh";
+        public static readonly string Vmin = "vmin";
+        public static readonly string Vmax = "vmax";
+        public static readonly string Dpi = "dpi";
+        public static readonly string Dpcm = "dpcm";
+        public static readonly string Dppx = "dppx";
+        public static readonly string Pt = "pt";
+        public static readonly string Rem = "rem";
+        public static readonly string Pc = "pc";
+        public static readonly string Percent = "%";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/UpdateFrequency.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/UpdateFrequency.cs
new file mode 100644
index 000000000..becfaf3bc
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/UpdateFrequency.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum UpdateFrequency : byte
+    {
+        None,
+        Slow,
+        Normal
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/VerticalAlignment.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/VerticalAlignment.cs
new file mode 100644
index 000000000..37d9c3b1f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/VerticalAlignment.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum VerticalAlignment : byte
+    {
+        Baseline,
+        Sub,
+        Super,
+        TextTop,
+        TextBottom,
+        Middle,
+        Top,
+        Bottom
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/Visibility.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Visibility.cs
new file mode 100644
index 000000000..90d1f33d1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Visibility.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum Visibility : byte
+    {
+        Visible,
+        Hidden,
+        Collapse
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/Whitespace.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Whitespace.cs
new file mode 100644
index 000000000..29dbb49a0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/Whitespace.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum Whitespace : byte
+    {
+        Normal,
+        Pre,
+        NoWrap,
+        PreWrap,
+        PreLine
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Enumerations/WordBreak.cs b/Source/HtmlRenderer/Core/CssEngine/Enumerations/WordBreak.cs
new file mode 100644
index 000000000..aae642504
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Enumerations/WordBreak.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal enum WordBreak : byte
+    {
+        Normal,
+        BreakAll,
+        KeepAll
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/CharExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/CharExtensions.cs
new file mode 100644
index 000000000..26ef23e5b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/CharExtensions.cs
@@ -0,0 +1,130 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+#if !NET40
+#endif
+
+    internal static class CharExtensions
+    {
+        public static int FromHex(this char c)
+        {
+            return c.IsDigit() ? c - Symbols.Zero : c - (c.IsLowercaseAscii() ? Symbols.CapitalW : Symbols.Seven);
+        }
+
+        public static string ToHex(this char character)
+        {
+            return ((int)character).ToString("x");
+        }
+
+        public static bool IsInRange(this char c, int lower, int upper)
+        {
+            return c >= lower && c <= upper;
+        }
+
+        public static bool IsNormalQueryCharacter(this char c)
+        {
+            return c.IsInRange(Symbols.ExclamationMark, Symbols.Tilde) &&
+                   c != Symbols.DoubleQuote &&
+                   c != Symbols.CurvedQuote && c != Symbols.Num &&
+                   c != Symbols.LessThan && c != Symbols.GreaterThan;
+        }
+
+        public static bool IsNormalPathCharacter(this char c)
+        {
+            return c.IsInRange(Symbols.Space, Symbols.Tilde) &&
+                   c != Symbols.DoubleQuote &&
+                   c != Symbols.CurvedQuote && c != Symbols.Num &&
+                   c != Symbols.LessThan && c != Symbols.GreaterThan &&
+                   c != Symbols.Space && c != Symbols.QuestionMark;
+        }
+
+        public static bool IsUppercaseAscii(this char c)
+        {
+            return c >= Symbols.CapitalA && c <= Symbols.CapitalZ;
+        }
+
+        public static bool IsLowercaseAscii(this char c)
+        {
+            return c >= Symbols.LowerA && c <= Symbols.LowerZ;
+        }
+
+        public static bool IsAlphanumericAscii(this char c)
+        {
+            return c.IsDigit() || c.IsUppercaseAscii() || c.IsLowercaseAscii();
+        }
+
+        public static bool IsHex(this char c)
+        {
+            return c.IsDigit() || (c >= Symbols.CapitalA && c <= Symbols.CapitalF) ||
+                   (c >= Symbols.LowerA && c <= Symbols.LowerF);
+        }
+
+        public static bool IsNonAscii(this char c)
+        {
+            return c != Symbols.EndOfFile && c >= Symbols.ExtendedAsciiStart;
+        }
+
+        public static bool IsNonPrintable(this char c)
+        {
+            return /*c >= Symbols.Null &&*/ c <= Symbols.Backspace
+                || (c >= Symbols.ShiftOut && c <= Symbols.UnitSeparator)
+                || (c >= Symbols.Delete && c < Symbols.NonBreakingSpace);
+        }
+
+        public static bool IsLetter(this char c)
+        {
+            return IsUppercaseAscii(c) || IsLowercaseAscii(c);
+        }
+
+        public static bool IsName(this char c)
+        {
+            return c.IsNonAscii() || c.IsLetter() || c == Symbols.Underscore || c == Symbols.Minus || c.IsDigit();
+        }
+
+        public static bool IsNameStart(this char c)
+        {
+            return c.IsNonAscii() || c.IsUppercaseAscii() || c.IsLowercaseAscii() || c == Symbols.Underscore;
+        }
+
+        public static bool IsLineBreak(this char c)
+        {
+            return c == Symbols.LineFeed || c == Symbols.CarriageReturn;
+        }
+
+        public static bool IsSpaceCharacter(this char c)
+        {
+            return c == Symbols.Space || c == Symbols.Tab || c == Symbols.LineFeed || c == Symbols.CarriageReturn || c == Symbols.FormFeed;
+        }
+
+        public static bool IsDigit(this char c)
+        {
+            return c >= Symbols.Zero && c <= Symbols.Nine;
+        }
+
+        // HTML forbids the use of Universal Character Set / Unicode code points
+        // - 0 to 31, except 9, 10, and 13 C0 control characters
+        // - 127 DEL character
+        // - 128 to 159 (0x80 to 0x9F, C1 control characters
+        // - 55296 to 57343 (0xD800 – xDFFF, UTF-16 surrogate halves)
+        // - 65534 and 65535 (xFFFE – xFFFF, non-characters, related to xFEFF, the byte order mark)
+        public static bool IsInvalid(this int c)
+        {
+            return c == 0 || c > Symbols.MaximumCodepoint ||
+                   (c > Symbols.UTF16SurrogateMin && c < Symbols.UTF16SurrogateMax);
+        }
+
+        public static bool IsOneOf(this char c, char a, char b)
+        {
+            return a == c || b == c;
+        }
+
+        public static bool IsOneOf(this char c, char o1, char o2, char o3)
+        {
+            return c == o1 || c == o2 || c == o3;
+        }
+
+        public static bool IsOneOf(this char c, char o1, char o2, char o3, char o4)
+        {
+            return c == o1 || c == o2 || c == o3 || c == o4;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/CollectionExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/CollectionExtensions.cs
new file mode 100644
index 000000000..ca617f4c6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/CollectionExtensions.cs
@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class CollectionExtensions
+    {
+        public static IEnumerable<T> Concat<T>(this IEnumerable<T> items, T element)
+        {
+            foreach (var item in items) yield return item;
+
+            yield return element;
+        }
+
+        public static T GetItemByIndex<T>(this IEnumerable<T> items, int index)
+        {
+            if (index < 0) throw new ArgumentOutOfRangeException(nameof(index));
+
+            var i = 0;
+
+            foreach (var item in items)
+            {
+                if (i++ == index)
+                {
+                    return item;
+                }
+            }
+
+            throw new ArgumentOutOfRangeException(nameof(index));
+        }
+
+        public static IEnumerable<object[]> ToObjectArray<T>(this IEnumerable<T> items)
+            => items.Select(i => new object[] { i });
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/ColorFunctionExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/ColorFunctionExtensions.cs
new file mode 100644
index 000000000..a92adb739
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/ColorFunctionExtensions.cs
@@ -0,0 +1,381 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Resolves the CSS color <em>function</em> forms from a tokenized value into a concrete
+    /// <see cref="Color"/>: the legacy/CSS Color 4 <c>rgb()/rgba()/hsl()/hsla()/hwb()/gray()</c> and the
+    /// CSS Color 4/5 <c>lab()/oklab()/lch()/oklch()/color-mix()</c>. Tokenization is the CSS-OM's job, so
+    /// this consumes the already-parsed <see cref="FunctionToken"/> stream (nested functions arrive as a
+    /// single token) rather than re-scanning the source text.
+    /// </summary>
+    internal static class ColorFunctionExtensions
+    {
+        /// <summary>
+        /// Fully resolves a tokenized color value to a concrete <see cref="Color"/> - named colors and
+        /// hex via <see cref="ValueExtensions.ToColor"/>, plus every color <em>function</em>
+        /// (rgb/hsl/hwb/gray/lab/oklab/lch/oklch/color-mix). Unlike <c>ToColor</c> (which the CSS-OM
+        /// cascade uses and which deliberately preserves a function's specified form for serialization),
+        /// this is the render-layer resolver: it always computes the sRGB value.
+        /// </summary>
+        public static Color? ToResolvedColor(this IEnumerable<Token> value)
+        {
+            var basic = value.ToColor();
+            if (basic.HasValue) return basic;
+
+            var element = value.OnlyOrDefault();
+
+            // A hex color nested inside a function (e.g. a color-mix() operand) tokenizes as a Hash
+            // keyword token rather than a ColorToken, so ToColor misses it - resolve it here.
+            if (element != null && element.Type == TokenType.Hash) return Color.FromHex(element.Data);
+
+            var function = element as FunctionToken;
+            return function != null ? ParseColorFunction(function) : null;
+        }
+
+        public static Color? ParseColorFunction(FunctionToken function)
+        {
+            var name = function.Data;
+            var args = function.ArgumentTokens;
+
+            if (name.Equals(FunctionNames.Rgb, StringComparison.OrdinalIgnoreCase) ||
+                name.Equals(FunctionNames.Rgba, StringComparison.OrdinalIgnoreCase))
+                return ParseRgb(args);
+
+            if (name.Equals(FunctionNames.Hsl, StringComparison.OrdinalIgnoreCase) ||
+                name.Equals(FunctionNames.Hsla, StringComparison.OrdinalIgnoreCase))
+                return ParseHsl(args);
+
+            if (name.Equals(FunctionNames.Hwb, StringComparison.OrdinalIgnoreCase))
+                return ParseHwb(args);
+
+            if (name.Equals(FunctionNames.Gray, StringComparison.OrdinalIgnoreCase))
+                return ParseGray(args);
+
+            if (name.Equals(FunctionNames.Lab, StringComparison.OrdinalIgnoreCase))
+                return ParseRect(args, Color.FromLab, abReference: 125.0, lReference: 100.0);
+            if (name.Equals(FunctionNames.Oklab, StringComparison.OrdinalIgnoreCase))
+                return ParseRect(args, Color.FromOklab, abReference: 0.4, lReference: 1.0);
+            if (name.Equals(FunctionNames.Lch, StringComparison.OrdinalIgnoreCase))
+                return ParsePolar(args, Color.FromLch, chromaReference: 150.0, lReference: 100.0);
+            if (name.Equals(FunctionNames.Oklch, StringComparison.OrdinalIgnoreCase))
+                return ParsePolar(args, Color.FromOklch, chromaReference: 0.4, lReference: 1.0);
+
+            if (name.Equals(FunctionNames.ColorMix, StringComparison.OrdinalIgnoreCase))
+                return ParseColorMix(args);
+
+            return null;
+        }
+
+        // rgb()/rgba(): 3 components (int or % of 255) + optional alpha
+        private static Color? ParseRgb(IEnumerable<Token> args)
+        {
+            List<Token> comps;
+            Token alphaTok;
+            if (!Extract(args, 3, out comps, out alphaTok)) return null;
+            var r = AsTokens(comps[0]).ToRgbComponent();
+            var g = AsTokens(comps[1]).ToRgbComponent();
+            var b = AsTokens(comps[2]).ToRgbComponent();
+            if (r == null || g == null || b == null) return null;
+            var a = alphaTok == null ? 1f : AsTokens(alphaTok).ToAlphaValue() ?? 1f;
+            return new Color(r.Value, g.Value, b.Value, Clamp01Byte(a));
+        }
+
+        // hsl()/hsla(): hue angle + saturation% + lightness% + optional alpha
+        private static Color? ParseHsl(IEnumerable<Token> args)
+        {
+            List<Token> comps;
+            Token alphaTok;
+            if (!Extract(args, 3, out comps, out alphaTok)) return null;
+            var hue = HueDegrees(comps[0]);
+            var sat = AsTokens(comps[1]).ToPercent();
+            var light = AsTokens(comps[2]).ToPercent();
+            if (hue == null || sat == null || light == null) return null;
+            var a = alphaTok == null ? 1f : AsTokens(alphaTok).ToAlphaValue() ?? 1f;
+            return Color.FromHsla((float)(hue.Value / 360.0), sat.Value.NormalizedValue, light.Value.NormalizedValue, a);
+        }
+
+        // hwb(): hue angle + whiteness% + blackness% + optional alpha
+        private static Color? ParseHwb(IEnumerable<Token> args)
+        {
+            List<Token> comps;
+            Token alphaTok;
+            if (!Extract(args, 3, out comps, out alphaTok)) return null;
+            var hue = HueDegrees(comps[0]);
+            var white = AsTokens(comps[1]).ToPercent();
+            var black = AsTokens(comps[2]).ToPercent();
+            if (hue == null || white == null || black == null) return null;
+            var a = alphaTok == null ? 1f : AsTokens(alphaTok).ToAlphaValue() ?? 1f;
+            return Color.FromHwba((float)(hue.Value / 360.0), white.Value.NormalizedValue, black.Value.NormalizedValue, a);
+        }
+
+        // gray(): a single lightness component + optional alpha
+        private static Color? ParseGray(IEnumerable<Token> args)
+        {
+            List<Token> comps;
+            Token alphaTok;
+            if (!Extract(args, 1, out comps, out alphaTok)) return null;
+            var value = AsTokens(comps[0]).ToRgbComponent();
+            if (value == null) return null;
+            var a = alphaTok == null ? 1f : AsTokens(alphaTok).ToAlphaValue() ?? 1f;
+            return Color.FromGray(value.Value, a);
+        }
+
+        // lab()/oklab(): L + a + b + optional alpha
+        private static Color? ParseRect(IEnumerable<Token> args, Func<double, double, double, float, Color> build, double abReference, double lReference)
+        {
+            List<Token> comps;
+            Token alphaTok;
+            if (!Extract(args, 3, out comps, out alphaTok)) return null;
+            var l = Component(comps[0], lReference);
+            var a = Component(comps[1], abReference);
+            var b = Component(comps[2], abReference);
+            if (l == null || a == null || b == null) return null;
+            var alpha = alphaTok == null ? 1f : AsTokens(alphaTok).ToAlphaValue() ?? 1f;
+            return build(l.Value, a.Value, b.Value, alpha);
+        }
+
+        // lch()/oklch(): L + C + hue angle + optional alpha
+        private static Color? ParsePolar(IEnumerable<Token> args, Func<double, double, double, float, Color> build, double chromaReference, double lReference)
+        {
+            List<Token> comps;
+            Token alphaTok;
+            if (!Extract(args, 3, out comps, out alphaTok)) return null;
+            var l = Component(comps[0], lReference);
+            var c = Component(comps[1], chromaReference);
+            var h = HueDegrees(comps[2]);
+            if (l == null || c == null || h == null) return null;
+            var alpha = alphaTok == null ? 1f : AsTokens(alphaTok).ToAlphaValue() ?? 1f;
+            return build(l.Value, c.Value, h.Value, alpha);
+        }
+
+        // color-mix(in <space> [<hue-method>], c1 [p1], c2 [p2])
+        private static Color? ParseColorMix(IEnumerable<Token> args)
+        {
+            var segments = SplitByComma(args);
+            if (segments.Count != 3) return null;
+
+            var config = segments[0].Where(token => token.Type != TokenType.Whitespace)
+                .Select(token => token.Data.ToLowerInvariant()).ToList();
+            if (config.Count < 2 || config[0] != "in") return null;
+            var space = MapSpace(config[1]);
+            var hue = MapHue(config, 2);
+
+            Color c1, c2;
+            double? p1, p2;
+            if (!ParseMixOperand(segments[1], out c1, out p1)) return null;
+            if (!ParseMixOperand(segments[2], out c2, out p2)) return null;
+
+            // CSS Color 5 §3 normalization: a missing percentage is 100% minus the other; percentages
+            // scale to sum 1, and a pre-normalization sum below 100% scales the result alpha down.
+            if (p1 == null && p2 == null) { p1 = 0.5; p2 = 0.5; }
+            else if (p1 == null) p1 = Math.Max(0, 1.0 - p2.Value);
+            else if (p2 == null) p2 = Math.Max(0, 1.0 - p1.Value);
+
+            var sum = p1.Value + p2.Value;
+            if (sum <= 0) return null;
+            var alphaMultiplier = sum < 1.0 ? sum : 1.0;
+            var t = p2.Value / sum;
+
+            return Color.Mix(c1, c2, t, space, hue, alphaMultiplier);
+        }
+
+        private static bool ParseMixOperand(List<Token> segment, out Color color, out double? percent)
+        {
+            color = default(Color);
+            percent = null;
+
+            var tokens = new List<Token>();
+            foreach (var token in segment)
+            {
+                if (token.Type != TokenType.Whitespace) tokens.Add(token);
+            }
+            if (tokens.Count == 0) return false;
+
+            // The optional percentage may appear before or after the color (CSS Color 5 §3.1), e.g.
+            // both `red 30%` and `30% red` are valid.
+            if (tokens[tokens.Count - 1].Type == TokenType.Percentage)
+            {
+                var value = AsTokens(tokens[tokens.Count - 1]).ToPercent();
+                percent = value.HasValue ? value.Value.NormalizedValue : (double?)null;
+                tokens.RemoveAt(tokens.Count - 1);
+            }
+            else if (tokens[0].Type == TokenType.Percentage)
+            {
+                var value = AsTokens(tokens[0]).ToPercent();
+                percent = value.HasValue ? value.Value.NormalizedValue : (double?)null;
+                tokens.RemoveAt(0);
+            }
+
+            // A color-mix operand may itself be any color form (named/hex/rgb/oklch/...), so resolve it
+            // through the full render-layer resolver rather than the named/hex-only ToColor.
+            var resolved = tokens.ToResolvedColor();
+            if (resolved == null) return false;
+            color = resolved.Value;
+            return true;
+        }
+
+        // Token helpers
+
+        // Partitions a function's argument tokens into `count` component tokens and an optional alpha
+        // token. Whitespace and commas separate; a "/" delimiter (CSS Color 4) marks the alpha that
+        // follows. Without a slash, a trailing extra value (legacy rgba/hsla comma alpha) is the alpha.
+        private static bool Extract(IEnumerable<Token> args, int count, out List<Token> components, out Token alpha)
+        {
+            components = new List<Token>();
+            alpha = null;
+
+            var values = new List<Token>();
+            var slashIndex = -1;
+            foreach (var token in args)
+            {
+                switch (token.Type)
+                {
+                    case TokenType.Whitespace:
+                    case TokenType.Comma:
+                        continue;
+                    case TokenType.Delim when token.Data == "/":
+                        slashIndex = values.Count;
+                        continue;
+                    default:
+                        values.Add(token);
+                        break;
+                }
+            }
+
+            if (values.Count < count) return false;
+            for (var i = 0; i < count; i++) components.Add(values[i]);
+
+            var alphaAt = slashIndex >= 0 ? slashIndex : count;
+            if (alphaAt < values.Count) alpha = values[alphaAt];
+            return true;
+        }
+
+        private static List<List<Token>> SplitByComma(IEnumerable<Token> tokens)
+        {
+            var result = new List<List<Token>>();
+            var current = new List<Token>();
+            foreach (var token in tokens)
+            {
+                if (token.Type == TokenType.Comma)
+                {
+                    result.Add(current);
+                    current = new List<Token>();
+                }
+                else
+                {
+                    current.Add(token);
+                }
+            }
+            result.Add(current);
+            return result;
+        }
+
+        private static Token[] AsTokens(Token token)
+        {
+            return new[] { token };
+        }
+
+        // A number (returned as-is) or a percentage resolved against `reference`; "none" resolves to 0.
+        private static double? Component(Token token, double reference)
+        {
+            if (token.Type == TokenType.Ident && token.Data.Equals("none", StringComparison.OrdinalIgnoreCase))
+                return 0.0;
+            var number = AsTokens(token).ToSingle();
+            if (number.HasValue) return number.Value;
+            var percent = AsTokens(token).ToPercent();
+            return percent.HasValue ? percent.Value.NormalizedValue * reference : (double?)null;
+        }
+
+        private static double? HueDegrees(Token token)
+        {
+            if (token.Type == TokenType.Ident && token.Data.Equals("none", StringComparison.OrdinalIgnoreCase))
+                return 0.0;
+            var angle = AsTokens(token).ToAngleNumber();
+            if (!angle.HasValue) return null;
+
+            switch (angle.Value.Type)
+            {
+                case Angle.Unit.Grad: return angle.Value.Value * 0.9;
+                case Angle.Unit.Turn: return angle.Value.Value * 360.0;
+                case Angle.Unit.Rad: return angle.Value.Value * 180.0 / Math.PI;
+                default: return angle.Value.Value;
+            }
+        }
+
+        private static byte Clamp01Byte(float alpha)
+        {
+            return (byte)Math.Round(Math.Min(Math.Max(alpha, 0f), 1f) * 255);
+        }
+
+        private static ColorSpaceMath.Space MapSpace(string name)
+        {
+            switch (name)
+            {
+                case "srgb-linear": return ColorSpaceMath.Space.SrgbLinear;
+                case "display-p3": return ColorSpaceMath.Space.DisplayP3;
+                case "lab": return ColorSpaceMath.Space.Lab;
+                case "oklab": return ColorSpaceMath.Space.Oklab;
+                case "xyz":
+                case "xyz-d65": return ColorSpaceMath.Space.XyzD65;
+                case "xyz-d50": return ColorSpaceMath.Space.XyzD50;
+                case "hsl": return ColorSpaceMath.Space.Hsl;
+                case "hwb": return ColorSpaceMath.Space.Hwb;
+                case "lch": return ColorSpaceMath.Space.Lch;
+                case "oklch": return ColorSpaceMath.Space.Oklch;
+                default: return ColorSpaceMath.Space.Srgb;
+            }
+        }
+
+        private static ColorSpaceMath.HueMethod MapHue(List<string> idents, int startIndex)
+        {
+            for (var i = startIndex; i + 1 < idents.Count; i++)
+            {
+                if (idents[i + 1] != "hue") continue;
+                return MapHueName(idents[i]);
+            }
+            return ColorSpaceMath.HueMethod.Shorter;
+        }
+
+        private static ColorSpaceMath.HueMethod MapHueName(string name)
+        {
+            switch (name)
+            {
+                case "longer": return ColorSpaceMath.HueMethod.Longer;
+                case "increasing": return ColorSpaceMath.HueMethod.Increasing;
+                case "decreasing": return ColorSpaceMath.HueMethod.Decreasing;
+                default: return ColorSpaceMath.HueMethod.Shorter;
+            }
+        }
+
+        /// <summary>
+        /// Blends two colors per the CSS <c>palette-mix()</c> rules (CSS Fonts 4), reusing <c>color-mix()</c>'s
+        /// color-space mapping (<see cref="MapSpace"/>) and CSS Color 5 §3 percentage normalization so the two
+        /// functions interpolate identically. <paramref name="p1"/>/<paramref name="p2"/> are 0..100 percentages
+        /// (or null); <paramref name="hueName"/> is a hue-interpolation direction (or null for the default).
+        /// </summary>
+        internal static Color MixPaletteColors(Color c1, Color c2, string spaceName, string hueName, double? p1, double? p2)
+        {
+            // CSS keywords are case-insensitive; MapSpace/MapHueName match lowercase literals, so fold first
+            // (a mixed-case space would otherwise silently fall through to the sRGB/Shorter default).
+            var space = MapSpace(spaceName.ToLowerInvariant());
+            var hue = MapHueName(hueName.ToLowerInvariant());
+
+            double? f1 = p1.HasValue ? Math.Min(Math.Max(p1.Value, 0), 100) / 100.0 : (double?)null;
+            double? f2 = p2.HasValue ? Math.Min(Math.Max(p2.Value, 0), 100) / 100.0 : (double?)null;
+
+            if (f1 == null && f2 == null) { f1 = 0.5; f2 = 0.5; }
+            else if (f1 == null) f1 = 1.0 - f2;
+            else if (f2 == null) f2 = 1.0 - f1;
+
+            var sum = f1.Value + f2.Value;
+            if (sum <= 0) return c1;
+
+            var alphaMultiplier = sum < 1.0 ? sum : 1.0;
+            var t = f2.Value / sum;
+            return Color.Mix(c1, c2, t, space, hue, alphaMultiplier);
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/FormatExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/FormatExtensions.cs
new file mode 100644
index 000000000..f5d629de6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/FormatExtensions.cs
@@ -0,0 +1,28 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class FormatExtensions
+    {
+        public static string ToCss(this IStyleFormattable style)
+        {
+            return style.ToCss(CompressedStyleFormatter.Instance);
+        }
+
+        public static string ToCss(this IStyleFormattable style, IStyleFormatter formatter)
+        {
+            var sb = Pool.NewStringBuilder();
+            using (var writer = new StringWriter(sb))
+            {
+                style.ToCss(writer, formatter);
+            }
+
+            return sb.ToPool();
+        }
+
+        public static void ToCss(this IStyleFormattable style, TextWriter writer)
+        {
+            style.ToCss(writer, CompressedStyleFormatter.Instance);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/PortableExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/PortableExtensions.cs
new file mode 100644
index 000000000..c37739b2a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/PortableExtensions.cs
@@ -0,0 +1,14 @@
+#if !NET40 && !SL50
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class PortableExtensions
+    {
+        public static string ConvertFromUtf32(this int utf32)
+        {
+            return char.ConvertFromUtf32(utf32);
+        }
+    }
+}
+
+#endif
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/StringExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/StringExtensions.cs
new file mode 100644
index 000000000..83d3cb2af
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/StringExtensions.cs
@@ -0,0 +1,106 @@
+using System;
+using System.Globalization;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class StringExtensions
+    {
+        public static bool Has(this string value, char chr, int index = 0)
+        {
+            return value != null && value.Length > index && value[index] == chr;
+        }
+
+        public static bool Contains(this string[] list, string element,
+            StringComparison comparison = StringComparison.Ordinal)
+        {
+            return list.Any(t => t.Equals(element, comparison));
+        }
+
+        public static bool Is(this string current, string other)
+        {
+            return string.Equals(current, other, StringComparison.Ordinal);
+        }
+
+        public static bool Isi(this string current, string other)
+        {
+            return string.Equals(current, other, StringComparison.OrdinalIgnoreCase);
+        }
+
+        public static bool IsOneOf(this string element, string item1, string item2)
+        {
+            return element.Is(item1) || element.Is(item2);
+        }
+
+        public static string StylesheetString(this string value)
+        {
+            var builder = Pool.NewStringBuilder();
+            builder.Append(Symbols.DoubleQuote);
+
+            if (!string.IsNullOrEmpty(value))
+                for (var i = 0; i < value.Length; i++)
+                {
+                    var character = value[i];
+
+                    switch (character)
+                    {
+                        case Symbols.Null:
+                            throw new ParseException("Unable to parse null symbol");
+                        case Symbols.DoubleQuote:
+                        case Symbols.ReverseSolidus:
+                            builder.Append(Symbols.ReverseSolidus).Append(character);
+                            break;
+                        default:
+                            if (character.IsInRange(Symbols.StartOfHeading, Symbols.UnitSeparator)
+                                || character == Symbols.CurlyBracketOpen)
+                            {
+                                builder.Append(Symbols.ReverseSolidus)
+                                    .Append(character.ToHex())
+                                    .Append(i + 1 != value.Length ? " " : "");
+                            }
+                            else
+                            {
+                                builder.Append(character);
+                            }
+
+                            break;
+                    }
+                }
+
+            builder.Append(Symbols.DoubleQuote);
+            return builder.ToPool();
+        }
+
+        public static string StylesheetFunction(this string value, string argument)
+        {
+            return string.Concat(value, "(", argument, ")");
+        }
+
+        public static string StylesheetUrl(this string value)
+        {
+            var argument = value.StylesheetString();
+            return FunctionNames.Url.StylesheetFunction(argument);
+        }
+
+        public static string StylesheetUnit(this string value, out float result)
+        {
+            if (!string.IsNullOrEmpty(value))
+            {
+                var firstLetter = value.Length;
+
+                while (!value[firstLetter - 1].IsDigit() && --firstLetter > 0)
+                {
+                    // Intentional empty.
+                }
+
+                var parsed = float.TryParse(value.Substring(0, firstLetter), NumberStyles.Any,
+                    CultureInfo.InvariantCulture, out result);
+
+                if (firstLetter > 0 && parsed) return value.Substring(firstLetter);
+            }
+
+            result = default;
+            return null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/ValueConverterExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/ValueConverterExtensions.cs
new file mode 100644
index 000000000..441ef42e4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/ValueConverterExtensions.cs
@@ -0,0 +1,190 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class ValueConverterExtensions
+    {
+        public static IPropertyValue ConvertDefault(this IValueConverter converter)
+        {
+            return converter.Convert(Enumerable.Empty<Token>());
+        }
+
+        public static IPropertyValue VaryStart(this IValueConverter converter, List<Token> list)
+        {
+            for (var count = list.Count; count > 0; count--)
+            {
+                if (list[count - 1].Type == TokenType.Whitespace)
+                {
+                    continue;
+                }
+
+                var value = converter.Convert(list.Take(count));
+
+                if (value == null)
+                {
+                    continue;
+                }
+
+                list.RemoveRange(0, count);
+                list.Trim();
+                return value;
+            }
+
+            return converter.ConvertDefault();
+        }
+
+        public static IPropertyValue VaryAll(this IValueConverter converter, List<Token> list)
+        {
+            for (var i = 0; i < list.Count; i++)
+            {
+                if (list[i].Type == TokenType.Whitespace)
+                {
+                    continue;
+                }
+
+                for (var j = list.Count; j > i; j--)
+                {
+                    var count = j - i;
+
+                    if (list[j - 1].Type == TokenType.Whitespace)
+                    {
+                        continue;
+                    }
+
+                    var value = converter.Convert(list.Skip(i).Take(count));
+
+                    if (value == null) continue;
+                    list.RemoveRange(i, count);
+                    list.Trim();
+                    return value;
+                }
+            }
+
+            return converter.ConvertDefault();
+        }
+
+        public static IValueConverter Many(this IValueConverter converter, int min = 1, int max = ushort.MaxValue)
+        {
+            return new OneOrMoreValueConverter(converter, min, max);
+        }
+
+        public static IValueConverter FromList(this IValueConverter converter)
+        {
+            return new ListValueConverter(converter);
+        }
+
+        public static IValueConverter ToConverter<T>(this IReadOnlyDictionary<string, T> values)
+        {
+            return new DictionaryValueConverter<T>(values);
+        }
+
+        public static IValueConverter Periodic(this IValueConverter converter, params string[] labels)
+        {
+            return new PeriodicValueConverter(converter, labels);
+        }
+
+        public static IValueConverter RequiresEnd(this IValueConverter listConverter, IValueConverter endConverter)
+        {
+            return new EndListValueConverter(listConverter, endConverter);
+        }
+
+        public static IValueConverter Required(this IValueConverter converter)
+        {
+            return new RequiredValueConverter(converter);
+        }
+
+        public static IValueConverter Option(this IValueConverter converter)
+        {
+            return new OptionValueConverter(converter);
+        }
+
+        public static IValueConverter For(this IValueConverter converter, params string[] labels)
+        {
+            return new ConstraintValueConverter(converter, labels);
+        }
+
+        public static IValueConverter Option<T>(this IValueConverter converter, T defaultValue)
+        {
+            return new OptionValueConverter<T>(converter);
+        }
+
+        public static IValueConverter Or(this IValueConverter primary, IValueConverter secondary)
+        {
+            return new OrValueConverter(primary, secondary);
+        }
+
+        public static IValueConverter Or(this IValueConverter primary, string keyword)
+        {
+            return primary.Or<object>(keyword, null);
+        }
+
+        public static IValueConverter Or<T>(this IValueConverter primary, string keyword, T value)
+        {
+            var identifier = new IdentifierValueConverter<T>(keyword, value);
+            return new OrValueConverter(primary, identifier);
+        }
+
+        public static IValueConverter OrNone(this IValueConverter primary)
+        {
+            return primary.Or(Keywords.None);
+        }
+
+        public static IValueConverter OrDefault(this IValueConverter primary)
+        {
+            return primary.OrGlobalValue();
+        }
+
+        public static IValueConverter OrDefault<T>(this IValueConverter primary, T value)
+        {
+            return primary.OrInherit().Or(Keywords.Initial, value)
+                          .Or(Keywords.Revert)
+                          .Or(Keywords.RevertLayer)
+                          .Or(Keywords.Unset);
+        }
+
+        public static IValueConverter OrInherit(this IValueConverter primary)
+        {
+            return primary.Or(Keywords.Inherit);
+        }
+
+        public static IValueConverter OrAuto(this IValueConverter primary)
+        {
+            return primary.Or(Keywords.Auto);
+        }
+
+        public static IValueConverter OrGlobalValue(this IValueConverter primary)
+        {
+            return primary.OrInherit()
+                          .Or(Keywords.Initial)
+                          .Or(Keywords.Revert)
+                          .Or(Keywords.RevertLayer)
+                          .Or(Keywords.Unset);
+        }
+
+        public static IValueConverter ConditionalStartsWithKeyword(this IValueConverter primary, string when, params string[] keywords)
+        {
+            return new ConditionalStartsWithValueConverter(when, primary, keywords);
+        }
+
+        public static IValueConverter StartsWithKeyword(this IValueConverter converter, string keyword)
+        {
+            return new StartsWithValueConverter(TokenType.Ident, keyword, converter);
+        }
+
+        public static IValueConverter StartsWithDelimiter(this IValueConverter converter)
+        {
+            return new StartsWithValueConverter(TokenType.Delim, "/", converter);
+        }
+
+        public static IValueConverter WithCurrentColor(this IValueConverter converter)
+        {
+            return converter.Or(Keywords.CurrentColor, Color.Transparent);
+        }
+
+        public static IValueConverter WithFallback(this IValueConverter converter, int defaultValue)
+        {
+            return new FallbackValueConverter(converter, TokenValue.FromNumber(defaultValue));
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Extensions/ValueExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Extensions/ValueExtensions.cs
new file mode 100644
index 000000000..65126a5e2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Extensions/ValueExtensions.cs
@@ -0,0 +1,514 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class ValueExtensions
+    {
+        private static bool IsWeight(int value)
+        {
+            return value == 100 || value == 200 || value == 300 || value == 400 ||
+                   value == 500 || value == 600 || value == 700 || value == 800 ||
+                   value == 900;
+        }
+
+        public static Token OnlyOrDefault(this IEnumerable<Token> value)
+        {
+            var result = default(Token);
+
+            foreach (var item in value)
+            {
+                if (result == null)
+                {
+                    result = item;
+                    continue;
+                }
+
+                result = default;
+                break;
+            }
+
+            return result;
+        }
+
+        public static bool Is(this IEnumerable<Token> value, string expected)
+        {
+            var identifier = value.ToIdentifier();
+            return identifier != null && identifier.Isi(expected);
+        }
+
+        public static string ToUri(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.Url) return element.Data;
+
+            return null;
+        }
+
+        public static Length? ToDistance(this IEnumerable<Token> value)
+        {
+            var enumerable = value as Token[] ?? value.ToArray();
+            var percent = enumerable.ToPercent();
+
+            return percent.HasValue
+                ? new Length(percent.Value.Value, Length.Unit.Percent)
+                : enumerable.ToLength();
+        }
+
+        public static Length ToLength(this FontSize fontSize)
+        {
+            switch (fontSize)
+            {
+                case FontSize.Big: //1.5em
+                    return new Length(1.5f, Length.Unit.Em);
+                case FontSize.Huge: //2em
+                    return new Length(2f, Length.Unit.Em);
+                case FontSize.Large: //1.2em
+                    return new Length(1.2f, Length.Unit.Em);
+                case FontSize.Larger: //*120%
+                    return new Length(120f, Length.Unit.Percent);
+                case FontSize.Little: //0.75em
+                    return new Length(0.75f, Length.Unit.Em);
+                case FontSize.Small: //8/9em
+                    return new Length(8f / 9f, Length.Unit.Em);
+                case FontSize.Smaller: //*80%
+                    return new Length(80f, Length.Unit.Percent);
+                case FontSize.Tiny: //0.6em
+                    return new Length(0.6f, Length.Unit.Em);
+                default: //1em
+                    return new Length(1f, Length.Unit.Em);
+            }
+        }
+
+        public static Percent? ToPercent(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.Percentage)
+                return new Percent(((UnitToken)element).Value);
+
+            return null;
+        }
+
+        public static Percent? ToPercentOrFraction(this IEnumerable<Token> value)
+        {
+            var enumerable = value as Token[] ?? value.ToArray();
+            var percent = ToPercent(enumerable);
+
+            if (percent != null)
+            {
+                return percent;
+            }
+
+            var element = value.OnlyOrDefault();
+            if (!(element is NumberToken token))
+            {
+                return null;
+            }
+
+            try
+            {
+                var number = token.Value;
+                var percentage = number * 100;
+                return new Percent(percentage);
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        public static Number? ToPercentOrNumber(this IEnumerable<Token> value)
+        {
+            var enumerable = value as Token[] ?? value.ToArray();
+            var percent = ToPercent(enumerable);
+
+            if (percent != null)
+            {
+                return new Number(percent.Value.Value, Number.Unit.Percent);
+            }
+
+            var element = value.OnlyOrDefault();
+            if (!(element is NumberToken token))
+            {
+                return null;
+            }
+
+            try
+            {
+                return new Number(token.Value, Number.Unit.Float);
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        public static string ToCssString(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.String) return element.Data;
+
+            return null;
+        }
+
+        public static string ToLiterals(this IEnumerable<Token> value)
+        {
+            var elements = new List<string>();
+            var it = value.GetEnumerator();
+
+            if (it.MoveNext())
+            {
+                do
+                {
+                    if (it.Current?.Type != TokenType.Ident) return null;
+
+                    elements.Add(it.Current.Data);
+
+                    if (it.MoveNext() && it.Current?.Type != TokenType.Whitespace) return null;
+                } while (it.MoveNext());
+
+                it.Dispose();
+                return string.Join(" ", elements);
+            }
+
+            it.Dispose();
+            return null;
+        }
+
+        public static string ToIdentifier(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.Ident) return element.Data.ToLowerInvariant();
+
+            return null;
+        }
+
+        public static string ToIdentifierCaseInsensitive(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.Ident) return element.Data;
+
+            return null;
+        }
+
+        public static string ToAnimatableIdentifier(this IEnumerable<Token> value)
+        {
+            var identifier = value.ToIdentifier();
+
+            if (identifier != null &&
+                (identifier.Isi(Keywords.All) || PropertyFactory.Instance.IsAnimatable(identifier)))
+            {
+                return identifier;
+            }
+
+            return null;
+        }
+
+        public static float? ToSingle(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.Number) return ((NumberToken)element).Value;
+
+            return null;
+        }
+
+        public static float? ToNaturalSingle(this IEnumerable<Token> value)
+        {
+            var element = value.ToSingle();
+            return element >= 0f ? element : null;
+        }
+
+        public static float? ToGreaterOrEqualOneSingle(this IEnumerable<Token> value)
+        {
+            var element = value.ToSingle();
+            return element >= 1f ? element : null;
+        }
+
+        public static int? ToInteger(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.Number && ((NumberToken)element).IsInteger)
+            {
+                return ((NumberToken)element).IntegerValue;
+            }
+
+            return null;
+        }
+
+        public static int? ToNaturalInteger(this IEnumerable<Token> value)
+        {
+            var element = value.ToInteger();
+            return element >= 0 ? element : null;
+        }
+
+        public static int? ToPositiveInteger(this IEnumerable<Token> value)
+        {
+            var element = value.ToInteger();
+            return element > 0 ? element : null;
+        }
+
+        public static int? ToWeightInteger(this IEnumerable<Token> value)
+        {
+            var element = value.ToPositiveInteger();
+            return element.HasValue && IsWeight(element.Value) ? element : null;
+        }
+
+        public static int? ToBinary(this IEnumerable<Token> value)
+        {
+            var element = value.ToInteger();
+            return element.HasValue && (element.Value == 0 || element.Value == 1) ? element : null;
+        }
+
+        public static float? ToAlphaValue(this IEnumerable<Token> value)
+        {
+            var enumerable = value as Token[] ?? value.ToArray();
+            var element = enumerable.ToNaturalSingle();
+
+            if (element.HasValue) return Math.Min(element.Value, 1f);
+
+            var percent = enumerable.ToPercent();
+
+            return percent?.NormalizedValue;
+        }
+
+        public static byte? ToRgbComponent(this IEnumerable<Token> value)
+        {
+            var enumerable = value as Token[] ?? value.ToArray();
+            var element = enumerable.ToNaturalInteger();
+
+            if (element.HasValue) return (byte)Math.Min(element.Value, 255);
+
+            var percent = enumerable.ToPercent();
+
+            if (!percent.HasValue) return null;
+
+            return (byte)(255f * percent.Value.NormalizedValue);
+        }
+
+        public static Angle? ToAngle(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element == null || element.Type != TokenType.Dimension) return null;
+
+            var token = (UnitToken)element;
+            var unit = Angle.GetUnit(token.Unit);
+
+            if (unit != Angle.Unit.None) return new Angle(token.Value, unit);
+
+            return null;
+        }
+
+        public static Angle? ToAngleNumber(this IEnumerable<Token> value)
+        {
+            var enumerable = value as Token[] ?? value.ToArray();
+            var angle = enumerable.ToAngle();
+
+            if (angle.HasValue) return angle.Value;
+
+            var number = enumerable.ToSingle();
+
+            if (!number.HasValue) return null;
+
+            return new Angle(number.Value, Angle.Unit.Deg);
+        }
+
+        public static Length? ToLength(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null)
+            {
+                switch (element.Type)
+                {
+                    case TokenType.Dimension:
+                        {
+                            var token = (UnitToken)element;
+                            var unit = Length.GetUnit(token.Unit);
+
+                            if (unit != Length.Unit.None) return new Length(token.Value, unit);
+                            break;
+                        }
+                    case TokenType.Number when ((NumberToken)element).Value == 0f:
+                        return Length.Zero;
+                }
+            }
+
+            return null;
+        }
+
+        public static Resolution? ToResolution(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element == null || element.Type != TokenType.Dimension) return null;
+
+            var token = (UnitToken)element;
+            var unit = Resolution.GetUnit(token.Unit);
+
+            if (unit != Resolution.Unit.None) return new Resolution(token.Value, unit);
+
+            return null;
+        }
+
+        public static Time? ToTime(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element == null || element.Type != TokenType.Dimension) return null;
+
+            var token = (UnitToken)element;
+            var unit = Time.GetUnit(token.Unit);
+
+            if (unit != Time.Unit.None) return new Time(token.Value, unit);
+
+            return null;
+        }
+
+        public static Length? ToBorderWidth(this IEnumerable<Token> value)
+        {
+            var enumerable = value as Token[] ?? value.ToArray();
+            var length = enumerable.ToLength();
+
+            if (length != null) return length;
+
+            if (enumerable.Is(Keywords.Thin)) return Length.Thin;
+
+            if (enumerable.Is(Keywords.Medium)) return Length.Medium;
+
+            return enumerable.Is(Keywords.Thick) ? Length.Thick : length;
+        }
+
+        public static List<List<Token>> ToItems(this IEnumerable<Token> value)
+        {
+            var list = new List<List<Token>>();
+            var current = new List<Token>();
+            var nested = 0;
+            list.Add(current);
+
+            foreach (var token in value)
+            {
+                var whitespace = token.Type == TokenType.Whitespace;
+                var newItem = token.Type == TokenType.String || token.Type == TokenType.Url ||
+                              token.Type == TokenType.Function;
+
+                if (nested == 0 && (whitespace || newItem))
+                {
+                    if (current.Count != 0)
+                    {
+                        current = new List<Token>();
+                        list.Add(current);
+                    }
+
+                    if (whitespace) continue;
+                }
+                else if (token.Type == TokenType.RoundBracketOpen)
+                {
+                    nested++;
+                }
+                else if (token.Type == TokenType.RoundBracketClose)
+                {
+                    nested--;
+                }
+
+                current.Add(token);
+            }
+
+            return list;
+        }
+
+        public static void Trim(this List<Token> value)
+        {
+            var begin = 0;
+            var end = value.Count - 1;
+
+            while (begin < end)
+                if (value[begin].Type == TokenType.Whitespace)
+                    begin++;
+                else if (value[end].Type == TokenType.Whitespace)
+                    end--;
+                else
+                    break;
+
+            value.RemoveRange(++end, value.Count - end);
+            value.RemoveRange(0, begin);
+        }
+
+        public static List<List<Token>> ToList(this IEnumerable<Token> value)
+        {
+            var list = new List<List<Token>>();
+            var current = new List<Token>();
+            var nested = 0;
+            list.Add(current);
+
+            foreach (var token in value)
+            {
+                if (nested == 0 && token.Type == TokenType.Comma)
+                {
+                    current = new List<Token>();
+                    list.Add(current);
+                    continue;
+                }
+
+                switch (token.Type)
+                {
+                    case TokenType.RoundBracketOpen:
+                        nested++;
+                        break;
+                    case TokenType.RoundBracketClose:
+                        nested--;
+                        break;
+                    case TokenType.Whitespace when current.Count == 0:
+                        continue;
+                }
+
+                current.Add(token);
+            }
+
+            foreach (var token in list) token.Trim();
+
+            return list;
+        }
+
+        public static string ToText(this IEnumerable<Token> value)
+        {
+            return string.Join(string.Empty, value.Select(m => m.ToValue()));
+        }
+
+        public static bool ContainsFunction(this IEnumerable<Token> tokens, string functionName)
+        {
+            foreach (var token in tokens)
+            {
+                if (token is FunctionToken function &&
+                    (function.Data.Isi(functionName) || function.ArgumentTokens.ContainsFunction(functionName)))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        public static Color? ToColor(this IEnumerable<Token> value)
+        {
+            var element = value.OnlyOrDefault();
+
+            if (element != null && element.Type == TokenType.Ident) return Color.FromName(element.Data);
+
+            if (element != null && element.Type == TokenType.Color && !((ColorToken)element).IsValid)
+            {
+                return Color.FromHex(element.Data);
+            }
+
+            return null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Factories/AttributeSelectorFactory.cs b/Source/HtmlRenderer/Core/CssEngine/Factories/AttributeSelectorFactory.cs
new file mode 100644
index 000000000..dc067c397
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Factories/AttributeSelectorFactory.cs
@@ -0,0 +1,51 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttributeSelectorFactory
+    {
+        private static readonly Lazy<AttributeSelectorFactory> Lazy = new Lazy<AttributeSelectorFactory>(() => new AttributeSelectorFactory());
+
+        private AttributeSelectorFactory()
+        {
+        }
+
+        internal static AttributeSelectorFactory Instance => Lazy.Value;
+
+        public IAttrSelector Create(string combinator, string match, string value, string prefix)
+        {
+            var name = match;
+
+            if (!string.IsNullOrEmpty(prefix))
+            {
+                name = AttributeSelectorFactory.FormFront(prefix, match);
+                _ = AttributeSelectorFactory.FormMatch(prefix, match);
+            }
+
+            // A reflection-free dispatch (no Activator.CreateInstance) so the two-arg Attr*Selector
+            // constructors are statically reachable and survive trimming/AOT (IsTrimmable=true) - see
+            // upstream ExCSS commit c497ca7. Unknown combinators fall back to a presence selector.
+            switch (combinator)
+            {
+                case Combinators.Exactly: return new AttrMatchSelector(name, value);
+                case Combinators.InList: return new AttrListSelector(name, value);
+                case Combinators.InToken: return new AttrHyphenSelector(name, value);
+                case Combinators.Begins: return new AttrBeginsSelector(name, value);
+                case Combinators.Ends: return new AttrEndsSelector(name, value);
+                case Combinators.InText: return new AttrContainsSelector(name, value);
+                case Combinators.Unlike: return new AttrNotMatchSelector(name, value);
+                default: return new AttrAvailableSelector(name, value);
+            }
+        }
+
+        private static string FormFront(string prefix, string match)
+        {
+            return string.Concat(prefix, Combinators.Pipe, match);
+        }
+
+        private static string FormMatch(string prefix, string match)
+        {
+            return prefix.Is(Keywords.Asterisk) ? match : string.Concat(prefix, PseudoClassNames.Separator, match);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Factories/MediaFeatureFactory.cs b/Source/HtmlRenderer/Core/CssEngine/Factories/MediaFeatureFactory.cs
new file mode 100644
index 000000000..7464800de
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Factories/MediaFeatureFactory.cs
@@ -0,0 +1,92 @@
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MediaFeatureFactory
+    {
+        private static readonly Lazy<MediaFeatureFactory> Lazy = new Lazy<MediaFeatureFactory>(() => new MediaFeatureFactory());
+
+        #region Creators
+
+        private readonly Dictionary<string, Creator> _creators =
+            new Dictionary<string, Creator>(StringComparer.OrdinalIgnoreCase)
+            {
+                {FeatureNames.MinWidth, () => new WidthMediaFeature(FeatureNames.MinWidth)},
+                {FeatureNames.MaxWidth, () => new WidthMediaFeature(FeatureNames.MaxWidth)},
+                {FeatureNames.Width, () => new WidthMediaFeature(FeatureNames.Width)},
+                {FeatureNames.MinHeight, () => new HeightMediaFeature(FeatureNames.MinHeight)},
+                {FeatureNames.MaxHeight, () => new HeightMediaFeature(FeatureNames.MaxHeight)},
+                {FeatureNames.Height, () => new HeightMediaFeature(FeatureNames.Height)},
+                {FeatureNames.MinDeviceWidth, () => new DeviceWidthMediaFeature(FeatureNames.MinDeviceWidth)},
+                {FeatureNames.MaxDeviceWidth, () => new DeviceWidthMediaFeature(FeatureNames.MaxDeviceWidth)},
+                {FeatureNames.DeviceWidth, () => new DeviceWidthMediaFeature(FeatureNames.DeviceWidth)},
+                {FeatureNames.MinDevicePixelRatio, () => new DevicePixelRatioFeature(FeatureNames.MinDevicePixelRatio)},
+                {FeatureNames.MaxDevicePixelRatio, () => new DevicePixelRatioFeature(FeatureNames.MaxDevicePixelRatio)},
+                {FeatureNames.DevicePixelRatio, () => new DevicePixelRatioFeature(FeatureNames.DevicePixelRatio)},
+                {FeatureNames.MinDeviceHeight, () => new DeviceHeightMediaFeature(FeatureNames.MinDeviceHeight)},
+                {FeatureNames.MaxDeviceHeight, () => new DeviceHeightMediaFeature(FeatureNames.MaxDeviceHeight)},
+                {FeatureNames.DeviceHeight, () => new DeviceHeightMediaFeature(FeatureNames.DeviceHeight)},
+                {FeatureNames.MinAspectRatio, () => new AspectRatioMediaFeature(FeatureNames.MinAspectRatio)},
+                {FeatureNames.MaxAspectRatio, () => new AspectRatioMediaFeature(FeatureNames.MaxAspectRatio)},
+                {FeatureNames.AspectRatio, () => new AspectRatioMediaFeature(FeatureNames.AspectRatio)},
+                {
+                    FeatureNames.MinDeviceAspectRatio,
+                    () => new DeviceAspectRatioMediaFeature(FeatureNames.MinDeviceAspectRatio)
+                },
+                {
+                    FeatureNames.MaxDeviceAspectRatio,
+                    () => new DeviceAspectRatioMediaFeature(FeatureNames.MaxDeviceAspectRatio)
+                },
+                {
+                    FeatureNames.DeviceAspectRatio,
+                    () => new DeviceAspectRatioMediaFeature(FeatureNames.DeviceAspectRatio)
+                },
+                {FeatureNames.MinColor, () => new ColorMediaFeature(FeatureNames.MinColor)},
+                {FeatureNames.MaxColor, () => new ColorMediaFeature(FeatureNames.MaxColor)},
+                {FeatureNames.Color, () => new ColorMediaFeature(FeatureNames.Color)},
+                {FeatureNames.MinColorIndex, () => new ColorIndexMediaFeature(FeatureNames.MinColorIndex)},
+                {FeatureNames.MaxColorIndex, () => new ColorIndexMediaFeature(FeatureNames.MaxColorIndex)},
+                {FeatureNames.ColorIndex, () => new ColorIndexMediaFeature(FeatureNames.ColorIndex)},
+                {FeatureNames.MinMonochrome, () => new MonochromeMediaFeature(FeatureNames.MinMonochrome)},
+                {FeatureNames.MaxMonochrome, () => new MonochromeMediaFeature(FeatureNames.MaxMonochrome)},
+                {FeatureNames.Monochrome, () => new MonochromeMediaFeature(FeatureNames.Monochrome)},
+                {FeatureNames.MinResolution, () => new ResolutionMediaFeature(FeatureNames.MinResolution)},
+                {FeatureNames.MaxResolution, () => new ResolutionMediaFeature(FeatureNames.MaxResolution)},
+                {FeatureNames.Resolution, () => new ResolutionMediaFeature(FeatureNames.Resolution)},
+                {FeatureNames.Orientation, () => new OrientationMediaFeature()},
+                {FeatureNames.Grid, () => new GridMediaFeature()},
+                {FeatureNames.Scan, () => new ScanMediaFeature()},
+                {FeatureNames.UpdateFrequency, () => new UpdateFrequencyMediaFeature()},
+                {FeatureNames.Scripting, () => new ScriptingMediaFeature()},
+                {FeatureNames.Pointer, () => new PointerMediaFeature()},
+                {FeatureNames.Hover, () => new HoverMediaFeature()},
+                {FeatureNames.InlineSize, () => new SizeMediaFeature(FeatureNames.InlineSize)},
+                {FeatureNames.BlockSize, () => new SizeMediaFeature(FeatureNames.BlockSize)},
+                {FeatureNames.PrefersColorScheme, () => new PrefersColorSchemeMediaFeature()},
+                {FeatureNames.PrefersReducedMotion, () => new PrefersReducedMotionMediaFeature()},
+                {FeatureNames.PrefersContrast, () => new PrefersContrastMediaFeature()},
+                {FeatureNames.PrefersReducedTransparency, () => new PrefersReducedTransparencyMediaFeature()},
+                {FeatureNames.Update, () => new UpdateMediaFeature()},
+                {FeatureNames.AnyHover, () => new AnyHoverMediaFeature()},
+                {FeatureNames.AnyPointer, () => new AnyPointerMediaFeature()},
+            };
+
+        #endregion
+
+        private MediaFeatureFactory()
+        {
+        }
+
+        internal static MediaFeatureFactory Instance => Lazy.Value;
+
+        public MediaFeature Create(string name)
+        {
+            return _creators.TryGetValue(name, out var creator)
+                ? creator()
+                : default;
+        }
+
+        private delegate MediaFeature Creator();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Factories/PropertyFactory.cs b/Source/HtmlRenderer/Core/CssEngine/Factories/PropertyFactory.cs
new file mode 100644
index 000000000..f767eeda4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Factories/PropertyFactory.cs
@@ -0,0 +1,663 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PropertyFactory
+    {
+        private static readonly Lazy<PropertyFactory> Lazy = new Lazy<PropertyFactory>(() => new PropertyFactory());
+
+        private readonly List<string> _animatables = new List<string>();
+
+        private readonly Dictionary<string, LonghandCreator> _fontsBuilder = new Dictionary<string, LonghandCreator>(StringComparer.OrdinalIgnoreCase);
+
+        private readonly Dictionary<string, LonghandCreator> _longhandsBuilder = new Dictionary<string, LonghandCreator>(StringComparer.OrdinalIgnoreCase);
+
+        private readonly Dictionary<string, string[]> _mappingsBuilder = new Dictionary<string, string[]>();
+
+        private readonly Dictionary<string, ShorthandCreator> _shorthandsBuilder = new Dictionary<string, ShorthandCreator>(StringComparer.OrdinalIgnoreCase);
+
+        // Shorthands that parse and expand normally but are excluded from serialization reconstruction:
+        // the logical shorthands, whose longhands are the physical ones (margin-top/-bottom/…), so letting
+        // the serializer collapse e.g. margin-top+margin-bottom into `margin-block` would change existing
+        // output. Excluded from GetShorthands (the serialization query) only; CreateShorthand,
+        // GetLonghands and IsShorthand still work.
+        private readonly HashSet<string> _logicalShorthands = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        private readonly Dictionary<string, LonghandCreator> _fonts;
+
+        // @property descriptors (syntax / initial-value / inherits). Their values have no fixed CSS grammar
+        // (initial-value depends on the syntax; syntax is an arbitrary string), so each is stored raw via an
+        // UnknownProperty (Converters.Any) and validated later against the syntax string.
+        private readonly Dictionary<string, LonghandCreator> _propertyDescriptors;
+
+        // @font-palette-values descriptors (font-family / base-palette / override-colors). Stored raw via
+        // UnknownProperty and validated later when the palette is resolved.
+        private readonly Dictionary<string, LonghandCreator> _fontPaletteDescriptors;
+
+        private readonly Dictionary<string, LonghandCreator> _longhands;
+
+        private readonly Dictionary<string, string[]> _mappings;
+
+        private readonly Dictionary<string, ShorthandCreator> _shorthands;
+
+        private PropertyFactory()
+        {
+            AddLonghand(PropertyNames.AlignContent, () => new AlignContentProperty());
+            AddLonghand(PropertyNames.AlignItems, () => new AlignItemsProperty());
+            AddLonghand(PropertyNames.AlignSelf, () => new AlignSelfProperty());
+            AddShorthand(PropertyNames.Animation, () => new AnimationProperty(),
+                PropertyNames.AnimationName,
+                PropertyNames.AnimationDuration,
+                PropertyNames.AnimationTimingFunction,
+                PropertyNames.AnimationDelay,
+                PropertyNames.AnimationDirection,
+                PropertyNames.AnimationFillMode,
+                PropertyNames.AnimationIterationCount,
+                PropertyNames.AnimationPlayState);
+            AddLonghand(PropertyNames.AnimationDelay, () => new AnimationDelayProperty());
+            AddLonghand(PropertyNames.AnimationDirection, () => new AnimationDirectionProperty());
+            AddLonghand(PropertyNames.AnimationDuration, () => new AnimationDurationProperty());
+            AddLonghand(PropertyNames.AnimationFillMode, () => new AnimationFillModeProperty());
+            AddLonghand(PropertyNames.AnimationIterationCount, () => new AnimationIterationCountProperty());
+            AddLonghand(PropertyNames.AnimationName, () => new AnimationNameProperty());
+            AddLonghand(PropertyNames.AnimationPlayState, () => new AnimationPlayStateProperty());
+            AddLonghand(PropertyNames.AnimationTimingFunction, () => new AnimationTimingFunctionProperty());
+
+            AddShorthand(PropertyNames.Background, () => new BackgroundProperty(),
+                PropertyNames.BackgroundAttachment,
+                PropertyNames.BackgroundClip,
+                PropertyNames.BackgroundColor,
+                PropertyNames.BackgroundImage,
+                PropertyNames.BackgroundOrigin,
+                PropertyNames.BackgroundPosition,
+                PropertyNames.BackgroundRepeat,
+                PropertyNames.BackgroundSize);
+            AddLonghand(PropertyNames.BackgroundAttachment, () => new BackgroundAttachmentProperty());
+            AddLonghand(PropertyNames.BackgroundColor, () => new BackgroundColorProperty(), true);
+            AddLonghand(PropertyNames.BackgroundClip, () => new BackgroundClipProperty());
+            AddLonghand(PropertyNames.BackgroundOrigin, () => new BackgroundOriginProperty());
+            AddLonghand(PropertyNames.BackgroundSize, () => new BackgroundSizeProperty(), true);
+            AddLonghand(PropertyNames.BackgroundImage, () => new BackgroundImageProperty());
+            AddLonghand(PropertyNames.BackgroundPosition, () => new BackgroundPositionProperty(), true);
+            AddLonghand(PropertyNames.BackgroundRepeat, () => new BackgroundRepeatProperty());
+
+            AddLonghand(PropertyNames.BorderSpacing, () => new BorderSpacingProperty());
+            AddLonghand(PropertyNames.BorderCollapse, () => new BorderCollapseProperty());
+            AddLonghand(PropertyNames.BoxSizing, () => new BoxSizingProperty());
+            AddLonghand(PropertyNames.BoxShadow, () => new BoxShadowProperty(), true);
+            AddLonghand(PropertyNames.AspectRatio, () => new AspectRatioProperty());
+            AddLonghand(PropertyNames.ClipPath, () => new ClipPathProperty(), true);
+            AddLonghand(PropertyNames.BoxDecorationBreak, () => new BoxDecorationBreak());
+            AddLonghand(PropertyNames.BreakAfter, () => new BreakAfterProperty());
+            AddLonghand(PropertyNames.BreakBefore, () => new BreakBeforeProperty());
+            AddLonghand(PropertyNames.BreakInside, () => new BreakInsideProperty());
+            AddLonghand(PropertyNames.BackfaceVisibility, () => new BackfaceVisibilityProperty());
+
+            AddShorthand(PropertyNames.BorderRadius, () => new BorderRadiusProperty(),
+                PropertyNames.BorderTopLeftRadius,
+                PropertyNames.BorderTopRightRadius,
+                PropertyNames.BorderBottomRightRadius,
+                PropertyNames.BorderBottomLeftRadius);
+            AddLonghand(PropertyNames.BorderTopLeftRadius, () => new BorderTopLeftRadiusProperty(), true);
+            AddLonghand(PropertyNames.BorderTopRightRadius, () => new BorderTopRightRadiusProperty(), true);
+            AddLonghand(PropertyNames.BorderBottomLeftRadius, () => new BorderBottomLeftRadiusProperty(), true);
+            AddLonghand(PropertyNames.BorderBottomRightRadius, () => new BorderBottomRightRadiusProperty(), true);
+
+            AddShorthand(PropertyNames.BorderImage, () => new BorderImageProperty(),
+                PropertyNames.BorderImageOutset,
+                PropertyNames.BorderImageRepeat,
+                PropertyNames.BorderImageSlice,
+                PropertyNames.BorderImageSource,
+                PropertyNames.BorderImageWidth);
+            AddLonghand(PropertyNames.BorderImageOutset, () => new BorderImageOutsetProperty());
+            AddLonghand(PropertyNames.BorderImageRepeat, () => new BorderImageRepeatProperty());
+            AddLonghand(PropertyNames.BorderImageSource, () => new BorderImageSourceProperty());
+            AddLonghand(PropertyNames.BorderImageSlice, () => new BorderImageSliceProperty());
+            AddLonghand(PropertyNames.BorderImageWidth, () => new BorderImageWidthProperty());
+
+            AddShorthand(PropertyNames.BorderColor, () => new BorderColorProperty(),
+                PropertyNames.BorderTopColor,
+                PropertyNames.BorderRightColor,
+                PropertyNames.BorderBottomColor,
+                PropertyNames.BorderLeftColor);
+            AddShorthand(PropertyNames.BorderStyle, () => new BorderStyleProperty(),
+                PropertyNames.BorderTopStyle,
+                PropertyNames.BorderRightStyle,
+                PropertyNames.BorderBottomStyle,
+                PropertyNames.BorderLeftStyle);
+            AddShorthand(PropertyNames.BorderWidth, () => new BorderWidthProperty(),
+                PropertyNames.BorderTopWidth,
+                PropertyNames.BorderRightWidth,
+                PropertyNames.BorderBottomWidth,
+                PropertyNames.BorderLeftWidth);
+            AddShorthand(PropertyNames.BorderTop, () => new BorderTopProperty(),
+                PropertyNames.BorderTopWidth,
+                PropertyNames.BorderTopStyle,
+                PropertyNames.BorderTopColor);
+            AddShorthand(PropertyNames.BorderRight, () => new BorderRightProperty(),
+                PropertyNames.BorderRightWidth,
+                PropertyNames.BorderRightStyle,
+                PropertyNames.BorderRightColor);
+            AddShorthand(PropertyNames.BorderBottom, () => new BorderBottomProperty(),
+                PropertyNames.BorderBottomWidth,
+                PropertyNames.BorderBottomStyle,
+                PropertyNames.BorderBottomColor);
+            AddShorthand(PropertyNames.BorderLeft, () => new BorderLeftProperty(),
+                PropertyNames.BorderLeftWidth,
+                PropertyNames.BorderLeftStyle,
+                PropertyNames.BorderLeftColor);
+
+            AddShorthand(PropertyNames.Border, () => new BorderProperty(),
+                PropertyNames.BorderTopWidth,
+                PropertyNames.BorderTopStyle,
+                PropertyNames.BorderTopColor,
+                PropertyNames.BorderRightWidth,
+                PropertyNames.BorderRightStyle,
+                PropertyNames.BorderRightColor,
+                PropertyNames.BorderBottomWidth,
+                PropertyNames.BorderBottomStyle,
+                PropertyNames.BorderBottomColor,
+                PropertyNames.BorderLeftWidth,
+                PropertyNames.BorderLeftStyle,
+                PropertyNames.BorderLeftColor);
+            AddLonghand(PropertyNames.BorderTopColor, () => new BorderTopColorProperty(), true);
+            AddLonghand(PropertyNames.BorderLeftColor, () => new BorderLeftColorProperty(), true);
+            AddLonghand(PropertyNames.BorderRightColor, () => new BorderRightColorProperty(), true);
+            AddLonghand(PropertyNames.BorderBottomColor, () => new BorderBottomColorProperty(), true);
+            AddLonghand(PropertyNames.BorderTopStyle, () => new BorderTopStyleProperty());
+            AddLonghand(PropertyNames.BorderLeftStyle, () => new BorderLeftStyleProperty());
+            AddLonghand(PropertyNames.BorderRightStyle, () => new BorderRightStyleProperty());
+            AddLonghand(PropertyNames.BorderBottomStyle, () => new BorderBottomStyleProperty());
+            AddLonghand(PropertyNames.BorderTopWidth, () => new BorderTopWidthProperty(), true);
+            AddLonghand(PropertyNames.BorderLeftWidth, () => new BorderLeftWidthProperty(), true);
+            AddLonghand(PropertyNames.BorderRightWidth, () => new BorderRightWidthProperty(), true);
+            AddLonghand(PropertyNames.BorderBottomWidth, () => new BorderBottomWidthProperty(), true);
+
+            AddLonghand(PropertyNames.Bottom, () => new BottomProperty(), true);
+
+            AddShorthand(PropertyNames.Columns, () => new ColumnsProperty(),
+                PropertyNames.ColumnWidth,
+                PropertyNames.ColumnCount);
+            AddLonghand(PropertyNames.ColumnCount, () => new ColumnCountProperty(), true);
+            AddLonghand(PropertyNames.ColumnWidth, () => new ColumnWidthProperty(), true);
+
+            AddLonghand(PropertyNames.ColumnFill, () => new ColumnFillProperty());
+            AddLonghand(PropertyNames.ColumnGap, () => new ColumnGapProperty(), true);
+            AddLonghand(PropertyNames.ColumnSpan, () => new ColumnSpanProperty());
+
+            AddShorthand(PropertyNames.ColumnRule, () => new ColumnRuleProperty(),
+                PropertyNames.ColumnRuleWidth,
+                PropertyNames.ColumnRuleStyle,
+                PropertyNames.ColumnRuleColor);
+            AddLonghand(PropertyNames.ColumnRuleColor, () => new ColumnRuleColorProperty(), true);
+            AddLonghand(PropertyNames.ColumnRuleStyle, () => new ColumnRuleStyleProperty());
+            AddLonghand(PropertyNames.ColumnRuleWidth, () => new ColumnRuleWidthProperty(), true);
+
+            AddLonghand(PropertyNames.CaptionSide, () => new CaptionSideProperty());
+            AddLonghand(PropertyNames.Clear, () => new ClearProperty());
+            AddLonghand(PropertyNames.Clip, () => new ClipProperty(), true);
+            AddLonghand(PropertyNames.Color, () => new ColorProperty(), true);
+            AddLonghand(PropertyNames.ContainerName, () => new ContainerNameProperty());
+            AddLonghand(PropertyNames.ContainerType, () => new ContainerTypeProperty());
+            AddLonghand(PropertyNames.Content, () => new ContentProperty());
+            AddLonghand(PropertyNames.CounterIncrement, () => new CounterIncrementProperty());
+            AddLonghand(PropertyNames.CounterReset, () => new CounterResetProperty());
+            AddLonghand(PropertyNames.Cursor, () => new CursorProperty());
+            AddLonghand(PropertyNames.Direction, () => new DirectionProperty());
+            AddLonghand(PropertyNames.Display, () => new DisplayProperty());
+            AddLonghand(PropertyNames.EmptyCells, () => new EmptyCellsProperty());
+            AddLonghand(PropertyNames.Fill, () => new FillProperty(), true);
+            AddLonghand(PropertyNames.FillOpacity, () => new FillOpacityProperty(), true);
+            AddLonghand(PropertyNames.FillRule, () => new FillRuleProperty(), true);
+            AddShorthand(PropertyNames.Flex, () => new FlexProperty(),
+                PropertyNames.FlexGrow,
+                PropertyNames.FlexShrink,
+                PropertyNames.FlexBasis);
+            AddLonghand(PropertyNames.FlexBasis, () => new FlexBasisProperty(), true);
+            AddLonghand(PropertyNames.FlexDirection, () => new FlexDirectionProperty());
+            AddShorthand(PropertyNames.FlexFlow, () => new FlexFlowProperty(),
+                PropertyNames.FlexDirection,
+                PropertyNames.FlexWrap);
+            AddLonghand(PropertyNames.FlexGrow, () => new FlexGrowProperty());
+            AddLonghand(PropertyNames.FlexShrink, () => new FlexShrinkProperty());
+            AddLonghand(PropertyNames.FlexWrap, () => new FlexWrapProperty());
+            AddLonghand(PropertyNames.Float, () => new FloatProperty());
+
+            AddShorthand(PropertyNames.Font, () => new FontProperty(),
+                PropertyNames.FontFamily,
+                PropertyNames.FontSize,
+                PropertyNames.FontStretch,
+                PropertyNames.FontStyle,
+                PropertyNames.FontVariant,
+                PropertyNames.FontWeight,
+                PropertyNames.LineHeight);
+            AddLonghand(PropertyNames.FontFamily, () => new FontFamilyProperty(), false, true);
+            AddLonghand(PropertyNames.FontPalette, () => new FontPaletteProperty());
+            AddLonghand(PropertyNames.FontSize, () => new FontSizeProperty(), true);
+            AddLonghand(PropertyNames.FontSizeAdjust, () => new FontSizeAdjustProperty(), true);
+            AddLonghand(PropertyNames.FontStyle, () => new FontStyleProperty(), false, true);
+            AddLonghand(PropertyNames.FontVariant, () => new FontVariantProperty(), false, true);
+            AddLonghand(PropertyNames.FontWeight, () => new FontWeightProperty(), true, true);
+            AddLonghand(PropertyNames.FontStretch, () => new FontStretchProperty(), true, true);
+
+            AddShorthand(PropertyNames.Gap, () => new GapProperty(),
+                PropertyNames.RowGap,
+                PropertyNames.ColumnGap);
+
+            AddLonghand(PropertyNames.Height, () => new HeightProperty(), true);
+            AddLonghand(PropertyNames.Hyphens, () => new HyphensProperty());
+
+            AddLonghand(PropertyNames.JustifyContent, () => new JustifyContentProperty());
+
+            AddLonghand(PropertyNames.Left, () => new LeftProperty(), true);
+            AddLonghand(PropertyNames.LetterSpacing, () => new LetterSpacingProperty());
+            AddLonghand(PropertyNames.LineHeight, () => new LineHeightProperty(), true);
+
+            AddShorthand(PropertyNames.ListStyle, () => new ListStyleProperty(),
+                PropertyNames.ListStyleType,
+                PropertyNames.ListStyleImage,
+                PropertyNames.ListStylePosition);
+            AddLonghand(PropertyNames.ListStyleImage, () => new ListStyleImageProperty());
+            AddLonghand(PropertyNames.ListStylePosition, () => new ListStylePositionProperty());
+            AddLonghand(PropertyNames.ListStyleType, () => new ListStyleTypeProperty());
+
+            AddShorthand(PropertyNames.Margin, () => new MarginProperty(),
+                PropertyNames.MarginTop,
+                PropertyNames.MarginRight,
+                PropertyNames.MarginBottom,
+                PropertyNames.MarginLeft);
+            AddLonghand(PropertyNames.MarginRight, () => new MarginRightProperty(), true);
+            AddLonghand(PropertyNames.MarginLeft, () => new MarginLeftProperty(), true);
+            AddLonghand(PropertyNames.MarginTop, () => new MarginTopProperty(), true);
+            AddLonghand(PropertyNames.MarginBottom, () => new MarginBottomProperty(), true);
+
+            AddLonghand(PropertyNames.MaxHeight, () => new MaxHeightProperty(), true);
+            AddLonghand(PropertyNames.MaxWidth, () => new MaxWidthProperty(), true);
+            AddLonghand(PropertyNames.MinHeight, () => new MinHeightProperty(), true);
+            AddLonghand(PropertyNames.MinWidth, () => new MinWidthProperty(), true);
+            AddLonghand(PropertyNames.Opacity, () => new OpacityProperty(), true);
+            AddLonghand(PropertyNames.Order, () => new OrderProperty(), true);
+            AddLonghand(PropertyNames.Orphans, () => new OrphansProperty());
+
+            AddShorthand(PropertyNames.Outline, () => new OutlineProperty(),
+                PropertyNames.OutlineWidth,
+                PropertyNames.OutlineStyle,
+                PropertyNames.OutlineColor);
+            AddLonghand(PropertyNames.OutlineColor, () => new OutlineColorProperty(), true);
+            AddLonghand(PropertyNames.OutlineStyle, () => new OutlineStyleProperty());
+            AddLonghand(PropertyNames.OutlineWidth, () => new OutlineWidthProperty(), true);
+
+            AddLonghand(PropertyNames.Overflow, () => new OverflowProperty());
+            AddLonghand(PropertyNames.OverflowWrap, () => new OverflowWrapProperty());
+
+            AddShorthand(PropertyNames.Padding, () => new PaddingProperty(),
+                PropertyNames.PaddingTop,
+                PropertyNames.PaddingRight,
+                PropertyNames.PaddingBottom,
+                PropertyNames.PaddingLeft);
+            AddLonghand(PropertyNames.PaddingTop, () => new PaddingTopProperty(), true);
+            AddLonghand(PropertyNames.PaddingRight, () => new PaddingRightProperty(), true);
+            AddLonghand(PropertyNames.PaddingLeft, () => new PaddingLeftProperty(), true);
+            AddLonghand(PropertyNames.PaddingBottom, () => new PaddingBottomProperty(), true);
+
+            AddLonghand(PropertyNames.PageBreakAfter, () => new PageBreakAfterProperty());
+            AddLonghand(PropertyNames.PageBreakBefore, () => new PageBreakBeforeProperty());
+            AddLonghand(PropertyNames.PageBreakInside, () => new PageBreakInsideProperty());
+            AddLonghand(PropertyNames.Perspective, () => new PerspectiveProperty(), true);
+            AddLonghand(PropertyNames.PerspectiveOrigin, () => new PerspectiveOriginProperty(), true);
+            AddLonghand(PropertyNames.Position, () => new PositionProperty());
+            AddLonghand(PropertyNames.Quotes, () => new QuotesProperty());
+            AddLonghand(PropertyNames.Right, () => new RightProperty(), true);
+            AddLonghand(PropertyNames.RowGap, () => new RowGapProperty(), true);
+            AddLonghand(PropertyNames.Stroke, () => new StrokeProperty(), true);
+            AddLonghand(PropertyNames.StrokeDasharray, () => new StrokeDasharrayProperty(), true);
+            AddLonghand(PropertyNames.StrokeDashoffset, () => new StrokeDashoffsetProperty(), true);
+            AddLonghand(PropertyNames.StrokeLinecap, () => new StrokeLinecapProperty(), true);
+            AddLonghand(PropertyNames.StrokeLinejoin, () => new StrokeLinejoinProperty(), true);
+            AddLonghand(PropertyNames.StrokeMiterlimit, () => new StrokeMiterlimitProperty(), true);
+            AddLonghand(PropertyNames.StrokeOpacity, () => new StrokeOpacityProperty(), true);
+            AddLonghand(PropertyNames.StrokeWidth, () => new StrokeWidthProperty(), true);
+            AddLonghand(PropertyNames.StringSet, () => new StringSetProperty());
+            AddLonghand(PropertyNames.PageName, () => new PageNameProperty());
+            AddLonghand(PropertyNames.TableLayout, () => new TableLayoutProperty());
+            AddLonghand(PropertyNames.TextAlign, () => new TextAlignProperty());
+            AddLonghand(PropertyNames.TextAlignLast, () => new TextAlignLastProperty());
+            AddLonghand(PropertyNames.TextAnchor, () => new TextAnchorProperty());
+
+            AddShorthand(PropertyNames.TextDecoration, () => new TextDecorationProperty(),
+                PropertyNames.TextDecorationLine,
+                PropertyNames.TextDecorationStyle,
+                PropertyNames.TextDecorationColor);
+            AddLonghand(PropertyNames.TextDecorationStyle, () => new TextDecorationStyleProperty());
+            AddLonghand(PropertyNames.TextDecorationLine, () => new TextDecorationLineProperty());
+            AddLonghand(PropertyNames.TextDecorationColor, () => new TextDecorationColorProperty(), true);
+
+            AddLonghand(PropertyNames.TextIndent, () => new TextIndentProperty(), true);
+            AddLonghand(PropertyNames.TextJustify, () => new TextJustifyProperty());
+            AddLonghand(PropertyNames.TextTransform, () => new TextTransformProperty());
+            AddLonghand(PropertyNames.TextShadow, () => new TextShadowProperty(), true);
+            AddLonghand(PropertyNames.Transform, () => new TransformProperty(), true);
+            AddLonghand(PropertyNames.TransformOrigin, () => new TransformOriginProperty(), true);
+            AddLonghand(PropertyNames.TransformStyle, () => new TransformStyleProperty());
+
+            AddShorthand(PropertyNames.Transition, () => new TransitionProperty(),
+                PropertyNames.TransitionProperty,
+                PropertyNames.TransitionDuration,
+                PropertyNames.TransitionTimingFunction,
+                PropertyNames.TransitionDelay);
+            AddLonghand(PropertyNames.TransitionDelay, () => new TransitionDelayProperty());
+            AddLonghand(PropertyNames.TransitionDuration, () => new TransitionDurationProperty());
+            AddLonghand(PropertyNames.TransitionTimingFunction, () => new TransitionTimingFunctionProperty());
+            AddLonghand(PropertyNames.TransitionProperty, () => new TransitionPropertyProperty());
+
+            AddLonghand(PropertyNames.Top, () => new TopProperty(), true);
+            AddLonghand(PropertyNames.UnicodeBidirectional, () => new UnicodeBidirectionalProperty());
+            AddLonghand(PropertyNames.VerticalAlign, () => new VerticalAlignProperty(), true);
+            AddLonghand(PropertyNames.Visibility, () => new VisibilityProperty(), true);
+            AddLonghand(PropertyNames.WhiteSpace, () => new WhiteSpaceProperty());
+            AddLonghand(PropertyNames.Widows, () => new WidowsProperty());
+            AddLonghand(PropertyNames.Width, () => new WidthProperty(), true);
+            AddLonghand(PropertyNames.WordBreak, () => new WordBreakProperty(), true);
+            AddLonghand(PropertyNames.WordSpacing, () => new WordSpacingProperty(), true);
+            AddLonghand(PropertyNames.WordWrap, () => new OverflowWrapProperty());
+            AddLonghand(PropertyNames.ZIndex, () => new ZIndexProperty(), true);
+            AddLonghand(PropertyNames.ObjectFit, () => new ObjectFitProperty());
+            AddLonghand(PropertyNames.ObjectPosition, () => new ObjectPositionProperty(), true);
+            AddLonghand(PropertyNames.Size, () => new PageSizeProperty());
+
+            _fontsBuilder.Add(PropertyNames.Src, () => new SrcProperty());
+            _fontsBuilder.Add(PropertyNames.UnicodeRange, () => new UnicodeRangeProperty());
+
+            // CSS Grid Layout Level 1/2. The engine parses and validates the full grid property set;
+            // the renderer has no grid layout engine yet, so these cascade and are then ignored at the
+            // box boundary.
+            AddLonghand(PropertyNames.GridTemplateColumns, () => new GridTemplateColumnsProperty());
+            AddLonghand(PropertyNames.GridTemplateRows, () => new GridTemplateRowsProperty());
+            AddLonghand(PropertyNames.GridTemplateAreas, () => new GridTemplateAreasProperty());
+            AddLonghand(PropertyNames.GridColumnStart, () => new GridColumnStartProperty());
+            AddLonghand(PropertyNames.GridColumnEnd, () => new GridColumnEndProperty());
+            AddLonghand(PropertyNames.GridRowStart, () => new GridRowStartProperty());
+            AddLonghand(PropertyNames.GridRowEnd, () => new GridRowEndProperty());
+
+            AddShorthand(PropertyNames.GridColumn, () => new GridColumnProperty(),
+                PropertyNames.GridColumnStart, PropertyNames.GridColumnEnd);
+            AddShorthand(PropertyNames.GridRow, () => new GridRowProperty(),
+                PropertyNames.GridRowStart, PropertyNames.GridRowEnd);
+            AddShorthand(PropertyNames.GridArea, () => new GridAreaProperty(),
+                PropertyNames.GridRowStart, PropertyNames.GridColumnStart,
+                PropertyNames.GridRowEnd, PropertyNames.GridColumnEnd);
+
+            AddLonghand(PropertyNames.GridAutoFlow, () => new GridAutoFlowProperty());
+            AddLonghand(PropertyNames.GridAutoColumns, () => new GridAutoColumnsProperty());
+            AddLonghand(PropertyNames.GridAutoRows, () => new GridAutoRowsProperty());
+
+            // The grid mega-shorthands parse/expand like any other, but are excluded from serialization
+            // reconstruction (via _logicalShorthands) - reconstructing a `grid`/`grid-template` from its
+            // longhands is not worth the complexity and could change existing output.
+            AddLogicalShorthand(PropertyNames.GridTemplate, () => new GridTemplateProperty(),
+                PropertyNames.GridTemplateRows, PropertyNames.GridTemplateColumns, PropertyNames.GridTemplateAreas);
+            AddLogicalShorthand(PropertyNames.Grid, () => new GridProperty(),
+                PropertyNames.GridTemplateRows, PropertyNames.GridTemplateColumns, PropertyNames.GridTemplateAreas,
+                PropertyNames.GridAutoFlow, PropertyNames.GridAutoRows, PropertyNames.GridAutoColumns);
+
+            AddLonghand(PropertyNames.JustifyItems, () => new JustifyItemsProperty());
+            AddLonghand(PropertyNames.JustifySelf, () => new JustifySelfProperty());
+            AddShorthand(PropertyNames.PlaceItems, () => new PlaceItemsProperty(),
+                PropertyNames.AlignItems, PropertyNames.JustifyItems);
+            AddShorthand(PropertyNames.PlaceContent, () => new PlaceContentProperty(),
+                PropertyNames.AlignContent, PropertyNames.JustifyContent);
+            AddShorthand(PropertyNames.PlaceSelf, () => new PlaceSelfProperty(),
+                PropertyNames.AlignSelf, PropertyNames.JustifySelf);
+
+            // CSS Logical Properties and Values Level 1. Layout here is always LTR / horizontal-tb,
+            // so each logical property is registered to produce/export the existing physical
+            // longhands (block-start = top, block-end = bottom, inline-start = left,
+            // inline-end = right). Nothing downstream needs to change, since it already handles
+            // every physical longhand.
+
+            // Logical margin longhands (aliases to the physical longhand classes).
+            AddLonghand(PropertyNames.MarginBlockStart, () => new MarginTopProperty(), true);
+            AddLonghand(PropertyNames.MarginBlockEnd, () => new MarginBottomProperty(), true);
+            AddLonghand(PropertyNames.MarginInlineStart, () => new MarginLeftProperty(), true);
+            AddLonghand(PropertyNames.MarginInlineEnd, () => new MarginRightProperty(), true);
+            // Logical margin shorthands.
+            AddLogicalShorthand(PropertyNames.MarginBlock, () => new MarginBlockProperty(),
+                PropertyNames.MarginTop,
+                PropertyNames.MarginBottom);
+            AddLogicalShorthand(PropertyNames.MarginInline, () => new MarginInlineProperty(),
+                PropertyNames.MarginLeft,
+                PropertyNames.MarginRight);
+
+            // Logical padding longhands (aliases to the physical longhand classes).
+            AddLonghand(PropertyNames.PaddingBlockStart, () => new PaddingTopProperty(), true);
+            AddLonghand(PropertyNames.PaddingBlockEnd, () => new PaddingBottomProperty(), true);
+            AddLonghand(PropertyNames.PaddingInlineStart, () => new PaddingLeftProperty(), true);
+            AddLonghand(PropertyNames.PaddingInlineEnd, () => new PaddingRightProperty(), true);
+            // Logical padding shorthands.
+            AddLogicalShorthand(PropertyNames.PaddingBlock, () => new PaddingBlockProperty(),
+                PropertyNames.PaddingTop,
+                PropertyNames.PaddingBottom);
+            AddLogicalShorthand(PropertyNames.PaddingInline, () => new PaddingInlineProperty(),
+                PropertyNames.PaddingLeft,
+                PropertyNames.PaddingRight);
+
+            // Logical inset longhands (aliases to the physical coordinate longhand classes).
+            AddLonghand(PropertyNames.InsetBlockStart, () => new TopProperty(), true);
+            AddLonghand(PropertyNames.InsetBlockEnd, () => new BottomProperty(), true);
+            AddLonghand(PropertyNames.InsetInlineStart, () => new LeftProperty(), true);
+            AddLonghand(PropertyNames.InsetInlineEnd, () => new RightProperty(), true);
+            // Inset shorthands.
+            AddLogicalShorthand(PropertyNames.Inset, () => new InsetProperty(),
+                PropertyNames.Top,
+                PropertyNames.Right,
+                PropertyNames.Bottom,
+                PropertyNames.Left);
+            AddLogicalShorthand(PropertyNames.InsetBlock, () => new InsetBlockProperty(),
+                PropertyNames.Top,
+                PropertyNames.Bottom);
+            AddLogicalShorthand(PropertyNames.InsetInline, () => new InsetInlineProperty(),
+                PropertyNames.Left,
+                PropertyNames.Right);
+
+            // Logical per-edge border longhands (aliases to the physical longhand classes).
+            AddLonghand(PropertyNames.BorderBlockStartWidth, () => new BorderTopWidthProperty(), true);
+            AddLonghand(PropertyNames.BorderBlockStartStyle, () => new BorderTopStyleProperty());
+            AddLonghand(PropertyNames.BorderBlockStartColor, () => new BorderTopColorProperty(), true);
+            AddLonghand(PropertyNames.BorderBlockEndWidth, () => new BorderBottomWidthProperty(), true);
+            AddLonghand(PropertyNames.BorderBlockEndStyle, () => new BorderBottomStyleProperty());
+            AddLonghand(PropertyNames.BorderBlockEndColor, () => new BorderBottomColorProperty(), true);
+            AddLonghand(PropertyNames.BorderInlineStartWidth, () => new BorderLeftWidthProperty(), true);
+            AddLonghand(PropertyNames.BorderInlineStartStyle, () => new BorderLeftStyleProperty());
+            AddLonghand(PropertyNames.BorderInlineStartColor, () => new BorderLeftColorProperty(), true);
+            AddLonghand(PropertyNames.BorderInlineEndWidth, () => new BorderRightWidthProperty(), true);
+            AddLonghand(PropertyNames.BorderInlineEndStyle, () => new BorderRightStyleProperty());
+            AddLonghand(PropertyNames.BorderInlineEndColor, () => new BorderRightColorProperty(), true);
+
+            // Logical per-edge border shorthands (aliases to the physical edge shorthand classes).
+            AddLogicalShorthand(PropertyNames.BorderBlockStart, () => new BorderTopProperty(),
+                PropertyNames.BorderTopWidth,
+                PropertyNames.BorderTopStyle,
+                PropertyNames.BorderTopColor);
+            AddLogicalShorthand(PropertyNames.BorderBlockEnd, () => new BorderBottomProperty(),
+                PropertyNames.BorderBottomWidth,
+                PropertyNames.BorderBottomStyle,
+                PropertyNames.BorderBottomColor);
+            AddLogicalShorthand(PropertyNames.BorderInlineStart, () => new BorderLeftProperty(),
+                PropertyNames.BorderLeftWidth,
+                PropertyNames.BorderLeftStyle,
+                PropertyNames.BorderLeftColor);
+            AddLogicalShorthand(PropertyNames.BorderInlineEnd, () => new BorderRightProperty(),
+                PropertyNames.BorderRightWidth,
+                PropertyNames.BorderRightStyle,
+                PropertyNames.BorderRightColor);
+
+            // Logical two-edge border shorthands (both block/inline edges the same value).
+            AddLogicalShorthand(PropertyNames.BorderBlock, () => new BorderBlockProperty(),
+                PropertyNames.BorderTopWidth,
+                PropertyNames.BorderTopStyle,
+                PropertyNames.BorderTopColor,
+                PropertyNames.BorderBottomWidth,
+                PropertyNames.BorderBottomStyle,
+                PropertyNames.BorderBottomColor);
+            AddLogicalShorthand(PropertyNames.BorderInline, () => new BorderInlineProperty(),
+                PropertyNames.BorderLeftWidth,
+                PropertyNames.BorderLeftStyle,
+                PropertyNames.BorderLeftColor,
+                PropertyNames.BorderRightWidth,
+                PropertyNames.BorderRightStyle,
+                PropertyNames.BorderRightColor);
+
+            // Logical two-edge border width/style/color shorthands.
+            AddLogicalShorthand(PropertyNames.BorderBlockWidth, () => new BorderBlockWidthProperty(),
+                PropertyNames.BorderTopWidth,
+                PropertyNames.BorderBottomWidth);
+            AddLogicalShorthand(PropertyNames.BorderBlockStyle, () => new BorderBlockStyleProperty(),
+                PropertyNames.BorderTopStyle,
+                PropertyNames.BorderBottomStyle);
+            AddLogicalShorthand(PropertyNames.BorderBlockColor, () => new BorderBlockColorProperty(),
+                PropertyNames.BorderTopColor,
+                PropertyNames.BorderBottomColor);
+            AddLogicalShorthand(PropertyNames.BorderInlineWidth, () => new BorderInlineWidthProperty(),
+                PropertyNames.BorderLeftWidth,
+                PropertyNames.BorderRightWidth);
+            AddLogicalShorthand(PropertyNames.BorderInlineStyle, () => new BorderInlineStyleProperty(),
+                PropertyNames.BorderLeftStyle,
+                PropertyNames.BorderRightStyle);
+            AddLogicalShorthand(PropertyNames.BorderInlineColor, () => new BorderInlineColorProperty(),
+                PropertyNames.BorderLeftColor,
+                PropertyNames.BorderRightColor);
+
+            _fonts = _fontsBuilder;
+
+            _propertyDescriptors = new Dictionary<string, LonghandCreator>(StringComparer.OrdinalIgnoreCase)
+            {
+                { PropertyNames.Syntax, () => new UnknownProperty(PropertyNames.Syntax) },
+                { PropertyNames.InitialValue, () => new UnknownProperty(PropertyNames.InitialValue) },
+                { PropertyNames.Inherits, () => new UnknownProperty(PropertyNames.Inherits) },
+            };
+
+            _fontPaletteDescriptors = new Dictionary<string, LonghandCreator>(StringComparer.OrdinalIgnoreCase)
+            {
+                { PropertyNames.FontFamily, () => new UnknownProperty(PropertyNames.FontFamily) },
+                { PropertyNames.BasePalette, () => new UnknownProperty(PropertyNames.BasePalette) },
+                { PropertyNames.OverrideColors, () => new UnknownProperty(PropertyNames.OverrideColors) },
+            };
+
+            _longhands = _longhandsBuilder;
+            _mappings = _mappingsBuilder;
+            _shorthands = _shorthandsBuilder;
+        }
+
+        internal static PropertyFactory Instance => Lazy.Value;
+
+        private void AddShorthand(string name, ShorthandCreator creator, params string[] longhands)
+        {
+            _shorthandsBuilder.Add(name, creator);
+            _mappingsBuilder.Add(name, longhands);
+        }
+
+        // A logical shorthand: registered for parsing/expansion, but excluded from serialization
+        // reconstruction (see the _logicalShorthands field comment).
+        private void AddLogicalShorthand(string name, ShorthandCreator creator, params string[] longhands)
+        {
+            AddShorthand(name, creator, longhands);
+            _logicalShorthands.Add(name);
+        }
+
+        private void AddLonghand(string name, LonghandCreator creator, bool animatable = false, bool font = false)
+        {
+            _longhandsBuilder.Add(name, creator);
+
+            if (animatable) _animatables.Add(name);
+
+            if (font) _fontsBuilder.Add(name, creator);
+        }
+
+        public Property Create(string name)
+        {
+            return CreateLonghand(name) ?? CreateShorthand(name) ?? CreateCustomProperty(name);
+        }
+
+        private static Property CreateCustomProperty(string name)
+        {
+            return IsCustomPropertyName(name) ? new CustomProperty(name) : null;
+        }
+
+        internal static bool IsCustomPropertyName(string name)
+        {
+            return name != null && name.Length > 2 && name[0] == '-' && name[1] == '-';
+        }
+
+        public Property CreateFont(string name)
+        {
+            return _fonts.TryGetValue(name, out var propertyCreator) ? propertyCreator() : null;
+        }
+
+        public Property CreatePropertyDescriptor(string name)
+        {
+            return _propertyDescriptors.TryGetValue(name, out var propertyCreator) ? propertyCreator() : null;
+        }
+
+        public Property CreateFontPaletteDescriptor(string name)
+        {
+            return _fontPaletteDescriptors.TryGetValue(name, out var propertyCreator) ? propertyCreator() : null;
+        }
+
+        public Property CreateViewport(string name)
+        {
+            var feature = MediaFeatureFactory.Instance.Create(name);
+
+            return feature != null ? new FeatureProperty(feature) : null;
+        }
+
+        public Property CreateLonghand(string name)
+        {
+            return _longhands.TryGetValue(name, out var createProperty) ? createProperty() : null;
+        }
+
+        public ShorthandProperty CreateShorthand(string name)
+        {
+            return _shorthands.TryGetValue(name, out var propertyCreator) ? propertyCreator() : null;
+        }
+
+        public Property[] CreateLonghandsFor(string name)
+        {
+            var propertyNames = GetLonghands(name);
+
+            return propertyNames.Select(CreateLonghand).ToArray();
+        }
+
+        public bool IsShorthand(string name)
+        {
+            return _shorthands.ContainsKey(name);
+        }
+
+        public bool IsAnimatable(string name)
+        {
+            return _longhands.ContainsKey(name)
+                ? _animatables.Contains(name)
+                : GetLonghands(name).Any(_ => _animatables.Contains(name));
+        }
+
+        public string[] GetLonghands(string name)
+        {
+            return _mappings.TryGetValue(name, out var mapping)
+                ? mapping
+                : Array.Empty<string>();
+        }
+
+        public IEnumerable<string> GetShorthands(string name)
+        {
+            return from mapping in _mappings
+                   where !_logicalShorthands.Contains(mapping.Key)
+                         && mapping.Value.Contains(name, StringComparison.OrdinalIgnoreCase)
+                   select mapping.Key;
+        }
+
+        private delegate Property LonghandCreator();
+
+        private delegate ShorthandProperty ShorthandCreator();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Factories/PseudoClassSelectorFactory.cs b/Source/HtmlRenderer/Core/CssEngine/Factories/PseudoClassSelectorFactory.cs
new file mode 100644
index 000000000..30a454772
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Factories/PseudoClassSelectorFactory.cs
@@ -0,0 +1,84 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PseudoClassSelectorFactory
+    {
+        private static readonly Lazy<PseudoClassSelectorFactory> Lazy =
+            new Lazy<PseudoClassSelectorFactory>(() => new PseudoClassSelectorFactory());
+
+        #region Selectors
+
+        private static Dictionary<string, ISelector> BuildSelectors()
+        {
+            var selectors = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+                {
+                    PseudoClassNames.Root,
+                    PseudoClassNames.Scope,
+                    PseudoClassNames.Empty,
+                    PseudoClassNames.AnyLink,
+                    PseudoClassNames.Link,
+                    PseudoClassNames.Visited,
+                    PseudoClassNames.Active,
+                    PseudoClassNames.Hover,
+                    PseudoClassNames.Focus,
+                    PseudoClassNames.FocusVisible,
+                    PseudoClassNames.FocusWithin,
+                    PseudoClassNames.Target,
+                    PseudoClassNames.Enabled,
+                    PseudoClassNames.Disabled,
+                    PseudoClassNames.Default,
+                    PseudoClassNames.Checked,
+                    PseudoClassNames.Indeterminate,
+                    PseudoClassNames.PlaceholderShown,
+                    PseudoClassNames.Unchecked,
+                    PseudoClassNames.Valid,
+                    PseudoClassNames.Invalid,
+                    PseudoClassNames.Required,
+                    PseudoClassNames.ReadOnly,
+                    PseudoClassNames.ReadWrite,
+                    PseudoClassNames.InRange,
+                    PseudoClassNames.OutOfRange,
+                    PseudoClassNames.Optional,
+                    PseudoClassNames.Shadow,
+                }
+                .ToDictionary(x => x, PseudoClassSelector.Create);
+
+            selectors.Add(PseudoElementNames.Before,
+                PseudoElementSelectorFactory.Instance.Create(PseudoElementNames.Before));
+            selectors.Add(PseudoElementNames.After,
+                PseudoElementSelectorFactory.Instance.Create(PseudoElementNames.After));
+            selectors.Add(PseudoElementNames.FirstLine,
+                PseudoElementSelectorFactory.Instance.Create(PseudoElementNames.FirstLine));
+            selectors.Add(PseudoElementNames.FirstLetter,
+                PseudoElementSelectorFactory.Instance.Create(PseudoElementNames.FirstLetter));
+
+            // Structural pseudo-classes: bare idents are equivalent to their nth-*(1) function form
+            // (see CSS Selectors spec), so wire them to the same ChildSelector subtypes that
+            // "nth-child(...)" etc. produce, rather than a generic PseudoClassSelector with no
+            // positional semantics. Kind uses AllSelector.Create() (never null) to match the
+            // invariant ChildFunctionState<T>.Produce() upholds for the function-form parse path.
+            selectors.Add(PseudoClassNames.FirstChild, new FirstChildSelector().With(0, 1, AllSelector.Create()));
+            selectors.Add(PseudoClassNames.LastChild, new LastChildSelector().With(0, 1, AllSelector.Create()));
+            selectors.Add(PseudoClassNames.FirstOfType, new FirstTypeSelector().With(0, 1, AllSelector.Create()));
+            selectors.Add(PseudoClassNames.LastOfType, new LastTypeSelector().With(0, 1, AllSelector.Create()));
+            selectors.Add(PseudoClassNames.OnlyChild, new OnlyChildSelector());
+            selectors.Add(PseudoClassNames.OnlyType, new OnlyOfTypeSelector());
+
+            return selectors;
+        }
+
+        private static readonly Dictionary<string, ISelector> Selectors = BuildSelectors();
+
+        #endregion
+
+        internal static PseudoClassSelectorFactory Instance => Lazy.Value;
+
+        public ISelector Create(string name)
+        {
+            return Selectors.TryGetValue(name, out var selector) ? selector : null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Factories/PseudoElementSelectorFactory.cs b/Source/HtmlRenderer/Core/CssEngine/Factories/PseudoElementSelectorFactory.cs
new file mode 100644
index 000000000..46dc7947e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Factories/PseudoElementSelectorFactory.cs
@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PseudoElementSelectorFactory
+    {
+        private static readonly Lazy<PseudoElementSelectorFactory> Lazy =
+            new Lazy<PseudoElementSelectorFactory>(() => new PseudoElementSelectorFactory());
+
+        private readonly StylesheetParser _parser;
+
+        #region Selectors
+
+        private readonly Dictionary<string, ISelector> _selectors =
+            new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+                {
+                    //TODO some lack implementation (selection, content, ...)
+                    // some implementations are dubious (first-line, first-letter, ...)
+                    PseudoElementNames.Before,
+                    PseudoElementNames.After,
+                    PseudoElementNames.Marker,
+                    PseudoElementNames.Selection,
+                    PseudoElementNames.FirstLine,
+                    PseudoElementNames.FirstLetter,
+                    PseudoElementNames.Content,
+                }
+                .ToDictionary(x => x, PseudoElementSelector.Create)
+                ;
+
+        #endregion
+
+        internal PseudoElementSelectorFactory(StylesheetParser parser = null)
+        {
+            _parser = parser;
+        }
+
+        internal static PseudoElementSelectorFactory Instance => Lazy.Value;
+
+        public ISelector Create(string name)
+        {
+            return _selectors.TryGetValue(name, out var selector) ? selector :
+                ((_parser?.Options.AllowInvalidSelectors ?? false) ?
+                PseudoElementSelector.Create(name) : null);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Formatting/CompressedStyleFormatter.cs b/Source/HtmlRenderer/Core/CssEngine/Formatting/CompressedStyleFormatter.cs
new file mode 100644
index 000000000..0bc6be3e7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Formatting/CompressedStyleFormatter.cs
@@ -0,0 +1,123 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class CompressedStyleFormatter : IStyleFormatter
+    {
+        public static readonly IStyleFormatter Instance = new CompressedStyleFormatter();
+
+        string IStyleFormatter.Declaration(string name, string value, bool important)
+        {
+            var rest = string.Concat(value, important ? " !important" : string.Empty);
+            return string.Concat(name, ": ", rest);
+        }
+
+        string IStyleFormatter.Constraint(string name, string value, string constraintDelimiter)
+        {
+            var ending = value != null ? constraintDelimiter + value : string.Empty;
+            return string.Concat("(", name, ending, ")");
+        }
+
+        string IStyleFormatter.Rule(string name, string value)
+        {
+            return string.Concat(name, " ", value, ";");
+        }
+
+        string IStyleFormatter.Rule(string name, string prelude, string rules)
+        {
+            var text = string.IsNullOrEmpty(prelude) ? string.Empty : prelude + " ";
+            return string.Concat(name, " ", text, rules);
+        }
+
+        string IStyleFormatter.Style(string selector, IStyleFormattable rules)
+        {
+            var sb = Pool.NewStringBuilder().Append(selector).Append(" { ");
+            var length = sb.Length;
+            using (var writer = new StringWriter(sb))
+            {
+                rules.ToCss(writer, this);
+            }
+
+            if (sb.Length > length) sb.Append(' ');
+            return sb.Append('}').ToPool();
+        }
+
+        string IStyleFormatter.Comment(string data)
+        {
+            return string.Join("/* ", data, " */");
+        }
+
+        string IStyleFormatter.Sheet(IEnumerable<IStyleFormattable> rules)
+        {
+            var sb = Pool.NewStringBuilder();
+            WriteJoined(sb, rules, Environment.NewLine);
+            return sb.ToPool();
+        }
+
+        string IStyleFormatter.Block(IEnumerable<IStyleFormattable> rules)
+        {
+            var sb = Pool.NewStringBuilder().Append('{');
+            using (var writer = new StringWriter(sb))
+            {
+                foreach (var rule in rules)
+                {
+                    writer.Write(' ');
+                    rule.ToCss(writer, this);
+                }
+            }
+
+            return sb.Append(' ').Append('}').ToPool();
+        }
+
+        string IStyleFormatter.Declarations(IEnumerable<string> declarations)
+        {
+            return string.Join("; ", declarations);
+        }
+
+        string IStyleFormatter.Medium(bool exclusive,
+            bool inverse,
+            string type,
+            IEnumerable<IStyleFormattable> constraints)
+        {
+            var sb = Pool.NewStringBuilder();
+            var first = true;
+            if (exclusive)
+                sb.Append("only ");
+            else if (inverse) sb.Append("not ");
+
+            if (!string.IsNullOrEmpty(type))
+            {
+                sb.Append(type);
+                first = false;
+            }
+
+            WriteJoined(sb, constraints, " and ", first);
+            return sb.ToPool();
+        }
+
+        private void WriteJoined(StringBuilder sb,
+            IEnumerable<IStyleFormattable> elements,
+            string separator,
+            bool first = true)
+        {
+            using(var writer = new StringWriter(sb)){
+                foreach (var element in elements)
+                {
+                    if (first)
+                    {
+                        first = false;
+                    }
+                    else
+                    {
+                        writer.Write(separator);
+                    }
+
+                    element.ToCss(writer, this);
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Functions/DocumentFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Functions/DocumentFunction.cs
new file mode 100644
index 000000000..78bcf0edf
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Functions/DocumentFunction.cs
@@ -0,0 +1,23 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class DocumentFunction : StylesheetNode, IDocumentFunction
+    {
+        internal DocumentFunction(string name, string data)
+        {
+            Name = name;
+            Data = data;
+        }
+
+        public string Name { get; }
+        public string Data { get; }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(Name.StylesheetFunction(Data.StylesheetString()));
+        }
+
+        public abstract bool Matches(Url url);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Functions/DomainFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Functions/DomainFunction.cs
new file mode 100644
index 000000000..5a2ec496d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Functions/DomainFunction.cs
@@ -0,0 +1,20 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DomainFunction : DocumentFunction
+    {
+        private readonly string _subdomain;
+
+        public DomainFunction(string url) : base(FunctionNames.Domain, url)
+        {
+            _subdomain = "." + url;
+        }
+
+        public override bool Matches(Url url)
+        {
+            var domain = url.HostName;
+            return domain.Isi(Data) || domain.EndsWith(_subdomain, StringComparison.OrdinalIgnoreCase);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Functions/IConditionFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Functions/IConditionFunction.cs
new file mode 100644
index 000000000..cdbc55908
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Functions/IConditionFunction.cs
@@ -0,0 +1,7 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IConditionFunction : IStylesheetNode
+    {
+        bool Check();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Functions/IDocumentFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Functions/IDocumentFunction.cs
new file mode 100644
index 000000000..f78c8c888
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Functions/IDocumentFunction.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IDocumentFunction : IStylesheetNode
+    {
+        string Name { get; }
+        string Data { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Functions/RegexpFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Functions/RegexpFunction.cs
new file mode 100644
index 000000000..cfe6b9194
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Functions/RegexpFunction.cs
@@ -0,0 +1,19 @@
+using System.Text.RegularExpressions;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RegexpFunction : DocumentFunction
+    {
+        private readonly Regex _regex;
+
+        public RegexpFunction(string url) : base(FunctionNames.Regexp, url)
+        {
+            _regex = new Regex(url, RegexOptions.ECMAScript | RegexOptions.CultureInvariant);
+        }
+
+        public override bool Matches(Url url)
+        {
+            return _regex.IsMatch(url.Href);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Functions/UrlFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Functions/UrlFunction.cs
new file mode 100644
index 000000000..67d42898f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Functions/UrlFunction.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UrlFunction : DocumentFunction
+    {
+        private readonly Url _expected;
+
+        public UrlFunction(string url) : base(FunctionNames.Url, url)
+        {
+            _expected = Url.Create(Data);
+        }
+
+        public override bool Matches(Url actual)
+        {
+            return !_expected.IsInvalid && _expected.Equals(actual);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Functions/UrlPrefixFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Functions/UrlPrefixFunction.cs
new file mode 100644
index 000000000..c409491a1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Functions/UrlPrefixFunction.cs
@@ -0,0 +1,16 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UrlPrefixFunction : DocumentFunction
+    {
+        public UrlPrefixFunction(string url) : base(FunctionNames.UrlPrefix, url)
+        {
+        }
+
+        public override bool Matches(Url url)
+        {
+            return url.Href.StartsWith(Data, StringComparison.OrdinalIgnoreCase);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/GridLineGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/GridLineGrammar.cs
new file mode 100644
index 000000000..70682250f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/GridLineGrammar.cs
@@ -0,0 +1,83 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// A parsed grid <c>&lt;grid-line&gt;</c> (one edge of <c>grid-column</c>/<c>grid-row</c>/<c>grid-area</c>):
+    /// <c>auto</c>, an integer line number (may be negative — counting from the end edge), <c>span N</c>, or
+    /// a named line reference (a bare <c>&lt;custom-ident&gt;</c>, or <c>&lt;custom-ident&gt; &lt;integer&gt;</c>
+    /// for the Nth line with that name). <c>span &lt;custom-ident&gt;</c> is out of v1 scope.
+    /// </summary>
+    internal sealed class GridLine
+    {
+        public bool IsAuto { get; private set; }
+        public bool IsSpan { get; private set; }
+
+        /// <summary>The line number (for a line reference), the span count (when <see cref="IsSpan"/>), or
+        /// the 1-based Nth index for a named line (defaults to 1).</summary>
+        public int Value { get; private set; } = 1;
+
+        /// <summary>The custom-ident of a named line reference, or null when this is not a named line.</summary>
+        public string Name { get; private set; }
+
+        public static readonly GridLine Auto = new GridLine { IsAuto = true };
+        public static GridLine Span(int n) => new GridLine { IsSpan = true, Value = n };
+        public static GridLine Line(int n) => new GridLine { Value = n };
+        public static GridLine Named(string name) => new GridLine { Name = name, Value = 1 };
+        public static GridLine NamedNth(string name, int n) => new GridLine { Name = name, Value = n };
+    }
+
+    /// <summary>
+    /// Shared grammar for a single grid <c>&lt;grid-line&gt;</c> value. Used by Layer A (to validate the
+    /// <c>grid-column-start</c>/<c>-end</c>/<c>grid-row-start</c>/<c>-end</c> longhands) and by Layer B (the
+    /// grid placement engine).
+    /// </summary>
+    internal static class GridLineGrammar
+    {
+        internal static GridLine TryParse(IReadOnlyList<Token> tokens)
+        {
+            var toks = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            if (toks.Length == 0) return null;
+
+            // auto
+            if (toks.Length == 1 && toks[0].Type == TokenType.Ident && toks[0].Data.Isi(Keywords.Auto))
+                return GridLine.Auto;
+
+            // <integer>
+            if (toks.Length == 1 && toks[0] is NumberToken number && number.IsInteger && number.IntegerValue != 0)
+                return GridLine.Line(number.IntegerValue);
+
+            // span <integer [1,∞]>
+            if (toks.Length == 2 && toks[0].Type == TokenType.Ident && toks[0].Data.Isi(Keywords.Span)
+                && toks[1] is NumberToken spanCount && spanCount.IsInteger && spanCount.IntegerValue >= 1)
+                return GridLine.Span(spanCount.IntegerValue);
+
+            // <custom-ident> — a named line reference.
+            if (toks.Length == 1 && IsCustomIdent(toks[0]))
+                return GridLine.Named(toks[0].Data);
+
+            // <custom-ident> <integer> / <integer> <custom-ident> — the Nth line with that name (order-independent).
+            if (toks.Length == 2)
+            {
+                if (IsCustomIdent(toks[0]) && toks[1] is NumberToken n1 && n1.IsInteger && n1.IntegerValue != 0)
+                    return GridLine.NamedNth(toks[0].Data, n1.IntegerValue);
+                if (IsCustomIdent(toks[1]) && toks[0] is NumberToken n2 && n2.IsInteger && n2.IntegerValue != 0)
+                    return GridLine.NamedNth(toks[1].Data, n2.IntegerValue);
+            }
+
+            return null;
+        }
+
+        /// <summary>Whether the token is a <c>&lt;custom-ident&gt;</c> usable as a grid line name — an ident
+        /// that is not one of the reserved keywords a grid-line value or the CSS-wide keywords may take.</summary>
+        private static bool IsCustomIdent(Token token)
+        {
+            if (token.Type != TokenType.Ident) return false;
+            var d = token.Data;
+            return !d.Isi(Keywords.Auto) && !d.Isi(Keywords.Span) && !d.Isi(Keywords.None)
+                && !d.Isi(Keywords.Inherit) && !d.Isi(Keywords.Initial) && !d.Isi(Keywords.Unset)
+                && !d.Isi(Keywords.Revert) && !d.Isi(Keywords.RevertLayer) && !d.Isi("default");
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/GridTemplateAreasGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/GridTemplateAreasGrammar.cs
new file mode 100644
index 000000000..d03e444c7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/GridTemplateAreasGrammar.cs
@@ -0,0 +1,94 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// A parsed <c>grid-template-areas</c> value (CSS Grid §7.3): a rectangular grid of named cells. Each
+    /// named area's 0-based inclusive bounding rectangle is recorded; a <c>.</c> (or a run of only dots) is
+    /// an unnamed empty cell.
+    /// </summary>
+    internal sealed class GridAreas
+    {
+        public int RowCount { get; set; }
+        public int ColCount { get; set; }
+
+        /// <summary>The area name at each cell (<c>[row, col]</c>), or null for an empty <c>.</c> cell.</summary>
+        public string[,] Cells { get; set; }
+
+        /// <summary>Each named area's 0-based inclusive rectangle (rowStart, colStart, rowEnd, colEnd).</summary>
+        public IReadOnlyDictionary<string, (int R1, int C1, int R2, int C2)> Areas { get; set; }
+    }
+
+    /// <summary>
+    /// Shared grammar for a <c>grid-template-areas</c> value (a series of quoted strings). Used by Layer A
+    /// (accept/reject) and Layer B (the engine derives implicit <c>name-start</c>/<c>name-end</c> lines).
+    /// Returns null for anything invalid — including the <c>none</c> keyword, which the property accepts
+    /// separately.
+    /// </summary>
+    internal static class GridTemplateAreasGrammar
+    {
+        internal static GridAreas TryParse(IReadOnlyList<Token> tokens)
+        {
+            var toks = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            if (toks.Length == 0) return null;
+
+            // Every token must be a string; each string is one row.
+            if (toks.Any(t => t.Type != TokenType.String)) return null;
+
+            var rows = new List<string[]>(toks.Length);
+            int colCount = -1;
+            foreach (var t in toks)
+            {
+                var cells = ((StringToken)t).Data
+                    .Split((char[])null, System.StringSplitOptions.RemoveEmptyEntries);
+                if (cells.Length == 0) return null;          // an empty string is invalid
+                if (colCount < 0) colCount = cells.Length;
+                else if (cells.Length != colCount) return null; // ragged rows are invalid
+
+                var normalized = new string[colCount];
+                for (var c = 0; c < colCount; c++)
+                {
+                    if (IsEmptyCell(cells[c])) { normalized[c] = null; continue; }
+                    // A named cell is a <custom-ident> — a null token (a mixed "a.b" is invalid, not a name).
+                    if (cells[c].Contains('.')) return null;
+                    normalized[c] = cells[c];
+                }
+                rows.Add(normalized);
+            }
+
+            var rowCount = rows.Count;
+            var grid = new string[rowCount, colCount];
+            var bounds = new Dictionary<string, (int R1, int C1, int R2, int C2)>();
+
+            for (var r = 0; r < rowCount; r++)
+                for (var c = 0; c < colCount; c++)
+                {
+                    var name = rows[r][c];
+                    grid[r, c] = name;
+                    if (name is null) continue;
+                    if (bounds.TryGetValue(name, out var b))
+                        bounds[name] = (System.Math.Min(b.R1, r), System.Math.Min(b.C1, c),
+                                        System.Math.Max(b.R2, r), System.Math.Max(b.C2, c));
+                    else
+                        bounds[name] = (r, c, r, c);
+                }
+
+            // Each named area must be a single filled rectangle: every cell in its bounding box carries the
+            // name (which also guarantees no cell with the name lies outside the box).
+            foreach (var entry in bounds)
+            {
+                var name = entry.Key;
+                var b = entry.Value;
+                for (var r = b.R1; r <= b.R2; r++)
+                    for (var c = b.C1; c <= b.C2; c++)
+                        if (grid[r, c] != name) return null;
+            }
+
+            return new GridAreas { RowCount = rowCount, ColCount = colCount, Cells = grid, Areas = bounds };
+        }
+
+        /// <summary>A cell of only U+002E FULL STOP characters (<c>.</c>, <c>...</c>) is an empty cell.</summary>
+        private static bool IsEmptyCell(string cell) => cell.All(ch => ch == '.');
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/GridTrackListGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/GridTrackListGrammar.cs
new file mode 100644
index 000000000..c344d1a6c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/GridTrackListGrammar.cs
@@ -0,0 +1,428 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The kind of a single grid <c>&lt;track-size&gt;</c>/<c>&lt;track-breadth&gt;</c>
+    /// (CSS Grid Layout Module Level 1/2 §7.2).</summary>
+    internal enum GridTrackKind
+    {
+        Length,       // a <length> (raw component string in Value, resolved by Layer B ParseLength)
+        Percent,      // a <percentage> (raw component string in Value)
+        Flex,         // a <flex> / fr value (Flex holds the fr number)
+        Auto,
+        MinContent,
+        MaxContent,
+        FitContent,   // fit-content(<length-percentage>) — the argument is in Value
+        Minmax        // minmax(Min, Max)
+    }
+
+    /// <summary>Which flavour of layout-time <c>repeat()</c> a template carries (CSS Grid §7.2.3.2).</summary>
+    internal enum GridAutoRepeatKind { None, AutoFill, AutoFit }
+
+    /// <summary>
+    /// A single grid <c>&lt;track-size&gt;</c>. Fixed/percentage/fit-content values keep their authored
+    /// component string (<see cref="Value"/>) for Layer B to resolve against the container; <c>fr</c> keeps
+    /// its numeric factor (<see cref="Flex"/>); <c>minmax()</c> keeps its two sub-breadths.
+    /// </summary>
+    internal sealed class GridTrackSize
+    {
+        public GridTrackKind Kind { get; private set; }
+        public string Value { get; private set; }
+        public double Flex { get; private set; }
+        public GridTrackSize Min { get; private set; }
+        public GridTrackSize Max { get; private set; }
+
+        public static GridTrackSize Length(string v) => new GridTrackSize { Kind = GridTrackKind.Length, Value = v };
+        public static GridTrackSize Percent(string v) => new GridTrackSize { Kind = GridTrackKind.Percent, Value = v };
+        public static GridTrackSize FlexFactor(double fr) => new GridTrackSize { Kind = GridTrackKind.Flex, Flex = fr };
+        public static readonly GridTrackSize Auto = new GridTrackSize { Kind = GridTrackKind.Auto };
+        public static readonly GridTrackSize MinContent = new GridTrackSize { Kind = GridTrackKind.MinContent };
+        public static readonly GridTrackSize MaxContent = new GridTrackSize { Kind = GridTrackKind.MaxContent };
+        public static GridTrackSize FitContentTo(string v) => new GridTrackSize { Kind = GridTrackKind.FitContent, Value = v };
+        public static GridTrackSize Minmax(GridTrackSize min, GridTrackSize max) => new GridTrackSize { Kind = GridTrackKind.Minmax, Min = min, Max = max };
+    }
+
+    /// <summary>
+    /// A parsed <c>grid-template-columns</c>/<c>grid-template-rows</c> value: the fixed (fully
+    /// <c>repeat(N,…)</c>-expanded) tracks, plus at most one layout-time <c>repeat(auto-fill|auto-fit,…)</c>
+    /// section recorded as an insertion point since its count is resolved during layout.
+    /// </summary>
+    internal sealed class GridTemplate
+    {
+        /// <summary>The fixed tracks (with the auto-repeat section, if any, NOT included here — it is
+        /// spliced in at <see cref="AutoRepeatInsertIndex"/> at layout time).</summary>
+        public IReadOnlyList<GridTrackSize> Tracks { get; set; } = new List<GridTrackSize>();
+
+        public GridAutoRepeatKind AutoRepeat { get; set; } = GridAutoRepeatKind.None;
+
+        /// <summary>The repeated track template for an <c>auto-fill</c>/<c>auto-fit</c> section.</summary>
+        public IReadOnlyList<GridTrackSize> AutoRepeatTracks { get; set; }
+
+        /// <summary>The index into <see cref="Tracks"/> at which the auto-repeat section is inserted.</summary>
+        public int AutoRepeatInsertIndex { get; set; }
+
+        /// <summary>Named lines declared with <c>[name]</c> in the top-level track list: name → the sorted,
+        /// deduped 1-based line numbers it labels (line 1 is before the first track). Empty when none.</summary>
+        public IReadOnlyDictionary<string, IReadOnlyList<int>> LineNames { get; set; }
+            = new Dictionary<string, IReadOnlyList<int>>();
+
+        /// <summary>The <c>subgrid</c> keyword (CSS Grid Layout Module Level 2 §9): this axis adopts the parent
+        /// grid's tracks instead of defining its own. A subgrid template carries no <see cref="Tracks"/> — only
+        /// any explicit <c>[name]</c> line names declared after the keyword (in <see cref="LineNames"/>).</summary>
+        public bool IsSubgrid { get; set; }
+
+        public bool IsNone => !IsSubgrid && Tracks.Count == 0 && AutoRepeat == GridAutoRepeatKind.None;
+    }
+
+    /// <summary>
+    /// Shared grammar for the grid <c>&lt;track-list&gt;</c> (<c>grid-template-columns</c>/
+    /// <c>grid-template-rows</c>) and <c>&lt;track-size&gt;+</c> (<c>grid-auto-columns</c>/
+    /// <c>grid-auto-rows</c>). Used by both Layer A (accept/reject at parse) and Layer B (compute used
+    /// tracks during layout), so the grammar is defined once — the <see cref="AspectRatioGrammar"/>/
+    /// <see cref="BasicShapeGrammar"/> precedent. Top-level named lines (<c>[name]</c>) are collected into
+    /// <see cref="GridTemplate.LineNames"/>; named lines inside <c>repeat()</c> are out of scope and
+    /// rejected.
+    /// </summary>
+    internal static class GridTrackListGrammar
+    {
+        /// <summary>
+        /// Parses a <c>&lt;track-list&gt;</c> (the <c>grid-template-columns</c>/<c>-rows</c> value). Returns
+        /// null when the value is not a valid track list — <b>including the literal <c>none</c></b>, which
+        /// the property accepts separately.
+        /// </summary>
+        internal static GridTemplate TryParse(IReadOnlyList<Token> tokens)
+        {
+            var toks = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            if (toks.Length == 0) return null;
+
+            // subgrid (CSS Grid Level 2 §9): the axis adopts the parent grid's tracks. The keyword may be
+            // followed by an optional <line-name-list> ([name] groups only; repeat() of line names is a v1
+            // deferral, mirroring the "named lines inside repeat()" restriction below). No <track-size> is
+            // allowed after subgrid.
+            if (toks[0].Type == TokenType.Ident && toks[0].Data.Isi(Keywords.Subgrid))
+                return TryParseSubgrid(toks);
+
+            var fixedTracks = new List<GridTrackSize>();
+            var autoRepeat = GridAutoRepeatKind.None;
+            List<GridTrackSize> autoRepeatTracks = null;
+            var autoRepeatIndex = -1;
+            var lineNames = new Dictionary<string, SortedSet<int>>();
+
+            var i = 0;
+            while (i < toks.Length)
+            {
+                // [name …] — one or more named lines at the current line position (1-based; line 1 is before
+                // the first track). Whitespace is already stripped, so the bracket group is contiguous.
+                if (toks[i].Type == TokenType.SquareBracketOpen)
+                {
+                    var lineIndex = fixedTracks.Count + 1;
+                    i++;
+                    while (i < toks.Length && toks[i].Type != TokenType.SquareBracketClose)
+                    {
+                        if (toks[i].Type != TokenType.Ident) return null; // only idents inside [ ]
+                        var name = toks[i].Data;
+                        if (!lineNames.TryGetValue(name, out var set))
+                            lineNames[name] = set = new SortedSet<int>();
+                        set.Add(lineIndex);
+                        i++;
+                    }
+                    if (i >= toks.Length) return null; // unclosed [
+                    i++; // consume ]
+                    continue;
+                }
+
+                if (toks[i] is FunctionToken fn && fn.Data.Isi(FunctionNames.Repeat))
+                {
+                    if (!TryParseRepeat(fn, out var repeatKind, out var repeatTracks)) return null;
+
+                    if (repeatKind == GridAutoRepeatKind.None)
+                    {
+                        // repeat(N, …) — expand inline.
+                        fixedTracks.AddRange(repeatTracks);
+                    }
+                    else
+                    {
+                        // repeat(auto-fill|auto-fit, …) — at most one per track list.
+                        if (autoRepeat != GridAutoRepeatKind.None) return null;
+                        autoRepeat = repeatKind;
+                        autoRepeatTracks = repeatTracks;
+                        autoRepeatIndex = fixedTracks.Count;
+                    }
+
+                    i++;
+                    continue;
+                }
+
+                if (!TryParseTrackSize(toks[i], out var track)) return null;
+                fixedTracks.Add(track);
+                i++;
+            }
+
+            if (fixedTracks.Count == 0 && autoRepeat == GridAutoRepeatKind.None) return null;
+
+            return new GridTemplate
+            {
+                Tracks = fixedTracks,
+                AutoRepeat = autoRepeat,
+                AutoRepeatTracks = autoRepeatTracks,
+                AutoRepeatInsertIndex = autoRepeatIndex < 0 ? 0 : autoRepeatIndex,
+                LineNames = lineNames.ToDictionary(
+                    kv => kv.Key,
+                    kv => (IReadOnlyList<int>)kv.Value.ToList())
+            };
+        }
+
+        /// <summary>
+        /// Parses a <c>subgrid [ &lt;line-name-list&gt; ]?</c> value (the leading <c>subgrid</c> ident already
+        /// matched by the caller). The optional line-name list is a run of <c>[name …]</c> bracket groups, one
+        /// group per grid line (line 1 is before the first adopted track); each group's names are recorded at
+        /// that 1-based line index. Anything else after <c>subgrid</c> (a track size, an unclosed/ill-formed
+        /// bracket, a non-ident inside <c>[ ]</c>) is invalid.
+        /// </summary>
+        private static GridTemplate TryParseSubgrid(Token[] toks)
+        {
+            var lineNames = new Dictionary<string, SortedSet<int>>();
+            var lineIndex = 1;
+            var i = 1; // skip the subgrid ident
+
+            while (i < toks.Length)
+            {
+                if (toks[i].Type != TokenType.SquareBracketOpen) return null; // only [name] groups may follow
+                i++;
+                while (i < toks.Length && toks[i].Type != TokenType.SquareBracketClose)
+                {
+                    if (toks[i].Type != TokenType.Ident) return null;
+                    var name = toks[i].Data;
+                    if (!lineNames.TryGetValue(name, out var set))
+                        lineNames[name] = set = new SortedSet<int>();
+                    set.Add(lineIndex);
+                    i++;
+                }
+                if (i >= toks.Length) return null; // unclosed [
+                i++; // consume ]
+                lineIndex++;
+            }
+
+            return new GridTemplate
+            {
+                IsSubgrid = true,
+                LineNames = lineNames.ToDictionary(
+                    kv => kv.Key,
+                    kv => (IReadOnlyList<int>)kv.Value.ToList())
+            };
+        }
+
+        /// <summary>
+        /// Parses a <c>&lt;track-size&gt;+</c> list (<c>grid-auto-columns</c>/<c>grid-auto-rows</c>) — one or
+        /// more track sizes, no <c>repeat()</c>. Returns null on any invalid token.
+        /// </summary>
+        internal static IReadOnlyList<GridTrackSize> TryParseTrackSizeList(IReadOnlyList<Token> tokens)
+        {
+            var toks = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            if (toks.Length == 0) return null;
+
+            var result = new List<GridTrackSize>();
+            foreach (var token in toks)
+            {
+                if (!TryParseTrackSize(token, out var track)) return null;
+                result.Add(track);
+            }
+
+            return result;
+        }
+
+        private static bool TryParseRepeat(FunctionToken fn, out GridAutoRepeatKind kind, out List<GridTrackSize> tracks)
+        {
+            kind = GridAutoRepeatKind.None;
+            tracks = null;
+
+            var args = fn.ArgumentTokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            var groups = SplitByComma(args);
+            if (groups.Count < 2) return false;
+
+            // First group is the repetition count: an integer, or auto-fill / auto-fit.
+            var first = groups[0];
+            if (first.Count != 1) return false;
+
+            var countTokens = 0;
+            if (IsIdent(first[0], Keywords.AutoFill)) kind = GridAutoRepeatKind.AutoFill;
+            else if (IsIdent(first[0], Keywords.AutoFit)) kind = GridAutoRepeatKind.AutoFit;
+            else if (first[0] is NumberToken n && n.IsInteger && n.IntegerValue >= 1) countTokens = n.IntegerValue;
+            else return false;
+
+            // Remaining groups are the repeated <track-size>s. (A repeat body may not itself contain a
+            // repeat(), which SplitByComma naturally enforces since a nested function is one token.)
+            var body = new List<GridTrackSize>();
+            for (var gi = 1; gi < groups.Count; gi++)
+            {
+                foreach (var token in groups[gi])
+                {
+                    if (!TryParseTrackSize(token, out var track)) return false;
+                    body.Add(track);
+                }
+            }
+
+            if (body.Count == 0) return false;
+
+            if (kind != GridAutoRepeatKind.None)
+            {
+                tracks = body;
+                return true;
+            }
+
+            // repeat(N, body) — expand N copies now.
+            tracks = new List<GridTrackSize>(body.Count * countTokens);
+            for (var r = 0; r < countTokens; r++)
+                tracks.AddRange(body);
+            return true;
+        }
+
+        private static bool TryParseTrackSize(Token token, out GridTrackSize track)
+        {
+            track = null;
+
+            // minmax(<inflexible-breadth>, <track-breadth>), fit-content(<length-percentage>), and a
+            // math function (calc()/min()/max()/clamp()) that resolves to a <length-percentage>.
+            if (token is FunctionToken fn)
+            {
+                if (fn.Data.Isi(FunctionNames.Minmax)) return TryParseMinmax(fn, out track);
+                if (fn.Data.Isi(FunctionNames.FitContent)) return TryParseFitContent(fn, out track);
+                if (IsLengthPercentageCalc(fn)) { track = GridTrackSize.Length(fn.ToValue()); return true; }
+                return false;
+            }
+
+            if (TryParseBreadth(token, out track)) return true;
+            return false;
+        }
+
+        private static bool TryParseBreadth(Token token, out GridTrackSize track)
+        {
+            track = null;
+
+            // A math function (calc()/min()/max()/clamp()) computes to a <length-percentage> at used-value
+            // time; keep its reconstructed text (Layer B ParseLength evaluates it). This lets a calc() be a
+            // track breadth anywhere a length/percentage is allowed — bare, and inside minmax()/repeat().
+            if (token is FunctionToken calc && IsLengthPercentageCalc(calc))
+            {
+                track = GridTrackSize.Length(calc.ToValue());
+                return true;
+            }
+
+            if (token.Type == TokenType.Ident)
+            {
+                if (token.Data.Isi(Keywords.Auto)) { track = GridTrackSize.Auto; return true; }
+                if (token.Data.Isi(Keywords.MinContent)) { track = GridTrackSize.MinContent; return true; }
+                if (token.Data.Isi(Keywords.MaxContent)) { track = GridTrackSize.MaxContent; return true; }
+                return false;
+            }
+
+            if (token.Type == TokenType.Percentage) { track = GridTrackSize.Percent(token.ToValue()); return true; }
+
+            if (token is UnitToken unit && token.Type == TokenType.Dimension)
+            {
+                if (unit.Unit.Isi("fr"))
+                {
+                    if (unit.Value < 0) return false;
+                    track = GridTrackSize.FlexFactor(unit.Value);
+                    return true;
+                }
+
+                // Any other dimension is a <length> — the raw string is resolved by Layer B ParseLength.
+                track = GridTrackSize.Length(token.ToValue());
+                return true;
+            }
+
+            // Unitless zero is a valid length.
+            var zero = token as NumberToken;
+            if (zero != null && zero.Value == 0f) { track = GridTrackSize.Length("0"); return true; }
+
+            return false;
+        }
+
+        private static bool TryParseMinmax(FunctionToken fn, out GridTrackSize track)
+        {
+            track = null;
+            var groups = SplitByComma(fn.ArgumentTokens.Where(t => t.Type != TokenType.Whitespace).ToArray());
+            if (groups.Count != 2 || groups[0].Count != 1 || groups[1].Count != 1) return false;
+
+            if (!TryParseBreadth(groups[0][0], out var min)) return false;
+            if (!TryParseBreadth(groups[1][0], out var max)) return false;
+
+            // The min of a minmax() is an <inflexible-breadth> — a flex value is invalid there.
+            if (min.Kind == GridTrackKind.Flex) return false;
+
+            track = GridTrackSize.Minmax(min, max);
+            return true;
+        }
+
+        private static bool TryParseFitContent(FunctionToken fn, out GridTrackSize track)
+        {
+            track = null;
+            var args = fn.ArgumentTokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            if (args.Length != 1) return false;
+
+            // fit-content(<length-percentage>).
+            var arg = args[0];
+            if (arg.Type == TokenType.Percentage) { track = GridTrackSize.FitContentTo(arg.ToValue()); return true; }
+            if (arg is UnitToken && arg.Type == TokenType.Dimension && !((UnitToken)arg).Unit.Isi("fr"))
+            {
+                track = GridTrackSize.FitContentTo(arg.ToValue());
+                return true;
+            }
+            var zeroArg = arg as NumberToken;
+            if (zeroArg != null && zeroArg.Value == 0f) { track = GridTrackSize.FitContentTo("0"); return true; }
+            var calc = arg as FunctionToken;
+            if (calc != null && IsLengthPercentageCalc(calc))
+            {
+                track = GridTrackSize.FitContentTo(calc.ToValue());
+                return true;
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Whether <paramref name="fn"/> is a math function (<c>calc()</c>/<c>min()</c>/<c>max()</c>/
+        /// <c>clamp()</c>) that resolves to a <c>&lt;length-percentage&gt;</c>. Validated at parse time
+        /// (mirroring <see cref="BasicShapeGrammar"/>'s calc handling) so a wrong-category math function
+        /// (e.g. an angle) drops the whole track list rather than silently resolving to 0 during layout;
+        /// its reconstructed text is resolved by Layer B <c>ParseLength</c>.
+        /// </summary>
+        private static bool IsLengthPercentageCalc(FunctionToken fn)
+        {
+            if (!CalcParser.IsCalcFamily(fn.Data)) return false;
+
+            var node = CalcParser.Parse(fn);
+            if (node == null) return false;
+
+            var category = CalcTypeChecker.Check(node);
+            return category == CalcCategory.Length
+                || category == CalcCategory.Percentage
+                || category == CalcCategory.LengthPercentage;
+        }
+
+        private static bool IsIdent(Token token, string keyword) =>
+            token.Type == TokenType.Ident && token.Data.Isi(keyword);
+
+        private static List<List<Token>> SplitByComma(IReadOnlyList<Token> tokens)
+        {
+            var groups = new List<List<Token>>();
+            var current = new List<Token>();
+            foreach (var token in tokens)
+            {
+                if (token.Type == TokenType.Comma)
+                {
+                    groups.Add(current);
+                    current = new List<Token>();
+                }
+                else
+                {
+                    current.Add(token);
+                }
+            }
+            groups.Add(current);
+            return groups;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AnyHoverMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AnyHoverMediaFeature.cs
new file mode 100644
index 000000000..a58ee27a0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AnyHoverMediaFeature.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>any-hover</c> media feature (Media Queries 4). Matched against the renderer's fixed
+    /// <c>none</c> stance (a static PDF has no hover-capable input) in <c>MediaQueryMatcher</c>.
+    /// </summary>
+    internal sealed class AnyHoverMediaFeature : MediaFeature
+    {
+        public AnyHoverMediaFeature() : base(FeatureNames.AnyHover)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AnyPointerMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AnyPointerMediaFeature.cs
new file mode 100644
index 000000000..576e2c3c5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AnyPointerMediaFeature.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>any-pointer</c> media feature (Media Queries 4). Matched against the renderer's fixed
+    /// <c>none</c> stance (a static PDF has no pointing device) in <c>MediaQueryMatcher</c>.
+    /// </summary>
+    internal sealed class AnyPointerMediaFeature : MediaFeature
+    {
+        public AnyPointerMediaFeature() : base(FeatureNames.AnyPointer)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AspectRatioMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AspectRatioMediaFeature.cs
new file mode 100644
index 000000000..aef492a50
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/AspectRatioMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AspectRatioMediaFeature : MediaFeature
+    {
+        public AspectRatioMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.RatioConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ColorIndexMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ColorIndexMediaFeature.cs
new file mode 100644
index 000000000..16de94bcb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ColorIndexMediaFeature.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class ColorIndexMediaFeature : MediaFeature
+    {
+        public ColorIndexMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter =>
+            IsMinimum || IsMaximum
+                ? NaturalIntegerConverter
+                : NaturalIntegerConverter.Option(1);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ColorMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ColorMediaFeature.cs
new file mode 100644
index 000000000..e089f4352
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ColorMediaFeature.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class ColorMediaFeature : MediaFeature
+    {
+        public ColorMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter =>
+            IsMinimum || IsMaximum
+                ? PositiveIntegerConverter
+                : PositiveIntegerConverter.Option(1);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceAspectRatioMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceAspectRatioMediaFeature.cs
new file mode 100644
index 000000000..32267dca9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceAspectRatioMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DeviceAspectRatioMediaFeature : MediaFeature
+    {
+        public DeviceAspectRatioMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.RatioConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceHeightMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceHeightMediaFeature.cs
new file mode 100644
index 000000000..c45731873
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceHeightMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DeviceHeightMediaFeature : MediaFeature
+    {
+        public DeviceHeightMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.LengthConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DevicePixelRatioFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DevicePixelRatioFeature.cs
new file mode 100644
index 000000000..426968859
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DevicePixelRatioFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DevicePixelRatioFeature : MediaFeature
+    {
+        public DevicePixelRatioFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.NaturalNumberConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceWidthMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceWidthMediaFeature.cs
new file mode 100644
index 000000000..7e18f071b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/DeviceWidthMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DeviceWidthMediaFeature : MediaFeature
+    {
+        public DeviceWidthMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.LengthConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/GridMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/GridMediaFeature.cs
new file mode 100644
index 000000000..b8b22fe72
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/GridMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class GridMediaFeature : MediaFeature
+    {
+        public GridMediaFeature() : base(FeatureNames.Grid)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.BinaryConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/HeightMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/HeightMediaFeature.cs
new file mode 100644
index 000000000..30c7907a0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/HeightMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class HeightMediaFeature : MediaFeature
+    {
+        public HeightMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.LengthConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/HoverMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/HoverMediaFeature.cs
new file mode 100644
index 000000000..edc20ccd1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/HoverMediaFeature.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class HoverMediaFeature : MediaFeature
+    {
+        private static readonly IValueConverter TheConverter = Map.HoverAbilities.ToConverter();
+
+        public HoverMediaFeature() : base(FeatureNames.Hover)
+        {
+        }
+
+        internal override IValueConverter Converter => TheConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/MediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/MediaFeature.cs
new file mode 100644
index 000000000..4a6125b06
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/MediaFeature.cs
@@ -0,0 +1,131 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// How a media feature's stored value constrains the device value, unifying the <c>min-</c>/<c>max-</c>
+    /// name-prefix forms with the Media Queries 4 range operators (<c>&gt;=</c>/<c>&lt;=</c>/<c>&gt;</c>/<c>&lt;</c>).
+    /// </summary>
+    internal enum MediaFeatureComparison
+    {
+        /// <summary>Exact match (the <c>feature: value</c> form, or a boolean feature).</summary>
+        Exact,
+        /// <summary>Device value must be ≥ the feature value (<c>min-*</c> or <c>&gt;=</c>).</summary>
+        Minimum,
+        /// <summary>Device value must be ≤ the feature value (<c>max-*</c> or <c>&lt;=</c>).</summary>
+        Maximum,
+        /// <summary>Device value must be strictly &gt; the feature value.</summary>
+        GreaterThan,
+        /// <summary>Device value must be strictly &lt; the feature value.</summary>
+        LessThan
+    }
+
+    internal abstract class MediaFeature : StylesheetNode, IMediaFeature
+    {
+        private TokenValue _tokenValue;
+        private TokenType _constraintDelimiter;
+
+        internal MediaFeature(string name)
+        {
+            Name = name;
+            IsMinimum = name.StartsWith("min-");
+            IsMaximum = name.StartsWith("max-");
+        }
+
+        internal abstract IValueConverter Converter { get; }
+
+        public bool IsMinimum { get; }
+
+        public bool IsMaximum { get; }
+
+        public string Name { get; }
+
+        public string Value => HasValue ? _tokenValue.Text : string.Empty;
+
+        public bool HasValue => _tokenValue != null && _tokenValue.Count > 0;
+
+        /// <summary>
+        /// The comparison the stored value imposes on the device value, derived from the <c>min-</c>/
+        /// <c>max-</c> name prefix or, for the range syntax (<c>width &gt;= 48rem</c>), the parsed operator.
+        /// </summary>
+        internal MediaFeatureComparison Comparison
+        {
+            get
+            {
+                if (IsMinimum) return MediaFeatureComparison.Minimum;
+                if (IsMaximum) return MediaFeatureComparison.Maximum;
+
+                switch (_constraintDelimiter)
+                {
+                    case TokenType.GreaterThanOrEqual: return MediaFeatureComparison.Minimum;
+                    case TokenType.GreaterThan: return MediaFeatureComparison.GreaterThan;
+                    case TokenType.LessThanOrEqual: return MediaFeatureComparison.Maximum;
+                    case TokenType.LessThan: return MediaFeatureComparison.LessThan;
+                    default: return MediaFeatureComparison.Exact;
+                }
+            }
+        }
+
+        /// <summary>The stored value parsed as a <see cref="Length"/>, or <c>null</c> if absent/not a length.</summary>
+        internal Length? AsLength() => HasValue ? _tokenValue.ToLength() : null;
+
+        /// <summary>The stored value parsed as a <see cref="Resolution"/>, or <c>null</c> if absent/not a resolution.</summary>
+        internal Resolution? AsResolution() => HasValue ? _tokenValue.ToResolution() : null;
+
+        /// <summary>
+        /// The stored value parsed as a numeric ratio (<c>&lt;number&gt; [ / &lt;number&gt; ]?</c>), e.g.
+        /// <c>16/9</c>, or <c>null</c> if absent/unparseable.
+        /// </summary>
+        internal double? AsRatio()
+        {
+            if (!HasValue) return null;
+
+            var numbers = _tokenValue.OfType<NumberToken>().Select(token => (double)token.Value).ToList();
+
+            if (numbers.Count >= 2) return numbers[1] != 0 ? numbers[0] / numbers[1] : (double?)null;
+            if (numbers.Count == 1) return numbers[0] > 0 ? numbers[0] : (double?)null;
+            return null;
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var constraintDelimiter = GetConstraintDelimiter();
+            var value = HasValue ? Value : null;
+            writer.Write(formatter.Constraint(Name, value, GetConstraintDelimiter()));
+        }
+
+        private string GetConstraintDelimiter()
+        {
+            if (_constraintDelimiter == TokenType.Colon)
+                return ": ";
+            if (_constraintDelimiter == TokenType.GreaterThan)
+                return " > ";
+            if (_constraintDelimiter == TokenType.LessThan)
+                return " < ";
+            if (_constraintDelimiter == TokenType.Equal)
+                return " = ";
+            if (_constraintDelimiter == TokenType.GreaterThanOrEqual)
+                return " >= ";
+            if (_constraintDelimiter == TokenType.LessThanOrEqual)
+                return " <= ";
+            return ": ";
+        }
+
+        internal bool TrySetValue(TokenValue tokenValue, TokenType constraintDelimiter)
+        {
+            bool result;
+
+            if (tokenValue == null)
+                result = !IsMinimum && !IsMaximum && Converter.ConvertDefault() != null;
+            else
+                result = Converter.Convert(tokenValue) != null;
+
+            if (result) _tokenValue = tokenValue;
+
+            _constraintDelimiter = constraintDelimiter;
+
+            return result;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/MonochromeMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/MonochromeMediaFeature.cs
new file mode 100644
index 000000000..3f8641163
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/MonochromeMediaFeature.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class MonochromeMediaFeature : MediaFeature
+    {
+        public MonochromeMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter =>
+            IsMinimum || IsMaximum ? NaturalIntegerConverter : NaturalIntegerConverter.Option(1);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/OrientationMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/OrientationMediaFeature.cs
new file mode 100644
index 000000000..bf71f50b4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/OrientationMediaFeature.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OrientationMediaFeature : MediaFeature
+    {
+        private static readonly IValueConverter TheConverter = Converters.Toggle(Keywords.Portrait, Keywords.Landscape);
+
+        public OrientationMediaFeature() : base(FeatureNames.Orientation)
+        {
+        }
+
+        internal override IValueConverter Converter => TheConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PointerMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PointerMediaFeature.cs
new file mode 100644
index 000000000..bb8d2fc03
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PointerMediaFeature.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PointerMediaFeature : MediaFeature
+    {
+        private static readonly IValueConverter TheConverter = Map.PointerAccuracies.ToConverter();
+
+        public PointerMediaFeature() : base(FeatureNames.Pointer)
+        {
+        }
+
+        internal override IValueConverter Converter => TheConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersColorSchemeMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersColorSchemeMediaFeature.cs
new file mode 100644
index 000000000..1f4bbb601
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersColorSchemeMediaFeature.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>prefers-color-scheme</c> media feature (Media Queries 5). The value is validated as any
+    /// identifier here; the actual <c>light</c>/<c>dark</c> match against the configured scheme happens
+    /// in <c>MediaQueryMatcher</c>.
+    /// </summary>
+    internal sealed class PrefersColorSchemeMediaFeature : MediaFeature
+    {
+        public PrefersColorSchemeMediaFeature() : base(FeatureNames.PrefersColorScheme)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersContrastMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersContrastMediaFeature.cs
new file mode 100644
index 000000000..40f3301d2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersContrastMediaFeature.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>prefers-contrast</c> media feature (Media Queries 5). Matched against the renderer's fixed
+    /// <c>no-preference</c> stance in <c>MediaQueryMatcher</c>.
+    /// </summary>
+    internal sealed class PrefersContrastMediaFeature : MediaFeature
+    {
+        public PrefersContrastMediaFeature() : base(FeatureNames.PrefersContrast)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersReducedMotionMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersReducedMotionMediaFeature.cs
new file mode 100644
index 000000000..717844821
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersReducedMotionMediaFeature.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>prefers-reduced-motion</c> media feature (Media Queries 5). Matched against the renderer's
+    /// fixed <c>reduce</c> stance (a static PDF has no motion) in <c>MediaQueryMatcher</c>.
+    /// </summary>
+    internal sealed class PrefersReducedMotionMediaFeature : MediaFeature
+    {
+        public PrefersReducedMotionMediaFeature() : base(FeatureNames.PrefersReducedMotion)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersReducedTransparencyMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersReducedTransparencyMediaFeature.cs
new file mode 100644
index 000000000..ef84cf8ce
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/PrefersReducedTransparencyMediaFeature.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>prefers-reduced-transparency</c> media feature (Media Queries 5). Matched against the
+    /// renderer's fixed <c>no-preference</c> stance in <c>MediaQueryMatcher</c>.
+    /// </summary>
+    internal sealed class PrefersReducedTransparencyMediaFeature : MediaFeature
+    {
+        public PrefersReducedTransparencyMediaFeature() : base(FeatureNames.PrefersReducedTransparency)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ResolutionMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ResolutionMediaFeature.cs
new file mode 100644
index 000000000..a6f2365e4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ResolutionMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ResolutionMediaFeature : MediaFeature
+    {
+        public ResolutionMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.ResolutionConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ScanMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ScanMediaFeature.cs
new file mode 100644
index 000000000..a222a3e1f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ScanMediaFeature.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ScanMediaFeature : MediaFeature
+    {
+        private static readonly IValueConverter TheConverter =
+            Converters.Toggle(Keywords.Interlace, Keywords.Progressive);
+
+        public ScanMediaFeature() : base(FeatureNames.Scan)
+        {
+        }
+
+        internal override IValueConverter Converter => TheConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ScriptingMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ScriptingMediaFeature.cs
new file mode 100644
index 000000000..f1ff7707c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/ScriptingMediaFeature.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ScriptingMediaFeature : MediaFeature
+    {
+        private static readonly IValueConverter TheConverter = Map.ScriptingStates.ToConverter();
+
+        public ScriptingMediaFeature() : base(FeatureNames.Scripting)
+        {
+        }
+
+        internal override IValueConverter Converter => TheConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/SizeMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/SizeMediaFeature.cs
new file mode 100644
index 000000000..7c2451280
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/SizeMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class SizeMediaFeature : MediaFeature
+    {
+        public SizeMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.LengthConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UnknownMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UnknownMediaFeature.cs
new file mode 100644
index 000000000..6e71d5251
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UnknownMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnknownMediaFeature : MediaFeature
+    {
+        public UnknownMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UpdateFrequencyMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UpdateFrequencyMediaFeature.cs
new file mode 100644
index 000000000..86b00bd0c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UpdateFrequencyMediaFeature.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UpdateFrequencyMediaFeature : MediaFeature
+    {
+        private static readonly IValueConverter TheConverter = Map.UpdateFrequencies.ToConverter();
+
+        public UpdateFrequencyMediaFeature() : base(FeatureNames.UpdateFrequency)
+        {
+        }
+
+        internal override IValueConverter Converter => TheConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UpdateMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UpdateMediaFeature.cs
new file mode 100644
index 000000000..59eab7e2b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/UpdateMediaFeature.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>update</c> media feature (Media Queries 4): how frequently the output device can modify the
+    /// appearance of content. A printed/exported PDF cannot update once produced, so it is matched against
+    /// <c>none</c> in <c>MediaQueryMatcher</c>.
+    /// </summary>
+    internal sealed class UpdateMediaFeature : MediaFeature
+    {
+        public UpdateMediaFeature() : base(FeatureNames.Update)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/WidthMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/WidthMediaFeature.cs
new file mode 100644
index 000000000..7c74b8437
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/MediaFeatures/WidthMediaFeature.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class WidthMediaFeature : MediaFeature
+    {
+        public WidthMediaFeature(string name) : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.LengthConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/CodepointRange.cs b/Source/HtmlRenderer/Core/CssEngine/Model/CodepointRange.cs
new file mode 100644
index 000000000..5cd5d7de3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/CodepointRange.cs
@@ -0,0 +1,31 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// An inclusive range of Unicode scalar values (codepoints), e.g. the <c>U+0000-00FF</c> of a CSS
+    /// <c>@font-face</c> <c>unicode-range</c> descriptor. Both ends are inclusive - unlike
+    /// <see cref="System.Range"/>, which is half-open and index based. <c>int</c>-based (matching this
+    /// codebase's existing <see cref="Symbols.MaximumCodepoint"/>/<see cref="CharExtensions"/>
+    /// int-codepoint convention) rather than PeachPDF's <c>Rune</c>-based <c>RuneRange</c> - see
+    /// <see cref="Utils.UnicodeRangeParser"/> for why: <c>System.Text.Rune</c> only exists on
+    /// <c>net8.0</c>, not this project's <c>netstandard2.0</c> leg. Public: it appears in
+    /// <see cref="Adapters.RAdapter.AddFontFace"/>'s public signature, for a custom adapter implementation
+    /// outside this assembly.
+    /// </summary>
+    public readonly struct CodepointRange
+    {
+        public CodepointRange(int start, int end)
+        {
+            Start = start;
+            End = end;
+        }
+
+        /// <summary>The first codepoint covered by this range (inclusive).</summary>
+        public int Start { get; }
+
+        /// <summary>The last codepoint covered by this range (inclusive).</summary>
+        public int End { get; }
+
+        /// <summary>Whether <paramref name="codepoint"/> lies within this range (both ends inclusive).</summary>
+        public bool Contains(int codepoint) => codepoint >= Start && codepoint <= End;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Combinator.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Combinator.cs
new file mode 100644
index 000000000..e9dc5dfa7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Combinator.cs
@@ -0,0 +1,80 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class Combinator
+    {
+        public static readonly Combinator Child = new ChildCombinator();
+        public static readonly Combinator Deep = new DeepCombinator();
+        public static readonly Combinator Descendent = new DescendentCombinator();
+        public static readonly Combinator AdjacentSibling = new AdjacentSiblingCombinator();
+        public static readonly Combinator Sibling = new SiblingCombinator();
+        public static readonly Combinator Namespace = new NamespaceCombinator();
+        public static readonly Combinator Column = new ColumnCombinator();
+        public string Delimiter { get; protected set; }
+
+        public virtual ISelector Change(ISelector selector)
+        {
+            return selector;
+        }
+
+        private sealed class ChildCombinator : Combinator
+        {
+            public ChildCombinator()
+            {
+                Delimiter = Combinators.Child;
+            }
+        }
+
+        private sealed class DeepCombinator : Combinator
+        {
+            public DeepCombinator()
+            {
+                Delimiter = Combinators.Deep;
+            }
+        }
+
+        private sealed class DescendentCombinator : Combinator
+        {
+            public DescendentCombinator()
+            {
+                Delimiter = Combinators.Descendent;
+            }
+        }
+
+        private sealed class AdjacentSiblingCombinator : Combinator
+        {
+            public AdjacentSiblingCombinator()
+            {
+                Delimiter = Combinators.Adjacent;
+            }
+        }
+
+        private sealed class SiblingCombinator : Combinator
+        {
+            public SiblingCombinator()
+            {
+                Delimiter = Combinators.Sibling;
+            }
+        }
+
+        private sealed class NamespaceCombinator : Combinator
+        {
+            public NamespaceCombinator()
+            {
+                Delimiter = Combinators.Pipe;
+            }
+
+            public override ISelector Change(ISelector selector)
+            {
+                return NamespaceSelector.Create(selector.Text);
+            }
+        }
+
+        private sealed class ColumnCombinator : Combinator
+        {
+            public ColumnCombinator()
+            {
+                Delimiter = Combinators.Column;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Comment.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Comment.cs
new file mode 100644
index 000000000..2a32a14fd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Comment.cs
@@ -0,0 +1,19 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class Comment : StylesheetNode
+    {
+        public Comment(string data)
+        {
+            Data = data;
+        }
+
+        public string Data { get; }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Comment(Data));
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Converters.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Converters.cs
new file mode 100644
index 000000000..cb018d112
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Converters.cs
@@ -0,0 +1,614 @@
+using System;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class Converters
+    {
+        public static readonly IValueConverter LineWidthConverter =
+            new StructValueConverter<Length>(ValueExtensions.ToBorderWidth)
+                .Or(new CalcValueConverter(CalcCategory.Length));
+
+        public static readonly IValueConverter LengthConverter =
+            new StructValueConverter<Length>(ValueExtensions.ToLength)
+                .Or(new CalcValueConverter(CalcCategory.Length));
+
+        public static readonly IValueConverter ResolutionConverter =
+            new StructValueConverter<Resolution>(ValueExtensions.ToResolution);
+
+        public static readonly IValueConverter TimeConverter = new StructValueConverter<Time>(ValueExtensions.ToTime);
+        public static readonly IValueConverter UrlConverter = new UrlValueConverter();
+        public static readonly IValueConverter StringConverter = new StringValueConverter();
+        public static readonly IValueConverter EvenStringsConverter = new StringsValueConverter();
+
+        public static readonly IValueConverter LiteralsConverter =
+            new IdentifierValueConverter(ValueExtensions.ToLiterals);
+
+        public static readonly IValueConverter IdentifierConverter =
+            new IdentifierValueConverter(ValueExtensions.ToIdentifierCaseInsensitive);
+
+        public static readonly IValueConverter AnimatableConverter =
+            new IdentifierValueConverter(ValueExtensions.ToAnimatableIdentifier);
+
+        public static readonly IValueConverter IntegerConverter =
+            new StructValueConverter<int>(ValueExtensions.ToInteger);
+
+        public static readonly IValueConverter NaturalIntegerConverter =
+            new StructValueConverter<int>(ValueExtensions.ToNaturalInteger);
+
+        public static readonly IValueConverter WeightIntegerConverter =
+            new StructValueConverter<int>(ValueExtensions.ToWeightInteger);
+
+        public static readonly IValueConverter PositiveIntegerConverter =
+            new StructValueConverter<int>(ValueExtensions.ToPositiveInteger);
+
+        public static readonly IValueConverter
+            BinaryConverter = new StructValueConverter<int>(ValueExtensions.ToBinary);
+
+        public static readonly IValueConverter
+            AngleConverter = new StructValueConverter<Angle>(ValueExtensions.ToAngle)
+                .Or(new CalcValueConverter(CalcCategory.Angle));
+
+        public static readonly IValueConverter NumberConverter =
+            new StructValueConverter<float>(ValueExtensions.ToSingle)
+                .Or(new CalcValueConverter(CalcCategory.Number));
+
+        public static readonly IValueConverter NaturalNumberConverter =
+            new StructValueConverter<float>(ValueExtensions.ToNaturalSingle);
+
+        public static readonly IValueConverter PercentConverter =
+            new StructValueConverter<Percent>(ValueExtensions.ToPercent);
+
+        public static readonly IValueConverter RgbComponentConverter =
+            new StructValueConverter<byte>(ValueExtensions.ToRgbComponent);
+
+        public static readonly IValueConverter AlphaValueConverter =
+            new StructValueConverter<float>(ValueExtensions.ToAlphaValue);
+
+        public static readonly IValueConverter PureColorConverter =
+            new StructValueConverter<Color>(ValueExtensions.ToColor);
+
+        public static IValueConverter Any = new AnyValueConverter();
+
+        public static readonly IValueConverter LengthOrPercentConverter =
+            new StructValueConverter<Length>(ValueExtensions.ToDistance)
+                .Or(new CalcValueConverter(CalcCategory.LengthPercentage));
+
+        public static readonly IValueConverter PercentOrFractionConverter =
+            new StructValueConverter<Percent>(ValueExtensions.ToPercentOrFraction);
+
+        public static readonly IValueConverter PercentOrNumberConverter =
+            new StructValueConverter<Number>(ValueExtensions.ToPercentOrNumber);
+
+        public static readonly IValueConverter AngleNumberConverter =
+            new StructValueConverter<Angle>(ValueExtensions.ToAngleNumber)
+                .Or(new CalcValueConverter(CalcCategory.Angle | CalcCategory.Number));
+
+        public static readonly IValueConverter SideOrCornerConverter = WithAny(
+            Assign(Keywords.Left, -1.0).Or(Keywords.Right, 1.0).Option(0.0),
+            Assign(Keywords.Top, 1.0).Or(Keywords.Bottom, -1.0).Option(0.0)
+        );
+
+        // The 1/2/3/4-token background-position grammar (including the edge-relative offset syntax,
+        // e.g. "right 20px bottom 10px") is implemented once in BackgroundPositionGrammar and shared
+        // with the render layer's BackgroundLayerResolver, rather than re-implemented as a second,
+        // independent parser of the same value string - see that class's doc comment.
+        public static readonly IValueConverter PointConverter = new BackgroundPositionValueConverter();
+
+        public static readonly IValueConverter AttrConverter = new FunctionValueConverter(
+            FunctionNames.Attr, WithArgs(StringConverter.Or(IdentifierConverter)));
+
+        public static readonly IValueConverter StepsConverter = new FunctionValueConverter(
+            FunctionNames.Steps, WithArgs(
+                IntegerConverter.Required(),
+                Assign(Keywords.Start, true).Or(Keywords.End, false).Option(false)));
+
+        public static readonly IValueConverter CubicBezierConverter = Construct(() =>
+        {
+            var number = NumberConverter.Required();
+            return new FunctionValueConverter(FunctionNames.CubicBezier,
+                WithArgs(number, number, number, number));
+        });
+
+        public static readonly IValueConverter CounterConverter = Construct(() =>
+        {
+            var name = IdentifierConverter.Required();
+            var kind = IdentifierConverter.Option(Keywords.Decimal);
+            var def = StringConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Counter, WithArgs(name, kind)
+                .Or(new FunctionValueConverter(FunctionNames.Counters, WithArgs(name, def, kind))));
+        });
+
+        public static readonly IValueConverter ShapeConverter = Construct(() =>
+        {
+            var length = LengthConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Rect, WithArgs(length, length, length, length)
+                .Or(WithArgs(LengthConverter.Many(4, 4))));
+        }).OrAuto();
+
+        public static readonly IValueConverter LinearGradientConverter = Construct(() =>
+            new FunctionValueConverter(FunctionNames.LinearGradient, new LinearGradientConverter()).Or(
+                new FunctionValueConverter(FunctionNames.RepeatingLinearGradient, new LinearGradientConverter())));
+
+        public static readonly IValueConverter RadialGradientConverter = Construct(() =>
+            new FunctionValueConverter(FunctionNames.RadialGradient, new RadialGradientConverter()).Or(
+                new FunctionValueConverter(FunctionNames.RepeatingRadialGradient, new RadialGradientConverter())));
+
+        public static readonly IValueConverter ConicGradientConverter = Construct(() =>
+            new FunctionValueConverter(FunctionNames.ConicGradient, new ConicGradientConverter()).Or(
+                new FunctionValueConverter(FunctionNames.RepeatingConicGradient, new ConicGradientConverter())));
+
+        public static readonly IValueConverter RgbColorConverter = Construct(() =>
+        {
+            var number = RgbComponentConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Rgb, WithArgs(number, number, number));
+        });
+
+        public static readonly IValueConverter RgbaColorConverter = Construct(() =>
+        {
+            var value = RgbComponentConverter.Required();
+            var alpha = AlphaValueConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Rgba, WithArgs(value, value, value, alpha));
+        });
+
+        public static readonly IValueConverter HslColorConverter = Construct(() =>
+        {
+            var hue = AngleNumberConverter.Required();
+            var percent = PercentConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Hsl, WithArgs(hue, percent, percent));
+        });
+
+        public static readonly IValueConverter HslaColorConverter = Construct(() =>
+        {
+            var hue = AngleNumberConverter.Required();
+            var percent = PercentConverter.Required();
+            var alpha = AlphaValueConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Hsla, WithArgs(hue, percent, percent, alpha));
+        });
+
+        public static readonly IValueConverter GrayColorConverter = Construct(() =>
+        {
+            var value = RgbComponentConverter.Required();
+            var alpha = AlphaValueConverter.Option(1f);
+            return new FunctionValueConverter(FunctionNames.Gray, WithArgs(value, alpha));
+        });
+
+        public static readonly IValueConverter HwbColorConverter = Construct(() =>
+        {
+            var hue = AngleNumberConverter.Required();
+            var percent = PercentConverter.Required();
+            var alpha = AlphaValueConverter.Option(1f);
+            return new FunctionValueConverter(FunctionNames.Hwb, WithArgs(hue, percent, percent, alpha));
+        });
+
+        // CSS Color 4/5 function forms. These validate the function name and accept its argument list
+        // leniently (preserving the specified text for serialization and shorthand expansion); the
+        // exact grammar check and the sRGB resolution happen in the render layer
+        // (ColorFunctionExtensions), so a `background: oklch(...)` shorthand still carries its color
+        // through to the background-color longhand. Construct(...) defers the `Any` reference until
+        // first use, avoiding a static-init ordering dependency.
+        public static readonly IValueConverter LabColorConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Lab, Any));
+        public static readonly IValueConverter OklabColorConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Oklab, Any));
+        public static readonly IValueConverter LchColorConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Lch, Any));
+        public static readonly IValueConverter OklchColorConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Oklch, Any));
+        public static readonly IValueConverter ColorMixConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.ColorMix, Any));
+
+        // Lenient fallbacks for the CSS Color 4 space/slash syntax of the legacy functions. The strict
+        // comma-form converters above run first (so their canonical serialization is preserved); these
+        // catch the space-separated / slash-alpha forms the strict grammars reject, so e.g.
+        // `background: hsl(280 70% 55%)` or `rgb(1 2 3 / .5)` still populate the color longhand and get
+        // resolved in the render layer.
+        public static readonly IValueConverter RgbLenientConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Rgb, Any));
+        public static readonly IValueConverter RgbaLenientConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Rgba, Any));
+        public static readonly IValueConverter HslLenientConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Hsl, Any));
+        public static readonly IValueConverter HslaLenientConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Hsla, Any));
+        public static readonly IValueConverter HwbLenientConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Hwb, Any));
+
+        public static readonly IValueConverter PerspectiveConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Perspective, WithArgs(LengthConverter)));
+
+        public static readonly IValueConverter MatrixTransformConverter = Construct(() =>
+            new FunctionValueConverter(FunctionNames.Matrix, WithArgs(NumberConverter, 6)).Or(
+                new FunctionValueConverter(FunctionNames.Matrix3d, WithArgs(NumberConverter, 16))));
+
+        public static readonly IValueConverter TranslateTransformConverter = Construct(() =>
+        {
+            var distance = LengthOrPercentConverter.Required();
+            var option = LengthOrPercentConverter.Option(Length.Zero);
+            return new FunctionValueConverter(FunctionNames.Translate, WithArgs(distance, option)).Or(
+                new FunctionValueConverter(FunctionNames.Translate3d, WithArgs(distance, option, option))).Or(
+                new FunctionValueConverter(FunctionNames.TranslateX, WithArgs(LengthOrPercentConverter))).Or(
+                new FunctionValueConverter(FunctionNames.TranslateY, WithArgs(LengthOrPercentConverter))).Or(
+                new FunctionValueConverter(FunctionNames.TranslateZ, WithArgs(LengthOrPercentConverter)));
+        });
+
+        public static readonly IValueConverter ScaleTransformConverter = Construct(() =>
+        {
+            var number = NumberConverter.Required();
+            var option = NumberConverter.Option(float.NaN);
+            return new FunctionValueConverter(FunctionNames.Scale, WithArgs(number, option)).Or(
+                new FunctionValueConverter(FunctionNames.Scale3d, WithArgs(number, option, option))).Or(
+                new FunctionValueConverter(FunctionNames.ScaleX, WithArgs(NumberConverter))).Or(
+                new FunctionValueConverter(FunctionNames.ScaleY, WithArgs(NumberConverter))).Or(
+                new FunctionValueConverter(FunctionNames.ScaleZ, WithArgs(NumberConverter)));
+        });
+
+        public static readonly IValueConverter RotateTransformConverter = Construct(() =>
+        {
+            var number = NumberConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Rotate, WithArgs(AngleConverter)).Or(
+                new FunctionValueConverter(FunctionNames.Rotate3d,
+                    WithArgs(number, number, number, AngleConverter.Required()))).Or(
+                new FunctionValueConverter(FunctionNames.RotateX, WithArgs(AngleConverter))).Or(
+                new FunctionValueConverter(FunctionNames.RotateY, WithArgs(AngleConverter))).Or(
+                new FunctionValueConverter(FunctionNames.RotateZ, WithArgs(AngleConverter)));
+        });
+
+        public static readonly IValueConverter SkewTransformConverter = Construct(() =>
+        {
+            var angle = AngleConverter.Required();
+            return new FunctionValueConverter(FunctionNames.Skew, WithArgs(angle, angle)).Or(
+                new FunctionValueConverter(FunctionNames.SkewX, WithArgs(AngleConverter))).Or(
+                new FunctionValueConverter(FunctionNames.SkewY, WithArgs(AngleConverter)));
+        });
+
+        public static readonly IValueConverter DefaultFontFamiliesConverter = Map.DefaultFontFamilies.ToConverter();
+        public static readonly IValueConverter LineStyleConverter = Map.LineStyles.ToConverter();
+        public static readonly IValueConverter BackgroundAttachmentConverter = Map.BackgroundAttachments.ToConverter();
+        public static readonly IValueConverter BackgroundRepeatConverter = Map.BackgroundRepeats.ToConverter();
+        public static readonly IValueConverter BoxModelConverter = Map.BoxModels.ToConverter();
+        public static readonly IValueConverter AnimationDirectionConverter = Map.AnimationDirections.ToConverter();
+        public static readonly IValueConverter AnimationFillStyleConverter = Map.AnimationFillStyles.ToConverter();
+        public static readonly IValueConverter TextDecorationStyleConverter = Map.TextDecorationStyles.ToConverter();
+
+        public static readonly IValueConverter TextDecorationLinesConverter =
+            Map.TextDecorationLines.ToConverter().Many().OrNone();
+
+        public static readonly IValueConverter ListPositionConverter = Map.ListPositions.ToConverter();
+        public static readonly IValueConverter ListStyleConverter = Map.ListStyles.ToConverter();
+        public static readonly IValueConverter BreakModeConverter = Map.BreakModes.ToConverter();
+        public static readonly IValueConverter BreakInsideModeConverter = Map.BreakInsideModes.ToConverter();
+        public static readonly IValueConverter PageBreakModeConverter = Map.PageBreakModes.ToConverter();
+        public static readonly IValueConverter UnicodeModeConverter = Map.UnicodeModes.ToConverter();
+        public static readonly IValueConverter VisibilityConverter = Map.Visibilities.ToConverter();
+        public static readonly IValueConverter PlayStateConverter = Map.PlayStates.ToConverter();
+        public static readonly IValueConverter FontVariantConverter = Map.FontVariants.ToConverter();
+        public static readonly IValueConverter DirectionModeConverter = Map.DirectionModes.ToConverter();
+        public static readonly IValueConverter HorizontalAlignmentConverter = Map.HorizontalAlignments.ToConverter();
+        public static readonly IValueConverter VerticalAlignmentConverter = Map.VerticalAlignments.ToConverter();
+        public static readonly IValueConverter WhitespaceConverter = Map.WhitespaceModes.ToConverter();
+        public static readonly IValueConverter TextTransformConverter = Map.TextTransforms.ToConverter();
+        public static readonly IValueConverter TextAlignLastConverter = Map.TextAlignmentsLast.ToConverter();
+        public static readonly IValueConverter TextAnchorConverter = Map.TextAnchors.ToConverter();
+        public static readonly IValueConverter TextJustifyConverter = Map.TextJustifyOptions.ToConverter();
+        public static readonly IValueConverter ObjectFittingConverter = Map.ObjectFittings.ToConverter();
+        public static readonly IValueConverter PositionModeConverter = Map.PositionModes.ToConverter();
+        public static readonly IValueConverter OverflowModeConverter = Map.OverflowModes.ToConverter();
+        public static readonly IValueConverter FloatingConverter = Map.FloatingModes.ToConverter();
+        public static readonly IValueConverter DisplayModeConverter = Map.DisplayModes.ToConverter();
+        public static readonly IValueConverter ContainerTypeConverter = Map.ContainerTypes.ToConverter();
+        public static readonly IValueConverter ClearModeConverter = Map.ClearModes.ToConverter();
+        public static readonly IValueConverter FontStretchConverter = Map.FontStretches.ToConverter();
+        // "oblique" alone matches via the plain keyword map (tried first); "oblique <angle>" (CSS Fonts
+        // Level 4 - e.g. "oblique 10deg") only reaches the StartsWithValueConverter branch once the
+        // plain single-identifier match has already failed, i.e. there are more tokens to account for.
+        // AngleConverter is intentionally NOT Option()-wrapped here (unlike e.g. LineHeightConverter's
+        // own StartsWithDelimiter().Option() composition elsewhere) - StartsWithValueConverter.Construct
+        // trusts "the wrapped converter returned non-null" as its own "matched" signal, and an Option()
+        // converter's Construct never returns null, which would make every OTHER possible font-style
+        // value (plain keywords, initial, absent) falsely reconstruct as "oblique" whenever the "font"
+        // shorthand needs to be re-serialized from its decomposed longhand properties.
+        public static readonly IValueConverter FontStyleConverter = Map.FontStyles.ToConverter()
+            .Or(new StartsWithValueConverter(TokenType.Ident, Keywords.Oblique, AngleConverter));
+        public static readonly IValueConverter FontWeightConverter = Map.FontWeights.ToConverter();
+        public static readonly IValueConverter SystemFontConverter = Map.SystemFonts.ToConverter();
+        public static readonly IValueConverter StrokeLinecapConverter = Map.StrokeLinecaps.ToConverter();
+        public static readonly IValueConverter StrokeLinejoinConverter = Map.StrokeLinejoins.ToConverter();
+        public static readonly IValueConverter WordBreakConverter = Map.WordBreaks.ToConverter();
+        public static readonly IValueConverter OverflowWrapConverter = Map.OverflowWraps.ToConverter();
+        public static readonly IValueConverter FillRuleConverter = Map.FillRules.ToConverter();
+        public static readonly IValueConverter IntrinsicSizingConverter = Map.IntrinsicSizings.ToConverter();
+
+        public static readonly IValueConverter AlignContentConverter = Construct(() =>
+        {
+            var alignContentsConverter = Map.AlignContents.ToConverter();
+
+            return alignContentsConverter.Or(alignContentsConverter.ConditionalStartsWithKeyword(Keywords.Center, Keywords.Safe, Keywords.Unsafe))
+                                         .Or(alignContentsConverter.ConditionalStartsWithKeyword(Keywords.Baseline, Keywords.First, Keywords.Last))
+                                         .OrGlobalValue()
+                                         .OrDefault(Keywords.Normal);
+        });
+
+        public static readonly IValueConverter AlignItemsConverter = Construct(() =>
+        {
+            var alignItemsConverter = Map.AlignItems.ToConverter();
+
+            return alignItemsConverter.Or(alignItemsConverter.ConditionalStartsWithKeyword(Keywords.Center, Keywords.Safe, Keywords.Unsafe))
+                                      .Or(alignItemsConverter.ConditionalStartsWithKeyword(Keywords.Baseline, Keywords.First, Keywords.Last))
+                                      .OrGlobalValue();
+        });
+
+        public static readonly IValueConverter JustifyContentConverter = Construct(() =>
+        {
+            var justifyContentConverter = Map.JustifyContentOptions.ToConverter();
+
+            return justifyContentConverter.Or(justifyContentConverter.ConditionalStartsWithKeyword(Keywords.Center, Keywords.Safe, Keywords.Unsafe))
+                                          .Or(justifyContentConverter.ConditionalStartsWithKeyword(Keywords.Baseline, Keywords.First, Keywords.Last))
+                                          .OrGlobalValue();
+        });
+
+        public static readonly IValueConverter AlignSelfConverter = AlignItemsConverter.OrAuto();
+
+        // justify-items / justify-self share align-items/align-self's value grammar for the keywords the
+        // grid engine honors (start/end/center/stretch/normal; baseline falls back to start at layout).
+        public static readonly IValueConverter JustifyItemsConverter = AlignItemsConverter;
+        public static readonly IValueConverter JustifySelfConverter = AlignSelfConverter;
+
+        // place-items / place-content / place-self: <align> <justify>? — one value applies to both axes.
+        public static readonly IValueConverter PlaceItemsConverter =
+            AlignItemsConverter.Periodic(PropertyNames.AlignItems, PropertyNames.JustifyItems);
+        public static readonly IValueConverter PlaceContentConverter =
+            JustifyContentConverter.Periodic(PropertyNames.AlignContent, PropertyNames.JustifyContent);
+        public static readonly IValueConverter PlaceSelfConverter =
+            AlignSelfConverter.Periodic(PropertyNames.AlignSelf, PropertyNames.JustifySelf);
+
+        #region Specific
+
+        public static readonly IValueConverter OptionalIntegerConverter = IntegerConverter.OrAuto();
+
+        public static readonly IValueConverter PositiveOrInfiniteNumberConverter =
+            NaturalNumberConverter.Or(Keywords.Infinite, float.PositiveInfinity);
+
+        public static readonly IValueConverter OptionalNumberConverter = NumberConverter.OrNone();
+
+        //public static readonly IValueConverter LengthOrNormalConverter =
+        //    LengthConverter.Or(Keywords.Normal, new Length(1f, Length.Unit.Em));
+
+        public static readonly IValueConverter OptionalLengthConverter = LengthConverter.Or(Keywords.Normal);
+        public static readonly IValueConverter AutoLengthConverter = LengthConverter.OrAuto();
+        public static readonly IValueConverter OptionalLengthOrPercentConverter = LengthOrPercentConverter.OrNone();
+        public static readonly IValueConverter AutoLengthOrPercentConverter = LengthOrPercentConverter.OrAuto();
+        public static readonly IValueConverter OptionalPercentOrFractionConverter = PercentOrFractionConverter.OrDefault(1f);
+        public static readonly IValueConverter OptionalPercentOrNumberConverter = PercentOrNumberConverter.OrDefault(1f);
+
+        public static readonly IValueConverter FontSizeConverter =
+            LengthOrPercentConverter.Or(Map.FontSizes.ToConverter());
+
+        public static readonly IValueConverter FlexDirectionConverter = Map.FlexDirections.ToConverter()
+                                                                           .OrGlobalValue()
+                                                                           .OrDefault(FlexDirection.Row);
+
+        public static readonly IValueConverter FlexWrapConverter = Map.FlexWraps.ToConverter()
+                                                                      .OrGlobalValue()
+                                                                      .OrDefault(FlexWrap.NoWrap);
+
+        public static readonly IValueConverter FlexGrowShrinkConverter = NumberConverter
+                                                                        .OrGlobalValue()
+                                                                        .OrDefault(0);
+
+        public static readonly IValueConverter FlexBasisConverter = AutoLengthOrPercentConverter
+                                                                   .Or(IntrinsicSizingConverter)
+                                                                   .OrGlobalValue()
+                                                                   .OrDefault(Keywords.Auto);
+
+        public static readonly IValueConverter FlexFlowConverter = Construct(() =>
+        {
+            var directionConverter = FlexDirectionConverter.For(PropertyNames.FlexDirection);
+            var wrapConverter = FlexWrapConverter.For(PropertyNames.FlexWrap);
+
+            // flex-flow is "<'flex-direction'> || <'flex-wrap'>" (CSS Flexbox 1 §5.1): the double bar means
+            // the two values may appear in either order, so the pair has to be WithAny, not WithOrder.
+            return directionConverter
+                  .Or(wrapConverter)
+                  .Or(WithAny(directionConverter, wrapConverter));
+
+        });
+
+        public static readonly IValueConverter FlexConverter = Construct(() =>
+        {
+            var flexGrow = FlexGrowShrinkConverter.WithFallback(1).For(PropertyNames.FlexGrow);
+            var flexShrink = FlexGrowShrinkConverter.WithFallback(1).For(PropertyNames.FlexShrink);
+            var flexBasis = FlexBasisConverter.WithFallback(0).For(PropertyNames.FlexBasis);
+
+            return WithOrder(flexGrow, flexShrink, flexBasis)
+                  .OrGlobalValue()
+                  .OrNone();
+        });
+
+        #endregion
+
+        #region Composed
+
+        public static readonly IValueConverter LineHeightConverter =
+            LengthOrPercentConverter.Or(NumberConverter).Or(Keywords.Normal);
+
+        public static readonly IValueConverter BorderSliceConverter = PercentConverter.Or(NumberConverter);
+
+        public static readonly IValueConverter ImageBorderWidthConverter =
+            LengthOrPercentConverter.Or(NumberConverter).Or(Keywords.Auto);
+
+        public static readonly IValueConverter TransitionConverter = new DictionaryValueConverter<ITimingFunction>(
+            Map.TimingFunctions).Or(StepsConverter).Or(CubicBezierConverter);
+
+        public static readonly IValueConverter GradientConverter = LinearGradientConverter.Or(RadialGradientConverter).Or(ConicGradientConverter);
+
+        public static readonly IValueConverter TransformConverter = MatrixTransformConverter
+            .Or(ScaleTransformConverter)
+            .Or(RotateTransformConverter)
+            .Or(TranslateTransformConverter)
+            .Or(SkewTransformConverter)
+            .Or(PerspectiveConverter);
+
+        public static readonly IValueConverter ColorConverter = PureColorConverter
+            .Or(RgbColorConverter.Or(RgbaColorConverter))
+            .Or(HslColorConverter.Or(HslaColorConverter))
+            .Or(GrayColorConverter.Or(HwbColorConverter))
+            .Or(LabColorConverter.Or(OklabColorConverter))
+            .Or(LchColorConverter.Or(OklchColorConverter))
+            .Or(ColorMixConverter)
+            .Or(RgbLenientConverter.Or(RgbaLenientConverter))
+            .Or(HslLenientConverter.Or(HslaLenientConverter))
+            .Or(HwbLenientConverter);
+
+        public static readonly IValueConverter CurrentColorConverter = ColorConverter.WithCurrentColor();
+        public static readonly IValueConverter InvertedColorConverter = CurrentColorConverter.Or(Keywords.Invert);
+        public static readonly IValueConverter PaintConverter = UrlConverter.Or(CurrentColorConverter.OrNone());
+
+        public static readonly IValueConverter StrokeDasharrayConverter =
+            LengthOrPercentConverter.Or(NumberConverter).Many().OrNone();
+
+        public static readonly IValueConverter StrokeMiterlimitConverter =
+            new StructValueConverter<float>(ValueExtensions.ToGreaterOrEqualOneSingle);
+
+        public static readonly IValueConverter RatioConverter = WithOrder(
+            IntegerConverter.Required(),
+            IntegerConverter.StartsWithDelimiter().Required());
+
+        // A single grid <grid-line> (auto | <integer> | span <integer>), validated by GridLineGrammar.
+        public static readonly IValueConverter GridLineConverter = new GridLineValueConverter();
+
+        // grid-column / grid-row / grid-area: slash-separated <grid-line> components with the CSS Grid
+        // §8.3.1 omitted-value copy rule (a bare <custom-ident> propagates to the paired/all edges) — the
+        // generic WithOrder(...).Option() DSL resets omitted slots to auto, which is wrong for named areas.
+        public static readonly IValueConverter GridColumnConverter =
+            new GridColumnRowShorthandValueConverter(PropertyNames.GridColumnStart, PropertyNames.GridColumnEnd);
+
+        public static readonly IValueConverter GridRowConverter =
+            new GridColumnRowShorthandValueConverter(PropertyNames.GridRowStart, PropertyNames.GridRowEnd);
+
+        public static readonly IValueConverter GridAreaConverter = new GridAreaShorthandValueConverter();
+
+        public static readonly IValueConverter GridTemplateConverter = new GridTemplateShorthandValueConverter();
+
+        public static readonly IValueConverter GridConverter = new GridShorthandValueConverter();
+
+        public static readonly IValueConverter ShadowConverter = WithAny(
+            Assign(Keywords.Inset, true).Option(false),
+            LengthConverter.Many(2, 4).Required(),
+            ColorConverter.WithCurrentColor().Option(Color.Black));
+
+        public static readonly IValueConverter MultipleShadowConverter = ShadowConverter.FromList().OrNone();
+
+        // The image functions the engine validates but the renderer does not paint (CSS Images 4). Composed into
+        // ImageSourceConverter so every <image> property (background-image, list-style-image, cursor,
+        // content, and @property syntax:"<image>") accepts them syntactically; the render path
+        // (CssValueParser.ParseImage → CssImagePainter) still handles only url()/gradients, so they paint
+        // nothing (an unchanged engine-wide gap). See ExtendedImageConverters.cs.
+        public static readonly IValueConverter ImageSetImageConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.ImageSet, new ImageSetConverter()));
+        public static readonly IValueConverter CrossFadeImageConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.CrossFade, new CrossFadeConverter()));
+        public static readonly IValueConverter ElementImageConverter =
+            Construct(() => new FunctionValueConverter(FunctionNames.Element, new ElementImageConverter()));
+
+        public static readonly IValueConverter ImageSourceConverter = UrlConverter.Or(GradientConverter)
+            .Or(ImageSetImageConverter).Or(CrossFadeImageConverter).Or(ElementImageConverter);
+        public static readonly IValueConverter OptionalImageSourceConverter = ImageSourceConverter.OrNone();
+        public static readonly IValueConverter MultipleImageSourceConverter = OptionalImageSourceConverter.FromList();
+        public static readonly IValueConverter BorderRadiusShorthandConverter = new BorderRadiusConverter();
+
+        public static readonly IValueConverter BorderRadiusConverter = WithOrder(
+            LengthOrPercentConverter.Required(), LengthOrPercentConverter.Option());
+
+        public static readonly IValueConverter FontFamiliesConverter =
+            DefaultFontFamiliesConverter.Or(StringConverter).Or(LiteralsConverter).FromList();
+
+        // Shared with the render layer's BackgroundLayerResolver via BackgroundSizeGrammar - see
+        // BackgroundPositionGrammar's doc comment for why.
+        public static readonly IValueConverter BackgroundSizeConverter = new BackgroundSizeValueConverter();
+
+        public static readonly IValueConverter BackgroundRepeatsConverter = BackgroundRepeatConverter.Or(
+            Keywords.RepeatX).Or(Keywords.RepeatY).Or(
+            WithOrder(BackgroundRepeatConverter.Required(), BackgroundRepeatConverter.Required()));
+
+        #endregion
+
+        #region Toggles
+
+        public static readonly IValueConverter TableLayoutConverter = Toggle(Keywords.Fixed, Keywords.Auto);
+        public static readonly IValueConverter EmptyCellsConverter = Toggle(Keywords.Show, Keywords.Hide);
+        public static readonly IValueConverter CaptionSideConverter = Toggle(Keywords.Top, Keywords.Bottom);
+        public static readonly IValueConverter BackfaceVisibilityConverter = Toggle(Keywords.Visible, Keywords.Hidden);
+        public static readonly IValueConverter BorderCollapseConverter = Toggle(Keywords.Separate, Keywords.Collapse);
+        public static readonly IValueConverter BoxDecorationConverter = Toggle(Keywords.Clone, Keywords.Slice);
+        public static readonly IValueConverter ColumnSpanConverter = Toggle(Keywords.All, Keywords.None);
+        public static readonly IValueConverter ColumnFillConverter = Toggle(Keywords.Balance, Keywords.Auto);
+        public static readonly IValueConverter BoxSizingConverter = Toggle(Keywords.ContentBox, Keywords.BorderBox);
+
+        #endregion
+
+        #region Misc
+
+
+        public static IValueConverter Assign<T>(string identifier, T result)
+        {
+            return new IdentifierValueConverter<T>(identifier, result);
+        }
+
+        public static IValueConverter Toggle(string on, string off)
+        {
+            return Assign(on, true).Or(off, false);
+        }
+
+        #endregion
+
+        #region Order / Unordered
+
+        public static IValueConverter WithOrder(params IValueConverter[] converters)
+        {
+            return new OrderedOptionsConverter(converters);
+        }
+
+        public static IValueConverter WithAny(params IValueConverter[] converters)
+        {
+            return new UnorderedOptionsConverter(converters);
+        }
+
+        public static IValueConverter WithAnyOrderIndependent(params IValueConverter[] converters)
+        {
+            return new OrderIndependentOptionsConverter(converters);
+        }
+
+        public static IValueConverter Continuous(IValueConverter converter)
+        {
+            return new ContinuousValueConverter(converter);
+        }
+
+        #endregion
+
+        #region Helper
+
+        private static IValueConverter Construct(Func<IValueConverter> f)
+        {
+            return f();
+        }
+
+        private static IValueConverter WithArgs(IValueConverter converter, int arguments)
+        {
+            var converters = Enumerable.Repeat(converter, arguments).ToArray();
+            return WithArgs(converters);
+        }
+
+        private static IValueConverter WithArgs(IValueConverter converter)
+        {
+            return new ArgumentsValueConverter(converter);
+        }
+
+        private static IValueConverter WithArgs(params IValueConverter[] converters)
+        {
+            return new ArgumentsValueConverter(converters);
+        }
+
+        #endregion
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/IMediaFeature.cs b/Source/HtmlRenderer/Core/CssEngine/Model/IMediaFeature.cs
new file mode 100644
index 000000000..0b2433f91
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/IMediaFeature.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IMediaFeature : IStylesheetNode
+    {
+        string Name { get; }
+        string Value { get; }
+        bool HasValue { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/ISelector.cs b/Source/HtmlRenderer/Core/CssEngine/Model/ISelector.cs
new file mode 100644
index 000000000..c048ed817
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/ISelector.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface ISelector : IStylesheetNode
+    {
+        Priority Specificity { get; }
+        string Text { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/IStyleFormattable.cs b/Source/HtmlRenderer/Core/CssEngine/Model/IStyleFormattable.cs
new file mode 100644
index 000000000..b5415a1cc
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/IStyleFormattable.cs
@@ -0,0 +1,9 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IStyleFormattable
+    {
+        void ToCss(TextWriter writer, IStyleFormatter formatter);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/IStyleFormatter.cs b/Source/HtmlRenderer/Core/CssEngine/Model/IStyleFormatter.cs
new file mode 100644
index 000000000..1a1d737bd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/IStyleFormatter.cs
@@ -0,0 +1,18 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IStyleFormatter
+    {
+        string Sheet(IEnumerable<IStyleFormattable> rules);
+        string Block(IEnumerable<IStyleFormattable> rules);
+        string Declaration(string name, string value, bool important);
+        string Declarations(IEnumerable<string> declarations);
+        string Medium(bool exclusive, bool inverse, string type, IEnumerable<IStyleFormattable> constraints);
+        string Constraint(string name, string value, string constraintDelimiter);
+        string Rule(string name, string value);
+        string Rule(string name, string prelude, string rules);
+        string Style(string selector, IStyleFormattable rules);
+        string Comment(string data);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/IStylesheetNode.cs b/Source/HtmlRenderer/Core/CssEngine/Model/IStylesheetNode.cs
new file mode 100644
index 000000000..bf04ff971
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/IStylesheetNode.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IStylesheetNode : IStyleFormattable
+    {
+        IEnumerable<IStylesheetNode> Children { get; }
+        StylesheetText StylesheetText { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/IValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/Model/IValueConverter.cs
new file mode 100644
index 000000000..0f476644a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/IValueConverter.cs
@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IValueConverter
+    {
+        IPropertyValue Convert(IEnumerable<Token> value);
+        IPropertyValue Construct(Property[] properties);
+    }
+
+    internal static class PropertyExtensions
+    {
+        public static IPropertyValue Guard<T>(this Property[] properties)
+        {
+            if (properties.Length != 1) return null;
+
+            var value = properties[0].DeclaredValue;
+            return value is T ? properties[0].DeclaredValue : null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Map.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Map.cs
new file mode 100644
index 000000000..59b99c5a5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Map.cs
@@ -0,0 +1,605 @@
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class Map
+    {
+        public static readonly Dictionary<string, Whitespace> WhitespaceModes =
+            new Dictionary<string, Whitespace>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, Whitespace.Normal},
+                {Keywords.Pre, Whitespace.Pre},
+                {Keywords.Nowrap, Whitespace.NoWrap},
+                {Keywords.PreWrap, Whitespace.PreWrap},
+                {Keywords.PreLine, Whitespace.PreLine}
+            };
+        public static readonly Dictionary<string, TextTransform> TextTransforms =
+            new Dictionary<string, TextTransform>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, TextTransform.None},
+                {Keywords.Capitalize, TextTransform.Capitalize},
+                {Keywords.Uppercase, TextTransform.Uppercase},
+                {Keywords.Lowercase, TextTransform.Lowercase},
+                {Keywords.FullWidth, TextTransform.FullWidth}
+            };
+        public static readonly Dictionary<string, TextAlignLast> TextAlignmentsLast =
+            new Dictionary<string, TextAlignLast>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Auto, TextAlignLast.Auto},
+                {Keywords.Start, TextAlignLast.Start},
+                {Keywords.End, TextAlignLast.End},
+                {Keywords.Right, TextAlignLast.Right},
+                {Keywords.Left, TextAlignLast.Left},
+                {Keywords.Center, TextAlignLast.Center},
+                {Keywords.Justify, TextAlignLast.Justify}
+            };
+        public static readonly Dictionary<string, TextAnchor> TextAnchors =
+            new Dictionary<string, TextAnchor>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Start, TextAnchor.Start},
+                {Keywords.Middle, TextAnchor.Middle},
+                {Keywords.End, TextAnchor.End}
+            };
+        public static readonly Dictionary<string, TextJustify> TextJustifyOptions =
+            new Dictionary<string, TextJustify>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Auto, TextJustify.Auto},
+                {Keywords.Distribute, TextJustify.Distribute},
+                {Keywords.DistributeAllLines, TextJustify.DistributeAllLines},
+                {Keywords.DistributeCenterLast, TextJustify.DistributeCenterLast},
+                {Keywords.InterCluster, TextJustify.InterCluster},
+                {Keywords.InterIdeograph, TextJustify.InterIdeograph},
+                {Keywords.InterWord, TextJustify.InterWord},
+                {Keywords.Kashida, TextJustify.Kashida},
+                {Keywords.Newspaper, TextJustify.Newspaper}
+            };
+        public static readonly Dictionary<string, JustifyContent> JustifyContentOptions =
+            new Dictionary<string, JustifyContent>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Start, JustifyContent.Start},
+                {Keywords.Center, JustifyContent.Center},
+                {Keywords.End, JustifyContent.End},
+                {Keywords.FlexStart, JustifyContent.FlexStart},
+                {Keywords.FlexEnd, JustifyContent.FlexEnd},
+                {Keywords.Left, JustifyContent.Left},
+                {Keywords.Right, JustifyContent.Right},
+                {Keywords.Normal, JustifyContent.Normal },
+                {Keywords.SpaceBetween, JustifyContent.SpaceBetween},
+                {Keywords.SpaceAround, JustifyContent.SpaceAround},
+                {Keywords.SpaceEvenly, JustifyContent.SpaceEvenly},
+                {Keywords.Stretch, JustifyContent.Stretch },
+            };
+        public static readonly Dictionary<string, HorizontalAlignment> HorizontalAlignments =
+            new Dictionary<string, HorizontalAlignment>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Left, HorizontalAlignment.Left},
+                {Keywords.Right, HorizontalAlignment.Right},
+                {Keywords.Center, HorizontalAlignment.Center},
+                {Keywords.Justify, HorizontalAlignment.Justify}
+            };
+        public static readonly Dictionary<string, VerticalAlignment> VerticalAlignments =
+            new Dictionary<string, VerticalAlignment>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Baseline, VerticalAlignment.Baseline},
+                {Keywords.Sub, VerticalAlignment.Sub},
+                {Keywords.Super, VerticalAlignment.Super},
+                {Keywords.TextTop, VerticalAlignment.TextTop},
+                {Keywords.TextBottom, VerticalAlignment.TextBottom},
+                {Keywords.Middle, VerticalAlignment.Middle},
+                {Keywords.Top, VerticalAlignment.Top},
+                {Keywords.Bottom, VerticalAlignment.Bottom}
+            };
+        public static readonly Dictionary<string, LineStyle> LineStyles =
+            new Dictionary<string, LineStyle>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, LineStyle.None},
+                {Keywords.Solid, LineStyle.Solid},
+                {Keywords.Double, LineStyle.Double},
+                {Keywords.Dotted, LineStyle.Dotted},
+                {Keywords.Dashed, LineStyle.Dashed},
+                {Keywords.Inset, LineStyle.Inset},
+                {Keywords.Outset, LineStyle.Outset},
+                {Keywords.Ridge, LineStyle.Ridge},
+                {Keywords.Groove, LineStyle.Groove},
+                {Keywords.Hidden, LineStyle.Hidden}
+            };
+        public static readonly Dictionary<string, BoxModel> BoxModels =
+            new Dictionary<string, BoxModel>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.BorderBox, BoxModel.BorderBox},
+                {Keywords.PaddingBox, BoxModel.PaddingBox},
+                {Keywords.ContentBox, BoxModel.ContentBox}
+            };
+        public static readonly Dictionary<string, ITimingFunction> TimingFunctions =
+            new Dictionary<string, ITimingFunction>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Ease, new CubicBezierTimingFunction(0.25f, 0.1f, 0.25f, 1f)},
+                {Keywords.EaseIn, new CubicBezierTimingFunction(0.42f, 0f, 1f, 1f)},
+                {Keywords.EaseOut, new CubicBezierTimingFunction(0f, 0f, 0.58f, 1f)},
+                {Keywords.EaseInOut, new CubicBezierTimingFunction(0.42f, 0f, 0.58f, 1f)},
+                {Keywords.Linear, new CubicBezierTimingFunction(0f, 0f, 1f, 1f)},
+                {Keywords.StepStart, new StepsTimingFunction(1, true)},
+                {Keywords.StepEnd, new StepsTimingFunction(1)}
+            };
+        public static readonly Dictionary<string, AnimationFillStyle> AnimationFillStyles =
+            new Dictionary<string, AnimationFillStyle>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, AnimationFillStyle.None},
+                {Keywords.Forwards, AnimationFillStyle.Forwards},
+                {Keywords.Backwards, AnimationFillStyle.Backwards},
+                {Keywords.Both, AnimationFillStyle.Both}
+            };
+        public static readonly Dictionary<string, AnimationDirection> AnimationDirections =
+            new Dictionary<string, AnimationDirection>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, AnimationDirection.Normal},
+                {Keywords.Reverse, AnimationDirection.Reverse},
+                {Keywords.Alternate, AnimationDirection.Alternate},
+                {Keywords.AlternateReverse, AnimationDirection.AlternateReverse}
+            };
+        public static readonly Dictionary<string, Visibility> Visibilities =
+            new Dictionary<string, Visibility>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Visible, Visibility.Visible},
+                {Keywords.Hidden, Visibility.Hidden},
+                {Keywords.Collapse, Visibility.Collapse}
+            };
+        public static readonly Dictionary<string, PlayState> PlayStates =
+            new Dictionary<string, PlayState>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Running, PlayState.Running},
+                {Keywords.Paused, PlayState.Paused}
+            };
+        public static readonly Dictionary<string, FontVariant> FontVariants =
+            new Dictionary<string, FontVariant>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, FontVariant.Normal},
+                {Keywords.SmallCaps, FontVariant.SmallCaps}
+            };
+        public static readonly Dictionary<string, DirectionMode> DirectionModes =
+            new Dictionary<string, DirectionMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Ltr, DirectionMode.Ltr},
+                {Keywords.Rtl, DirectionMode.Rtl}
+            };
+        public static readonly Dictionary<string, ListStyle> ListStyles =
+            new Dictionary<string, ListStyle>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Disc, ListStyle.Disc},
+                {Keywords.Circle, ListStyle.Circle},
+                {Keywords.Square, ListStyle.Square},
+                {Keywords.Decimal, ListStyle.Decimal},
+                {Keywords.DecimalLeadingZero, ListStyle.DecimalLeadingZero},
+                {Keywords.LowerRoman, ListStyle.LowerRoman},
+                {Keywords.UpperRoman, ListStyle.UpperRoman},
+                {Keywords.LowerGreek, ListStyle.LowerGreek},
+                {Keywords.LowerLatin, ListStyle.LowerLatin},
+                {Keywords.UpperLatin, ListStyle.UpperLatin},
+                {Keywords.Armenian, ListStyle.Armenian},
+                {Keywords.Georgian, ListStyle.Georgian},
+                {Keywords.Hebrew, ListStyle.Hebrew},
+                {Keywords.LowerAlpha, ListStyle.LowerLatin},
+                {Keywords.UpperAlpha, ListStyle.UpperLatin},
+                {Keywords.None, ListStyle.None}
+            };
+        public static readonly Dictionary<string, ListPosition> ListPositions =
+            new Dictionary<string, ListPosition>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Inside, ListPosition.Inside},
+                {Keywords.Outside, ListPosition.Outside}
+            };
+        public static readonly Dictionary<string, FontSize> FontSizes =
+            new Dictionary<string, FontSize>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.XxSmall, FontSize.Tiny},
+                {Keywords.XSmall, FontSize.Little},
+                {Keywords.Small, FontSize.Small},
+                {Keywords.Medium, FontSize.Medium},
+                {Keywords.Large, FontSize.Large},
+                {Keywords.XLarge, FontSize.Big},
+                {Keywords.XxLarge, FontSize.Huge},
+                {Keywords.Larger, FontSize.Larger},
+                {Keywords.Smaller, FontSize.Smaller}
+            };
+        public static readonly Dictionary<string, TextDecorationStyle> TextDecorationStyles =
+            new Dictionary<string, TextDecorationStyle>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Solid, TextDecorationStyle.Solid},
+                {Keywords.Double, TextDecorationStyle.Double},
+                {Keywords.Dotted, TextDecorationStyle.Dotted},
+                {Keywords.Dashed, TextDecorationStyle.Dashed},
+                {Keywords.Wavy, TextDecorationStyle.Wavy}
+            };
+        public static readonly Dictionary<string, TextDecorationLine> TextDecorationLines =
+            new Dictionary<string, TextDecorationLine>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Underline, TextDecorationLine.Underline},
+                {Keywords.Overline, TextDecorationLine.Overline},
+                {Keywords.LineThrough, TextDecorationLine.LineThrough},
+                {Keywords.Blink, TextDecorationLine.Blink}
+            };
+        public static readonly Dictionary<string, BorderRepeat> BorderRepeatModes =
+            new Dictionary<string, BorderRepeat>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Stretch, BorderRepeat.Stretch},
+                {Keywords.Repeat, BorderRepeat.Repeat},
+                {Keywords.Round, BorderRepeat.Round}
+            };
+        public static readonly Dictionary<string, string> DefaultFontFamilies =
+            new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Serif, "Times New Roman"},
+                {Keywords.SansSerif, "Arial"},
+                {Keywords.Monospace, "Consolas"},
+                {Keywords.Cursive, "Cursive"},
+                {Keywords.Fantasy, "Comic Sans"}
+            };
+        public static readonly Dictionary<string, BackgroundAttachment> BackgroundAttachments =
+            new Dictionary<string, BackgroundAttachment>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Fixed, BackgroundAttachment.Fixed},
+                {Keywords.Local, BackgroundAttachment.Local},
+                {Keywords.Scroll, BackgroundAttachment.Scroll}
+            };
+        public static readonly Dictionary<string, FontStyle> FontStyles =
+            new Dictionary<string, FontStyle>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, FontStyle.Normal},
+                {Keywords.Italic, FontStyle.Italic},
+                {Keywords.Oblique, FontStyle.Oblique}
+            };
+        public static readonly Dictionary<string, FontStretch> FontStretches =
+            new Dictionary<string, FontStretch>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, FontStretch.Normal},
+                {Keywords.UltraCondensed, FontStretch.UltraCondensed},
+                {Keywords.ExtraCondensed, FontStretch.ExtraCondensed},
+                {Keywords.Condensed, FontStretch.Condensed},
+                {Keywords.SemiCondensed, FontStretch.SemiCondensed},
+                {Keywords.SemiExpanded, FontStretch.SemiExpanded},
+                {Keywords.Expanded, FontStretch.Expanded},
+                {Keywords.ExtraExpanded, FontStretch.ExtraExpanded},
+                {Keywords.UltraExpanded, FontStretch.UltraExpanded}
+            };
+        public static readonly Dictionary<string, BreakMode> BreakModes =
+            new Dictionary<string, BreakMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Auto, BreakMode.Auto},
+                {Keywords.Always, BreakMode.Always},
+                {Keywords.Avoid, BreakMode.Avoid},
+                {Keywords.Left, BreakMode.Left},
+                {Keywords.Right, BreakMode.Right},
+                {Keywords.Page, BreakMode.Page},
+                {Keywords.Column, BreakMode.Column},
+                {Keywords.AvoidPage, BreakMode.AvoidPage},
+                {Keywords.AvoidColumn, BreakMode.AvoidColumn}
+            };
+        public static readonly Dictionary<string, BreakMode> PageBreakModes =
+            new Dictionary<string, BreakMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Auto, BreakMode.Auto},
+                {Keywords.Always, BreakMode.Always},
+                {Keywords.Avoid, BreakMode.Avoid},
+                {Keywords.Left, BreakMode.Left},
+                {Keywords.Right, BreakMode.Right}
+            };
+        public static readonly Dictionary<string, BreakMode> BreakInsideModes =
+            new Dictionary<string, BreakMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Auto, BreakMode.Auto},
+                {Keywords.Avoid, BreakMode.Avoid},
+                {Keywords.AvoidPage, BreakMode.AvoidPage},
+                {Keywords.AvoidColumn, BreakMode.AvoidColumn},
+                {Keywords.AvoidRegion, BreakMode.AvoidRegion}
+            };
+        public static readonly Dictionary<string, float> HorizontalModes =
+            new Dictionary<string, float>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Left, 0f},
+                {Keywords.Center, 0.5f},
+                {Keywords.Right, 1f}
+            };
+        public static readonly Dictionary<string, float> VerticalModes =
+            new Dictionary<string, float>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Top, 0f},
+                {Keywords.Center, 0.5f},
+                {Keywords.Bottom, 1f}
+            };
+        public static readonly Dictionary<string, UnicodeMode> UnicodeModes =
+            new Dictionary<string, UnicodeMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, UnicodeMode.Normal},
+                {Keywords.Embed, UnicodeMode.Embed},
+                {Keywords.Isolate, UnicodeMode.Isolate},
+                {Keywords.IsolateOverride, UnicodeMode.IsolateOverride},
+                {Keywords.BidirectionalOverride, UnicodeMode.BidirectionalOverride},
+                {Keywords.Plaintext, UnicodeMode.Plaintext}
+            };
+        public static readonly Dictionary<string, SystemCursor> Cursors =
+            new Dictionary<string, SystemCursor>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Auto, SystemCursor.Auto},
+                {Keywords.Default, SystemCursor.Default},
+                {Keywords.None, SystemCursor.None},
+                {Keywords.ContextMenu, SystemCursor.ContextMenu},
+                {Keywords.Help, SystemCursor.Help},
+                {Keywords.Pointer, SystemCursor.Pointer},
+                {Keywords.Progress, SystemCursor.Progress},
+                {Keywords.Wait, SystemCursor.Wait},
+                {Keywords.Cell, SystemCursor.Cell},
+                {Keywords.Crosshair, SystemCursor.Crosshair},
+                {Keywords.Text, SystemCursor.Text},
+                {Keywords.VerticalText, SystemCursor.VerticalText},
+                {Keywords.Alias, SystemCursor.Alias},
+                {Keywords.Copy, SystemCursor.Copy},
+                {Keywords.Move, SystemCursor.Move},
+                {Keywords.NoDrop, SystemCursor.NoDrop},
+                {Keywords.NotAllowed, SystemCursor.NotAllowed},
+                {Keywords.EastResize, SystemCursor.EResize},
+                {Keywords.NorthResize, SystemCursor.NResize},
+                {Keywords.NorthEastResize, SystemCursor.NeResize},
+                {Keywords.NorthWestResize, SystemCursor.NwResize},
+                {Keywords.SouthResize, SystemCursor.SResize},
+                {Keywords.SouthEastResize, SystemCursor.SeResize},
+                {Keywords.SouthWestResize, SystemCursor.WResize},
+                {Keywords.WestResize, SystemCursor.WResize},
+                {Keywords.EastWestResize, SystemCursor.EwResize},
+                {Keywords.NorthSouthResize, SystemCursor.NsResize},
+                {Keywords.NorthEastSouthWestResize, SystemCursor.NeswResize},
+                {Keywords.NorthWestSouthEastResize, SystemCursor.NwseResize},
+                {Keywords.ColResize, SystemCursor.ColResize},
+                {Keywords.RowResize, SystemCursor.RowResize},
+                {Keywords.AllScroll, SystemCursor.AllScroll},
+                {Keywords.ZoomIn, SystemCursor.ZoomIn},
+                {Keywords.ZoomOut, SystemCursor.ZoomOut},
+                {Keywords.Grab, SystemCursor.Grab},
+                {Keywords.Grabbing, SystemCursor.Grabbing}
+            };
+        public static readonly Dictionary<string, PositionMode> PositionModes =
+            new Dictionary<string, PositionMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Static, PositionMode.Static},
+                {Keywords.Relative, PositionMode.Relative},
+                {Keywords.Absolute, PositionMode.Absolute},
+                {Keywords.Sticky, PositionMode.Sticky},
+                {Keywords.Fixed, PositionMode.Fixed}
+            };
+        public static readonly Dictionary<string, Overflow> OverflowModes =
+            new Dictionary<string, Overflow>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Visible, Overflow.Visible},
+                {Keywords.Hidden, Overflow.Hidden},
+                {Keywords.Scroll, Overflow.Scroll},
+                {Keywords.Auto, Overflow.Auto}
+            };
+        public static readonly Dictionary<string, Floating> FloatingModes =
+            new Dictionary<string, Floating>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, Floating.None},
+                {Keywords.Left, Floating.Left},
+                {Keywords.Right, Floating.Right}
+            };
+        public static readonly Dictionary<string, DisplayMode> DisplayModes =
+            new Dictionary<string, DisplayMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, DisplayMode.None},
+                {Keywords.Inline, DisplayMode.Inline},
+                {Keywords.Block, DisplayMode.Block},
+                {Keywords.InlineBlock, DisplayMode.InlineBlock},
+                {Keywords.ListItem, DisplayMode.ListItem},
+                {Keywords.InlineTable, DisplayMode.InlineTable},
+                {Keywords.Table, DisplayMode.Table},
+                {Keywords.TableCaption, DisplayMode.TableCaption},
+                {Keywords.TableCell, DisplayMode.TableCell},
+                {Keywords.TableColumn, DisplayMode.TableColumn},
+                {Keywords.TableColumnGroup, DisplayMode.TableColumnGroup},
+                {Keywords.TableFooterGroup, DisplayMode.TableFooterGroup},
+                {Keywords.TableHeaderGroup, DisplayMode.TableHeaderGroup},
+                {Keywords.TableRow, DisplayMode.TableRow},
+                {Keywords.TableRowGroup, DisplayMode.TableRowGroup},
+                {Keywords.Flex, DisplayMode.Flex},
+                {Keywords.InlineFlex, DisplayMode.InlineFlex},
+                {Keywords.Grid, DisplayMode.Grid},
+                {Keywords.InlineGrid, DisplayMode.InlineGrid}
+            };
+        public static readonly Dictionary<string, ClearMode> ClearModes =
+            new Dictionary<string, ClearMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, ClearMode.None},
+                {Keywords.Left, ClearMode.Left},
+                {Keywords.Right, ClearMode.Right},
+                {Keywords.Both, ClearMode.Both}
+            };
+        public static readonly Dictionary<string, BackgroundRepeat> BackgroundRepeats =
+            new Dictionary<string, BackgroundRepeat>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.NoRepeat, BackgroundRepeat.NoRepeat},
+                {Keywords.Repeat, BackgroundRepeat.Repeat},
+                {Keywords.Round, BackgroundRepeat.Round},
+                {Keywords.Space, BackgroundRepeat.Space}
+            };
+        public static readonly Dictionary<string, BlendMode> BlendModes =
+            new Dictionary<string, BlendMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Color, BlendMode.Color},
+                {Keywords.ColorBurn, BlendMode.ColorBurn},
+                {Keywords.ColorDodge, BlendMode.ColorDodge},
+                {Keywords.Darken, BlendMode.Darken},
+                {Keywords.Difference, BlendMode.Difference},
+                {Keywords.Exclusion, BlendMode.Exclusion},
+                {Keywords.HardLight, BlendMode.HardLight},
+                {Keywords.Hue, BlendMode.Hue},
+                {Keywords.Lighten, BlendMode.Lighten},
+                {Keywords.Luminosity, BlendMode.Luminosity},
+                {Keywords.Multiply, BlendMode.Multiply},
+                {Keywords.Normal, BlendMode.Normal},
+                {Keywords.Overlay, BlendMode.Overlay},
+                {Keywords.Saturation, BlendMode.Saturation},
+                {Keywords.Screen, BlendMode.Screen},
+                {Keywords.SoftLight, BlendMode.SoftLight}
+            };
+        public static readonly Dictionary<string, UpdateFrequency> UpdateFrequencies =
+            new Dictionary<string, UpdateFrequency>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, UpdateFrequency.None},
+                {Keywords.Slow, UpdateFrequency.Slow},
+                {Keywords.Normal, UpdateFrequency.Normal}
+            };
+        public static readonly Dictionary<string, ScriptingState> ScriptingStates =
+            new Dictionary<string, ScriptingState>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, ScriptingState.None},
+                {Keywords.InitialOnly, ScriptingState.InitialOnly},
+                {Keywords.Enabled, ScriptingState.Enabled}
+            };
+        public static readonly Dictionary<string, PointerAccuracy> PointerAccuracies =
+            new Dictionary<string, PointerAccuracy>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, PointerAccuracy.None},
+                {Keywords.Coarse, PointerAccuracy.Coarse},
+                {Keywords.Fine, PointerAccuracy.Fine}
+            };
+        public static readonly Dictionary<string, HoverAbility> HoverAbilities =
+            new Dictionary<string, HoverAbility>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, HoverAbility.None},
+                {Keywords.OnDemand, HoverAbility.OnDemand},
+                {Keywords.Hover, HoverAbility.Hover}
+            };
+        public static readonly Dictionary<string, RadialGradient.SizeMode> RadialGradientSizeModes =
+            new Dictionary<string, RadialGradient.SizeMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.ClosestSide, RadialGradient.SizeMode.ClosestSide},
+                {Keywords.FarthestSide, RadialGradient.SizeMode.FarthestSide},
+                {Keywords.ClosestCorner, RadialGradient.SizeMode.ClosestCorner},
+                {Keywords.FarthestCorner, RadialGradient.SizeMode.FarthestCorner}
+            };
+        public static readonly Dictionary<string, ObjectFitting> ObjectFittings =
+            new Dictionary<string, ObjectFitting>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.None, ObjectFitting.None},
+                {Keywords.Cover, ObjectFitting.Cover},
+                {Keywords.Contain, ObjectFitting.Contain},
+                {Keywords.Fill, ObjectFitting.Fill},
+                {Keywords.ScaleDown, ObjectFitting.ScaleDown}
+            };
+        public static readonly Dictionary<string, FontWeight> FontWeights =
+            new Dictionary<string, FontWeight>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, FontWeight.Normal},
+                {Keywords.Bold, FontWeight.Bold},
+                {Keywords.Bolder, FontWeight.Bolder},
+                {Keywords.Lighter, FontWeight.Lighter}
+            };
+        public static readonly Dictionary<string, SystemFont> SystemFonts =
+            new Dictionary<string, SystemFont>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Caption, SystemFont.Caption},
+                {Keywords.Icon, SystemFont.Icon},
+                {Keywords.Menu, SystemFont.Menu},
+                {Keywords.MessageBox, SystemFont.MessageBox},
+                {Keywords.SmallCaption, SystemFont.SmallCaption},
+                {Keywords.StatusBar, SystemFont.StatusBar}
+            };
+        public static readonly Dictionary<string, StrokeLinecap> StrokeLinecaps =
+            new Dictionary<string, StrokeLinecap>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Butt, StrokeLinecap.Butt},
+                {Keywords.Round, StrokeLinecap.Round},
+                {Keywords.Square, StrokeLinecap.Square}
+            };
+        public static readonly Dictionary<string, StrokeLinejoin> StrokeLinejoins =
+            new Dictionary<string, StrokeLinejoin>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Miter, StrokeLinejoin.Miter},
+                {Keywords.Round, StrokeLinejoin.Round},
+                {Keywords.Bevel, StrokeLinejoin.Bevel}
+            };
+        public static readonly Dictionary<string, WordBreak> WordBreaks =
+            new Dictionary<string, WordBreak>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, WordBreak.Normal},
+                {Keywords.BreakAll, WordBreak.BreakAll},
+                {Keywords.KeepAll, WordBreak.KeepAll}
+            };
+        public static readonly Dictionary<string, OverflowWrap> OverflowWraps =
+            new Dictionary<string, OverflowWrap>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, OverflowWrap.Normal},
+                {Keywords.BreakWord, OverflowWrap.BreakWord}
+            };
+        public static readonly Dictionary<string, FillRule> FillRules =
+            new Dictionary<string, FillRule>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Nonzero, FillRule.Nonzero},
+                {Keywords.Evenodd, FillRule.Evenodd}
+            };
+
+        public static readonly Dictionary<string, FlexDirection> FlexDirections =
+            new Dictionary<string, FlexDirection>(StringComparer.OrdinalIgnoreCase)
+            {
+                { Keywords.Row, FlexDirection.Row },
+                { Keywords.RowReverse, FlexDirection.RowReverse },
+                { Keywords.Column, FlexDirection.Column },
+                { Keywords.ColumnReverse, FlexDirection.ColumnReverse }
+            };
+
+        public static readonly Dictionary<string, FlexWrap> FlexWraps =
+            new Dictionary<string, FlexWrap>(StringComparer.OrdinalIgnoreCase)
+            {
+                { Keywords.Nowrap, FlexWrap.NoWrap },
+                { Keywords.Wrap, FlexWrap.Wrap },
+                { Keywords.WrapReverse, FlexWrap.WrapReverse }
+            };
+
+        public static readonly Dictionary<string, IntrinsicSizing> IntrinsicSizings =
+            new Dictionary<string, IntrinsicSizing>(StringComparer.OrdinalIgnoreCase)
+            {
+                { Keywords.MaxContent, IntrinsicSizing.MaxContent },
+                { Keywords.MinContent, IntrinsicSizing.MinContent },
+                { Keywords.FitContent, IntrinsicSizing.FitContent },
+                { Keywords.Content, IntrinsicSizing.Content }
+            };
+
+        public static readonly Dictionary<string, AlignContent> AlignContents =
+            new Dictionary<string, AlignContent>(StringComparer.OrdinalIgnoreCase)
+            {
+                { Keywords.Center, AlignContent.Center },
+                { Keywords.Start, AlignContent.Start },
+                { Keywords.End, AlignContent.End },
+                { Keywords.FlexStart, AlignContent.FlexStart },
+                { Keywords.FlexEnd, AlignContent.FlexEnd },
+                { Keywords.Normal, AlignContent.Normal },
+                { Keywords.Baseline, AlignContent.Baseline },
+                { Keywords.SpaceBetween, AlignContent.SpaceBetween },
+                { Keywords.SpaceAround, AlignContent.SpaceAround },
+                { Keywords.SpaceEvenly, AlignContent.SpaceEvenly },
+                { Keywords.Stretch, AlignContent.Stretch },
+            };
+
+        public static readonly Dictionary<string, AlignItem> AlignItems =
+            new Dictionary<string, AlignItem>(StringComparer.OrdinalIgnoreCase)
+            {
+                { Keywords.Normal, AlignItem.Normal },
+                { Keywords.Stretch, AlignItem.Stretch },
+                { Keywords.Center, AlignItem.Center },
+                { Keywords.Start, AlignItem.Start },
+                { Keywords.End, AlignItem.End },
+                { Keywords.FlexStart, AlignItem.FlexStart },
+                { Keywords.FlexEnd, AlignItem.FlexEnd },
+                { Keywords.SelfStart, AlignItem.SelfStart },
+                { Keywords.SelfEnd, AlignItem.SelfEnd },
+                { Keywords.Baseline, AlignItem.Baseline },
+            };
+
+        public static readonly Dictionary<string, ContainerType> ContainerTypes =
+            new Dictionary<string, ContainerType>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.Normal, ContainerType.Normal},
+                {Keywords.Size, ContainerType.Size},
+                {Keywords.InlineSize, ContainerType.InlineSize}
+            };
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/MediaList.cs b/Source/HtmlRenderer/Core/CssEngine/Model/MediaList.cs
new file mode 100644
index 000000000..3ea96e031
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/MediaList.cs
@@ -0,0 +1,76 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MediaList : StylesheetNode
+    {
+        private readonly StylesheetParser _parser;
+
+        internal MediaList(StylesheetParser parser)
+        {
+            _parser = parser;
+        }
+
+        public string this[int index] => Media.GetItemByIndex(index).ToCss();
+        public IEnumerable<Medium> Media => Children.OfType<Medium>();
+        public int Length => Media.Count();
+
+        public string MediaText
+        {
+            get => this.ToCss();
+            set
+            {
+                Clear();
+
+                foreach (var medium in _parser.ParseMediaList(value))
+                {
+                    if (medium == null) throw new ParseException("Unable to parse media list element");
+                    AppendChild(medium);
+                }
+            }
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var parts = Media.ToArray();
+            if (parts.Length <= 0) return;
+            parts[0].ToCss(writer, formatter);
+
+            for (var i = 1; i < parts.Length; i++)
+            {
+                writer.Write(", ");
+                parts[i].ToCss(writer, formatter);
+            }
+        }
+
+        public void Add(string newMedium)
+        {
+            var medium = _parser.ParseMedium(newMedium);
+            if (medium == null) throw new ParseException("Unable to parse medium");
+            AppendChild(medium);
+        }
+
+        public void Remove(string oldMedium)
+        {
+            var medium = _parser.ParseMedium(oldMedium);
+            if (medium == null) throw new ParseException("Unable to parse medium");
+
+            foreach (var item in Media)
+            {
+                if (!item.Equals(medium)) continue;
+
+                RemoveChild(item);
+                return;
+            }
+
+            throw new ParseException("Media list element not found");
+        }
+
+        public IEnumerator<Medium> GetEnumerator()
+        {
+            return Media.GetEnumerator();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Medium.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Medium.cs
new file mode 100644
index 000000000..56e69677b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Medium.cs
@@ -0,0 +1,49 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class Medium : StylesheetNode
+    {
+        public IEnumerable<MediaFeature> Features => Children.OfType<MediaFeature>();
+        public string Type { get; internal set; }
+        public bool IsExclusive { get; internal set; }
+        public bool IsInverse { get; internal set; }
+
+        public string Constraints
+        {
+            get
+            {
+                var constraints = Features.Select(m => m.ToCss());
+                return string.Join(" and ", constraints);
+            }
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (obj is Medium other &&
+                other.IsExclusive == IsExclusive &&
+                other.IsInverse == IsInverse &&
+                other.Type.Is(Type) &&
+                other.Features.Count() == Features.Count())
+            {
+                return other.Features.Select(feature =>
+                    Features.Any(m => m.Name.Is(feature.Name) && m.Value.Is(feature.Value))).All(isShared => isShared);
+            }
+
+            return false;
+        }
+
+        public override int GetHashCode()
+        {
+            // ReSharper disable once BaseObjectGetHashCodeCallInGetHashCode
+            return base.GetHashCode();
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Medium(IsExclusive, IsInverse, Type, Features));
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/ParseException.cs b/Source/HtmlRenderer/Core/CssEngine/Model/ParseException.cs
new file mode 100644
index 000000000..6d74f9089
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/ParseException.cs
@@ -0,0 +1,11 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal class ParseException : Exception
+    {
+        public ParseException(string message) : base(message)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/ParserExtensions.cs b/Source/HtmlRenderer/Core/CssEngine/Model/ParserExtensions.cs
new file mode 100644
index 000000000..45912f97a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/ParserExtensions.cs
@@ -0,0 +1,162 @@
+using TheArtOfDev.HtmlRenderer.Core.CssEngine.Conditions;
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class ParserExtensions
+    {
+        private static readonly Dictionary<string, Func<string, DocumentFunction>> FunctionTypes =
+            new Dictionary<string, Func<string, DocumentFunction>>(StringComparer.OrdinalIgnoreCase)
+            {
+                {FunctionNames.Url, url => new UrlFunction(url)},
+                {FunctionNames.Domain, url => new DomainFunction(url)},
+                {FunctionNames.UrlPrefix, url => new UrlPrefixFunction(url)}
+            };
+
+        private static readonly Dictionary<string, Func<IEnumerable<IConditionFunction>, IConditionFunction>>
+            GroupCreators =
+                new Dictionary<string, Func<IEnumerable<IConditionFunction>, IConditionFunction>>(
+                    StringComparer.OrdinalIgnoreCase)
+                {
+                    {Keywords.And, CreateAndCondition},
+                    {Keywords.Or, CreateOrCondition}
+                };
+
+        private static IConditionFunction CreateAndCondition(IEnumerable<IConditionFunction> conditions)
+        {
+            var andCondition = new AndCondition();
+            foreach (var condition in conditions)
+            {
+                andCondition.AppendChild(condition);
+            }
+            return andCondition;
+        }
+
+        private static IConditionFunction CreateOrCondition(IEnumerable<IConditionFunction> conditions)
+        {
+            var orCondition = new OrCondition();
+            foreach (var condition in conditions)
+            {
+                orCondition.AppendChild(condition);
+            }
+            return orCondition;
+        }
+
+        public static TokenType GetTypeFromName(this string functionName)
+        {
+            return FunctionTypes.TryGetValue(functionName, out _)
+                ? TokenType.Url
+                : TokenType.Function;
+        }
+
+        public static Func<IEnumerable<IConditionFunction>, IConditionFunction> GetCreator(this string conjunction)
+        {
+            GroupCreators.TryGetValue(conjunction, out var creator);
+            return creator;
+        }
+
+        public static int GetCode(this ParseError code)
+        {
+            return (int)code;
+        }
+
+        public static bool Is(this Token token, TokenType a)
+        {
+            var type = token.Type;
+            return type == a;
+        }
+
+        public static bool Is(this Token token, TokenType a, TokenType b)
+        {
+            var type = token.Type;
+            return type == a || type == b;
+        }
+
+        public static bool IsNot(this Token token, TokenType a, TokenType b)
+        {
+            var type = token.Type;
+            return type != a && type != b;
+        }
+
+        public static bool IsNot(this Token token, TokenType a, TokenType b, TokenType c)
+        {
+            var type = token.Type;
+            return type != a && type != b && type != c;
+        }
+
+        public static bool IsDeclarationName(this Token token)
+        {
+            return token.Type != TokenType.EndOfFile &&
+                   token.Type != TokenType.Colon &&
+                   token.Type != TokenType.Whitespace &&
+                   token.Type != TokenType.Comment &&
+                   token.Type != TokenType.CurlyBracketOpen &&
+                   token.Type != TokenType.Semicolon;
+        }
+
+        public static DocumentFunction ToDocumentFunction(this Token token)
+        {
+            switch (token.Type)
+            {
+                case TokenType.Url:
+                    {
+                        var functionName = ((UrlToken)token).FunctionName;
+                        FunctionTypes.TryGetValue(functionName, out var creator);
+                        return creator(token.Data);
+                    }
+                case TokenType.Function when token.Data.Isi(FunctionNames.Regexp):
+                    {
+                        var css = ((FunctionToken)token).ArgumentTokens.ToCssString();
+                        if (css != null)
+                        {
+                            return new RegexpFunction(css);
+                        }
+
+                        break;
+                    }
+            }
+
+            return null;
+        }
+
+        public static Rule CreateRule(this StylesheetParser parser, RuleType type)
+        {
+            switch (type)
+            {
+                case RuleType.Charset:
+                    return new CharsetRule(parser);
+                case RuleType.Document:
+                    return new DocumentRule(parser);
+                case RuleType.FontFace:
+                    return new FontFaceRule(parser);
+                case RuleType.Import:
+                    return new ImportRule(parser);
+                case RuleType.Keyframe:
+                    return new KeyframeRule(parser);
+                case RuleType.Keyframes:
+                    return new KeyframesRule(parser);
+                case RuleType.Media:
+                    return new MediaRule(parser);
+                case RuleType.Container:
+                    return new ContainerRule(parser);
+                case RuleType.Namespace:
+                    return new NamespaceRule(parser);
+                case RuleType.Page:
+                    return new PageRule(parser);
+                case RuleType.Style:
+                    return new StyleRule(parser);
+                case RuleType.Supports:
+                    return new SupportsRule(parser);
+                case RuleType.Viewport:
+                    return new ViewportRule(parser);
+                //case RuleType.Unknown:
+                //case RuleType.RegionStyle:
+                //case RuleType.FontFeatureValues:
+                //case RuleType.CounterStyle:
+                default:
+                    return null;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/ParserOptions.cs b/Source/HtmlRenderer/Core/CssEngine/Model/ParserOptions.cs
new file mode 100644
index 000000000..db9f87462
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/ParserOptions.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct ParserOptions
+    {
+        public bool IncludeUnknownRules { get; set; }
+        public bool IncludeUnknownDeclarations { get; set; }
+        public bool AllowInvalidSelectors { get; set; }
+        public bool AllowInvalidValues { get; set; }
+        public bool AllowInvalidConstraints { get; set; }
+        public bool PreserveComments { get; set; }
+        public bool PreserveDuplicateProperties { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Pool.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Pool.cs
new file mode 100644
index 000000000..5ac54ea84
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Pool.cs
@@ -0,0 +1,78 @@
+using System.Collections.Generic;
+using System.Text;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class Pool
+    {
+        private static readonly Stack<StringBuilder> Builder = new Stack<StringBuilder>();
+        private static readonly Stack<SelectorConstructor> Selector = new Stack<SelectorConstructor>();
+        private static readonly Stack<ValueBuilder> Value = new Stack<ValueBuilder>();
+        private static readonly object Lock = new object();
+
+        public static StringBuilder NewStringBuilder()
+        {
+            lock (Lock)
+            {
+                return Builder.Count == 0 ? new StringBuilder(1024) : Builder.Pop().Clear();
+            }
+        }
+
+        public static SelectorConstructor NewSelectorConstructor(AttributeSelectorFactory attributeSelector,
+            PseudoClassSelectorFactory pseudoClassSelector, PseudoElementSelectorFactory pseudoElementSelector)
+        {
+            lock (Lock)
+            {
+                return Selector.Count == 0
+                    ? new SelectorConstructor(attributeSelector, pseudoClassSelector, pseudoElementSelector)
+                    : Selector.Pop().Reset(attributeSelector, pseudoClassSelector, pseudoElementSelector);
+            }
+        }
+
+        public static ValueBuilder NewValueBuilder()
+        {
+            lock (Lock)
+            {
+                return Value.Count == 0
+                    ? new ValueBuilder()
+                    : Value.Pop().Reset();
+            }
+        }
+
+        public static string ToPool(this StringBuilder sb)
+        {
+            var result = sb.ToString();
+
+            lock (Lock)
+            {
+                Builder.Push(sb);
+            }
+
+            return result;
+        }
+
+        public static ISelector ToPool(this SelectorConstructor ctor)
+        {
+            var result = ctor.GetResult();
+
+            lock (Lock)
+            {
+                Selector.Push(ctor);
+            }
+
+            return result;
+        }
+
+        public static TokenValue ToPool(this ValueBuilder vb)
+        {
+            var result = vb.GetResult();
+
+            lock (Lock)
+            {
+                Value.Push(vb);
+            }
+
+            return result;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Priority.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Priority.cs
new file mode 100644
index 000000000..2cdda1f3f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Priority.cs
@@ -0,0 +1,103 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    [StructLayout(LayoutKind.Explicit, Pack = 1, CharSet = CharSet.Unicode)]
+    internal struct Priority : IEquatable<Priority>, IComparable<Priority>
+    {
+        [FieldOffset(0)] private readonly uint _priority;
+
+        public static readonly Priority Zero = new Priority(0u);
+        public static readonly Priority OneTag = new Priority(0, 0, 0, 1);
+        public static readonly Priority OneClass = new Priority(0, 0, 1, 0);
+        public static readonly Priority OneId = new Priority(0, 1, 0, 0);
+        public static readonly Priority Inline = new Priority(1, 0, 0, 0);
+
+        public Priority(uint priority)
+        {
+            Inlines = Ids = Classes = Tags = 0;
+            _priority = priority;
+        }
+
+        public Priority(byte inlines, byte ids, byte classes, byte tags)
+        {
+            _priority = 0;
+            Inlines = inlines;
+            Ids = ids;
+            Classes = classes;
+            Tags = tags;
+        }
+
+        [field: FieldOffset(2)]
+        public byte Ids { get; }
+
+        [field: FieldOffset(0)]
+        public byte Tags { get; }
+
+        [field: FieldOffset(1)]
+        public byte Classes { get; }
+
+        [field: FieldOffset(3)]
+        public byte Inlines { get; }
+
+        public static Priority operator +(Priority a, Priority b)
+        {
+            return new Priority(a._priority + b._priority);
+        }
+
+        public static bool operator ==(Priority a, Priority b)
+        {
+            return a._priority == b._priority;
+        }
+        public static bool operator >(Priority a, Priority b)
+        {
+            return a._priority > b._priority;
+        }
+
+        public static bool operator >=(Priority a, Priority b)
+        {
+            return a._priority >= b._priority;
+        }
+
+        public static bool operator <(Priority a, Priority b)
+        {
+            return a._priority < b._priority;
+        }
+
+        public static bool operator <=(Priority a, Priority b)
+        {
+            return a._priority <= b._priority;
+        }
+
+        public static bool operator !=(Priority a, Priority b)
+        {
+            return a._priority != b._priority;
+        }
+
+        public bool Equals(Priority other)
+        {
+            return _priority == other._priority;
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is Priority priority && Equals(priority);
+        }
+
+        public override int GetHashCode()
+        {
+            return (int)_priority;
+        }
+
+        public int CompareTo(Priority other)
+        {
+            return this == other ? 0 : (this > other ? 1 : -1);
+        }
+
+        public override string ToString()
+        {
+            return $"({Inlines}, {Ids}, {Classes}, {Tags})";
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/StyleDeclaration.cs b/Source/HtmlRenderer/Core/CssEngine/Model/StyleDeclaration.cs
new file mode 100644
index 000000000..f52cb70fc
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/StyleDeclaration.cs
@@ -0,0 +1,1706 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StyleDeclaration : StylesheetNode, IProperties
+    {
+        private readonly Rule _parent;
+        private readonly StylesheetParser _parser;
+        public event Action<string> Changed;
+
+        private StyleDeclaration(Rule parent, StylesheetParser parser)
+        {
+            _parent = parent;
+            _parser = parser;
+        }
+
+        internal StyleDeclaration(StylesheetParser parser) : this(null, parser)
+        {
+        }
+
+        internal StyleDeclaration() : this(null, null)
+        {
+        }
+
+        internal StyleDeclaration(Rule parent) : this(parent, parent.Parser)
+        {
+        }
+
+        public void Update(string value)
+        {
+            Clear();
+
+            if (!string.IsNullOrEmpty(value)) _parser.AppendDeclarations(this, value);
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var list = new List<string>();
+            var serialized = new List<string>();
+            foreach (var declaration in Declarations)
+            {
+                var property = declaration.Name;
+                if (IsStrictMode)
+                {
+                    if (serialized.Contains(property)) continue;
+
+                    var shorthands = PropertyFactory.Instance.GetShorthands(property).ToList();
+                    if (shorthands.Any())
+                    {
+                        var longhands = Declarations.Where(m => !serialized.Contains(m.Name)).ToList();
+                        foreach (var shorthand in shorthands.OrderByDescending(m =>
+                            PropertyFactory.Instance.GetLonghands(m).Length))
+                        {
+                            var rule = PropertyFactory.Instance.CreateShorthand(shorthand);
+                            var properties = PropertyFactory.Instance.GetLonghands(shorthand);
+                            var currentLonghands = longhands.Where(m => properties.Contains(m.Name)).ToArray();
+
+                            if (currentLonghands.Length == 0) continue;
+
+                            var important = currentLonghands.Count(m => m.IsImportant);
+
+                            if (important > 0 && important != currentLonghands.Length) continue;
+
+                            if (properties.Length != currentLonghands.Length) continue;
+
+                            var value = rule.Stringify(currentLonghands);
+
+                            if (string.IsNullOrEmpty(value)) continue;
+
+                            list.Add(CompressedStyleFormatter.Instance.Declaration(shorthand, value, important != 0));
+
+                            foreach (var longhand in currentLonghands)
+                            {
+                                serialized.Add(longhand.Name);
+                                longhands.Remove(longhand);
+                            }
+                        }
+                    }
+
+                    if (serialized.Contains(property)) continue;
+                    serialized.Add(property);
+                }
+
+                list.Add(declaration.ToCss(formatter));
+            }
+
+            writer.Write(formatter.Declarations(list));
+        }
+
+        public string RemoveProperty(string propertyName)
+        {
+            var value = GetPropertyValue(propertyName);
+            RemovePropertyByName(propertyName);
+            RaiseChanged();
+
+            return value;
+        }
+
+        private void RemovePropertyByName(string propertyName)
+        {
+            foreach (var declaration in Declarations)
+            {
+                if (!declaration.Name.Is(propertyName)) continue;
+                RemoveChild(declaration);
+                break;
+            }
+
+            if (!IsStrictMode || !PropertyFactory.Instance.IsShorthand(propertyName)) return;
+
+            var longhands = PropertyFactory.Instance.GetLonghands(propertyName);
+            foreach (var longhand in longhands) RemovePropertyByName(longhand);
+        }
+
+        public string GetPropertyPriority(string propertyName)
+        {
+            var property = GetProperty(propertyName);
+            if (property != null && property.IsImportant) return Keywords.Important;
+            if (!IsStrictMode || !PropertyFactory.Instance.IsShorthand(propertyName)) return string.Empty;
+
+            var longhands = PropertyFactory.Instance.GetLonghands(propertyName);
+
+            return longhands.Any(longhand => !GetPropertyPriority(longhand)
+                .Isi(Keywords.Important))
+                ? string.Empty
+                : Keywords.Important;
+        }
+
+        public string GetPropertyValue(string propertyName)
+        {
+            var property = GetProperty(propertyName);
+            if (property != null) return property.Value;
+
+            if (!IsStrictMode || !PropertyFactory.Instance.IsShorthand(propertyName)) return string.Empty;
+
+            var shortHand = PropertyFactory.Instance.CreateShorthand(propertyName);
+            var declarations = PropertyFactory.Instance.GetLonghands(propertyName);
+            var properties = new List<Property>();
+
+            foreach (var declaration in declarations)
+            {
+                property = GetProperty(declaration);
+                if (property == null) return string.Empty;
+                properties.Add(property);
+            }
+
+            return shortHand.Stringify(properties.ToArray());
+        }
+
+        public void SetPropertyValue(string propertyName, string propertyValue)
+        {
+            SetProperty(propertyName, propertyValue);
+        }
+
+        public void SetPropertyPriority(string propertyName, string priority)
+        {
+            if (!string.IsNullOrEmpty(priority) && !priority.Isi(Keywords.Important)) return;
+
+            var important = !string.IsNullOrEmpty(priority);
+            var mappings = IsStrictMode && PropertyFactory.Instance.IsShorthand(propertyName)
+                ? PropertyFactory.Instance.GetLonghands(propertyName)
+                : Enumerable.Repeat(propertyName, 1);
+
+            foreach (var mapping in mappings)
+            {
+                var property = GetProperty(mapping);
+                if (property != null) property.IsImportant = important;
+            }
+        }
+
+        public void SetProperty(string propertyName, string propertyValue, string priority = null)
+        {
+            if (!string.IsNullOrEmpty(propertyValue))
+            {
+                if (priority != null && !priority.Isi(Keywords.Important)) return;
+
+                var value = _parser.ParseValue(propertyValue);
+                if (value == null) return;
+
+                var property = CreateProperty(propertyName);
+                if (property == null || !property.TrySetValue(value)) return;
+
+                property.IsImportant = priority != null;
+                SetProperty(property);
+                RaiseChanged();
+            }
+            else
+            {
+                RemoveProperty(propertyName);
+            }
+        }
+
+        internal Property CreateProperty(string propertyName)
+        {
+            var property = GetProperty(propertyName);
+            if (property != null) return property;
+
+            property = PropertyFactory.Instance.Create(propertyName);
+            if (property != null || IsStrictMode) return property;
+
+            return new UnknownProperty(propertyName);
+        }
+
+        internal Property GetProperty(string name)
+        {
+            return Declarations.FirstOrDefault(m => m.Name.Isi(name));
+        }
+
+        internal void SetProperty(Property property)
+        {
+            if (property is ShorthandProperty shorthand)
+            {
+                SetShorthand(shorthand);
+            }
+            else
+            {
+                SetLonghand(property);
+            }
+        }
+
+        internal void SetDeclarations(IEnumerable<Property> declarations)
+        {
+            ChangeDeclarations(declarations, _ => false, (o, n) => !o.IsImportant || n.IsImportant);
+        }
+
+        internal void UpdateDeclarations(IEnumerable<Property> declarations)
+        {
+            ChangeDeclarations(declarations, m => !m.CanBeInherited, (o, _) => o.IsInherited);
+        }
+
+        private void ChangeDeclarations(IEnumerable<Property> declarations, Predicate<Property> defaultSkip,
+            Func<Property, Property, bool> removeExisting)
+        {
+            var propertyList = new List<Property>();
+            foreach (var newDeclaration in declarations)
+            {
+                var skip = defaultSkip(newDeclaration);
+                foreach (var oldDeclaration in Declarations)
+                {
+                    if (!oldDeclaration.Name.Is(newDeclaration.Name)) continue;
+
+                    if (removeExisting(oldDeclaration, newDeclaration))
+                        RemoveChild(oldDeclaration);
+                    else
+                        skip = true;
+                    break;
+                }
+
+                if (!skip) propertyList.Add(newDeclaration);
+            }
+
+            foreach (var declaration in propertyList) AppendChild(declaration);
+        }
+
+        private void SetLonghand(Property property)
+        {
+            if (!_parser.Options.PreserveDuplicateProperties)
+            {
+                foreach (var declaration in Declarations)
+                {
+                    if (!declaration.Name.Is(property.Name)) continue;
+                    RemoveChild(declaration);
+                    break;
+                }
+            }
+
+            AppendChild(property);
+        }
+
+        private void SetShorthand(ShorthandProperty shorthand)
+        {
+            if (shorthand.DeclaredValue.Original.ContainsFunction(FunctionNames.Var))
+            {
+                // A var() reference can't be split into per-longhand slices here — the referenced custom
+                // property's value is only known per-element, at cascade time. Keep the shorthand
+                // declaration whole so cascade-time substitution + shorthand expansion can handle it once resolved.
+                SetLonghand(shorthand);
+                return;
+            }
+
+            var properties = PropertyFactory.Instance.CreateLonghandsFor(shorthand.Name);
+            shorthand.Export(properties);
+
+            foreach (var property in properties) SetLonghand(property);
+        }
+
+        private void RaiseChanged()
+        {
+            Changed?.Invoke(CssText);
+        }
+
+        public IEnumerator<IProperty> GetEnumerator()
+        {
+            return Declarations.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        public IRule Parent => _parent;
+        public string this[int index] => Declarations.GetItemByIndex(index).Name;
+        public string this[string name] => GetPropertyValue(name);
+        public int Length => Declarations.Count();
+
+        public bool IsStrictMode => /* IsReadOnly ||*/ _parser.Options.IncludeUnknownDeclarations == false;
+
+        public IEnumerable<Property> Declarations => Children.OfType<Property>();
+
+        public string CssText
+        {
+            get => this.ToCss();
+            set
+            {
+                Update(value);
+                RaiseChanged();
+            }
+        }
+
+        public string AlignContent
+        {
+            get => GetPropertyValue(PropertyNames.AlignContent);
+            set => SetPropertyValue(PropertyNames.AlignContent, value);
+        }
+
+        public string AlignItems
+        {
+            get => GetPropertyValue(PropertyNames.AlignItems);
+            set => SetPropertyValue(PropertyNames.AlignItems, value);
+        }
+
+        public string AlignSelf
+        {
+            get => GetPropertyValue(PropertyNames.AlignSelf);
+            set => SetPropertyValue(PropertyNames.AlignSelf, value);
+        }
+
+        public string Accelerator
+        {
+            get => GetPropertyValue(PropertyNames.Accelerator);
+            set => SetPropertyValue(PropertyNames.Accelerator, value);
+        }
+
+        public string AlignmentBaseline
+        {
+            get => GetPropertyValue(PropertyNames.AlignBaseline);
+            set => SetPropertyValue(PropertyNames.AlignBaseline, value);
+        }
+
+        public string Animation
+        {
+            get => GetPropertyValue(PropertyNames.Animation);
+            set => SetPropertyValue(PropertyNames.Animation, value);
+        }
+
+        public string AnimationDelay
+        {
+            get => GetPropertyValue(PropertyNames.AnimationDelay);
+            set => SetPropertyValue(PropertyNames.AnimationDelay, value);
+        }
+
+        public string AnimationDirection
+        {
+            get => GetPropertyValue(PropertyNames.AnimationDirection);
+            set => SetPropertyValue(PropertyNames.AnimationDirection, value);
+        }
+
+        public string AnimationDuration
+        {
+            get => GetPropertyValue(PropertyNames.AnimationDuration);
+            set => SetPropertyValue(PropertyNames.AnimationDuration, value);
+        }
+
+        public string AnimationFillMode
+        {
+            get => GetPropertyValue(PropertyNames.AnimationFillMode);
+            set => SetPropertyValue(PropertyNames.AnimationFillMode, value);
+        }
+
+        public string AnimationIterationCount
+        {
+            get => GetPropertyValue(PropertyNames.AnimationIterationCount);
+            set => SetPropertyValue(PropertyNames.AnimationIterationCount, value);
+        }
+
+        public string AnimationName
+        {
+            get => GetPropertyValue(PropertyNames.AnimationName);
+            set => SetPropertyValue(PropertyNames.AnimationName, value);
+        }
+
+        public string AnimationPlayState
+        {
+            get => GetPropertyValue(PropertyNames.AnimationPlayState);
+            set => SetPropertyValue(PropertyNames.AnimationPlayState, value);
+        }
+
+        public string AnimationTimingFunction
+        {
+            get => GetPropertyValue(PropertyNames.AnimationTimingFunction);
+            set => SetPropertyValue(PropertyNames.AnimationTimingFunction, value);
+        }
+
+        public string BackfaceVisibility
+        {
+            get => GetPropertyValue(PropertyNames.BackfaceVisibility);
+            set => SetPropertyValue(PropertyNames.BackfaceVisibility, value);
+        }
+
+        public string Background
+        {
+            get => GetPropertyValue(PropertyNames.Background);
+            set => SetPropertyValue(PropertyNames.Background, value);
+        }
+
+        public string BackgroundAttachment
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundAttachment);
+            set => SetPropertyValue(PropertyNames.BackgroundAttachment, value);
+        }
+
+        public string BackgroundClip
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundClip);
+            set => SetPropertyValue(PropertyNames.BackgroundClip, value);
+        }
+
+        public string BackgroundColor
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundColor);
+            set => SetPropertyValue(PropertyNames.BackgroundColor, value);
+        }
+
+        public string BackgroundImage
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundImage);
+            set => SetPropertyValue(PropertyNames.BackgroundImage, value);
+        }
+
+        public string BackgroundOrigin
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundOrigin);
+            set => SetPropertyValue(PropertyNames.BackgroundOrigin, value);
+        }
+
+        public string BackgroundPosition
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundPosition);
+            set => SetPropertyValue(PropertyNames.BackgroundPosition, value);
+        }
+
+        public string BackgroundPositionX
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundPositionX);
+            set => SetPropertyValue(PropertyNames.BackgroundPositionX, value);
+        }
+
+        public string BackgroundPositionY
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundPositionY);
+            set => SetPropertyValue(PropertyNames.BackgroundPositionY, value);
+        }
+
+        public string BackgroundRepeat
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundRepeat);
+            set => SetPropertyValue(PropertyNames.BackgroundRepeat, value);
+        }
+
+        public string BackgroundSize
+        {
+            get => GetPropertyValue(PropertyNames.BackgroundSize);
+            set => SetPropertyValue(PropertyNames.BackgroundSize, value);
+        }
+
+        public string BaselineShift
+        {
+            get => GetPropertyValue(PropertyNames.BaselineShift);
+            set => SetPropertyValue(PropertyNames.BaselineShift, value);
+        }
+
+        public string Behavior
+        {
+            get => GetPropertyValue(PropertyNames.Behavior);
+            set => SetPropertyValue(PropertyNames.Behavior, value);
+        }
+
+        public string Bottom
+        {
+            get => GetPropertyValue(PropertyNames.Bottom);
+            set => SetPropertyValue(PropertyNames.Bottom, value);
+        }
+
+        public string Border
+        {
+            get => GetPropertyValue(PropertyNames.Border);
+            set => SetPropertyValue(PropertyNames.Border, value);
+        }
+
+        public string BorderBottom
+        {
+            get => GetPropertyValue(PropertyNames.BorderBottom);
+            set => SetPropertyValue(PropertyNames.BorderBottom, value);
+        }
+
+        public string BorderBottomColor
+        {
+            get => GetPropertyValue(PropertyNames.BorderBottomColor);
+            set => SetPropertyValue(PropertyNames.BorderBottomColor, value);
+        }
+
+        public string BorderBottomLeftRadius
+        {
+            get => GetPropertyValue(PropertyNames.BorderBottomLeftRadius);
+            set => SetPropertyValue(PropertyNames.BorderBottomLeftRadius, value);
+        }
+
+        public string BorderBottomRightRadius
+        {
+            get => GetPropertyValue(PropertyNames.BorderBottomRightRadius);
+            set => SetPropertyValue(PropertyNames.BorderBottomRightRadius, value);
+        }
+
+        public string BorderBottomStyle
+        {
+            get => GetPropertyValue(PropertyNames.BorderBottomStyle);
+            set => SetPropertyValue(PropertyNames.BorderBottomStyle, value);
+        }
+
+        public string BorderBottomWidth
+        {
+            get => GetPropertyValue(PropertyNames.BorderBottomWidth);
+            set => SetPropertyValue(PropertyNames.BorderBottomWidth, value);
+        }
+
+        public string BorderCollapse
+        {
+            get => GetPropertyValue(PropertyNames.BorderCollapse);
+            set => SetPropertyValue(PropertyNames.BorderCollapse, value);
+        }
+
+        public string BorderColor
+        {
+            get => GetPropertyValue(PropertyNames.BorderColor);
+            set => SetPropertyValue(PropertyNames.BorderColor, value);
+        }
+
+        public string BorderImage
+        {
+            get => GetPropertyValue(PropertyNames.BorderImage);
+            set => SetPropertyValue(PropertyNames.BorderImage, value);
+        }
+
+        public string BorderImageOutset
+        {
+            get => GetPropertyValue(PropertyNames.BorderImageOutset);
+            set => SetPropertyValue(PropertyNames.BorderImageOutset, value);
+        }
+
+        public string BorderImageRepeat
+        {
+            get => GetPropertyValue(PropertyNames.BorderImageRepeat);
+            set => SetPropertyValue(PropertyNames.BorderImageRepeat, value);
+        }
+
+        public string BorderImageSlice
+        {
+            get => GetPropertyValue(PropertyNames.BorderImageSlice);
+            set => SetPropertyValue(PropertyNames.BorderImageSlice, value);
+        }
+
+        public string BorderImageSource
+        {
+            get => GetPropertyValue(PropertyNames.BorderImageSource);
+            set => SetPropertyValue(PropertyNames.BorderImageSource, value);
+        }
+
+        public string BorderImageWidth
+        {
+            get => GetPropertyValue(PropertyNames.BorderImageWidth);
+            set => SetPropertyValue(PropertyNames.BorderImageWidth, value);
+        }
+
+        public string BorderLeft
+        {
+            get => GetPropertyValue(PropertyNames.BorderLeft);
+            set => SetPropertyValue(PropertyNames.BorderLeft, value);
+        }
+
+        public string BorderLeftColor
+        {
+            get => GetPropertyValue(PropertyNames.BorderLeftColor);
+            set => SetPropertyValue(PropertyNames.BorderLeftColor, value);
+        }
+
+        public string BorderLeftStyle
+        {
+            get => GetPropertyValue(PropertyNames.BorderLeftStyle);
+            set => SetPropertyValue(PropertyNames.BorderLeftStyle, value);
+        }
+
+        public string BorderLeftWidth
+        {
+            get => GetPropertyValue(PropertyNames.BorderLeftWidth);
+            set => SetPropertyValue(PropertyNames.BorderLeftWidth, value);
+        }
+
+        public string BorderRadius
+        {
+            get => GetPropertyValue(PropertyNames.BorderRadius);
+            set => SetPropertyValue(PropertyNames.BorderRadius, value);
+        }
+
+        public string BorderRight
+        {
+            get => GetPropertyValue(PropertyNames.BorderRight);
+            set => SetPropertyValue(PropertyNames.BorderRight, value);
+        }
+
+        public string BorderRightColor
+        {
+            get => GetPropertyValue(PropertyNames.BorderRightColor);
+            set => SetPropertyValue(PropertyNames.BorderRightColor, value);
+        }
+
+        public string BorderRightStyle
+        {
+            get => GetPropertyValue(PropertyNames.BorderRightStyle);
+            set => SetPropertyValue(PropertyNames.BorderRightStyle, value);
+        }
+
+        public string BorderRightWidth
+        {
+            get => GetPropertyValue(PropertyNames.BorderRightWidth);
+            set => SetPropertyValue(PropertyNames.BorderRightWidth, value);
+        }
+
+        public string BorderSpacing
+        {
+            get => GetPropertyValue(PropertyNames.BorderSpacing);
+            set => SetPropertyValue(PropertyNames.BorderSpacing, value);
+        }
+
+        public string BorderStyle
+        {
+            get => GetPropertyValue(PropertyNames.BorderStyle);
+            set => SetPropertyValue(PropertyNames.BorderStyle, value);
+        }
+
+        public string BorderTop
+        {
+            get => GetPropertyValue(PropertyNames.BorderTop);
+            set => SetPropertyValue(PropertyNames.BorderTop, value);
+        }
+
+        public string BorderTopColor
+        {
+            get => GetPropertyValue(PropertyNames.BorderTopColor);
+            set => SetPropertyValue(PropertyNames.BorderTopColor, value);
+        }
+
+        public string BorderTopLeftRadius
+        {
+            get => GetPropertyValue(PropertyNames.BorderTopLeftRadius);
+            set => SetPropertyValue(PropertyNames.BorderTopLeftRadius, value);
+        }
+
+        public string BorderTopRightRadius
+        {
+            get => GetPropertyValue(PropertyNames.BorderTopRightRadius);
+            set => SetPropertyValue(PropertyNames.BorderTopRightRadius, value);
+        }
+
+        public string BorderTopStyle
+        {
+            get => GetPropertyValue(PropertyNames.BorderTopStyle);
+            set => SetPropertyValue(PropertyNames.BorderTopStyle, value);
+        }
+
+        public string BorderTopWidth
+        {
+            get => GetPropertyValue(PropertyNames.BorderTopWidth);
+            set => SetPropertyValue(PropertyNames.BorderTopWidth, value);
+        }
+
+        public string BorderWidth
+        {
+            get => GetPropertyValue(PropertyNames.BorderWidth);
+            set => SetPropertyValue(PropertyNames.BorderWidth, value);
+        }
+
+        public string BoxShadow
+        {
+            get => GetPropertyValue(PropertyNames.BoxShadow);
+            set => SetPropertyValue(PropertyNames.BoxShadow, value);
+        }
+
+        public string BoxSizing
+        {
+            get => GetPropertyValue(PropertyNames.BoxSizing);
+            set => SetPropertyValue(PropertyNames.BoxSizing, value);
+        }
+
+        public string BreakAfter
+        {
+            get => GetPropertyValue(PropertyNames.BreakAfter);
+            set => SetPropertyValue(PropertyNames.BreakAfter, value);
+        }
+
+        public string BreakBefore
+        {
+            get => GetPropertyValue(PropertyNames.BreakBefore);
+            set => SetPropertyValue(PropertyNames.BreakBefore, value);
+        }
+
+        public string BreakInside
+        {
+            get => GetPropertyValue(PropertyNames.BreakInside);
+            set => SetPropertyValue(PropertyNames.BreakInside, value);
+        }
+
+        public string CaptionSide
+        {
+            get => GetPropertyValue(PropertyNames.CaptionSide);
+            set => SetPropertyValue(PropertyNames.CaptionSide, value);
+        }
+
+        public new string Clear
+        {
+            get => GetPropertyValue(PropertyNames.Clear);
+            set => SetPropertyValue(PropertyNames.Clear, value);
+        }
+
+        public string Clip
+        {
+            get => GetPropertyValue(PropertyNames.Clip);
+            set => SetPropertyValue(PropertyNames.Clip, value);
+        }
+
+        public string ClipBottom
+        {
+            get => GetPropertyValue(PropertyNames.ClipBottom);
+            set => SetPropertyValue(PropertyNames.ClipBottom, value);
+        }
+
+        public string ClipLeft
+        {
+            get => GetPropertyValue(PropertyNames.ClipLeft);
+            set => SetPropertyValue(PropertyNames.ClipLeft, value);
+        }
+
+        public string ClipPath
+        {
+            get => GetPropertyValue(PropertyNames.ClipPath);
+            set => SetPropertyValue(PropertyNames.ClipPath, value);
+        }
+
+        public string ClipRight
+        {
+            get => GetPropertyValue(PropertyNames.ClipRight);
+            set => SetPropertyValue(PropertyNames.ClipRight, value);
+        }
+
+        public string ClipRule
+        {
+            get => GetPropertyValue(PropertyNames.ClipRule);
+            set => SetPropertyValue(PropertyNames.ClipRule, value);
+        }
+
+        public string ClipTop
+        {
+            get => GetPropertyValue(PropertyNames.ClipTop);
+            set => SetPropertyValue(PropertyNames.ClipTop, value);
+        }
+
+        public string Color
+        {
+            get => GetPropertyValue(PropertyNames.Color);
+            set => SetPropertyValue(PropertyNames.Color, value);
+        }
+
+        public string ColorInterpolationFilters
+        {
+            get => GetPropertyValue(PropertyNames.ColorInterpolationFilters);
+            set => SetPropertyValue(PropertyNames.ColorInterpolationFilters, value);
+        }
+
+        public string ColumnCount
+        {
+            get => GetPropertyValue(PropertyNames.ColumnCount);
+            set => SetPropertyValue(PropertyNames.ColumnCount, value);
+        }
+
+        public string ColumnFill
+        {
+            get => GetPropertyValue(PropertyNames.ColumnFill);
+            set => SetPropertyValue(PropertyNames.ColumnFill, value);
+        }
+
+        public string ColumnGap
+        {
+            get => GetPropertyValue(PropertyNames.ColumnGap);
+            set => SetPropertyValue(PropertyNames.ColumnGap, value);
+        }
+
+        public string ColumnRule
+        {
+            get => GetPropertyValue(PropertyNames.ColumnRule);
+            set => SetPropertyValue(PropertyNames.ColumnRule, value);
+        }
+
+        public string ColumnRuleColor
+        {
+            get => GetPropertyValue(PropertyNames.ColumnRuleColor);
+            set => SetPropertyValue(PropertyNames.ColumnRuleColor, value);
+        }
+
+        public string ColumnRuleStyle
+        {
+            get => GetPropertyValue(PropertyNames.ColumnRuleStyle);
+            set => SetPropertyValue(PropertyNames.ColumnRuleStyle, value);
+        }
+
+        public string ColumnRuleWidth
+        {
+            get => GetPropertyValue(PropertyNames.ColumnRuleWidth);
+            set => SetPropertyValue(PropertyNames.ColumnRuleWidth, value);
+        }
+
+        public string Columns
+        {
+            get => GetPropertyValue(PropertyNames.Columns);
+            set => SetPropertyValue(PropertyNames.Columns, value);
+        }
+
+        public string ColumnSpan
+        {
+            get => GetPropertyValue(PropertyNames.ColumnSpan);
+            set => SetPropertyValue(PropertyNames.ColumnSpan, value);
+        }
+
+        public string ColumnWidth
+        {
+            get => GetPropertyValue(PropertyNames.ColumnWidth);
+            set => SetPropertyValue(PropertyNames.ColumnWidth, value);
+        }
+
+        public string ContainerName
+        {
+            get => GetPropertyValue(PropertyNames.ContainerName);
+            set => SetPropertyValue(PropertyNames.ContainerName, value);
+        }
+
+        public string ContainerType
+        {
+            get => GetPropertyValue(PropertyNames.ContainerType);
+            set => SetPropertyValue(PropertyNames.ContainerType, value);
+        }
+
+        public string Content
+        {
+            get => GetPropertyValue(PropertyNames.Content);
+            set => SetPropertyValue(PropertyNames.Content, value);
+        }
+
+        public string CounterIncrement
+        {
+            get => GetPropertyValue(PropertyNames.CounterIncrement);
+            set => SetPropertyValue(PropertyNames.CounterIncrement, value);
+        }
+
+        public string CounterReset
+        {
+            get => GetPropertyValue(PropertyNames.CounterReset);
+            set => SetPropertyValue(PropertyNames.CounterReset, value);
+        }
+
+        public string Float
+        {
+            get => GetPropertyValue(PropertyNames.Float);
+            set => SetPropertyValue(PropertyNames.Float, value);
+        }
+
+        public string Cursor
+        {
+            get => GetPropertyValue(PropertyNames.Cursor);
+            set => SetPropertyValue(PropertyNames.Cursor, value);
+        }
+
+        public string Direction
+        {
+            get => GetPropertyValue(PropertyNames.Direction);
+            set => SetPropertyValue(PropertyNames.Direction, value);
+        }
+
+        public string Display
+        {
+            get => GetPropertyValue(PropertyNames.Display);
+            set => SetPropertyValue(PropertyNames.Display, value);
+        }
+
+        public string DominantBaseline
+        {
+            get => GetPropertyValue(PropertyNames.DominantBaseline);
+            set => SetPropertyValue(PropertyNames.DominantBaseline, value);
+        }
+
+        public string EmptyCells
+        {
+            get => GetPropertyValue(PropertyNames.EmptyCells);
+            set => SetPropertyValue(PropertyNames.EmptyCells, value);
+        }
+
+        public string EnableBackground
+        {
+            get => GetPropertyValue(PropertyNames.EnableBackground);
+            set => SetPropertyValue(PropertyNames.EnableBackground, value);
+        }
+
+        public string Fill
+        {
+            get => GetPropertyValue(PropertyNames.Fill);
+            set => SetPropertyValue(PropertyNames.Fill, value);
+        }
+
+        public string FillOpacity
+        {
+            get => GetPropertyValue(PropertyNames.FillOpacity);
+            set => SetPropertyValue(PropertyNames.FillOpacity, value);
+        }
+
+        public string FillRule
+        {
+            get => GetPropertyValue(PropertyNames.FillRule);
+            set => SetPropertyValue(PropertyNames.FillRule, value);
+        }
+
+        public string Filter
+        {
+            get => GetPropertyValue(PropertyNames.Filter);
+            set => SetPropertyValue(PropertyNames.Filter, value);
+        }
+
+        public string Flex
+        {
+            get => GetPropertyValue(PropertyNames.Flex);
+            set => SetPropertyValue(PropertyNames.Flex, value);
+        }
+
+        public string FlexBasis
+        {
+            get => GetPropertyValue(PropertyNames.FlexBasis);
+            set => SetPropertyValue(PropertyNames.FlexBasis, value);
+        }
+
+        public string FlexDirection
+        {
+            get => GetPropertyValue(PropertyNames.FlexDirection);
+            set => SetPropertyValue(PropertyNames.FlexDirection, value);
+        }
+
+        public string FlexFlow
+        {
+            get => GetPropertyValue(PropertyNames.FlexFlow);
+            set => SetPropertyValue(PropertyNames.FlexFlow, value);
+        }
+
+        public string FlexGrow
+        {
+            get => GetPropertyValue(PropertyNames.FlexGrow);
+            set => SetPropertyValue(PropertyNames.FlexGrow, value);
+        }
+
+        public string FlexShrink
+        {
+            get => GetPropertyValue(PropertyNames.FlexShrink);
+            set => SetPropertyValue(PropertyNames.FlexShrink, value);
+        }
+
+        public string FlexWrap
+        {
+            get => GetPropertyValue(PropertyNames.FlexWrap);
+            set => SetPropertyValue(PropertyNames.FlexWrap, value);
+        }
+
+        public string Font
+        {
+            get => GetPropertyValue(PropertyNames.Font);
+            set => SetPropertyValue(PropertyNames.Font, value);
+        }
+
+        public string FontFamily
+        {
+            get => GetPropertyValue(PropertyNames.FontFamily);
+            set => SetPropertyValue(PropertyNames.FontFamily, value);
+        }
+
+        public string FontFeatureSettings
+        {
+            get => GetPropertyValue(PropertyNames.FontFeatureSettings);
+            set => SetPropertyValue(PropertyNames.FontFeatureSettings, value);
+        }
+
+        public string FontSize
+        {
+            get => GetPropertyValue(PropertyNames.FontSize);
+            set => SetPropertyValue(PropertyNames.FontSize, value);
+        }
+
+        public string FontSizeAdjust
+        {
+            get => GetPropertyValue(PropertyNames.FontSizeAdjust);
+            set => SetPropertyValue(PropertyNames.FontSizeAdjust, value);
+        }
+
+        public string FontStretch
+        {
+            get => GetPropertyValue(PropertyNames.FontStretch);
+            set => SetPropertyValue(PropertyNames.FontStretch, value);
+        }
+
+        public string FontStyle
+        {
+            get => GetPropertyValue(PropertyNames.FontStyle);
+            set => SetPropertyValue(PropertyNames.FontStyle, value);
+        }
+
+        public string FontVariant
+        {
+            get => GetPropertyValue(PropertyNames.FontVariant);
+            set => SetPropertyValue(PropertyNames.FontVariant, value);
+        }
+
+        public string FontWeight
+        {
+            get => GetPropertyValue(PropertyNames.FontWeight);
+            set => SetPropertyValue(PropertyNames.FontWeight, value);
+        }
+
+        public string Gap
+        {
+            get => GetPropertyValue(PropertyNames.Gap);
+            set => SetPropertyValue(PropertyNames.Gap, value);
+        }
+
+        public string GlyphOrientationHorizontal
+        {
+            get => GetPropertyValue(PropertyNames.GlyphOrientationHorizontal);
+            set => SetPropertyValue(PropertyNames.GlyphOrientationHorizontal, value);
+        }
+
+        public string GlyphOrientationVertical
+        {
+            get => GetPropertyValue(PropertyNames.GlyphOrientationVertical);
+            set => SetPropertyValue(PropertyNames.GlyphOrientationVertical, value);
+        }
+
+        public string Height
+        {
+            get => GetPropertyValue(PropertyNames.Height);
+            set => SetPropertyValue(PropertyNames.Height, value);
+        }
+
+        public string ImeMode
+        {
+            get => GetPropertyValue(PropertyNames.ImeMode);
+            set => SetPropertyValue(PropertyNames.ImeMode, value);
+        }
+
+        public string JustifyContent
+        {
+            get => GetPropertyValue(PropertyNames.JustifyContent);
+            set => SetPropertyValue(PropertyNames.JustifyContent, value);
+        }
+
+        public string LayoutGrid
+        {
+            get => GetPropertyValue(PropertyNames.LayoutGrid);
+            set => SetPropertyValue(PropertyNames.LayoutGrid, value);
+        }
+
+        public string LayoutGridChar
+        {
+            get => GetPropertyValue(PropertyNames.LayoutGridChar);
+            set => SetPropertyValue(PropertyNames.LayoutGridChar, value);
+        }
+
+        public string LayoutGridLine
+        {
+            get => GetPropertyValue(PropertyNames.LayoutGridLine);
+            set => SetPropertyValue(PropertyNames.LayoutGridLine, value);
+        }
+
+        public string LayoutGridMode
+        {
+            get => GetPropertyValue(PropertyNames.LayoutGridMode);
+            set => SetPropertyValue(PropertyNames.LayoutGridMode, value);
+        }
+
+        public string LayoutGridType
+        {
+            get => GetPropertyValue(PropertyNames.LayoutGridType);
+            set => SetPropertyValue(PropertyNames.LayoutGridType, value);
+        }
+
+        public string Left
+        {
+            get => GetPropertyValue(PropertyNames.Left);
+            set => SetPropertyValue(PropertyNames.Left, value);
+        }
+
+        public string LetterSpacing
+        {
+            get => GetPropertyValue(PropertyNames.LetterSpacing);
+            set => SetPropertyValue(PropertyNames.LetterSpacing, value);
+        }
+
+        public string LineHeight
+        {
+            get => GetPropertyValue(PropertyNames.LineHeight);
+            set => SetPropertyValue(PropertyNames.LineHeight, value);
+        }
+
+        public string ListStyle
+        {
+            get => GetPropertyValue(PropertyNames.ListStyle);
+            set => SetPropertyValue(PropertyNames.ListStyle, value);
+        }
+
+        public string ListStyleImage
+        {
+            get => GetPropertyValue(PropertyNames.ListStyleImage);
+            set => SetPropertyValue(PropertyNames.ListStyleImage, value);
+        }
+
+        public string ListStylePosition
+        {
+            get => GetPropertyValue(PropertyNames.ListStylePosition);
+            set => SetPropertyValue(PropertyNames.ListStylePosition, value);
+        }
+
+        public string ListStyleType
+        {
+            get => GetPropertyValue(PropertyNames.ListStyleType);
+            set => SetPropertyValue(PropertyNames.ListStyleType, value);
+        }
+
+        public string Margin
+        {
+            get => GetPropertyValue(PropertyNames.Margin);
+            set => SetPropertyValue(PropertyNames.Margin, value);
+        }
+
+        public string MarginBottom
+        {
+            get => GetPropertyValue(PropertyNames.MarginBottom);
+            set => SetPropertyValue(PropertyNames.MarginBottom, value);
+        }
+
+        public string MarginLeft
+        {
+            get => GetPropertyValue(PropertyNames.MarginLeft);
+            set => SetPropertyValue(PropertyNames.MarginLeft, value);
+        }
+
+        public string MarginRight
+        {
+            get => GetPropertyValue(PropertyNames.MarginRight);
+            set => SetPropertyValue(PropertyNames.MarginRight, value);
+        }
+
+        public string MarginTop
+        {
+            get => GetPropertyValue(PropertyNames.MarginTop);
+            set => SetPropertyValue(PropertyNames.MarginTop, value);
+        }
+
+        public string Marker
+        {
+            get => GetPropertyValue(PropertyNames.Marker);
+            set => SetPropertyValue(PropertyNames.Marker, value);
+        }
+
+        public string MarkerEnd
+        {
+            get => GetPropertyValue(PropertyNames.MarkerEnd);
+            set => SetPropertyValue(PropertyNames.MarkerEnd, value);
+        }
+
+        public string MarkerMid
+        {
+            get => GetPropertyValue(PropertyNames.MarkerMid);
+            set => SetPropertyValue(PropertyNames.MarkerMid, value);
+        }
+
+        public string MarkerStart
+        {
+            get => GetPropertyValue(PropertyNames.MarkerStart);
+            set => SetPropertyValue(PropertyNames.MarkerStart, value);
+        }
+
+        public string Mask
+        {
+            get => GetPropertyValue(PropertyNames.Mask);
+            set => SetPropertyValue(PropertyNames.Mask, value);
+        }
+
+        public string MaxHeight
+        {
+            get => GetPropertyValue(PropertyNames.MaxHeight);
+            set => SetPropertyValue(PropertyNames.MaxHeight, value);
+        }
+
+        public string MaxWidth
+        {
+            get => GetPropertyValue(PropertyNames.MaxWidth);
+            set => SetPropertyValue(PropertyNames.MaxWidth, value);
+        }
+
+        public string MinHeight
+        {
+            get => GetPropertyValue(PropertyNames.MinHeight);
+            set => SetPropertyValue(PropertyNames.MinHeight, value);
+        }
+
+        public string MinWidth
+        {
+            get => GetPropertyValue(PropertyNames.MinWidth);
+            set => SetPropertyValue(PropertyNames.MinWidth, value);
+        }
+
+        public string Opacity
+        {
+            get => GetPropertyValue(PropertyNames.Opacity);
+            set => SetPropertyValue(PropertyNames.Opacity, value);
+        }
+
+        public string Order
+        {
+            get => GetPropertyValue(PropertyNames.Order);
+            set => SetPropertyValue(PropertyNames.Order, value);
+        }
+
+        public string Orphans
+        {
+            get => GetPropertyValue(PropertyNames.Orphans);
+            set => SetPropertyValue(PropertyNames.Orphans, value);
+        }
+
+        public string Outline
+        {
+            get => GetPropertyValue(PropertyNames.Outline);
+            set => SetPropertyValue(PropertyNames.Outline, value);
+        }
+
+        public string OutlineColor
+        {
+            get => GetPropertyValue(PropertyNames.OutlineColor);
+            set => SetPropertyValue(PropertyNames.OutlineColor, value);
+        }
+
+        public string OutlineStyle
+        {
+            get => GetPropertyValue(PropertyNames.OutlineStyle);
+            set => SetPropertyValue(PropertyNames.OutlineStyle, value);
+        }
+
+        public string OutlineWidth
+        {
+            get => GetPropertyValue(PropertyNames.OutlineWidth);
+            set => SetPropertyValue(PropertyNames.OutlineWidth, value);
+        }
+
+        public string Overflow
+        {
+            get => GetPropertyValue(PropertyNames.Overflow);
+            set => SetPropertyValue(PropertyNames.Overflow, value);
+        }
+
+        public string OverflowX
+        {
+            get => GetPropertyValue(PropertyNames.OverflowX);
+            set => SetPropertyValue(PropertyNames.OverflowX, value);
+        }
+
+        public string OverflowY
+        {
+            get => GetPropertyValue(PropertyNames.OverflowY);
+            set => SetPropertyValue(PropertyNames.OverflowY, value);
+        }
+
+        public string OverflowWrap
+        {
+            get => GetPropertyValue(PropertyNames.WordWrap);
+            set => SetPropertyValue(PropertyNames.WordWrap, value);
+        }
+
+        public string Padding
+        {
+            get => GetPropertyValue(PropertyNames.Padding);
+            set => SetPropertyValue(PropertyNames.Padding, value);
+        }
+
+        public string PaddingBottom
+        {
+            get => GetPropertyValue(PropertyNames.PaddingBottom);
+            set => SetPropertyValue(PropertyNames.PaddingBottom, value);
+        }
+
+        public string PaddingLeft
+        {
+            get => GetPropertyValue(PropertyNames.PaddingLeft);
+            set => SetPropertyValue(PropertyNames.PaddingLeft, value);
+        }
+
+        public string PaddingRight
+        {
+            get => GetPropertyValue(PropertyNames.PaddingRight);
+            set => SetPropertyValue(PropertyNames.PaddingRight, value);
+        }
+
+        public string PaddingTop
+        {
+            get => GetPropertyValue(PropertyNames.PaddingTop);
+            set => SetPropertyValue(PropertyNames.PaddingTop, value);
+        }
+
+        public string PageBreakAfter
+        {
+            get => GetPropertyValue(PropertyNames.PageBreakAfter);
+            set => SetPropertyValue(PropertyNames.PageBreakAfter, value);
+        }
+
+        public string PageBreakBefore
+        {
+            get => GetPropertyValue(PropertyNames.PageBreakBefore);
+            set => SetPropertyValue(PropertyNames.PageBreakBefore, value);
+        }
+
+        public string PageBreakInside
+        {
+            get => GetPropertyValue(PropertyNames.PageBreakInside);
+            set => SetPropertyValue(PropertyNames.PageBreakInside, value);
+        }
+
+        public string Perspective
+        {
+            get => GetPropertyValue(PropertyNames.Perspective);
+            set => SetPropertyValue(PropertyNames.Perspective, value);
+        }
+
+        public string PerspectiveOrigin
+        {
+            get => GetPropertyValue(PropertyNames.PerspectiveOrigin);
+            set => SetPropertyValue(PropertyNames.PerspectiveOrigin, value);
+        }
+
+        public string PointerEvents
+        {
+            get => GetPropertyValue(PropertyNames.PointerEvents);
+            set => SetPropertyValue(PropertyNames.PointerEvents, value);
+        }
+
+        public string RowGap
+        {
+            get => GetPropertyValue(PropertyNames.RowGap);
+            set => SetPropertyValue(PropertyNames.RowGap, value);
+        }
+
+        public string Quotes
+        {
+            get => GetPropertyValue(PropertyNames.Quotes);
+            set => SetPropertyValue(PropertyNames.Quotes, value);
+        }
+
+        public string Position
+        {
+            get => GetPropertyValue(PropertyNames.Position);
+            set => SetPropertyValue(PropertyNames.Position, value);
+        }
+
+        public string Right
+        {
+            get => GetPropertyValue(PropertyNames.Right);
+            set => SetPropertyValue(PropertyNames.Right, value);
+        }
+
+        public string RubyAlign
+        {
+            get => GetPropertyValue(PropertyNames.RubyAlign);
+            set => SetPropertyValue(PropertyNames.RubyAlign, value);
+        }
+
+        public string RubyOverhang
+        {
+            get => GetPropertyValue(PropertyNames.RubyOverhang);
+            set => SetPropertyValue(PropertyNames.RubyOverhang, value);
+        }
+
+        public string RubyPosition
+        {
+            get => GetPropertyValue(PropertyNames.RubyPosition);
+            set => SetPropertyValue(PropertyNames.RubyPosition, value);
+        }
+
+        public string Scrollbar3DLightColor
+        {
+            get => GetPropertyValue(PropertyNames.Scrollbar3dLightColor);
+            set => SetPropertyValue(PropertyNames.Scrollbar3dLightColor, value);
+        }
+
+        public string ScrollbarArrowColor
+        {
+            get => GetPropertyValue(PropertyNames.ScrollbarArrowColor);
+            set => SetPropertyValue(PropertyNames.ScrollbarArrowColor, value);
+        }
+
+        public string ScrollbarDarkShadowColor
+        {
+            get => GetPropertyValue(PropertyNames.ScrollbarDarkShadowColor);
+            set => SetPropertyValue(PropertyNames.ScrollbarDarkShadowColor, value);
+        }
+
+        public string ScrollbarFaceColor
+        {
+            get => GetPropertyValue(PropertyNames.ScrollbarFaceColor);
+            set => SetPropertyValue(PropertyNames.ScrollbarFaceColor, value);
+        }
+
+        public string ScrollbarHighlightColor
+        {
+            get => GetPropertyValue(PropertyNames.ScrollbarHighlightColor);
+            set => SetPropertyValue(PropertyNames.ScrollbarHighlightColor, value);
+        }
+
+        public string ScrollbarShadowColor
+        {
+            get => GetPropertyValue(PropertyNames.ScrollbarShadowColor);
+            set => SetPropertyValue(PropertyNames.ScrollbarShadowColor, value);
+        }
+
+        public string ScrollbarTrackColor
+        {
+            get => GetPropertyValue(PropertyNames.ScrollbarTrackColor);
+            set => SetPropertyValue(PropertyNames.ScrollbarTrackColor, value);
+        }
+
+        public string Stroke
+        {
+            get => GetPropertyValue(PropertyNames.Stroke);
+            set => SetPropertyValue(PropertyNames.Stroke, value);
+        }
+
+        public string StrokeDasharray
+        {
+            get => GetPropertyValue(PropertyNames.StrokeDasharray);
+            set => SetPropertyValue(PropertyNames.StrokeDasharray, value);
+        }
+
+        public string StrokeDashoffset
+        {
+            get => GetPropertyValue(PropertyNames.StrokeDashoffset);
+            set => SetPropertyValue(PropertyNames.StrokeDashoffset, value);
+        }
+
+        public string StrokeLinecap
+        {
+            get => GetPropertyValue(PropertyNames.StrokeLinecap);
+            set => SetPropertyValue(PropertyNames.StrokeLinecap, value);
+        }
+
+        public string StrokeLinejoin
+        {
+            get => GetPropertyValue(PropertyNames.StrokeLinejoin);
+            set => SetPropertyValue(PropertyNames.StrokeLinejoin, value);
+        }
+
+        public string StrokeMiterlimit
+        {
+            get => GetPropertyValue(PropertyNames.StrokeMiterlimit);
+            set => SetPropertyValue(PropertyNames.StrokeMiterlimit, value);
+        }
+
+        public string StrokeOpacity
+        {
+            get => GetPropertyValue(PropertyNames.StrokeOpacity);
+            set => SetPropertyValue(PropertyNames.StrokeOpacity, value);
+        }
+
+        public string StrokeWidth
+        {
+            get => GetPropertyValue(PropertyNames.StrokeWidth);
+            set => SetPropertyValue(PropertyNames.StrokeWidth, value);
+        }
+
+        public string TableLayout
+        {
+            get => GetPropertyValue(PropertyNames.TableLayout);
+            set => SetPropertyValue(PropertyNames.TableLayout, value);
+        }
+
+        public string TextAlign
+        {
+            get => GetPropertyValue(PropertyNames.TextAlign);
+            set => SetPropertyValue(PropertyNames.TextAlign, value);
+        }
+
+        public string TextAlignLast
+        {
+            get => GetPropertyValue(PropertyNames.TextAlignLast);
+            set => SetPropertyValue(PropertyNames.TextAlignLast, value);
+        }
+
+        public string TextAnchor
+        {
+            get => GetPropertyValue(PropertyNames.TextAnchor);
+            set => SetPropertyValue(PropertyNames.TextAnchor, value);
+        }
+
+        public string TextAutospace
+        {
+            get => GetPropertyValue(PropertyNames.TextAutospace);
+            set => SetPropertyValue(PropertyNames.TextAutospace, value);
+        }
+
+        public string TextDecoration
+        {
+            get => GetPropertyValue(PropertyNames.TextDecoration);
+            set => SetPropertyValue(PropertyNames.TextDecoration, value);
+        }
+
+        public string TextIndent
+        {
+            get => GetPropertyValue(PropertyNames.TextIndent);
+            set => SetPropertyValue(PropertyNames.TextIndent, value);
+        }
+
+        public string TextJustify
+        {
+            get => GetPropertyValue(PropertyNames.TextJustify);
+            set => SetPropertyValue(PropertyNames.TextJustify, value);
+        }
+
+        public string TextOverflow
+        {
+            get => GetPropertyValue(PropertyNames.TextOverflow);
+            set => SetPropertyValue(PropertyNames.TextOverflow, value);
+        }
+
+        public string TextShadow
+        {
+            get => GetPropertyValue(PropertyNames.TextShadow);
+            set => SetPropertyValue(PropertyNames.TextShadow, value);
+        }
+
+        public string TextTransform
+        {
+            get => GetPropertyValue(PropertyNames.TextTransform);
+            set => SetPropertyValue(PropertyNames.TextTransform, value);
+        }
+
+        public string TextUnderlinePosition
+        {
+            get => GetPropertyValue(PropertyNames.TextUnderlinePosition);
+            set => SetPropertyValue(PropertyNames.TextUnderlinePosition, value);
+        }
+
+        public string Top
+        {
+            get => GetPropertyValue(PropertyNames.Top);
+            set => SetPropertyValue(PropertyNames.Top, value);
+        }
+
+        public string Transform
+        {
+            get => GetPropertyValue(PropertyNames.Transform);
+            set => SetPropertyValue(PropertyNames.Transform, value);
+        }
+
+        public string TransformOrigin
+        {
+            get => GetPropertyValue(PropertyNames.TransformOrigin);
+            set => SetPropertyValue(PropertyNames.TransformOrigin, value);
+        }
+
+        public string TransformStyle
+        {
+            get => GetPropertyValue(PropertyNames.TransformStyle);
+            set => SetPropertyValue(PropertyNames.TransformStyle, value);
+        }
+
+        public string Transition
+        {
+            get => GetPropertyValue(PropertyNames.Transition);
+            set => SetPropertyValue(PropertyNames.Transition, value);
+        }
+
+        public string TransitionDelay
+        {
+            get => GetPropertyValue(PropertyNames.TransitionDelay);
+            set => SetPropertyValue(PropertyNames.TransitionDelay, value);
+        }
+
+        public string TransitionDuration
+        {
+            get => GetPropertyValue(PropertyNames.TransitionDuration);
+            set => SetPropertyValue(PropertyNames.TransitionDuration, value);
+        }
+
+        public string TransitionProperty
+        {
+            get => GetPropertyValue(PropertyNames.TransitionProperty);
+            set => SetPropertyValue(PropertyNames.TransitionProperty, value);
+        }
+
+        public string TransitionTimingFunction
+        {
+            get => GetPropertyValue(PropertyNames.TransitionTimingFunction);
+            set => SetPropertyValue(PropertyNames.TransitionTimingFunction, value);
+        }
+
+        public string UnicodeBidirectional
+        {
+            get => GetPropertyValue(PropertyNames.UnicodeBidirectional);
+            set => SetPropertyValue(PropertyNames.UnicodeBidirectional, value);
+        }
+
+        public string VerticalAlign
+        {
+            get => GetPropertyValue(PropertyNames.VerticalAlign);
+            set => SetPropertyValue(PropertyNames.VerticalAlign, value);
+        }
+
+        public string Visibility
+        {
+            get => GetPropertyValue(PropertyNames.Visibility);
+            set => SetPropertyValue(PropertyNames.Visibility, value);
+        }
+
+        public string WhiteSpace
+        {
+            get => GetPropertyValue(PropertyNames.WhiteSpace);
+            set => SetPropertyValue(PropertyNames.WhiteSpace, value);
+        }
+
+        public string Widows
+        {
+            get => GetPropertyValue(PropertyNames.Widows);
+            set => SetPropertyValue(PropertyNames.Widows, value);
+        }
+
+        public string Width
+        {
+            get => GetPropertyValue(PropertyNames.Width);
+            set => SetPropertyValue(PropertyNames.Width, value);
+        }
+
+        public string WordBreak
+        {
+            get => GetPropertyValue(PropertyNames.WordBreak);
+            set => SetPropertyValue(PropertyNames.WordBreak, value);
+        }
+
+        public string WordSpacing
+        {
+            get => GetPropertyValue(PropertyNames.WordSpacing);
+            set => SetPropertyValue(PropertyNames.WordSpacing, value);
+        }
+
+        public string WritingMode
+        {
+            get => GetPropertyValue(PropertyNames.WritingMode);
+            set => SetPropertyValue(PropertyNames.WritingMode, value);
+        }
+
+        public string ZIndex
+        {
+            get => GetPropertyValue(PropertyNames.ZIndex);
+            set => SetPropertyValue(PropertyNames.ZIndex, value);
+        }
+
+        public string Zoom
+        {
+            get => GetPropertyValue(PropertyNames.Zoom);
+            set => SetPropertyValue(PropertyNames.Zoom, value);
+        }
+
+        public string Size
+        {
+            get => GetPropertyValue(PropertyNames.Size);
+            set => SetPropertyValue(PropertyNames.Size, value);
+        }
+
+        public string PageName
+        {
+            get => GetPropertyValue(PropertyNames.PageName);
+            set => SetPropertyValue(PropertyNames.PageName, value);
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Stylesheet.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Stylesheet.cs
new file mode 100644
index 000000000..ec5321af6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Stylesheet.cs
@@ -0,0 +1,70 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class Stylesheet : StylesheetNode
+    {
+        private readonly StylesheetParser _parser;
+
+        internal Stylesheet(StylesheetParser parser)
+        {
+            _parser = parser;
+            Rules = new RuleList(this);
+        }
+
+        internal RuleList Rules { get; }
+
+        internal bool IsUserAgent { get; set; }
+
+        /// <summary>
+        /// The resolved absolute URI this stylesheet was loaded from (null for stylesheets with no
+        /// external location, e.g. an inline &lt;style&gt; block or caller-supplied CSS text). Relative
+        /// <c>url()</c> references inside this stylesheet (nested <c>@import</c>, <c>@font-face src</c>)
+        /// resolve against this, not the document's base URI, matching browser behavior for fetched CSS.
+        /// </summary>
+        internal Uri BaseUri { get; set; }
+
+        public IEnumerable<ICharsetRule> CharacterSetRules => Rules.Where(r => r is CharsetRule).Cast<ICharsetRule>();
+        public IEnumerable<IFontFaceRule> FontfaceSetRules => Rules.Where(r => r is FontFaceRule).Cast<IFontFaceRule>();
+        public IEnumerable<IMediaRule> MediaRules => Rules.Where(r => r is MediaRule).Cast<IMediaRule>();
+        public IEnumerable<IContainerRule> ContainerRules => Rules.Where(r => r is ContainerRule).Cast<IContainerRule>();
+        public IEnumerable<IImportRule> ImportRules => Rules.Where(r => r is ImportRule).Cast<IImportRule>();
+
+        public IEnumerable<INamespaceRule> NamespaceRules =>
+            Rules.Where(r => r is NamespaceRule).Cast<INamespaceRule>();
+
+        public IEnumerable<IPageRule> PageRules => Rules.Where(r => r is PageRule).Cast<IPageRule>();
+        public IEnumerable<IStyleRule> StyleRules => Rules.Where(r => r is StyleRule).Cast<IStyleRule>();
+
+        public IRule Add(RuleType ruleType)
+        {
+            var rule = _parser.CreateRule(ruleType);
+            Rules.Add(rule);
+            return rule;
+        }
+
+        public void RemoveAt(int index)
+        {
+            Rules.RemoveAt(index);
+        }
+
+        public int Insert(string ruleText, int index)
+        {
+            var rule = _parser.ParseRule(ruleText);
+            rule.Owner = this;
+            Rules.Insert(index, rule);
+
+            return index;
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Sheet(Rules));
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/StylesheetNode.cs b/Source/HtmlRenderer/Core/CssEngine/Model/StylesheetNode.cs
new file mode 100644
index 000000000..f8b7f3e85
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/StylesheetNode.cs
@@ -0,0 +1,92 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class StylesheetNode : IStylesheetNode
+    {
+        private readonly List<IStylesheetNode> _children = new List<IStylesheetNode>();
+
+        protected void ReplaceAll(IStylesheetNode node)
+        {
+            Clear();
+            StylesheetText = node.StylesheetText;
+            foreach (var child in node.Children) AppendChild(child);
+        }
+
+        public StylesheetText StylesheetText { get; internal set; }
+
+        public IEnumerable<IStylesheetNode> Children => _children.AsEnumerable();
+
+        public abstract void ToCss(TextWriter writer, IStyleFormatter formatter);
+
+        public void AppendChild(IStylesheetNode child)
+        {
+            Setup(child);
+            _children.Add(child);
+        }
+
+        public void ReplaceChild(IStylesheetNode oldChild, IStylesheetNode newChild)
+        {
+            for (var i = 0; i < _children.Count; i++)
+            {
+                if (ReferenceEquals(oldChild, _children[i]))
+                {
+                    Teardown(oldChild);
+                    Setup(newChild);
+                    _children[i] = newChild;
+                    return;
+                }
+            }
+        }
+
+        public void InsertBefore(IStylesheetNode referenceChild, IStylesheetNode child)
+        {
+            if (referenceChild != null)
+            {
+                var index = _children.IndexOf(referenceChild);
+                InsertChild(index, child);
+            }
+            else
+            {
+                AppendChild(child);
+            }
+        }
+
+        public void InsertChild(int index, IStylesheetNode child)
+        {
+            Setup(child);
+            _children.Insert(index, child);
+        }
+
+        public void RemoveChild(IStylesheetNode child)
+        {
+            Teardown(child);
+            _children.Remove(child);
+        }
+
+        public void Clear()
+        {
+            for (var i = _children.Count - 1; i >= 0; i--)
+            {
+                var child = _children[i];
+                RemoveChild(child);
+            }
+        }
+
+        private void Setup(IStylesheetNode child)
+        {
+            if (!(child is Rule rule)) return;
+            rule.Owner = this as Stylesheet;
+            rule.Parent = this as IRule;
+        }
+
+        private static void Teardown(IStylesheetNode child)
+        {
+            if (!(child is Rule rule)) return;
+            rule.Parent = null;
+            rule.Owner = null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/StylesheetText.cs b/Source/HtmlRenderer/Core/CssEngine/Model/StylesheetText.cs
new file mode 100644
index 000000000..dd8de8296
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/StylesheetText.cs
@@ -0,0 +1,31 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal class StylesheetText
+    {
+        private readonly TextSource _source;
+
+        internal StylesheetText(TextRange range, TextSource source)
+        {
+            Range = range;
+            _source = source;
+        }
+
+        public TextRange Range { get; }
+
+        public string Text
+        {
+            get
+            {
+                var start = Math.Max(Range.Start.Position - 1, 0);
+                var length = Range.End.Position + 1 - Range.Start.Position;
+                var text = _source.Text;
+
+                if (start + length > text.Length) length = text.Length - start;
+
+                return text.Substring(start, length);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Symbols.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Symbols.cs
new file mode 100644
index 000000000..b9086e1b4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Symbols.cs
@@ -0,0 +1,90 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+
+
+    internal static class Symbols
+    {
+        //public static readonly string[] NewLines = { "\r\n", "\r", "\n" };
+
+        public const char StartOfHeading = (char)0x01;      // Non-printable SOH
+        public const char Backspace = (char)0x08;           // Non-printable BS
+        public const char UnitSeparator = (char)0x1F;       // Non-printable US
+        public const char ShiftOut = (char)0x0E;            // Non-printable SO
+        //public const char ShiftIn = (char)0x0F;             // Non-printable SI
+
+        public const char Zero = (char)0x30;                // 0
+        public const char Seven = (char)0x37;               // 7
+        public const char Nine = (char)0x39;                // 9
+
+        public const char CapitalA = (char)0x41;            // A
+        public const char CapitalF = (char)0x46;            // F
+        public const char CapitalW = (char)0x57;            // W
+        public const char CapitalZ = (char)0x5a;            // Z
+        public const char LowerA = (char)0x61;              // a
+        public const char LowerF = (char)0x66;              // f
+        public const char LowerZ = (char)0x7a;              // z
+        public const char Delete = (char)0x7f;              // DEL
+
+        public const char EndOfFile = char.MaxValue;
+        public const char Tilde = (char)0x7e;              // ~
+        public const char Pipe = (char)0x7c;               // |
+        public const char Null = (char)0x0;
+        //public const char Ampersand = (char) 0x26;          // &amp
+        public const char Num = (char)0x23;                // #
+        public const char Dollar = (char)0x24;             // $
+        public const char Semicolon = (char)0x3b;          // ;
+        public const char Asterisk = (char)0x2a;           // *
+        public const char Equality = (char)0x3d;           // =
+        public const char Plus = (char)0x2b;               // +
+        public const char Minus = (char)0x2d;              // -
+        public const char Comma = (char)0x2c;              // ,
+        public const char Dot = (char)0x2e;                // .
+        public const char Accent = (char)0x5e;             // ^
+        public const char At = (char)0x40;                 // @
+        public const char LessThan = (char)0x3c;           // <
+        public const char GreaterThan = (char)0x3e;        // >
+        public const char SingleQuote = (char)0x27;        // '
+        public const char DoubleQuote = (char)0x22;        // "
+        public const char CurvedQuote = (char)0x60;        // `
+        public const char QuestionMark = (char)0x3f;       // ?
+        public const char Tab = (char)0x09;                // tab
+        public const char LineFeed = (char)0x0a;           // line feeed
+        public const char CarriageReturn = (char)0x0d;     // return
+        public const char FormFeed = (char)0x0c;           // form feed
+        public const char Space = (char)0x20;              // space
+        public const char Solidus = (char)0x2f;            // solidus /
+        //public const char NoBreakSpace = (char) 0xa0;       // no breaking space
+        public const char ReverseSolidus = (char)0x5c;     // reverse solidus \
+        public const char Colon = (char)0x3a;              // :
+        public const char ExclamationMark = (char)0x21;    // !
+        public const char Replacement = (char)0xfffd;      // replacement
+        public const char Underscore = (char)0x5f;         // _
+        public const char RoundBracketOpen = (char)0x28;   // (
+        public const char RoundBracketClose = (char)0x29;  // )
+        public const char SquareBracketOpen = (char)0x5b;  // [
+        public const char SquareBracketClose = (char)0x5d; // ]
+        public const char CurlyBracketOpen = (char)0x7b;   // {
+        public const char CurlyBracketClose = (char)0x7d;  // }
+        public const char Percent = (char)0x25;            // %
+        public const int MaximumCodepoint = 0x10FFFF;       // The maximum allowed codepoint (defined in Unicode).
+        public const char ExtendedAsciiStart = (char)0x80;  // The value at or above which is no longer standard ascii
+        public const char NonBreakingSpace = (char)0xA0;    // 160 start of defined extended set 
+        public const char UTF16SurrogateMin = (char)0xD800; // 55296
+        public const char UTF16SurrogateMax = (char)0xDFFF; // 57343
+        public static Dictionary<char, char> Punycode = new Dictionary<char, char>()
+        {
+            {'。', '.'},
+            {'．', '.'},
+            {'Ｇ', 'g'},
+            {'ｏ', 'o'},
+            {'ｃ', 'c'},
+            {'Ｘ', 'x'},
+            {'０', '0'},
+            {'１', '1'},
+            {'２', '2'},
+            {'５', '5'}
+        };
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/TaskEx.cs b/Source/HtmlRenderer/Core/CssEngine/Model/TaskEx.cs
new file mode 100644
index 000000000..48888161d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/TaskEx.cs
@@ -0,0 +1,26 @@
+using System.Collections.Generic;
+
+#if !NET40 && !SL50
+
+namespace System.Threading.Tasks
+{
+    internal static class TaskEx
+    {
+        public static Task Run(Action action, CancellationToken cancel)
+        {
+            return Task.Run(action, cancel);
+        }
+
+        public static Task Delay(int millisecondsDelay, CancellationToken cancel)
+        {
+            return Task.Delay(millisecondsDelay, cancel);
+        }
+
+        public static Task WhenAll(IEnumerable<Task> tasks)
+        {
+            return Task.WhenAll(tasks);
+        }
+    }
+}
+
+#endif
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/TextPosition.cs b/Source/HtmlRenderer/Core/CssEngine/Model/TextPosition.cs
new file mode 100644
index 000000000..3dafe490c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/TextPosition.cs
@@ -0,0 +1,97 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct TextPosition : IEquatable<TextPosition>, IComparable<TextPosition>
+    {
+        public static readonly TextPosition Empty = new TextPosition();
+
+        private readonly ushort _line;
+        private readonly ushort _column;
+
+        public TextPosition(ushort line, ushort column, int position)
+        {
+            _line = line;
+            _column = column;
+            Position = position;
+        }
+
+        public int Line => _line;
+        public int Column => _column;
+        public int Position { get; }
+
+        public TextPosition Shift(int columns)
+        {
+            return new TextPosition(_line, (ushort)(_column + columns), Position + columns);
+        }
+
+        public TextPosition After(char chr)
+        {
+            var line = _line;
+            var column = _column;
+
+            if (chr != Symbols.LineFeed) return new TextPosition(line, ++column, Position + 1);
+
+            ++line;
+            column = 0;
+
+            return new TextPosition(line, ++column, Position + 1);
+        }
+
+        public TextPosition After(string str)
+        {
+            var line = _line;
+            var column = _column;
+
+            foreach (var chr in str)
+            {
+                if (chr == Symbols.LineFeed)
+                {
+                    ++line;
+                    column = 0;
+                }
+
+                ++column;
+            }
+
+            return new TextPosition(line, column, Position + str.Length);
+        }
+
+        public override string ToString()
+        {
+            return $"Line {_line}, Column {_column}, Position {Position}";
+        }
+
+        public override int GetHashCode()
+        {
+            return Position ^ ((_line | _column) + _line);
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is TextPosition other && Equals(other);
+        }
+
+        public bool Equals(TextPosition other)
+        {
+            return Position == other.Position &&
+                   _column == other._column &&
+                   _line == other._line;
+        }
+
+        public static bool operator >(TextPosition a, TextPosition b)
+        {
+            return a.Position > b.Position;
+        }
+
+        public static bool operator <(TextPosition a, TextPosition b)
+        {
+            return a.Position < b.Position;
+        }
+
+        public int CompareTo(TextPosition other)
+        {
+            return Equals(other) ? 0 : this > other ? 1 : -1;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/TextRange.cs b/Source/HtmlRenderer/Core/CssEngine/Model/TextRange.cs
new file mode 100644
index 000000000..01c365fff
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/TextRange.cs
@@ -0,0 +1,55 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct TextRange : IEquatable<TextRange>, IComparable<TextRange>
+    {
+        public TextRange(TextPosition start, TextPosition end)
+        {
+            Start = start;
+            End = end;
+        }
+
+        public TextPosition Start { get; }
+        public TextPosition End { get; }
+
+        public override string ToString()
+        {
+            return $"({Start}) -- ({End})";
+        }
+
+        public override int GetHashCode()
+        {
+            return End.GetHashCode() ^ Start.GetHashCode();
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is TextRange other && Equals(other);
+        }
+
+        public bool Equals(TextRange other)
+        {
+            return Start.Equals(other.Start) && End.Equals(other.End);
+        }
+
+        public static bool operator >(TextRange a, TextRange b)
+        {
+            return a.Start > b.End;
+        }
+
+        public static bool operator <(TextRange a, TextRange b)
+        {
+            return a.End < b.Start;
+        }
+
+        public int CompareTo(TextRange other)
+        {
+            if (this > other) return 1;
+
+            if (other > this) return -1;
+
+            return 0;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/TextSource.cs b/Source/HtmlRenderer/Core/CssEngine/Model/TextSource.cs
new file mode 100644
index 000000000..154661073
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/TextSource.cs
@@ -0,0 +1,230 @@
+using System;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextSource : IDisposable
+    {
+        private const int BufferSize = 4096;
+        private readonly Stream _baseStream;
+        private readonly MemoryStream _raw;
+        private readonly byte[] _buffer;
+        private readonly char[] _chars;
+
+        private StringBuilder _content;
+        private EncodingConfidence _confidence;
+        private bool _finished;
+        private Encoding _encoding;
+        private Decoder _decoder;
+
+        public void Dispose()
+        {
+            var isDisposed = _content == null;
+
+            if (isDisposed) return;
+
+            _raw.Dispose();
+            _content.Clear().ToPool();
+            _content = null;
+        }
+
+        private enum EncodingConfidence : byte
+        {
+            Tentative,
+            Certain,
+            Irrelevant
+        }
+
+        private TextSource(Encoding encoding)
+        {
+            _buffer = new byte[BufferSize];
+            _chars = new char[BufferSize + 1];
+            _raw = new MemoryStream();
+            Index = 0;
+            _encoding = encoding ?? TextEncoding.Utf8;
+            _decoder = _encoding.GetDecoder();
+        }
+
+        public TextSource(string source) : this(null, TextEncoding.Utf8)
+        {
+            _finished = true;
+            _content.Append(source);
+            _confidence = EncodingConfidence.Irrelevant;
+        }
+
+        public TextSource(Stream baseStream, Encoding encoding = null) : this(encoding)
+        {
+            _baseStream = baseStream;
+            _content = Pool.NewStringBuilder();
+            _confidence = EncodingConfidence.Tentative;
+        }
+
+        public string Text => _content.ToString();
+        public char this[int index] => _content[index];
+        public int Index { get; set; }
+        public int Length => _content.Length;
+
+        public Encoding CurrentEncoding
+        {
+            get => _encoding;
+            set
+            {
+                if (_confidence != EncodingConfidence.Tentative) return;
+
+                if (_encoding.IsUnicode())
+                {
+                    _confidence = EncodingConfidence.Certain;
+                    return;
+                }
+
+                if (value.IsUnicode()) value = TextEncoding.Utf8;
+
+                if (value == _encoding)
+                {
+                    _confidence = EncodingConfidence.Certain;
+                    return;
+                }
+
+                _encoding = value;
+                _decoder = value.GetDecoder();
+
+                var raw = _raw.ToArray();
+                var rawChars = new char[_encoding.GetMaxCharCount(raw.Length)];
+                var charLength = _decoder.GetChars(raw, 0, raw.Length, rawChars, 0);
+                var content = new string(rawChars, 0, charLength);
+                var index = Math.Min(Index, content.Length);
+
+                if (content.Substring(0, index).Is(_content.ToString(0, index)))
+                {
+                    // If everything seems to fit up to this point, do an
+                    // instant switch
+                    _confidence = EncodingConfidence.Certain;
+                    _content.Remove(index, _content.Length - index);
+                    _content.Append(content.Substring(index));
+                }
+                else
+                {
+                    // Otherwise consider restart from beginning ...
+                    Index = 0;
+                    _content.Clear().Append(content);
+                    throw new NotSupportedException();
+                }
+            }
+        }
+
+        public char ReadCharacter()
+        {
+            if (Index < _content.Length) return _content[Index++];
+
+            ExpandBuffer(BufferSize);
+            var index = Index++;
+            return index < _content.Length ? _content[index] : Symbols.EndOfFile;
+        }
+
+        public string ReadCharacters(int characters)
+        {
+            var start = Index;
+            var end = start + characters;
+
+            if (end <= _content.Length)
+            {
+                Index += characters;
+                return _content.ToString(start, characters);
+            }
+
+            ExpandBuffer(Math.Max(BufferSize, characters));
+            Index += characters;
+            characters = Math.Min(characters, _content.Length - start);
+            return _content.ToString(start, characters);
+        }
+
+        public async Task PrefetchAllAsync(CancellationToken cancellationToken)
+        {
+            if (_content.Length == 0) await DetectByteOrderMarkAsync(cancellationToken).ConfigureAwait(false);
+
+            while (!_finished) await ReadIntoBufferAsync(cancellationToken).ConfigureAwait(false);
+        }
+
+#pragma warning disable IDE0060 // Remove unused parameter
+        private async Task DetectByteOrderMarkAsync(CancellationToken cancellationToken)
+#pragma warning restore IDE0060 // Remove unused parameter
+        {
+            var count = await _baseStream.ReadAsync(_buffer, 0, BufferSize, cancellationToken).ConfigureAwait(false);
+            var offset = 0;
+
+            //TODO readable hex values
+            if (count > 2 && _buffer[0] == 0xef && _buffer[1] == 0xbb && _buffer[2] == 0xbf)
+            {
+                _encoding = TextEncoding.Utf8;
+                offset = 3;
+            }
+            else if (count > 3 && _buffer[0] == 0xff && _buffer[1] == 0xfe && _buffer[2] == 0x0 && _buffer[3] == 0x0)
+            {
+                _encoding = TextEncoding.Utf32Le;
+                offset = 4;
+            }
+            else if (count > 3 && _buffer[0] == 0x0 && _buffer[1] == 0x0 && _buffer[2] == 0xfe && _buffer[3] == 0xff)
+            {
+                _encoding = TextEncoding.Utf32Be;
+                offset = 4;
+            }
+            else if (count > 1 && _buffer[0] == 0xfe && _buffer[1] == 0xff)
+            {
+                _encoding = TextEncoding.Utf16Be;
+                offset = 2;
+            }
+            else if (count > 1 && _buffer[0] == 0xff && _buffer[1] == 0xfe)
+            {
+                _encoding = TextEncoding.Utf16Le;
+                offset = 2;
+            }
+            else if (count > 3 && _buffer[0] == 0x84 && _buffer[1] == 0x31 && _buffer[2] == 0x95 && _buffer[3] == 0x33)
+            {
+                _encoding = TextEncoding.Gb18030;
+                offset = 4;
+            }
+
+            if (offset > 0)
+            {
+                count -= offset;
+                Array.Copy(_buffer, offset, _buffer, 0, count);
+                _decoder = _encoding.GetDecoder();
+                _confidence = EncodingConfidence.Certain;
+            }
+
+            AppendContentFromBuffer(count);
+        }
+
+        private async Task ReadIntoBufferAsync(CancellationToken cancellationToken)
+        {
+            var returned = await _baseStream.ReadAsync(_buffer, 0, BufferSize, cancellationToken).ConfigureAwait(false);
+            AppendContentFromBuffer(returned);
+        }
+
+        private void ExpandBuffer(long size)
+        {
+            if (!_finished && _content.Length == 0) DetectByteOrderMarkAsync(CancellationToken.None).Wait();
+
+            while (size + Index > _content.Length && !_finished) ReadIntoBuffer();
+        }
+
+        private void ReadIntoBuffer()
+        {
+            var returned = _baseStream.Read(_buffer, 0, BufferSize);
+            AppendContentFromBuffer(returned);
+        }
+
+        private void AppendContentFromBuffer(int size)
+        {
+            _finished = size == 0;
+            var charLength = _decoder.GetChars(_buffer, 0, size, _chars, 0);
+
+            if (_confidence != EncodingConfidence.Certain) _raw.Write(_buffer, 0, size);
+
+            _content.Append(_chars, 0, charLength);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/TokenValue.cs b/Source/HtmlRenderer/Core/CssEngine/Model/TokenValue.cs
new file mode 100644
index 000000000..8b7738e95
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/TokenValue.cs
@@ -0,0 +1,58 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TokenValue : StylesheetNode, IEnumerable<Token>
+    {
+        private readonly List<Token> _tokens;
+        public static TokenValue Initial = FromString(Keywords.Initial);
+        public static TokenValue Empty = new TokenValue(Enumerable.Empty<Token>());
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(_tokens.ToText());
+        }
+
+        private TokenValue(Token token)
+        {
+            _tokens = new List<Token> { token };
+        }
+
+        public TokenValue(IEnumerable<Token> tokens)
+        {
+            _tokens = new List<Token>(tokens);
+        }
+
+        public static TokenValue FromString(string text)
+        {
+            var token = new Token(TokenType.Ident, text, TextPosition.Empty);
+            return new TokenValue(token);
+        }
+
+        public static TokenValue FromNumber(int number)
+        {
+            var token = new NumberToken(number.ToString(CultureInfo.InvariantCulture), TextPosition.Empty);
+            return new TokenValue(token);
+        }
+
+        public Token this[int index] => _tokens[index];
+
+        public int Count => _tokens.Count;
+
+        public string Text => this.ToCss();
+
+        public IEnumerator<Token> GetEnumerator()
+        {
+            return _tokens.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/TransformMatrix.cs b/Source/HtmlRenderer/Core/CssEngine/Model/TransformMatrix.cs
new file mode 100644
index 000000000..a0b3df859
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/TransformMatrix.cs
@@ -0,0 +1,106 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TransformMatrix : IEquatable<TransformMatrix>
+    {
+        public static readonly TransformMatrix Zero = new TransformMatrix();
+        public static readonly TransformMatrix One = new TransformMatrix(1f, 0f, 0f, 0f, 1f, 0f, 0f, 0f, 1f, 0f, 0f, 0f, 0f, 0f, 0f);
+        private readonly float[,] _matrix;
+
+        public bool Equals(TransformMatrix other)
+        {
+            var a = _matrix;
+            var b = other._matrix;
+
+            for (var i = 0; i < 4; i++)
+            {
+                for (var j = 0; j < 4; j++)
+                {
+                    if (a[i, j] != b[i, j])
+                    {
+                        return false;
+                    }
+                }
+            }
+
+            return true;
+        }
+
+        private TransformMatrix()
+        {
+            _matrix = new float[4, 4];
+        }
+
+        public TransformMatrix(float[] values) : this()
+        {
+            if (values == null)
+            {
+                throw new ArgumentNullException(nameof(values));
+            }
+
+            if (values.Length != 16)
+            {
+                throw new ArgumentException("You need to provide 16 (4x4) values.", nameof(values));
+            }
+
+            for (int i = 0, k = 0; i < 4; i++)
+            {
+                for (var j = 0; j < 4; j++, k++)
+                {
+                    _matrix[j, i] = values[k];
+                }
+            }
+        }
+
+        public TransformMatrix(
+            float m11, float m12, float m13,
+            float m21, float m22, float m23,
+            float m31, float m32, float m33,
+            float tx, float ty, float tz,
+            float px, float py, float pz)
+            : this()
+        {
+            _matrix[0, 0] = m11;
+            _matrix[0, 1] = m12;
+            _matrix[0, 2] = m13;
+            _matrix[1, 0] = m21;
+            _matrix[1, 1] = m22;
+            _matrix[1, 2] = m23;
+            _matrix[2, 0] = m31;
+            _matrix[2, 1] = m32;
+            _matrix[2, 2] = m33;
+            _matrix[0, 3] = tx;
+            _matrix[1, 3] = ty;
+            _matrix[2, 3] = tz;
+            _matrix[3, 0] = px;
+            _matrix[3, 1] = py;
+            _matrix[3, 2] = pz;
+            _matrix[3, 3] = 1f;
+        }
+
+        public float Tx => _matrix[0, 3];
+        public float Ty => _matrix[1, 3];
+        public float Tz => _matrix[2, 3];
+
+        public override bool Equals(object obj)
+        {
+            return obj is TransformMatrix other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            var sum = 0f;
+
+            for (var i = 0; i < 4; i++)
+            {
+                for (var j = 0; j < 4; j++)
+                {
+                    sum += _matrix[i, j] * (4 * i + j);
+                }
+            }
+
+            return (int)sum;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/Url.cs b/Source/HtmlRenderer/Core/CssEngine/Model/Url.cs
new file mode 100644
index 000000000..d45a45212
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/Url.cs
@@ -0,0 +1,873 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    ///     Url class according to RFC3986. 
+    /// </summary>
+    internal sealed class Url : IEquatable<Url>
+    {
+        private const string CurrentDirectory = ".";
+        private const string CurrentDirectoryAlternative = "%2e";
+        private const string UpperDirectory = "..";
+        private static readonly string[] UpperDirectoryAlternatives = { "%2e%2e", ".%2e", "%2e." };
+        private static readonly Url DefaultBase = new Url(string.Empty, string.Empty, string.Empty);
+
+        private string _fragment;
+        private string _query;
+        private string _path;
+        private string _scheme;
+        private string _port;
+        private string _host;
+        private bool _relative;
+
+        public static implicit operator Uri(Url value)
+        {
+            return new Uri(value.Serialize(), value.IsRelative ? UriKind.Relative : UriKind.Absolute);
+        }
+
+        private Url(string scheme, string host, string port)
+        {
+            Data = string.Empty;
+            _path = string.Empty;
+            _scheme = scheme;
+            _host = host;
+            _port = port;
+            _relative = ProtocolNames.IsRelative(_scheme);
+        }
+
+        public Url(string address)
+        {
+            IsInvalid = ParseUrl(address);
+        }
+
+        public Url(Url baseAddress, string relativeAddress)
+        {
+            IsInvalid = ParseUrl(relativeAddress, baseAddress);
+        }
+
+        public Url(Url address)
+        {
+            _fragment = address._fragment;
+            _query = address._query;
+            _path = address._path;
+            _scheme = address._scheme;
+            _port = address._port;
+            _host = address._host;
+            UserName = address.UserName;
+            Password = address.Password;
+            _relative = address._relative;
+            Data = address.Data;
+        }
+
+        public static Url Create(string address)
+        {
+            return new Url(address);
+        }
+
+        public static Url Convert(Uri uri)
+        {
+            return new Url(uri.OriginalString);
+        }
+
+        public string Origin
+        {
+            get
+            {
+                if (_scheme.Is(ProtocolNames.Blob))
+                {
+                    var url = new Url(Data);
+
+                    if (!url.IsInvalid) return url.Origin;
+                }
+                else if (ProtocolNames.IsOriginable(_scheme))
+                {
+                    var output = Pool.NewStringBuilder();
+
+                    if (string.IsNullOrEmpty(_host)) return output.ToPool();
+
+                    if (!string.IsNullOrEmpty(_scheme)) output.Append(_scheme).Append(Symbols.Colon);
+
+                    output.Append(Symbols.Solidus).Append(Symbols.Solidus).Append(_host);
+
+                    if (!string.IsNullOrEmpty(_port)) output.Append(Symbols.Colon).Append(_port);
+
+                    return output.ToPool();
+                }
+
+                return null;
+            }
+        }
+
+        public bool IsInvalid { get; private set; }
+
+        public bool IsRelative => _relative && string.IsNullOrEmpty(_scheme);
+
+        public string UserName { get; set; }
+        public string Password { get; set; }
+        public string Data { get; private set; }
+
+        public string Fragment
+        {
+            get => _fragment;
+            set
+            {
+                if (value == null)
+                    _fragment = null;
+                else
+                    ParseFragment(value, 0);
+            }
+        }
+
+        public string Host
+        {
+            get => HostName + (string.IsNullOrEmpty(_port) ? string.Empty : ":" + _port);
+            set => ParseHostName(value ?? string.Empty, 0, false, true);
+        }
+
+        public string HostName
+        {
+            get => _host;
+            set => ParseHostName(value ?? string.Empty, 0, true);
+        }
+
+        public string Href
+        {
+            get => Serialize();
+            set => IsInvalid = ParseUrl(value ?? string.Empty);
+        }
+
+        public string Path
+        {
+            get => _path;
+            set => ParsePath(value ?? string.Empty, 0, true);
+        }
+
+        public string Port
+        {
+            get => _port;
+            set => ParsePort(value ?? string.Empty, 0, true);
+        }
+
+        public string Scheme
+        {
+            get => _scheme;
+            set => ParseScheme(value ?? string.Empty, true);
+        }
+
+        public string Query
+        {
+            get => _query;
+            set => ParseQuery(value ?? string.Empty, 0, true);
+        }
+
+        public override int GetHashCode() => new
+        {
+            _fragment,
+            _query,
+            _path,
+            _scheme,
+            _port,
+            _host,
+            UserName,
+            Password,
+            _relative,
+            Data
+        }.GetHashCode();
+
+        public override bool Equals(object obj)
+        {
+            return obj is Url url && Equals(url);
+        }
+
+        public bool Equals(Url other)
+        {
+            return _fragment.Is(other._fragment) && _query.Is(other._query) &&
+                   _path.Is(other._path) && _scheme.Isi(other._scheme) &&
+                   _port.Is(other._port) && _host.Isi(other._host) &&
+                   UserName.Is(other.UserName) && Password.Is(other.Password) &&
+                   Data.Is(other.Data);
+        }
+
+        public override string ToString()
+        {
+            return Serialize();
+        }
+
+        private string Serialize()
+        {
+            var output = Pool.NewStringBuilder();
+
+            if (!string.IsNullOrEmpty(_scheme)) output.Append(_scheme).Append(Symbols.Colon);
+
+            if (_relative)
+            {
+                if (!string.IsNullOrEmpty(_host) || !string.IsNullOrEmpty(_scheme))
+                {
+                    output.Append(Symbols.Solidus).Append(Symbols.Solidus);
+
+                    if (!string.IsNullOrEmpty(UserName) || Password != null)
+                    {
+                        output.Append(UserName);
+
+                        if (Password != null) output.Append(Symbols.Colon).Append(Password);
+
+                        output.Append(Symbols.At);
+                    }
+
+                    output.Append(_host);
+
+                    if (!string.IsNullOrEmpty(_port)) output.Append(Symbols.Colon).Append(_port);
+
+                    output.Append(Symbols.Solidus);
+                }
+
+                output.Append(_path);
+            }
+            else
+            {
+                output.Append(Data);
+            }
+
+            if (_query != null) output.Append(Symbols.QuestionMark).Append(_query);
+
+            if (_fragment != null) output.Append(Symbols.Num).Append(_fragment);
+
+            return output.ToPool();
+        }
+
+        private bool ParseUrl(string input, Url baseUrl = null)
+        {
+            Reset(baseUrl ?? DefaultBase);
+            return !ParseScheme(input.Trim());
+        }
+
+        private void Reset(Url baseUrl)
+        {
+            Data = string.Empty;
+            _scheme = baseUrl._scheme;
+            _host = baseUrl._host;
+            _path = baseUrl._path;
+            _port = baseUrl._port;
+            _relative = ProtocolNames.IsRelative(_scheme);
+        }
+
+        private bool ParseScheme(string input, bool onlyScheme = false)
+        {
+            if (input.Length <= 0 || !input[0].IsLetter()) return !onlyScheme && RelativeState(input, 0);
+
+            var index = 1;
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+
+                if (c.IsAlphanumericAscii() || c == Symbols.Plus || c == Symbols.Minus || c == Symbols.Dot)
+                {
+                    index++;
+                }
+                else if (c == Symbols.Colon)
+                {
+                    var originalScheme = _scheme;
+                    _scheme = input.Substring(0, index).ToLowerInvariant();
+
+                    if (!onlyScheme)
+                    {
+                        _relative = ProtocolNames.IsRelative(_scheme);
+
+                        if (_scheme.Is(ProtocolNames.File))
+                        {
+                            _host = string.Empty;
+                            _port = string.Empty;
+                            return RelativeState(input, index + 1);
+                        }
+
+                        if (!_relative)
+                        {
+                            _host = string.Empty;
+                            _port = string.Empty;
+                            _path = string.Empty;
+                            return ParseSchemeData(input, index + 1);
+                        }
+
+                        if (_scheme.Is(originalScheme))
+                        {
+                            c = input[++index];
+
+                            if (c == Symbols.Solidus && index + 2 < input.Length &&
+                                input[index + 1] == Symbols.Solidus)
+                                return IgnoreSlashesState(input, index + 2);
+
+                            return RelativeState(input, index);
+                        }
+
+                        if (index < input.Length - 1 && input[++index] == Symbols.Solidus &&
+                            ++index < input.Length && input[index] == Symbols.Solidus)
+                            index++;
+
+                        return IgnoreSlashesState(input, index);
+                    }
+
+                    return true;
+                }
+                else
+                {
+                    break;
+                }
+            }
+
+            return !onlyScheme && RelativeState(input, 0);
+        }
+
+        private bool ParseSchemeData(string input, int index)
+        {
+            var buffer = Pool.NewStringBuilder();
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+
+                if (c == Symbols.QuestionMark)
+                {
+                    Data = buffer.ToPool();
+                    return ParseQuery(input, index + 1);
+                }
+
+                if (c == Symbols.Num)
+                {
+                    Data = buffer.ToPool();
+                    return ParseFragment(input, index + 1);
+                }
+
+                if (c == Symbols.Percent && index + 2 < input.Length && input[index + 1].IsHex() &&
+                    input[index + 2].IsHex())
+                {
+                    buffer.Append(input[index++]);
+                    buffer.Append(input[index++]);
+                    buffer.Append(input[index]);
+                }
+                else if (c.IsInRange(Symbols.Space, Symbols.Tilde))
+                {
+                    buffer.Append(c);
+                }
+                else if (c != Symbols.Tab && c != Symbols.LineFeed && c != Symbols.CarriageReturn)
+                {
+                    index += Utf8PercentEncode(buffer, input, index);
+                }
+
+                index++;
+            }
+
+            Data = buffer.ToPool();
+            return true;
+        }
+
+        private bool RelativeState(string input, int index)
+        {
+            _relative = true;
+
+            if (index != input.Length)
+            {
+                switch (input[index])
+                {
+                    case Symbols.QuestionMark:
+                        return ParseQuery(input, index + 1);
+
+                    case Symbols.Num:
+                        return ParseFragment(input, index + 1);
+
+                    case Symbols.Solidus:
+                    case Symbols.ReverseSolidus:
+                        if (index == input.Length - 1) return ParsePath(input, index);
+
+                        var c = input[++index];
+
+                        if (c.IsOneOf(Symbols.Solidus, Symbols.ReverseSolidus))
+                            return _scheme.Is(ProtocolNames.File)
+                                ? ParseFileHost(input, index + 1)
+                                : IgnoreSlashesState(input, index + 1);
+
+                        if (!_scheme.Is(ProtocolNames.File)) return ParsePath(input, index - 1);
+
+                        _host = string.Empty;
+                        _port = string.Empty;
+
+                        return ParsePath(input, index - 1);
+                }
+
+                if (input[index].IsLetter() &&
+                    _scheme.Is(ProtocolNames.File) &&
+                    index + 1 < input.Length &&
+                    input[index + 1].IsOneOf(Symbols.Colon, Symbols.Solidus) &&
+                    (index + 2 == input.Length || input[index + 2].IsOneOf(Symbols.Solidus, Symbols.ReverseSolidus,
+                        Symbols.Num, Symbols.QuestionMark)))
+                {
+                    _host = string.Empty;
+                    _path = string.Empty;
+                    _port = string.Empty;
+                }
+
+                return ParsePath(input, index);
+            }
+
+            return true;
+        }
+
+        private bool IgnoreSlashesState(string input, int index)
+        {
+            while (index < input.Length)
+            {
+                if (!input[index].IsOneOf(Symbols.ReverseSolidus, Symbols.Solidus)) return ParseAuthority(input, index);
+
+                index++;
+            }
+
+            return false;
+        }
+
+        private bool ParseAuthority(string input, int index)
+        {
+            var start = index;
+            var buffer = Pool.NewStringBuilder();
+            var user = default(string);
+            var pass = default(string);
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+
+                if (c == Symbols.At)
+                {
+                    if (user == null)
+                        user = buffer.ToString();
+                    else
+                        pass = buffer.ToString();
+
+                    UserName = user;
+                    Password = pass;
+                    buffer.Append("%40");
+                    start = index + 1;
+                }
+                else if (c == Symbols.Colon && user == null)
+                {
+                    user = buffer.ToString();
+                    pass = string.Empty;
+                    buffer.Clear();
+                }
+                else if (c == Symbols.Percent && index + 2 < input.Length && input[index + 1].IsHex() &&
+                         input[index + 2].IsHex())
+                {
+                    buffer.Append(input[index++]).Append(input[index++]).Append(input[index]);
+                }
+                else if (c.IsOneOf(Symbols.Tab, Symbols.LineFeed, Symbols.CarriageReturn))
+                {
+                    // Parse Error
+                }
+                else if (c.IsOneOf(Symbols.Solidus, Symbols.ReverseSolidus, Symbols.Num, Symbols.QuestionMark))
+                {
+                    break;
+                }
+                else if (c != Symbols.Colon &&
+                         (c == Symbols.Num || c == Symbols.QuestionMark || c.IsNormalPathCharacter()))
+                {
+                    buffer.Append(c);
+                }
+                else
+                {
+                    index += Utf8PercentEncode(buffer, input, index);
+                }
+
+                index++;
+            }
+
+            buffer.ToPool();
+            return ParseHostName(input, start);
+        }
+
+        private bool ParseFileHost(string input, int index)
+        {
+            var start = index;
+            _path = string.Empty;
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+
+                if (c == Symbols.Solidus ||
+                    c == Symbols.ReverseSolidus ||
+                    c == Symbols.Num ||
+                    c == Symbols.QuestionMark)
+                    break;
+
+                index++;
+            }
+
+            var length = index - start;
+
+            if (length == 2 &&
+                input[index - 2].IsLetter() &&
+                (input[index - 1] == Symbols.Pipe || input[index - 1] == Symbols.Colon))
+                return ParsePath(input, index - 2);
+            if (length != 0) _host = SanatizeHost(input, start, length);
+
+            return ParsePath(input, index);
+        }
+
+        private bool ParseHostName(string input, int index, bool onlyHost = false, bool onlyPort = false)
+        {
+            var inBracket = false;
+            var start = index;
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+
+                switch (c)
+                {
+                    case Symbols.SquareBracketClose:
+                        inBracket = false;
+                        break;
+
+                    case Symbols.SquareBracketOpen:
+                        inBracket = true;
+                        break;
+
+                    case Symbols.Colon:
+                        if (inBracket)
+                            break;
+
+                        _host = SanatizeHost(input, start, index - start);
+
+                        if (!onlyHost) return ParsePort(input, index + 1, onlyPort);
+
+                        return true;
+
+                    case Symbols.Solidus:
+                    case Symbols.ReverseSolidus:
+                    case Symbols.Num:
+                    case Symbols.QuestionMark:
+                        _host = SanatizeHost(input, start, index - start);
+                        var error = string.IsNullOrEmpty(_host);
+
+                        if (!onlyHost) return ParsePath(input, index) && !error;
+
+                        return !error;
+                }
+
+                index++;
+            }
+
+            _host = SanatizeHost(input, start, index - start);
+
+            if (!onlyHost)
+            {
+                _path = string.Empty;
+                _query = null;
+                _fragment = null;
+            }
+
+            return true;
+        }
+
+        private bool ParsePort(string input, int index, bool onlyPort = false)
+        {
+            var start = index;
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+
+                if (c == Symbols.QuestionMark || c == Symbols.Solidus || c == Symbols.ReverseSolidus ||
+                    c == Symbols.Num)
+                    break;
+                if (c.IsDigit() || c == Symbols.Tab || c == Symbols.LineFeed || c == Symbols.CarriageReturn)
+                    index++;
+                else
+                    return false;
+            }
+
+            _port = SanatizePort(input, start, index - start);
+
+            if (PortNumbers.GetDefaultPort(_scheme) == _port) _port = string.Empty;
+
+            if (!onlyPort)
+            {
+                _path = string.Empty;
+                return ParsePath(input, index);
+            }
+
+            return true;
+        }
+
+        private bool ParsePath(string input, int index, bool onlyPath = false)
+        {
+            var init = index;
+
+            if (index < input.Length &&
+                (input[index] == Symbols.Solidus || input[index] == Symbols.ReverseSolidus))
+                index++;
+
+            var paths = new List<string>();
+
+            if (!onlyPath && !string.IsNullOrEmpty(_path) && index - init == 0)
+            {
+                var split = _path.Split(Symbols.Solidus);
+
+                if (split.Length > 1)
+                {
+                    paths.AddRange(split);
+                    paths.RemoveAt(split.Length - 1);
+                }
+            }
+
+            var originalCount = paths.Count;
+            var buffer = Pool.NewStringBuilder();
+
+            while (index <= input.Length)
+            {
+                var c = index == input.Length ? Symbols.EndOfFile : input[index];
+                var breakNow = !onlyPath && (c == Symbols.Num || c == Symbols.QuestionMark);
+
+                if (c == Symbols.EndOfFile || c == Symbols.Solidus || c == Symbols.ReverseSolidus || breakNow)
+                {
+                    var path = buffer.ToString();
+                    var close = false;
+                    buffer.Clear();
+
+                    if (path.Isi(CurrentDirectoryAlternative))
+                        path = CurrentDirectory;
+                    else if (path.Isi(UpperDirectoryAlternatives[0]) ||
+                             path.Isi(UpperDirectoryAlternatives[1]) ||
+                             path.Isi(UpperDirectoryAlternatives[2]))
+                        path = UpperDirectory;
+
+                    if (path.Is(UpperDirectory))
+                    {
+                        if (paths.Count > 0) paths.RemoveAt(paths.Count - 1);
+
+                        close = true;
+                    }
+                    else if (!path.Is(CurrentDirectory))
+                    {
+                        if (_scheme.Is(ProtocolNames.File) &&
+                            paths.Count == originalCount &&
+                            path.Length == 2 &&
+                            path[0].IsLetter() &&
+                            path[1] == Symbols.Pipe)
+                        {
+                            path = path.Replace(Symbols.Pipe, Symbols.Colon);
+                            paths.Clear();
+                        }
+
+                        paths.Add(path);
+                    }
+                    else
+                    {
+                        close = true;
+                    }
+
+                    if (close && c != Symbols.Solidus && c != Symbols.ReverseSolidus) paths.Add(string.Empty);
+
+                    if (breakNow) break;
+                }
+                else if (c == Symbols.Percent &&
+                         index + 2 < input.Length &&
+                         input[index + 1].IsHex() &&
+                         input[index + 2].IsHex())
+                {
+                    buffer.Append(input[index++]);
+                    buffer.Append(input[index++]);
+                    buffer.Append(input[index]);
+                }
+                else if (c == Symbols.Tab || c == Symbols.LineFeed || c == Symbols.CarriageReturn)
+                {
+                    // Parse Error
+                }
+                else if (c.IsNormalPathCharacter())
+                {
+                    buffer.Append(c);
+                }
+                else
+                {
+                    index += Utf8PercentEncode(buffer, input, index);
+                }
+
+                index++;
+            }
+
+            buffer.ToPool();
+            _path = string.Join("/", paths);
+
+            if (index < input.Length)
+            {
+                if (input[index] == Symbols.QuestionMark) return ParseQuery(input, index + 1);
+
+                return ParseFragment(input, index + 1);
+            }
+
+            return true;
+        }
+
+        private bool ParseQuery(string input, int index, bool onlyQuery = false)
+        {
+            var buffer = Pool.NewStringBuilder();
+            var fragment = false;
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+                fragment = !onlyQuery && input[index] == Symbols.Num;
+
+                if (fragment) break;
+
+                if (c.IsNormalQueryCharacter())
+                    buffer.Append(c);
+                else
+                    index += Utf8PercentEncode(buffer, input, index);
+
+                index++;
+            }
+
+            _query = buffer.ToPool();
+            return !fragment || ParseFragment(input, index + 1);
+        }
+
+        private bool ParseFragment(string input, int index)
+        {
+            var buffer = Pool.NewStringBuilder();
+
+            while (index < input.Length)
+            {
+                var c = input[index];
+
+                switch (c)
+                {
+                    case Symbols.EndOfFile:
+                    case Symbols.Null:
+                    case Symbols.Tab:
+                    case Symbols.LineFeed:
+                    case Symbols.CarriageReturn:
+                        break;
+                    default:
+                        buffer.Append(c);
+                        break;
+                }
+
+                index++;
+            }
+
+            _fragment = buffer.ToPool();
+            return true;
+        }
+
+        private static int Utf8PercentEncode(StringBuilder buffer, string source, int index)
+        {
+            var length = char.IsSurrogatePair(source, index) ? 2 : 1;
+            var bytes = TextEncoding.Utf8.GetBytes(source.Substring(index, length));
+
+            foreach (var byteVal in bytes) buffer.Append(Symbols.Percent).Append(byteVal.ToString("X2"));
+
+            return length - 1;
+        }
+
+        private static string SanatizeHost(string hostName, int start, int length)
+        {
+            if (length > 1 && hostName[start] == Symbols.SquareBracketOpen &&
+                hostName[start + length - 1] == Symbols.SquareBracketClose)
+                return hostName.Substring(start, length);
+
+            var chars = new byte[4 * length];
+            var count = 0;
+            var n = start + length;
+
+            for (var i = start; i < n; i++)
+                switch (hostName[i])
+                {
+                    // U+0000, U+0009, U+000A, U+000D, U+0020, "#", "%", "/", ":", "?", "@", "[", "\", and "]"
+                    case Symbols.Null:
+                    case Symbols.Tab:
+                    case Symbols.Space:
+                    case Symbols.LineFeed:
+                    case Symbols.CarriageReturn:
+                    case Symbols.Num:
+                    case Symbols.Solidus:
+                    case Symbols.Colon:
+                    case Symbols.QuestionMark:
+                    case Symbols.At:
+                    case Symbols.SquareBracketOpen:
+                    case Symbols.SquareBracketClose:
+                    case Symbols.ReverseSolidus:
+                        break;
+                    case Symbols.Dot:
+                        chars[count++] = (byte)hostName[i];
+                        break;
+                    case Symbols.Percent:
+                        if (i + 2 < n && hostName[i + 1].IsHex() && hostName[i + 2].IsHex())
+                        {
+                            var weight = hostName[i + 1].FromHex() * 16 + hostName[i + 2].FromHex();
+                            chars[count++] = (byte)weight;
+                            i += 2;
+                        }
+                        else
+                        {
+                            chars[count++] = (byte)Symbols.Percent;
+                        }
+
+                        break;
+                    default:
+
+                        if (Symbols.Punycode.TryGetValue(hostName[i], out var chr))
+                        {
+                            chars[count++] = (byte)chr;
+                        }
+                        else if (hostName[i].IsAlphanumericAscii() == false)
+                        {
+                            var l = i + 1 < n && char.IsSurrogatePair(hostName, i) ? 2 : 1;
+
+                            if (l == 1 && hostName[i] != Symbols.Minus && !char.IsLetterOrDigit(hostName[i])) break;
+
+                            var bytes = TextEncoding.Utf8.GetBytes(hostName.Substring(i, l));
+
+                            foreach (var byteVal in bytes) chars[count++] = byteVal;
+
+                            i += l - 1;
+                        }
+                        else
+                        {
+                            chars[count++] = (byte)char.ToLowerInvariant(hostName[i]);
+                        }
+
+                        break;
+                }
+
+            return TextEncoding.Utf8.GetString(chars, 0, count);
+        }
+
+        private static string SanatizePort(string port, int start, int length)
+        {
+            var chars = new char[length];
+            var count = 0;
+            var n = start + length;
+
+            for (var i = start; i < n; i++)
+                switch (port[i])
+                {
+                    case Symbols.Tab:
+                    case Symbols.LineFeed:
+                    case Symbols.CarriageReturn:
+                        break;
+                    default:
+                        if (count == 1 && chars[0] == '0')
+                            chars[0] = port[i];
+                        else
+                            chars[count++] = port[i];
+
+                        break;
+                }
+
+            return new string(chars, 0, count);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Model/ValueBuilder.cs b/Source/HtmlRenderer/Core/CssEngine/Model/ValueBuilder.cs
new file mode 100644
index 000000000..d1efa2e7b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Model/ValueBuilder.cs
@@ -0,0 +1,148 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ValueBuilder
+    {
+        public ValueBuilder()
+        {
+            _values = new List<Token>();
+            Reset();
+        }
+
+        private readonly List<Token> _values;
+        private Token _buffer;
+        private bool _valid;
+        private int _open;
+
+        public bool IsReady => _open == 0 && _values.Count > 0;
+
+        public bool IsValid => _valid && IsReady;
+        public bool IsImportant { get; private set; }
+
+        public TokenValue GetResult()
+        {
+            return new TokenValue(_values);
+        }
+
+        public void Apply(Token token)
+        {
+            switch (token.Type)
+            {
+                case TokenType.RoundBracketOpen:
+                    _open++;
+                    Add(token);
+                    break;
+                case TokenType.Function:
+                    Add(token);
+                    break;
+                case TokenType.Ident:
+                    IsImportant = CheckImportant(token);
+                    break;
+                case TokenType.RoundBracketClose:
+                    _open--;
+                    Add(token);
+                    break;
+                case TokenType.Whitespace:
+                    if (_values.Count > 0 && IsSlash(_values[_values.Count - 1]) == false)
+                        _buffer = token;
+                    break;
+                case TokenType.Dimension:
+                case TokenType.Percentage:
+                case TokenType.Color:
+                case TokenType.Hash:
+                case TokenType.Delim:
+                case TokenType.String:
+                case TokenType.Url:
+                case TokenType.Number:
+                case TokenType.Comma:
+                case TokenType.GreaterThan:
+                case TokenType.GreaterThanOrEqual:
+                case TokenType.LessThan:
+                case TokenType.LessThanOrEqual:
+                case TokenType.Range:
+                    // A U+... unicode-range value (an @font-face descriptor) is a sequence of Range tokens;
+                    // without this they'd hit the default arm and mark the whole value invalid, so the
+                    // descriptor would be dropped under strict (non-tolerant) parsing - the pipeline default.
+                    Add(token);
+                    break;
+                case TokenType.SquareBracketOpen:
+                case TokenType.SquareBracketClose:
+                    // Square brackets are valid in a value: grid line names, e.g.
+                    // `grid-template-columns: [sidebar-start] 200px [sidebar-end]`. Without this they'd hit
+                    // the default arm and the whole declaration would be dropped under strict parsing.
+                    Add(token);
+                    break;
+                case TokenType.Comment:
+                    break;
+                default:
+                    _valid = false;
+                    Add(token);
+                    break;
+            }
+        }
+
+        public ValueBuilder Reset()
+        {
+            _open = 0;
+            _valid = true;
+            _buffer = null;
+            IsImportant = false;
+            _values.Clear();
+            return this;
+        }
+
+        private bool CheckImportant(Token token)
+        {
+            if (_values.Count != 0 && token.Data == Keywords.Important)
+            {
+                var previous = _values[_values.Count - 1];
+                if (IsExclamationMark(previous))
+                {
+                    do
+                    {
+                        _values.RemoveAt(_values.Count - 1);
+                    } while (_values.Count > 0 && _values[_values.Count - 1].Type == TokenType.Whitespace);
+
+                    return true;
+                }
+            }
+
+            Add(token);
+            return IsImportant;
+        }
+
+        private void Add(Token token)
+        {
+            if (_buffer != null && !IsCommaOrSlash(token))
+                _values.Add(_buffer);
+            else if (_values.Count != 0 && !IsComma(token) && IsComma(_values[_values.Count - 1]))
+                _values.Add(Token.Whitespace);
+
+            _buffer = null;
+
+            if (IsImportant) _valid = false;
+            _values.Add(token);
+        }
+
+        private static bool IsCommaOrSlash(Token token)
+        {
+            return IsComma(token) || IsSlash(token);
+        }
+
+        private static bool IsComma(Token token)
+        {
+            return token.Type == TokenType.Comma;
+        }
+
+        private static bool IsExclamationMark(Token token)
+        {
+            return token.Type == TokenType.Delim && token.Data.Has(Symbols.ExclamationMark);
+        }
+
+        private static bool IsSlash(Token token)
+        {
+            return token.Type == TokenType.Delim && token.Data.Has(Symbols.Solidus);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/PaletteMixGrammar.cs b/Source/HtmlRenderer/Core/CssEngine/PaletteMixGrammar.cs
new file mode 100644
index 000000000..26e416908
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/PaletteMixGrammar.cs
@@ -0,0 +1,184 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>One operand of a <c>palette-mix()</c>: a palette reference and an optional mixing percentage.</summary>
+    internal sealed class PaletteMixOperand
+    {
+        public PaletteMixOperand(string palette, double? percentage)
+        {
+            Palette = palette;
+            Percentage = percentage;
+        }
+
+        public string Palette { get; }
+        public double? Percentage { get; }
+    }
+
+    /// <summary>
+    /// A parsed <c>palette-mix()</c> value (CSS Fonts Module Level 4). The two operands are blended per CPAL
+    /// entry in <see cref="ColorSpace"/> (with an optional polar <see cref="HueMethod"/>), weighted by the
+    /// operand percentages.
+    /// </summary>
+    internal sealed class ParsedPaletteMix
+    {
+        public ParsedPaletteMix(string colorSpace, string hueMethod, PaletteMixOperand first, PaletteMixOperand second)
+        {
+            ColorSpace = colorSpace;
+            HueMethod = hueMethod;
+            First = first;
+            Second = second;
+        }
+
+        public string ColorSpace { get; }
+        public string HueMethod { get; }
+        public PaletteMixOperand First { get; }
+        public PaletteMixOperand Second { get; }
+    }
+
+    /// <summary>
+    /// The single, shared grammar for the CSS <c>palette-mix()</c> function
+    /// (<a href="https://www.w3.org/TR/css-fonts-4/#font-palette-values">CSS Fonts 4</a>):
+    /// <code>palette-mix( &lt;color-interpolation-method&gt; , [ [ normal | light | dark | &lt;palette-identifier&gt; ] &lt;percentage&gt;? ]#{2} )</code>.
+    /// Used by both Layer A (the <c>font-palette</c> value converter, which drops a malformed value at parse
+    /// time) and Layer B (<c>ActualFontPalette</c> resolution), so the two layers cannot disagree. Color-space
+    /// membership is owned by <see cref="ColorInterpolationMethodGrammar"/> (its predicates classify the space
+    /// and hue direction here), keeping a single source of truth for which spaces are valid.
+    /// </summary>
+    internal static class PaletteMixGrammar
+    {
+        private const string FunctionName = "palette-mix";
+        private const string In = "in";
+        private const string Hue = "hue";
+
+        public static ParsedPaletteMix TryParse(IReadOnlyList<Token> value)
+        {
+            var fn = SinglePaletteMixFunction(value);
+            if (fn == null)
+                return null;
+
+            var groups = SplitTopLevelComma(new List<Token>(fn.ArgumentTokens));
+            if (groups.Count != 3)
+                return null;
+
+            if (!TryParseMethod(groups[0], out var space, out var hue) ||
+                !TryParseOperand(groups[1], out var first) ||
+                !TryParseOperand(groups[2], out var second))
+                return null;
+
+            // Both percentages explicitly zero has no valid interpretation (mirrors color-mix()).
+            if (first.Percentage == 0 && second.Percentage == 0)
+                return null;
+
+            return new ParsedPaletteMix(space, hue, first, second);
+        }
+
+        private static FunctionToken SinglePaletteMixFunction(IReadOnlyList<Token> value)
+        {
+            FunctionToken found = null;
+            foreach (var token in value)
+            {
+                if (token.Type == TokenType.Whitespace)
+                    continue;
+                var fn = token as FunctionToken;
+                if (found != null || fn == null || !fn.Data.Isi(FunctionName))
+                    return null;
+                found = fn;
+            }
+
+            return found;
+        }
+
+        // in <color-space> [ <hue-interpolation-method> hue ]?  (the hue method only after a polar space)
+        private static bool TryParseMethod(List<Token> tokens, out string space, out string hue)
+        {
+            space = null;
+            hue = null;
+
+            int i = 0;
+
+            if (i >= tokens.Count || !IsIdent(tokens[i], out var inWord) || !inWord.Isi(In))
+                return false;
+            i++;
+
+            if (i >= tokens.Count || !IsIdent(tokens[i], out var spaceName) ||
+                !ColorInterpolationMethodGrammar.IsColorSpace(spaceName))
+                return false;
+            space = spaceName;
+            i++;
+
+            if (i < tokens.Count)
+            {
+                // A trailing "<dir> hue" is valid only for a polar color space.
+                if (!ColorInterpolationMethodGrammar.IsPolarColorSpace(spaceName))
+                    return false;
+                if (!IsIdent(tokens[i], out var dir) || !ColorInterpolationMethodGrammar.IsHueDirection(dir))
+                    return false;
+                i++;
+                if (i >= tokens.Count || !IsIdent(tokens[i], out var hueWord) || !hueWord.Isi(Hue))
+                    return false;
+                hue = dir;
+                i++;
+            }
+
+            return i == tokens.Count;
+        }
+
+        // [ normal | light | dark | <dashed-ident> ] <percentage>?
+        private static bool TryParseOperand(List<Token> tokens, out PaletteMixOperand operand)
+        {
+            operand = null;
+
+            if (tokens.Count == 0 || tokens.Count > 2)
+                return false;
+
+            if (!IsIdent(tokens[0], out var palette) || !IsPaletteIdentifier(palette))
+                return false;
+
+            double? percentage = null;
+            if (tokens.Count == 2)
+            {
+                var pct = tokens[1] as UnitToken;
+                if (pct == null || pct.Type != TokenType.Percentage)
+                    return false;
+                percentage = pct.Value;
+            }
+
+            operand = new PaletteMixOperand(palette, percentage);
+            return true;
+        }
+
+        private static bool IsPaletteIdentifier(string ident) =>
+            ident.Isi(Keywords.Normal) || ident.Isi("light") || ident.Isi("dark") ||
+            ident.StartsWith("--", System.StringComparison.Ordinal);
+
+        // Splits the argument tokens on top-level commas, dropping whitespace (insignificant in this grammar).
+        private static List<List<Token>> SplitTopLevelComma(List<Token> tokens)
+        {
+            var groups = new List<List<Token>> { new List<Token>() };
+            foreach (var token in tokens)
+            {
+                if (token.Type == TokenType.Whitespace)
+                    continue;
+                if (token.Type == TokenType.Comma)
+                    groups.Add(new List<Token>());
+                else
+                    groups[groups.Count - 1].Add(token);
+            }
+
+            return groups;
+        }
+
+        private static bool IsIdent(Token token, out string data)
+        {
+            if (token.Type == TokenType.Ident)
+            {
+                data = token.Data;
+                return true;
+            }
+
+            data = string.Empty;
+            return false;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Parser/Lexer.cs b/Source/HtmlRenderer/Core/CssEngine/Parser/Lexer.cs
new file mode 100644
index 000000000..d920be4fd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Parser/Lexer.cs
@@ -0,0 +1,1265 @@
+using System;
+using System.Globalization;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class Lexer : LexerBase
+    {
+        public event EventHandler<TokenizerError> Error;
+        private TextPosition _position;
+
+        public Lexer(TextSource source) : base(source)
+        {
+            IsInValue = false;
+        }
+
+        public Lexer(string source) : base(new TextSource(source))
+        {
+            IsInValue = false;
+        }
+
+        public bool IsInValue { get; set; }
+
+        public Token Get()
+        {
+            var current = GetNext();
+            _position = GetCurrentPosition();
+            return Data(current);
+        }
+
+
+        internal void RaiseErrorOccurred(ParseError error, TextPosition position)
+        {
+            var handler = Error;
+            if (handler == null) return;
+
+            var errorEvent = new TokenizerError(error, position);
+            handler.Invoke(this, errorEvent);
+        }
+
+        private Token Data(char current)
+        {
+            _position = GetCurrentPosition();
+            switch (current)
+            {
+                case Symbols.FormFeed:
+                case Symbols.LineFeed:
+                case Symbols.CarriageReturn:
+                case Symbols.Tab:
+                case Symbols.Space:
+                    return NewWhitespace(current);
+                case Symbols.DoubleQuote:
+                    return StringDoubleQuote();
+                case Symbols.Num:
+                    return IsInValue ? ColorLiteral() : HashStart();
+                case Symbols.Dollar:
+                    current = GetNext();
+                    return current == Symbols.Equality ? NewMatch(Combinators.Ends) : NewDelimiter(GetPrevious());
+                case Symbols.SingleQuote:
+                    return StringSingleQuote();
+                case Symbols.RoundBracketOpen:
+                    return NewOpenRound();
+                case Symbols.RoundBracketClose:
+                    return NewCloseRound();
+                case Symbols.Asterisk:
+                    current = GetNext();
+                    return current == Symbols.Equality ? NewMatch(Combinators.InText) : NewDelimiter(GetPrevious());
+                case Symbols.Plus:
+                    {
+                        var c1 = GetNext();
+                        if (c1 != Symbols.EndOfFile)
+                        {
+                            var c2 = GetNext();
+                            Back(2);
+
+                            if (c1.IsDigit() || c1 == Symbols.Dot && c2.IsDigit()) return NumberStart(current);
+                        }
+                        else
+                        {
+                            Back();
+                        }
+
+                        return NewDelimiter(current);
+                    }
+                case Symbols.Comma:
+                    return NewComma();
+
+                case Symbols.Dot:
+                    {
+                        var c = GetNext();
+                        return c.IsDigit() ? NumberStart(GetPrevious()) : NewDelimiter(GetPrevious());
+                    }
+                case Symbols.Minus:
+                    {
+                        var c1 = GetNext();
+                        if (c1 != Symbols.EndOfFile)
+                        {
+                            var c2 = GetNext();
+                            Back(2);
+                            if (c1.IsDigit() || c1 == Symbols.Dot && c2.IsDigit()) return NumberStart(current);
+                            if (c1.IsNameStart()) return IdentStart(current);
+                            if (c1 == Symbols.ReverseSolidus && !c2.IsLineBreak() && c2 != Symbols.EndOfFile)
+                                return IdentStart(current);
+
+                            if (c1 == Symbols.Minus)
+                            {
+                                if (c2 == Symbols.GreaterThan)
+                                {
+                                    Advance(2);
+                                    return NewCloseComment();
+                                }
+
+                                return IdentStart(current);
+                            }
+
+                            return NewDelimiter(current);
+                        }
+
+                        Back();
+
+                        return NewDelimiter(current);
+                    }
+                case Symbols.Solidus:
+                    current = GetNext();
+                    return current == Symbols.Asterisk
+                        ? Comment()
+                        : NewDelimiter(GetPrevious());
+
+                case Symbols.ReverseSolidus:
+                    current = GetNext();
+                    if (current.IsLineBreak())
+                    {
+                        RaiseErrorOccurred(ParseError.LineBreakUnexpected);
+                        return NewDelimiter(GetPrevious());
+                    }
+
+                    if (current != Symbols.EndOfFile) return IdentStart(GetPrevious());
+
+                    RaiseErrorOccurred(ParseError.EOF);
+                    return NewDelimiter(GetPrevious());
+
+                case Symbols.Colon:
+                    return NewColon();
+                case Symbols.Semicolon:
+                    return NewSemicolon();
+                case Symbols.LessThan:
+                    current = GetNext();
+                    if (current == Symbols.ExclamationMark)
+                    {
+                        current = GetNext();
+                        if (current == Symbols.Minus)
+                        {
+                            current = GetNext();
+                            if (current == Symbols.Minus) return NewOpenComment();
+                            // ReSharper disable once RedundantAssignment
+                            current = GetPrevious();
+                        }
+
+                        GetPrevious();
+                        return NewDelimiter(GetPrevious());
+                    }
+                    else if (current == Symbols.Equality)
+                    {
+                        Advance();
+                        return NewLessThanOrEqual();
+                    }
+                    else
+                    {
+                        return NewLessThan();
+                    }
+                case Symbols.At:
+                    return AtKeywordStart();
+                case Symbols.SquareBracketOpen:
+                    return NewOpenSquare();
+                case Symbols.SquareBracketClose:
+                    return NewCloseSquare();
+                case Symbols.Accent:
+                    current = GetNext();
+                    return current == Symbols.Equality
+                        ? NewMatch(Combinators.Begins)
+                        : NewDelimiter(GetPrevious());
+                case Symbols.CurlyBracketOpen:
+                    return NewOpenCurly();
+                case Symbols.CurlyBracketClose:
+                    return NewCloseCurly();
+                case '0':
+                case '1':
+                case '2':
+                case '3':
+                case '4':
+                case '5':
+                case '6':
+                case '7':
+                case '8':
+                case '9':
+                    return NumberStart(current);
+                case 'U':
+                case 'u':
+                    current = GetNext();
+                    if (current != Symbols.Plus) return IdentStart(GetPrevious());
+                    current = GetNext();
+                    if (current.IsHex() || current == Symbols.QuestionMark) return UnicodeRange(current);
+                    // ReSharper disable once RedundantAssignment
+                    current = GetPrevious();
+                    return IdentStart(GetPrevious());
+
+                case Symbols.Pipe:
+                    current = GetNext();
+                    if (current == Symbols.Equality)
+                        return NewMatch(Combinators.InToken);
+                    else if (current == Symbols.Pipe) return NewColumn();
+
+                    return NewDelimiter(GetPrevious());
+
+                case Symbols.Tilde:
+                    current = GetNext();
+                    return current == Symbols.Equality
+                        ? NewMatch(Combinators.InList)
+                        : NewDelimiter(GetPrevious());
+
+                case Symbols.EndOfFile:
+                    return NewEof();
+                case Symbols.ExclamationMark:
+                    current = GetNext();
+                    return current == Symbols.Equality
+                        ? NewMatch(Combinators.Unlike)
+                        : NewDelimiter(GetPrevious());
+                case Symbols.GreaterThan:
+                    if (GetNext() == Symbols.Equality)
+                    {
+                        Advance();
+                        return NewGreaterThanOrEqual();
+                    }
+                    GetPrevious();
+                    return NewGreaterThan();
+                default:
+                    return current.IsNameStart() ? IdentStart(current) : NewDelimiter(current);
+            }
+        }
+
+        private Token StringDoubleQuote()
+        {
+            while (true)
+            {
+                var current = GetNext();
+                switch (current)
+                {
+                    case Symbols.DoubleQuote:
+                    case Symbols.EndOfFile:
+                        return NewString(FlushBuffer(), Symbols.DoubleQuote);
+                    case Symbols.FormFeed:
+                    case Symbols.LineFeed:
+                        RaiseErrorOccurred(ParseError.LineBreakUnexpected);
+                        Back();
+                        return NewString(FlushBuffer(), Symbols.DoubleQuote, true);
+                    case Symbols.ReverseSolidus:
+                        current = GetNext();
+                        if (current.IsLineBreak())
+                        {
+                            StringBuffer.AppendLine();
+                        }
+                        else if (current != Symbols.EndOfFile)
+                        {
+                            StringBuffer.Append(ConsumeEscape(current));
+                        }
+                        else
+                        {
+                            RaiseErrorOccurred(ParseError.EOF);
+                            Back();
+                            return NewString(FlushBuffer(), Symbols.DoubleQuote, true);
+                        }
+
+                        break;
+                    default:
+                        StringBuffer.Append(current);
+                        break;
+                }
+            }
+        }
+
+        private Token StringSingleQuote()
+        {
+            while (true)
+            {
+                var current = GetNext();
+                switch (current)
+                {
+                    case Symbols.SingleQuote:
+                    case Symbols.EndOfFile:
+                        return NewString(FlushBuffer(), Symbols.SingleQuote);
+                    case Symbols.FormFeed:
+                    case Symbols.LineFeed:
+                        RaiseErrorOccurred(ParseError.LineBreakUnexpected);
+                        Back();
+                        return NewString(FlushBuffer(), Symbols.SingleQuote, true);
+                    case Symbols.ReverseSolidus:
+                        current = GetNext();
+                        if (current.IsLineBreak())
+                        {
+                            StringBuffer.AppendLine();
+                        }
+                        else if (current != Symbols.EndOfFile)
+                        {
+                            StringBuffer.Append(ConsumeEscape(current));
+                        }
+                        else
+                        {
+                            RaiseErrorOccurred(ParseError.EOF);
+                            Back();
+                            return NewString(FlushBuffer(), Symbols.SingleQuote, true);
+                        }
+
+                        break;
+                    default:
+                        StringBuffer.Append(current);
+                        break;
+                }
+            }
+        }
+
+        private Token ColorLiteral()
+        {
+            var current = GetNext();
+
+            // '#' not followed by a name code point or a valid escape is a plain delimiter (CSS Syntax §4.3.4).
+            if (!current.IsName() && !IsValidEscape(current))
+            {
+                Back();
+                return NewDelimiter(Symbols.Num);
+            }
+
+            Back();
+
+            // A '#' always begins a <hash-token>, consuming a whole <name> (CSS Syntax §4.3.4). Classify it as
+            // a color literal only when the name is entirely hex digits (e.g. "#f00"); otherwise keep it as an
+            // id hash-token (e.g. "#hero" — an id-selector inside element()), instead of truncating at the
+            // first non-hex character (which turned "#hero" into an empty color plus a stray "hero" ident).
+            var allHex = true;
+
+            while (true)
+            {
+                current = GetNext();
+
+                if (current.IsName())
+                {
+                    allHex = allHex && current.IsHex();
+                    StringBuffer.Append(current);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    StringBuffer.Append(ConsumeEscape(current));
+                    allHex = false;
+                }
+                else
+                {
+                    Back();
+                    var text = FlushBuffer();
+                    return allHex ? NewColor(text) : NewHash(text);
+                }
+            }
+        }
+
+        private Token HashStart()
+        {
+            var current = GetNext();
+            if (current.IsNameStart())
+            {
+                StringBuffer.Append(current);
+                return HashRest();
+            }
+
+            if (IsValidEscape(current))
+            {
+                current = GetNext();
+                StringBuffer.Append(ConsumeEscape(current));
+                return HashRest();
+            }
+
+            if (current == Symbols.ReverseSolidus)
+            {
+                RaiseErrorOccurred(ParseError.InvalidCharacter);
+                Back();
+                return NewDelimiter(Symbols.Num);
+            }
+
+            Back();
+            return NewDelimiter(Symbols.Num);
+        }
+
+        private Token HashRest()
+        {
+            while (true)
+            {
+                var current = GetNext();
+                if (current.IsName())
+                {
+                    StringBuffer.Append(current);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    StringBuffer.Append(ConsumeEscape(current));
+                }
+                else if (current == Symbols.ReverseSolidus)
+                {
+                    RaiseErrorOccurred(ParseError.InvalidCharacter);
+                    Back();
+                    return NewHash(FlushBuffer());
+                }
+                else
+                {
+                    Back();
+                    return NewHash(FlushBuffer());
+                }
+            }
+        }
+
+        private Token Comment()
+        {
+            var current = GetNext();
+            while (current != Symbols.EndOfFile)
+                if (current == Symbols.Asterisk)
+                {
+                    current = GetNext();
+                    if (current == Symbols.Solidus) return NewComment(FlushBuffer());
+                    StringBuffer.Append(Symbols.Asterisk);
+                }
+                else
+                {
+                    StringBuffer.Append(current);
+                    current = GetNext();
+                }
+
+            RaiseErrorOccurred(ParseError.EOF);
+            return NewComment(FlushBuffer(), true);
+        }
+
+        private Token AtKeywordStart()
+        {
+            var current = GetNext();
+            if (current == Symbols.Minus)
+            {
+                current = GetNext();
+                if (current.IsNameStart() || IsValidEscape(current))
+                {
+                    StringBuffer.Append(Symbols.Minus);
+                    return AtKeywordRest(current);
+                }
+
+                Back(2);
+                return NewDelimiter(Symbols.At);
+            }
+
+            if (current.IsNameStart())
+            {
+                StringBuffer.Append(current);
+                return AtKeywordRest(GetNext());
+            }
+
+            if (IsValidEscape(current))
+            {
+                current = GetNext();
+                StringBuffer.Append(ConsumeEscape(current));
+                return AtKeywordRest(GetNext());
+            }
+
+            Back();
+            return NewDelimiter(Symbols.At);
+        }
+
+        private Token AtKeywordRest(char current)
+        {
+            while (true)
+            {
+                if (current.IsName())
+                {
+                    StringBuffer.Append(current);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    StringBuffer.Append(ConsumeEscape(current));
+                }
+                else
+                {
+                    Back();
+                    return NewAtKeyword(FlushBuffer());
+                }
+
+                current = GetNext();
+            }
+        }
+
+        private Token IdentStart(char current)
+        {
+            if (current == Symbols.Minus)
+            {
+                current = GetNext();
+                if (current.IsNameStart() || current == Symbols.Minus || IsValidEscape(current))
+                {
+                    StringBuffer.Append(Symbols.Minus);
+                    return IdentRest(current);
+                }
+
+                Back();
+                return NewDelimiter(Symbols.Minus);
+            }
+
+            if (current.IsNameStart())
+            {
+                StringBuffer.Append(current);
+                return IdentRest(GetNext());
+            }
+
+            if (current == Symbols.ReverseSolidus && IsValidEscape(current))
+            {
+                current = GetNext();
+                StringBuffer.Append(ConsumeEscape(current));
+                return IdentRest(GetNext());
+            }
+
+            return Data(current);
+        }
+
+        private Token IdentRest(char current)
+        {
+            while (true)
+            {
+                if (current.IsName())
+                {
+                    StringBuffer.Append(current);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    StringBuffer.Append(ConsumeEscape(current));
+                }
+                else if (current == Symbols.RoundBracketOpen)
+                {
+                    var name = FlushBuffer();
+                    var type = name.GetTypeFromName();
+                    return type == TokenType.Function ? NewFunction(name) : UrlStart(name);
+                }
+                else
+                {
+                    Back();
+                    return NewIdent(FlushBuffer());
+                }
+
+                current = GetNext();
+            }
+        }
+        //private Token TransformFunctionWhitespace(char current)
+        //{
+        //    while (true)
+        //    {
+        //        current = GetNext();
+        //        if (current == Symbols.RoundBracketOpen)
+        //        {
+        //            Back();
+        //            return NewFunction(FlushBuffer());
+        //        }
+        //        if (!current.IsSpaceCharacter())
+        //        {
+        //            Back(2);
+        //            return NewIdent(FlushBuffer());
+        //        }
+        //    }
+        //}
+
+        private Token NumberStart(char current)
+        {
+            while (true)
+            {
+                if (current.IsOneOf(Symbols.Plus, Symbols.Minus))
+                {
+                    StringBuffer.Append(current);
+                    current = GetNext();
+                    if (current == Symbols.Dot)
+                    {
+                        StringBuffer.Append(current);
+                        StringBuffer.Append(GetNext());
+                        return NumberFraction();
+                    }
+
+                    StringBuffer.Append(current);
+                    return NumberRest();
+                }
+
+                if (current == Symbols.Dot)
+                {
+                    StringBuffer.Append(current);
+                    StringBuffer.Append(GetNext());
+                    return NumberFraction();
+                }
+
+                if (current.IsDigit())
+                {
+                    StringBuffer.Append(current);
+                    return NumberRest();
+                }
+
+                current = GetNext();
+            }
+        }
+
+        private Token NumberRest()
+        {
+            var current = GetNext();
+            while (true)
+            {
+                if (current.IsDigit())
+                {
+                    StringBuffer.Append(current);
+                }
+                else if (current.IsNameStart())
+                {
+                    var number = FlushBuffer();
+                    StringBuffer.Append(current);
+                    return Dimension(number);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    var number = FlushBuffer();
+                    StringBuffer.Append(ConsumeEscape(current));
+                    return Dimension(number);
+                }
+                else
+                {
+                    break;
+                }
+
+                current = GetNext();
+            }
+
+            switch (current)
+            {
+                case Symbols.Dot:
+                    current = GetNext();
+                    if (current.IsDigit())
+                    {
+                        StringBuffer.Append(Symbols.Dot).Append(current);
+                        return NumberFraction();
+                    }
+
+                    Back();
+                    return NewNumber(FlushBuffer());
+                case '%':
+                    return NewPercentage(FlushBuffer());
+                case 'e':
+                case 'E':
+                    return NumberExponential(current);
+                case Symbols.Minus:
+                    return NumberDash();
+                default:
+                    Back();
+                    return NewNumber(FlushBuffer());
+            }
+        }
+
+        private Token NumberFraction()
+        {
+            var current = GetNext();
+            while (true)
+            {
+                if (current.IsDigit())
+                {
+                    StringBuffer.Append(current);
+                }
+                else if (current.IsNameStart())
+                {
+                    var number = FlushBuffer();
+                    StringBuffer.Append(current);
+                    return Dimension(number);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    var number = FlushBuffer();
+                    StringBuffer.Append(ConsumeEscape(current));
+                    return Dimension(number);
+                }
+                else
+                {
+                    break;
+                }
+
+                current = GetNext();
+            }
+
+            switch (current)
+            {
+                case 'e':
+                case 'E':
+                    return NumberExponential(current);
+                case '%':
+                    return NewPercentage(FlushBuffer());
+                case Symbols.Minus:
+                    return NumberDash();
+                default:
+                    Back();
+                    return NewNumber(FlushBuffer());
+            }
+        }
+
+        private Token Dimension(string number)
+        {
+            while (true)
+            {
+                var current = GetNext();
+                if (current.IsLetter())
+                {
+                    StringBuffer.Append(current);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    StringBuffer.Append(ConsumeEscape(current));
+                }
+                else
+                {
+                    Back();
+                    return NewDimension(number, FlushBuffer());
+                }
+            }
+        }
+
+        private Token SciNotation()
+        {
+            while (true)
+            {
+                var current = GetNext();
+                if (current.IsDigit())
+                {
+                    StringBuffer.Append(current);
+                }
+                else
+                {
+                    Back();
+                    return NewNumber(FlushBuffer());
+                }
+            }
+        }
+
+        private Token UrlStart(string functionName)
+        {
+            var current = SkipSpaces();
+            switch (current)
+            {
+                case Symbols.EndOfFile:
+                    RaiseErrorOccurred(ParseError.EOF);
+                    return NewUrl(functionName, string.Empty, true);
+                case Symbols.DoubleQuote:
+                    return UrlDoubleQuote(functionName);
+                case Symbols.SingleQuote:
+                    return UrlSingleQuote(functionName);
+                case Symbols.RoundBracketClose:
+                    return NewUrl(functionName, string.Empty);
+                default:
+                    return UrlUnquoted(current, functionName);
+            }
+        }
+
+        private Token UrlDoubleQuote(string functionName)
+        {
+            while (true)
+            {
+                var current = GetNext();
+                if (current.IsLineBreak())
+                {
+                    RaiseErrorOccurred(ParseError.LineBreakUnexpected);
+                    return UrlBad(functionName);
+                }
+
+                switch (current)
+                {
+                    case Symbols.EndOfFile:
+                        return NewUrl(functionName, FlushBuffer());
+                    case Symbols.DoubleQuote:
+                        return UrlEnd(functionName);
+                }
+
+                if (current != Symbols.ReverseSolidus)
+                {
+                    StringBuffer.Append(current);
+                }
+                else
+                {
+                    current = GetNext();
+                    if (current == Symbols.EndOfFile)
+                    {
+                        Back(2);
+                        RaiseErrorOccurred(ParseError.EOF);
+                        return NewUrl(functionName, FlushBuffer(), true);
+                    }
+
+                    if (current.IsLineBreak())
+                        StringBuffer.AppendLine();
+                    else
+                        StringBuffer.Append(ConsumeEscape(current));
+                }
+            }
+        }
+
+        private Token UrlSingleQuote(string functionName)
+        {
+            while (true)
+            {
+                var current = GetNext();
+                if (current.IsLineBreak())
+                {
+                    RaiseErrorOccurred(ParseError.LineBreakUnexpected);
+                    return UrlBad(functionName);
+                }
+
+                switch (current)
+                {
+                    case Symbols.EndOfFile:
+                        return NewUrl(functionName, FlushBuffer());
+                    case Symbols.SingleQuote:
+                        return UrlEnd(functionName);
+                }
+
+                if (current != Symbols.ReverseSolidus)
+                {
+                    StringBuffer.Append(current);
+                }
+                else
+                {
+                    current = GetNext();
+                    if (current == Symbols.EndOfFile)
+                    {
+                        Back(2);
+                        RaiseErrorOccurred(ParseError.EOF);
+                        return NewUrl(functionName, FlushBuffer(), true);
+                    }
+
+                    if (current.IsLineBreak())
+                        StringBuffer.AppendLine();
+                    else
+                        StringBuffer.Append(ConsumeEscape(current));
+                }
+            }
+        }
+
+        private Token UrlUnquoted(char current, string functionName)
+        {
+            while (true)
+            {
+                if (current.IsSpaceCharacter()) return UrlEnd(functionName);
+                if (current.IsOneOf(Symbols.RoundBracketClose, Symbols.EndOfFile))
+                    return NewUrl(functionName, FlushBuffer());
+                if (current.IsOneOf(Symbols.DoubleQuote, Symbols.SingleQuote, Symbols.RoundBracketOpen) ||
+                    current.IsNonPrintable())
+                {
+                    RaiseErrorOccurred(ParseError.InvalidCharacter);
+                    return UrlBad(functionName);
+                }
+
+                if (current != Symbols.ReverseSolidus)
+                {
+                    StringBuffer.Append(current);
+                }
+                else if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    StringBuffer.Append(ConsumeEscape(current));
+                }
+                else
+                {
+                    RaiseErrorOccurred(ParseError.InvalidCharacter);
+                    return UrlBad(functionName);
+                }
+
+                current = GetNext();
+            }
+        }
+
+        private Token UrlEnd(string functionName)
+        {
+            while (true)
+            {
+                var current = GetNext();
+                if (current == Symbols.RoundBracketClose) return NewUrl(functionName, FlushBuffer());
+
+                if (current.IsSpaceCharacter()) continue;
+
+                RaiseErrorOccurred(ParseError.InvalidCharacter);
+                Back();
+                return UrlBad(functionName);
+            }
+        }
+
+        private Token UrlBad(string functionName)
+        {
+            var current = Current;
+            var curly = 0;
+            var round = 1;
+            while (current != Symbols.EndOfFile)
+            {
+                if (current == Symbols.Semicolon)
+                {
+                    Back();
+                    return NewUrl(functionName, FlushBuffer(), true);
+                }
+
+                if (current == Symbols.CurlyBracketClose && --curly == -1)
+                {
+                    Back();
+                    return NewUrl(functionName, FlushBuffer(), true);
+                }
+
+                if (current == Symbols.RoundBracketClose && --round == 0)
+                    return NewUrl(functionName, FlushBuffer(), true);
+                if (IsValidEscape(current))
+                {
+                    current = GetNext();
+                    StringBuffer.Append(ConsumeEscape(current));
+                }
+                else
+                {
+                    if (current == Symbols.RoundBracketOpen)
+                        ++round;
+                    else if (curly == Symbols.CurlyBracketOpen) ++curly;
+                    StringBuffer.Append(current);
+                }
+
+                current = GetNext();
+            }
+
+            RaiseErrorOccurred(ParseError.EOF);
+            return NewUrl(functionName, FlushBuffer(), true);
+        }
+
+        private Token UnicodeRange(char current)
+        {
+            for (var i = 0; i < 6 && current.IsHex(); i++)
+            {
+                StringBuffer.Append(current);
+                current = GetNext();
+            }
+
+            // Fewer than 6 hex digits may be followed by '?' wildcards (which pad the value and are
+            // mutually exclusive with the start-end range form) OR - like a full 6-digit start - by a
+            // '-<hex>' range end (e.g. U+41-5A). Only the wildcard form is handled here; a '-' falls
+            // through to the shared range handling below.
+            if (StringBuffer.Length != 6 && current == Symbols.QuestionMark)
+            {
+                // The wildcard budget must be captured up front: appending to StringBuffer inside the loop
+                // would otherwise shrink a "6 - StringBuffer.Length" bound on every iteration, so only half
+                // the available wildcards were ever consumed (U+?????? stopped after three).
+                var wildcards = 6 - StringBuffer.Length;
+
+                for (var i = 0; i < wildcards; i++)
+                {
+                    if (current != Symbols.QuestionMark)
+                    {
+                        // ReSharper disable once RedundantAssignment
+                        current = GetPrevious();
+                        break;
+                    }
+
+                    StringBuffer.Append(current);
+                    current = GetNext();
+                }
+
+                return NewRange(FlushBuffer());
+            }
+
+            if (current == Symbols.Minus)
+            {
+                current = GetNext();
+                if (current.IsHex())
+                {
+                    var start = FlushBuffer();
+                    for (var i = 0; i < 6; i++)
+                    {
+                        if (!current.IsHex())
+                        {
+                            // ReSharper disable once RedundantAssignment
+                            current = GetPrevious();
+                            break;
+                        }
+
+                        StringBuffer.Append(current);
+                        current = GetNext();
+                    }
+
+                    var end = FlushBuffer();
+                    return NewRange(start, end);
+                }
+
+                Back(2);
+                return NewRange(FlushBuffer());
+            }
+
+            Back();
+            return NewRange(FlushBuffer());
+        }
+
+        private Token NewMatch(string match)
+        {
+            return new Token(TokenType.Match, match, _position);
+        }
+
+        private Token NewColumn()
+        {
+            return new Token(TokenType.Column, Combinators.Column, _position);
+        }
+
+        private Token NewCloseCurly()
+        {
+            return new Token(TokenType.CurlyBracketClose, "}", _position);
+        }
+
+        private Token NewOpenCurly()
+        {
+            return new Token(TokenType.CurlyBracketOpen, "{", _position);
+        }
+
+        private Token NewCloseSquare()
+        {
+            return new Token(TokenType.SquareBracketClose, "]", _position);
+        }
+
+        private Token NewOpenSquare()
+        {
+            return new Token(TokenType.SquareBracketOpen, "[", _position);
+        }
+
+        private Token NewOpenComment()
+        {
+            return new Token(TokenType.Cdo, "<!--", _position);
+        }
+
+        private Token NewSemicolon()
+        {
+            return new Token(TokenType.Semicolon, ";", _position);
+        }
+
+        private Token NewColon()
+        {
+            return new Token(TokenType.Colon, ":", _position);
+        }
+
+        private Token NewCloseComment()
+        {
+            return new Token(TokenType.Cdc, "-->", _position);
+        }
+
+        private Token NewComma()
+        {
+            return new Token(TokenType.Comma, ",", _position);
+        }
+
+        private Token NewCloseRound()
+        {
+            return new Token(TokenType.RoundBracketClose, ")", _position);
+        }
+
+        private Token NewOpenRound()
+        {
+            return new Token(TokenType.RoundBracketOpen, "(", _position);
+        }
+
+        private Token NewString(string value, char quote, bool bad = false)
+        {
+            return new StringToken(value, bad, quote, _position);
+        }
+
+        private Token NewHash(string value)
+        {
+            return new KeywordToken(TokenType.Hash, value, _position);
+        }
+
+        private Token NewComment(string value, bool bad = false)
+        {
+            return new CommentToken(value, bad, _position);
+        }
+
+        private Token NewAtKeyword(string value)
+        {
+            return new KeywordToken(TokenType.AtKeyword, value, _position);
+        }
+
+        private Token NewIdent(string value)
+        {
+            return new KeywordToken(TokenType.Ident, value, _position);
+        }
+
+        private Token NewFunction(string value)
+        {
+            var function = new FunctionToken(value, _position);
+
+            // Tracks paren depth so a bare (non-function) parenthesized group nested inside the
+            // function's arguments - e.g. calc((1px + 2px) * 3) - doesn't get mistaken for the end of
+            // the function: only the closing paren that matches this function's own opening paren (depth
+            // returning to 0) should terminate it. A nested function call's own parens are already fully
+            // consumed by its own (recursive) call to this method before it's added as a single token
+            // here, so they never surface as bare RoundBracketOpen/Close tokens at this level.
+            var depth = 1;
+            var token = Get();
+            while (token.Type != TokenType.EndOfFile)
+            {
+                function.AddArgumentToken(token);
+
+                if (token.Type == TokenType.RoundBracketOpen)
+                {
+                    depth++;
+                }
+                else if (token.Type == TokenType.RoundBracketClose)
+                {
+                    depth--;
+                    if (depth == 0) break;
+                }
+
+                token = Get();
+            }
+
+            return function;
+        }
+
+        private Token NewPercentage(string value)
+        {
+            return new UnitToken(TokenType.Percentage, value, "%", _position);
+        }
+
+        private Token NewDimension(string value, string unit)
+        {
+            return new UnitToken(TokenType.Dimension, value, unit, _position);
+        }
+
+        private Token NewUrl(string functionName, string data, bool bad = false)
+        {
+            return new UrlToken(functionName, data, bad, _position);
+        }
+
+        private Token NewRange(string range)
+        {
+            return new RangeToken(range, _position);
+        }
+
+        private Token NewRange(string start, string end)
+        {
+            return new RangeToken(start, end, _position);
+        }
+
+        private Token NewWhitespace(char character)
+        {
+            return new Token(TokenType.Whitespace, character.ToString(), _position);
+        }
+
+        private Token NewNumber(string number)
+        {
+            return new NumberToken(number, _position);
+        }
+
+        private Token NewDelimiter(char c)
+        {
+            return new Token(TokenType.Delim, c.ToString(), _position);
+        }
+
+        private Token NewColor(string text)
+        {
+            return new ColorToken(text, _position);
+        }
+
+        private Token NewEof()
+        {
+            return new Token(TokenType.EndOfFile, string.Empty, _position);
+        }
+
+        private Token NewGreaterThan() => new Token(TokenType.GreaterThan, ">", _position);
+        private Token NewGreaterThanOrEqual() => new Token(TokenType.GreaterThanOrEqual, ">=", _position);
+        private Token NewLessThan() => new Token(TokenType.LessThan, "<", _position);
+        private Token NewLessThanOrEqual() => new Token(TokenType.LessThanOrEqual, "<=", _position);
+        private Token NewEqual() => new Token(TokenType.Equal, "=", _position);
+
+
+        private Token NumberExponential(char letter)
+        {
+            var current = GetNext();
+            if (current.IsDigit())
+            {
+                StringBuffer.Append(letter).Append(current);
+                return SciNotation();
+            }
+
+            if (current == Symbols.Plus || current == Symbols.Minus)
+            {
+                var op = current;
+                current = GetNext();
+                if (current.IsDigit())
+                {
+                    StringBuffer.Append(letter).Append(op).Append(current);
+                    return SciNotation();
+                }
+
+                Back();
+            }
+
+            var number = FlushBuffer();
+            StringBuffer.Append(letter);
+            Back();
+            return Dimension(number);
+        }
+
+        private Token NumberDash()
+        {
+            var current = GetNext();
+            if (current.IsNameStart())
+            {
+                var number = FlushBuffer();
+                StringBuffer.Append(Symbols.Minus).Append(current);
+                return Dimension(number);
+            }
+
+            if (IsValidEscape(current))
+            {
+                current = GetNext();
+                var number = FlushBuffer();
+                StringBuffer.Append(Symbols.Minus).Append(ConsumeEscape(current));
+                return Dimension(number);
+            }
+
+            Back(2);
+            return NewNumber(FlushBuffer());
+        }
+
+        private string ConsumeEscape(char current)
+        {
+            if (!current.IsHex()) return current.ToString();
+
+            var isHex = true;
+            var escape = new char[6];
+            var length = 0;
+            while (isHex && length < escape.Length)
+            {
+                escape[length++] = current;
+                current = GetNext();
+                isHex = current.IsHex();
+            }
+
+            if (!current.IsSpaceCharacter()) Back();
+            var code = int.Parse(new string(escape, 0, length), NumberStyles.HexNumber);
+            if (!code.IsInvalid()) return code.ConvertFromUtf32();
+            current = Symbols.Replacement;
+            return current.ToString();
+        }
+
+        private bool IsValidEscape(char current)
+        {
+            if (current != Symbols.ReverseSolidus) return false;
+            current = GetNext();
+            Back();
+            return current != Symbols.EndOfFile && !current.IsLineBreak();
+        }
+
+        private void RaiseErrorOccurred(ParseError code)
+        {
+            RaiseErrorOccurred(code, GetCurrentPosition());
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Parser/LexerBase.cs b/Source/HtmlRenderer/Core/CssEngine/Parser/LexerBase.cs
new file mode 100644
index 000000000..c326435f4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Parser/LexerBase.cs
@@ -0,0 +1,189 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class LexerBase : IDisposable
+    {
+        private readonly Stack<ushort> _columns;
+
+        protected LexerBase(TextSource source)
+        {
+            StringBuffer = Pool.NewStringBuilder();
+            _columns = new Stack<ushort>();
+            Source = source;
+            Current = Symbols.Null;
+            Column = 0;
+            Line = 1;
+        }
+
+        public string FlushBuffer()
+        {
+            var content = StringBuffer.ToString();
+            StringBuffer.Clear();
+            return content;
+        }
+
+        public void Dispose()
+        {
+            var isDisposed = StringBuffer == null;
+            if (!isDisposed)
+            {
+                var disposable = Source as IDisposable;
+                disposable?.Dispose();
+                StringBuffer.Clear().ToPool();
+                StringBuffer = null;
+            }
+        }
+
+        public TextPosition GetCurrentPosition()
+        {
+            return new TextPosition(Line, Column, Position);
+        }
+
+        /// <summary>
+        /// Repositions the lexer so the next token is re-lexed from character index
+        /// <paramref name="sourceIndex"/> (a raw <see cref="Source"/> index, as returned by
+        /// <see cref="InsertionPoint"/>). Unlike setting <see cref="InsertionPoint"/> (whose
+        /// <c>BackNative</c> loop is not a faithful inverse across <c>\r\n</c> normalization), this
+        /// restores the character stream exactly — line/column tracking is not rewound (it only affects
+        /// reported positions, never token content). Used by <see cref="StylesheetComposer"/> to rewind a
+        /// CSS-Nesting classification look-ahead so a declaration re-lexes cleanly in value mode.
+        /// </summary>
+        public void RewindTo(int sourceIndex)
+        {
+            Source.Index = sourceIndex;
+            // Non-EOF so the next Advance() actually reads Source[sourceIndex] rather than short-circuiting.
+            Current = Symbols.Null;
+        }
+
+        protected char SkipSpaces()
+        {
+            var c = GetNext();
+            while (c.IsSpaceCharacter())
+                c = GetNext();
+            return c;
+        }
+
+        protected char GetNext()
+        {
+            Advance();
+            return Current;
+        }
+
+        protected char GetPrevious()
+        {
+            Back();
+            return Current;
+        }
+
+        protected void Advance()
+        {
+            if (Current != Symbols.EndOfFile) AdvanceNative();
+        }
+
+        protected void Advance(int distance)
+        {
+            while (distance-- > 0 && Current != Symbols.EndOfFile) AdvanceNative();
+        }
+
+        protected void Back()
+        {
+            if (InsertionPoint > 0) BackNative();
+        }
+
+        protected void Back(int distance)
+        {
+            while (distance-- > 0 && InsertionPoint > 0) BackNative();
+        }
+
+        private void AdvanceNative()
+        {
+            if (Current == Symbols.LineFeed)
+            {
+                _columns.Push(Column);
+                Column = 1;
+                Line++;
+            }
+            else
+            {
+                Column++;
+            }
+
+            Current = NormalizeForward(Source.ReadCharacter());
+        }
+
+        private void BackNative()
+        {
+            Source.Index -= 1;
+            if (Source.Index == 0)
+            {
+                Column = 0;
+                Current = Symbols.Null;
+                return;
+            }
+
+            var c = NormalizeBackward(Source[Source.Index - 1]);
+            if (c == Symbols.LineFeed)
+            {
+                Column = _columns.Count != 0 ? _columns.Pop() : (ushort)1;
+                Line--;
+                Current = c;
+            }
+            else if (c != Symbols.Null)
+            {
+                Current = c;
+                Column--;
+            }
+        }
+
+        private char NormalizeForward(char symbol)
+        {
+            if (symbol != Symbols.CarriageReturn) return symbol;
+            if (Source.ReadCharacter() != Symbols.LineFeed) Source.Index--;
+            return Symbols.LineFeed;
+        }
+
+        private char NormalizeBackward(char symbol)
+        {
+            if (symbol != Symbols.CarriageReturn) return symbol;
+            if (Source.Index < Source.Length && Source[Source.Index] == Symbols.LineFeed)
+            {
+                BackNative();
+                return Symbols.Null;
+            }
+
+            return Symbols.LineFeed;
+        }
+
+        protected StringBuilder StringBuffer { get; private set; }
+
+        public TextSource Source { get; }
+
+        public ushort Line { get; private set; }
+        public ushort Column { get; private set; }
+        public int Position => Source.Index;
+        protected char Current { get; private set; }
+
+        public int InsertionPoint
+        {
+            get => Source.Index;
+            protected set
+            {
+                var delta = Source.Index - value;
+                while (delta > 0)
+                {
+                    BackNative();
+                    delta--;
+                }
+
+                while (delta < 0)
+                {
+                    AdvanceNative();
+                    delta++;
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Parser/SelectorConstructor.cs b/Source/HtmlRenderer/Core/CssEngine/Parser/SelectorConstructor.cs
new file mode 100644
index 000000000..12abeb4b9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Parser/SelectorConstructor.cs
@@ -0,0 +1,966 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class SelectorConstructor
+    {
+        private readonly Stack<Combinator> _combinators;
+        private State _state;
+        private ISelector _temp;
+        private ListSelector _group;
+        private ComplexSelector _complex;
+        private string _attrName;
+        private string _attrValue;
+        private string _attrOp;
+        private string _attrNs;
+        private bool _valid;
+        private bool _ready;
+        private AttributeSelectorFactory _attributeSelector;
+        private PseudoElementSelectorFactory _pseudoElementSelector;
+        private PseudoClassSelectorFactory _pseudoClassSelector;
+
+        public SelectorConstructor(AttributeSelectorFactory attributeSelector,
+            PseudoClassSelectorFactory pseudoClassSelector, PseudoElementSelectorFactory pseudoElementSelector)
+        {
+            _combinators = new Stack<Combinator>();
+            Reset(attributeSelector, pseudoClassSelector, pseudoElementSelector);
+        }
+
+        private enum State : byte
+        {
+            Data,
+            Attribute,
+            AttributeOperator,
+            AttributeValue,
+            AttributeEnd,
+            Class,
+            PseudoClass,
+            PseudoElement
+        }
+
+        private static readonly Dictionary<string, Func<SelectorConstructor, FunctionState>> PseudoClassFunctions =
+            new Dictionary<string, Func<SelectorConstructor, FunctionState>>(StringComparer.OrdinalIgnoreCase)
+            {
+                {PseudoClassNames.NthChild, ctx => new ChildFunctionState<FirstChildSelector>(ctx)},
+                {PseudoClassNames.NthLastChild, ctx => new ChildFunctionState<LastChildSelector>(ctx)},
+                {PseudoClassNames.NthOfType, ctx => new ChildFunctionState<FirstTypeSelector>(ctx, false)},
+                {PseudoClassNames.NthLastOfType, ctx => new ChildFunctionState<LastTypeSelector>(ctx, false)},
+                {PseudoClassNames.NthColumn, ctx => new ChildFunctionState<FirstColumnSelector>(ctx, false)},
+                {PseudoClassNames.NthLastColumn, ctx => new ChildFunctionState<LastColumnSelector>(ctx, false)},
+                {PseudoClassNames.Not, ctx => new NotFunctionState(ctx)},
+                {PseudoClassNames.Dir, _ => new DirFunctionState()},
+                {PseudoClassNames.Lang, _ => new LangFunctionState()},
+                {PseudoClassNames.Contains, _ => new ContainsFunctionState()},
+                {PseudoClassNames.Has, ctx => new HasFunctionState(ctx)},
+                {PseudoClassNames.Matches, ctx => new MatchesFunctionState(ctx, PseudoClassNames.Matches)},
+                {PseudoClassNames.Is, ctx => new MatchesFunctionState(ctx, PseudoClassNames.Is)},
+                {PseudoClassNames.Where, ctx => new MatchesFunctionState(ctx, PseudoClassNames.Where)},
+                {PseudoClassNames.HostContext, ctx => new HostContextFunctionState(ctx)}
+            };
+
+        public bool IsValid => _valid && _ready;
+        public bool IsNested { get; private set; }
+
+        public ISelector GetResult()
+        {
+            if (!IsValid)
+            {
+                var selector = new UnknownSelector();
+                return selector;
+            }
+
+            if (_complex != null)
+            {
+                _complex.ConcludeSelector(_temp);
+                _temp = _complex;
+                _complex = null;
+            }
+
+            if (_group == null || _group.Length == 0) return _temp ?? AllSelector.Create();
+
+            if (_temp == null && _group.Length == 1) return _group[0];
+
+            if (_temp != null)
+            {
+                _group.Add(_temp);
+                _temp = null;
+            }
+
+            return _group;
+        }
+
+        public void Apply(Token token)
+        {
+            if (token.Type == TokenType.Comment) return;
+
+            switch (_state)
+            {
+                case State.Data:
+                    OnData(token);
+                    break;
+                case State.Class:
+                    OnClass(token);
+                    break;
+                case State.Attribute:
+                    OnAttribute(token);
+                    break;
+                case State.AttributeOperator:
+                    OnAttributeOperator(token);
+                    break;
+                case State.AttributeValue:
+                    OnAttributeValue(token);
+                    break;
+                case State.AttributeEnd:
+                    OnAttributeEnd(token);
+                    break;
+                case State.PseudoClass:
+                    OnPseudoClass(token);
+                    break;
+                case State.PseudoElement:
+                    OnPseudoElement(token);
+                    break;
+                default:
+                    _valid = false;
+                    break;
+            }
+        }
+
+        public SelectorConstructor Reset(AttributeSelectorFactory attributeSelector,
+            PseudoClassSelectorFactory pseudoClassSelector, PseudoElementSelectorFactory pseudoElementSelector)
+        {
+            _attrName = null;
+            _attrValue = null;
+            _attrNs = null;
+            _attrOp = string.Empty;
+            _state = State.Data;
+            _combinators.Clear();
+            _temp = null;
+            _group = null;
+            _complex = null;
+            _valid = true;
+            IsNested = false;
+            _ready = true;
+            _attributeSelector = attributeSelector;
+            _pseudoClassSelector = pseudoClassSelector;
+            _pseudoElementSelector = pseudoElementSelector;
+            return this;
+        }
+
+        private void OnData(Token token)
+        {
+            switch (token.Type)
+            {
+                case TokenType.SquareBracketOpen:
+                    _attrName = null;
+                    _attrValue = null;
+                    _attrOp = string.Empty;
+                    _attrNs = null;
+                    _state = State.Attribute;
+                    _ready = false;
+                    break;
+                case TokenType.Colon:
+                    _state = State.PseudoClass;
+                    _ready = false;
+                    break;
+                case TokenType.Hash:
+                    Insert(IdSelector.Create(token.Data));
+                    _ready = true;
+                    break;
+                case TokenType.Ident:
+                    Insert(TypeSelector.Create(token.Data));
+                    _ready = true;
+                    break;
+                case TokenType.Whitespace:
+                    Insert(Combinator.Descendent);
+                    break;
+                case TokenType.Delim:
+                    OnDelim(token);
+                    break;
+                case TokenType.GreaterThan:
+                    OnDelim(token);
+                    break;
+                case TokenType.Comma:
+                    InsertOr();
+                    _ready = false;
+                    break;
+                default:
+                    _valid = false;
+                    break;
+            }
+        }
+
+        private void OnAttribute(Token token)
+        {
+            if (token.Type == TokenType.Whitespace) return;
+
+            if (token.Type == TokenType.Ident || token.Type == TokenType.String)
+            {
+                _state = State.AttributeOperator;
+                _attrName = token.Data;
+            }
+            else if (token.Type == TokenType.Delim && token.Data.Is(Combinators.Pipe))
+            {
+                _state = State.Attribute;
+                _attrNs = string.Empty;
+            }
+            else if (token.Type == TokenType.Delim && token.Data.Is(Keywords.Asterisk))
+            {
+                _state = State.AttributeOperator;
+                _attrName = token.ToValue();
+            }
+            else
+            {
+                _state = State.Data;
+                _valid = false;
+            }
+        }
+
+        private void OnAttributeOperator(Token token)
+        {
+            if (token.Type == TokenType.Whitespace) return;
+
+            if (token.Type == TokenType.SquareBracketClose)
+            {
+                _state = State.AttributeValue;
+                OnAttributeEnd(token);
+            }
+            else if (token.Type == TokenType.Match || token.Type == TokenType.Delim)
+            {
+                _state = State.AttributeValue;
+                _attrOp = token.ToValue();
+
+                if (_attrOp != Combinators.Pipe) return;
+                _attrNs = _attrName;
+                _attrName = null;
+                _attrOp = string.Empty;
+                _state = State.Attribute;
+            }
+            else
+            {
+                _state = State.AttributeEnd;
+                _valid = false;
+            }
+        }
+
+        private void OnAttributeValue(Token token)
+        {
+            if (token.Type == TokenType.Whitespace) return;
+
+            if (token.Type == TokenType.Ident || token.Type == TokenType.String ||
+                token.Type == TokenType.Number)
+            {
+                _state = State.AttributeEnd;
+                _attrValue = token.Data;
+            }
+            else
+            {
+                _state = State.Data;
+                _valid = false;
+            }
+        }
+
+        private void OnAttributeEnd(Token token)
+        {
+            if (token.Type == TokenType.Whitespace) return;
+            _state = State.Data;
+            _ready = true;
+            if (token.Type == TokenType.SquareBracketClose)
+            {
+                var selector = _attributeSelector.Create(_attrOp, _attrName, _attrValue, _attrNs);
+                Insert(selector);
+            }
+            else
+            {
+                _valid = false;
+            }
+        }
+
+        private void OnPseudoClass(Token token)
+        {
+            _state = State.Data;
+            _ready = true;
+            switch (token.Type)
+            {
+                case TokenType.Colon:
+                    _state = State.PseudoElement;
+                    return;
+                case TokenType.Function:
+                    {
+                        var sel = GetPseudoFunction(token as FunctionToken);
+                        if (sel != null)
+                        {
+                            Insert(sel);
+                            return;
+                        }
+                    }
+                    break;
+                case TokenType.Ident:
+                    {
+                        var sel = _pseudoClassSelector.Create(token.Data);
+                        if (sel != null)
+                        {
+                            Insert(sel);
+                            return;
+                        }
+                    }
+                    break;
+            }
+
+            _valid = false;
+        }
+
+        private void OnPseudoElement(Token token)
+        {
+            _state = State.Data;
+            _ready = true;
+            if (token.Type == TokenType.Ident)
+            {
+                var sel = _pseudoElementSelector.Create(token.Data);
+                if (sel != null)
+                {
+                    _valid = _valid && !IsNested;
+                    Insert(sel);
+                    return;
+                }
+            }
+
+            _valid = false;
+        }
+
+        private void OnClass(Token token)
+        {
+            _state = State.Data;
+            _ready = true;
+            if (token.Type == TokenType.Ident)
+                Insert(ClassSelector.Create(token.Data));
+            else
+                _valid = false;
+        }
+
+        private void InsertOr()
+        {
+            if (_temp == null) return;
+
+            _group = _group ?? new ListSelector();
+
+            if (_complex != null)
+            {
+                _complex.ConcludeSelector(_temp);
+                _group.Add(_complex);
+                _complex = null;
+            }
+            else
+            {
+                _group.Add(_temp);
+            }
+
+            _temp = null;
+        }
+
+        private void Insert(ISelector selector)
+        {
+            if (_temp != null)
+            {
+                if (_combinators.Count == 0)
+                {
+                    var compound = _temp as CompoundSelector ?? new CompoundSelector { _temp };
+
+                    compound.Add(selector);
+                    _temp = compound;
+                }
+                else
+                {
+                    _complex = _complex ?? new ComplexSelector();
+
+                    var combinator = GetCombinator();
+                    _complex.AppendSelector(_temp, combinator);
+                    _temp = WrapPseudoElement(selector);
+                }
+            }
+            else
+            {
+                _combinators.Clear();
+                _temp = selector;
+            }
+        }
+
+        // CssData.DoesSelectorMatch(CompoundSelector, box) is the only place that synthesizes
+        // ::before/::after (and ::marker) child boxes as a match side effect, and it only runs for a
+        // pseudo-element that's the last member of a CompoundSelector. A pseudo-element preceded by a
+        // combinator (e.g. "E :after", with whitespace) would otherwise become a bare, unwrapped _temp
+        // here - which CssData's ComplexSelector subject-match dispatches straight to the plain
+        // DoesSelectorMatch(PseudoElementSelector, box) overload (which only checks whether the flag is
+        // already set, never sets it), so the pseudo-element box would never actually get created.
+        // Wrapping it in a single-member CompoundSelector as soon as it becomes a standalone selector
+        // routes it through the one, already-correct synthesis path instead of needing a second
+        // implementation of the same logic in CssData.
+        //
+        // Deliberately NOT applied in the other "_temp == null" branch above (a pseudo-element with no
+        // combinator at all, i.e. it's the entire selector - "*:before" written as bare ":before"): that
+        // shape has no ancestor restriction, so synthesizing on every match would mean synthesizing on
+        // literally every element in the document. The UA stylesheet's own
+        // ":before, :after { white-space: pre-line }" rule (CssDefaults.cs) is exactly this shape and
+        // relies on the existing non-synthesizing behavior - it exists to style already-synthesized
+        // pseudo-element boxes, not to create one on every element.
+        private static ISelector WrapPseudoElement(ISelector selector) =>
+            selector is PseudoElementSelector ? new CompoundSelector { selector } : selector;
+
+        private Combinator GetCombinator()
+        {
+            while (_combinators.Count > 1 && _combinators.Peek() == Combinator.Descendent) _combinators.Pop();
+
+            if (_combinators.Count <= 1) return _combinators.Pop();
+
+            var last = _combinators.Pop();
+            var previous = _combinators.Pop();
+            if (last == Combinator.Child && previous == Combinator.Child)
+            {
+                if (_combinators.Count == 0 || _combinators.Peek() != Combinator.Child)
+                    last = Combinator.Descendent;
+                else if (_combinators.Pop() == Combinator.Child) last = Combinator.Deep;
+            }
+            else if (last == Combinator.Namespace && previous == Combinator.Namespace)
+            {
+                last = Combinator.Column;
+            }
+            else
+            {
+                _combinators.Push(previous);
+            }
+
+            while (_combinators.Count > 0) _valid = _combinators.Pop() == Combinator.Descendent && _valid;
+
+            return last;
+        }
+
+        private void Insert(Combinator combinator)
+        {
+            _combinators.Push(combinator);
+        }
+
+        private void OnDelim(Token token)
+        {
+            switch (token.Data[0])
+            {
+                case Symbols.Comma:
+                    InsertOr();
+                    _ready = false;
+                    break;
+                case Symbols.GreaterThan:
+                    Insert(Combinator.Child);
+                    _ready = false;
+                    break;
+                case Symbols.Plus:
+                    Insert(Combinator.AdjacentSibling);
+                    _ready = false;
+                    break;
+                case Symbols.Tilde:
+                    Insert(Combinator.Sibling);
+                    _ready = false;
+                    break;
+                case Symbols.Asterisk:
+                    Insert(AllSelector.Create());
+                    _ready = true;
+                    break;
+                case Symbols.Dot:
+                    _state = State.Class;
+                    _ready = false;
+                    break;
+                case Symbols.Pipe:
+                    if (_combinators.Count > 0 && _combinators.Peek() == Combinator.Descendent)
+                        Insert(TypeSelector.Create(string.Empty));
+                    Insert(Combinator.Namespace);
+                    _ready = false;
+                    break;
+                default:
+                    _valid = false;
+                    break;
+            }
+        }
+
+        private ISelector GetPseudoFunction(FunctionToken arguments)
+        {
+            if (!PseudoClassFunctions.TryGetValue(arguments.Data, out var creator)) return null;
+
+            using (var function = creator(this))
+            {
+                _ready = false;
+                if (arguments.Any(token => function.Finished(token)))
+                {
+                    var sel = function.Produce();
+                    if (IsNested && function is NotFunctionState)
+                    {
+                        sel = null;
+                    }
+                    _ready = true;
+                    return sel;
+                }
+            }
+
+            return null;
+        }
+
+        private SelectorConstructor CreateChild()
+        {
+            return Pool.NewSelectorConstructor(_attributeSelector, _pseudoClassSelector, _pseudoElementSelector);
+        }
+
+        private abstract class FunctionState : IDisposable
+        {
+            public virtual void Dispose()
+            {
+            }
+
+            public bool Finished(Token token)
+            {
+                return OnToken(token);
+            }
+
+            public abstract ISelector Produce();
+            protected abstract bool OnToken(Token token);
+        }
+
+        private sealed class NotFunctionState : FunctionState
+        {
+            private readonly SelectorConstructor _selector;
+
+            public NotFunctionState(SelectorConstructor parent)
+            {
+                _selector = parent.CreateChild();
+                _selector.IsNested = true;
+            }
+
+            protected override bool OnToken(Token token)
+            {
+                if (token.Type == TokenType.RoundBracketClose && _selector._state == State.Data)
+                {
+                    return true;
+                }
+
+                _selector.Apply(token);
+                return false;
+
+            }
+
+            public override ISelector Produce()
+            {
+                var valid = _selector.IsValid;
+                var sel = _selector.GetResult();
+                return valid ? new NotSelector(sel) : null;
+            }
+
+            public override void Dispose()
+            {
+                base.Dispose();
+                _selector.ToPool();
+            }
+        }
+
+        private sealed class HasFunctionState : FunctionState
+        {
+            private readonly SelectorConstructor _nested;
+
+            public HasFunctionState(SelectorConstructor parent)
+            {
+                _nested = parent.CreateChild();
+            }
+
+            protected override bool OnToken(Token token)
+            {
+                if (token.Type == TokenType.RoundBracketClose && _nested._state == State.Data)
+                {
+                    return true;
+                }
+                _nested.Apply(token);
+                return false;
+
+            }
+
+            public override ISelector Produce()
+            {
+                var valid = _nested.IsValid;
+                var sel = _nested.GetResult();
+
+                return valid ? new HasSelector(sel) : null;
+            }
+
+            public override void Dispose()
+            {
+                base.Dispose();
+                _nested.ToPool();
+            }
+        }
+
+        private sealed class MatchesFunctionState : FunctionState
+        {
+            private readonly SelectorConstructor _selector;
+            private readonly string _keyword;
+
+            public MatchesFunctionState(SelectorConstructor parent, string keyword)
+            {
+                _selector = parent.CreateChild();
+                _keyword = keyword;
+            }
+
+            protected override bool OnToken(Token token)
+            {
+                if (token.Type == TokenType.RoundBracketClose && _selector._state == State.Data)
+                {
+                    return true;
+                }
+
+                _selector.Apply(token);
+                return false;
+
+            }
+
+            public override ISelector Produce()
+            {
+                var valid = _selector.IsValid;
+                var sel = _selector.GetResult();
+                return valid ? new MatchesSelector(sel, _keyword) : null;
+            }
+
+            public override void Dispose()
+            {
+                base.Dispose();
+                _selector.ToPool();
+            }
+        }
+
+        private sealed class DirFunctionState : FunctionState
+        {
+            private bool _valid = true;
+            private string _value;
+
+            protected override bool OnToken(Token token)
+            {
+                if (token.Type == TokenType.Ident)
+                {
+                    _value = token.Data;
+                }
+                else if (token.Type == TokenType.RoundBracketClose)
+                {
+                    return true;
+                }
+                else if (token.Type != TokenType.Whitespace)
+                {
+                    _valid = false;
+                }
+                return false;
+            }
+
+            public override ISelector Produce()
+            {
+                if (!_valid || _value == null) return null;
+
+                var code = PseudoClassNames.Dir.StylesheetFunction(_value);
+                return PseudoClassSelector.Create(code);
+            }
+        }
+
+        private sealed class LangFunctionState : FunctionState
+        {
+            private bool _valid = true;
+            private string _value;
+
+            protected override bool OnToken(Token token)
+            {
+                if (token.Type == TokenType.Ident)
+                {
+                    _value = token.Data;
+                }
+                else if (token.Type == TokenType.RoundBracketClose)
+                {
+                    return true;
+                }
+                else if (token.Type != TokenType.Whitespace)
+                {
+                    _valid = false;
+                }
+
+                return false;
+            }
+
+            public override ISelector Produce()
+            {
+                if (!_valid || _value == null)
+                {
+                    return null;
+                }
+                var code = PseudoClassNames.Lang.StylesheetFunction(_value);
+                return PseudoClassSelector.Create(code);
+
+            }
+        }
+
+        private sealed class ContainsFunctionState : FunctionState
+        {
+            private bool _valid = true;
+            private string _value;
+
+            protected override bool OnToken(Token token)
+            {
+                if ((token.Type == TokenType.Ident || token.Type == TokenType.String))
+                {
+                    _value = token.Data;
+                }
+                else if (token.Type == TokenType.RoundBracketClose)
+                {
+                    return true;
+                }
+                else if (token.Type != TokenType.Whitespace)
+                {
+                    _valid = false;
+                }
+
+                return false;
+            }
+
+            public override ISelector Produce()
+            {
+                if (!_valid || _value == null)
+                {
+                    return null;
+                }
+                var code = PseudoClassNames.Contains.StylesheetFunction(_value);
+                return PseudoClassSelector.Create(code);
+
+            }
+        }
+
+        private sealed class HostContextFunctionState : FunctionState
+        {
+            private readonly SelectorConstructor _selector;
+
+            public HostContextFunctionState(SelectorConstructor parent)
+            {
+                _selector = parent.CreateChild();
+            }
+
+            protected override bool OnToken(Token token)
+            {
+                if (token.Type == TokenType.RoundBracketClose && _selector._state == State.Data)
+                {
+                    return true;
+                }
+                _selector.Apply(token);
+                return false;
+
+            }
+
+            public override ISelector Produce()
+            {
+                var valid = _selector.IsValid;
+                var sel = _selector.GetResult();
+                if (!valid)
+                {
+                    return null;
+                }
+
+                var code = PseudoClassNames.HostContext.StylesheetFunction(sel.Text);
+                return PseudoClassSelector.Create(code);
+
+            }
+
+            public override void Dispose()
+            {
+                base.Dispose();
+                _selector.ToPool();
+            }
+        }
+
+        private sealed class ChildFunctionState<T> : FunctionState
+            where T : ChildSelector, ISelector, new()
+        {
+            private readonly SelectorConstructor _parent;
+            private readonly bool _allowOf;
+            private SelectorConstructor _nested;
+            private int _offset;
+            private int _sign;
+            private ParseState _state;
+            private int _step;
+            private bool _valid;
+
+            public ChildFunctionState(SelectorConstructor parent, bool withOptionalSelector = true)
+            {
+                _parent = parent;
+                _allowOf = withOptionalSelector;
+                _valid = true;
+                _sign = 1;
+                _state = ParseState.Initial;
+            }
+
+            public override ISelector Produce()
+            {
+                var invalid = !_valid || (_nested != null && !_nested.IsValid);
+                var sel = _nested?.ToPool() ?? AllSelector.Create();
+                if (invalid)
+                {
+                    return null;
+                }
+                return new T().With(_step, _offset, sel);
+            }
+
+            protected override bool OnToken(Token token)
+            {
+                switch (_state)
+                {
+                    case ParseState.Initial: return OnInitial(token);
+                    case ParseState.AfterInitialSign: return OnAfterInitialSign(token);
+                    case ParseState.Offset: return OnOffset(token);
+                    case ParseState.AfterOffsetSign: return OnAfterOffsetSign(token);
+                    case ParseState.BeforeOf: return OnBeforeOf(token);
+                    default: return OnAfter(token);
+                }
+            }
+
+            private bool OnAfterInitialSign(Token token)
+            {
+                switch (token.Type)
+                {
+                    case TokenType.Number:
+                        return OnOffset(token);
+                    case TokenType.Dimension:
+                        {
+                            var dim = (UnitToken)token;
+                            _valid = _valid && dim.Unit.Isi("n") && int.TryParse(token.Data, out _step);
+                            _step *= _sign;
+                            _sign = 1;
+                            _state = ParseState.Offset;
+                            return false;
+                        }
+                    case TokenType.Ident when token.Data.Isi("n"):
+                        _step = _sign;
+                        _sign = 1;
+                        _state = ParseState.Offset;
+                        return false;
+                }
+
+                if (_state == ParseState.Initial && token.Type == TokenType.Ident && token.Data.Isi("-n"))
+                {
+                    _step = -1;
+                    _state = ParseState.Offset;
+                    return false;
+                }
+
+                _valid = false;
+                return token.Type == TokenType.RoundBracketClose;
+            }
+
+            private bool OnAfter(Token token)
+            {
+                if (token.Type == TokenType.RoundBracketClose && _nested._state == State.Data)
+                {
+                    return true;
+                }
+                _nested.Apply(token);
+                return false;
+
+            }
+
+            private bool OnBeforeOf(Token token)
+            {
+                if (token.Type == TokenType.Whitespace) return false;
+                if (token.Data.Isi(Keywords.Of))
+                {
+                    _valid = _allowOf;
+                    _state = ParseState.AfterOf;
+                    _nested = _parent.CreateChild();
+                    return false;
+                }
+
+                if (token.Type == TokenType.RoundBracketClose) return true;
+                _valid = false;
+                return false;
+            }
+
+            private bool OnOffset(Token token)
+            {
+                switch (token.Type)
+                {
+                    case TokenType.Whitespace:
+                        return false;
+                    case TokenType.Delim when token.Data.IsOneOf("+", "-"):
+                        // The An+B offset's sign is a standalone delim token when whitespace separates it
+                        // from B - the "<n-dimension> ['+' | '-'] <signless-integer>" production of
+                        // <a-n-plus-b> (CSS Syntax 3 §6.2); §6.1 gives `3n + 1` as a valid example. The
+                        // compact form `10n+1` instead arrives as a single signed <number>, handled by the
+                        // Number case below. Without this branch a spaced sign fell through to OnBeforeOf
+                        // and invalidated the selector.
+                        _sign = token.Data == "-" ? -1 : 1;
+                        _state = ParseState.AfterOffsetSign;
+                        return false;
+                    case TokenType.Number:
+                        _valid = _valid && ((NumberToken)token).IsInteger && int.TryParse(token.Data, out _offset);
+                        _offset *= _sign;
+                        _state = ParseState.BeforeOf;
+                        return false;
+                    default:
+                        return OnBeforeOf(token);
+                }
+            }
+
+            private bool OnAfterOffsetSign(Token token)
+            {
+                switch (token.Type)
+                {
+                    case TokenType.Whitespace:
+                        return false;
+                    case TokenType.Number when !token.Data.StartsWith("+", StringComparison.Ordinal) && !token.Data.StartsWith("-", StringComparison.Ordinal):
+                        // The production requires a <signless-integer> here, defined as "a <number-token>
+                        // with its type flag set to integer, and no sign character" (CSS Syntax 3 §6.2), so
+                        // `10n + -1` and `10n + +1` are invalid - §6.1 lists `3n + -6` as an invalid example.
+                        _valid = _valid && ((NumberToken)token).IsInteger && int.TryParse(token.Data, out _offset);
+                        _offset *= _sign;
+                        _state = ParseState.BeforeOf;
+                        return false;
+                    default:
+                        _valid = false;
+                        return token.Type == TokenType.RoundBracketClose;
+                }
+            }
+
+            private bool OnInitial(Token token)
+            {
+                if (token.Type == TokenType.Whitespace) return false;
+                if (token.Data.Isi(Keywords.Odd))
+                {
+                    _state = ParseState.BeforeOf;
+                    _step = 2;
+                    _offset = 1;
+                    return false;
+                }
+
+                if (token.Data.Isi(Keywords.Even))
+                {
+                    _state = ParseState.BeforeOf;
+                    _step = 2;
+                    _offset = 0;
+                    return false;
+                }
+
+                if (token.Type == TokenType.Delim && token.Data.IsOneOf("+", "-"))
+                {
+                    _sign = token.Data == "-" ? -1 : +1;
+                    _state = ParseState.AfterInitialSign;
+                    return false;
+                }
+
+                return OnAfterInitialSign(token);
+            }
+
+            private enum ParseState : byte
+            {
+                Initial,
+                AfterInitialSign,
+                Offset,
+                AfterOffsetSign,
+                BeforeOf,
+                AfterOf
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Parser/StylesheetComposer.cs b/Source/HtmlRenderer/Core/CssEngine/Parser/StylesheetComposer.cs
new file mode 100644
index 000000000..d28f5fff8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Parser/StylesheetComposer.cs
@@ -0,0 +1,1627 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StylesheetComposer
+    {
+        private readonly Lexer _lexer;
+        private readonly StylesheetParser _parser;
+        private readonly Stack<StylesheetNode> _nodes;
+
+        // The source index (raw, into _lexer.Source) immediately before the most recently read token.
+        // Captured by NextToken so a CSS-Nesting classification look-ahead can rewind to a construct's
+        // exact start without any position arithmetic (which is unreliable across \r\n normalization and
+        // unicode escapes) and can slice the nested prelude's source text.
+        private int _markBeforeLastToken;
+
+        public StylesheetComposer(Lexer lexer, StylesheetParser parser)
+        {
+            _lexer = lexer;
+            _parser = parser;
+            _nodes = new Stack<StylesheetNode>();
+        }
+
+        public Rule CreateAtRule(Token token)
+        {
+            if (token.Data.Is(RuleNames.Media)) return CreateMedia(token);
+
+            if (token.Data.Is(RuleNames.FontFace)) return CreateFontFace(token);
+
+            if (token.Data.Is(RuleNames.Keyframes)) return CreateKeyframes(token);
+
+            if (token.Data.Is(RuleNames.Import)) return CreateImport(token);
+
+            if (token.Data.Is(RuleNames.Charset)) return CreateCharset(token);
+
+            if (token.Data.Is(RuleNames.Namespace)) return CreateNamespace(token);
+
+            if (token.Data.Is(RuleNames.Page)) return CreatePage(token);
+
+            if (token.Data.Is(RuleNames.Supports)) return CreateSupports(token);
+
+            if (token.Data.Is(RuleNames.ViewPort)) return CreateViewport(token);
+
+            if (token.Data.Is(RuleNames.Container)) return CreateContainer(token);
+
+            if (token.Data.Is(RuleNames.Property)) return CreateProperty(token);
+
+            if (token.Data.Is(RuleNames.FontPaletteValues)) return CreateFontPaletteValues(token);
+
+            if (token.Data.Is(RuleNames.Layer)) return CreateLayer(token);
+
+            return token.Data.Is(RuleNames.Document) ? CreateDocument(token) : CreateUnknown(token);
+        }
+
+        public Rule CreateRule(Token token)
+        {
+            switch (token.Type)
+            {
+                case TokenType.AtKeyword:
+                    return CreateAtRule(token);
+
+                case TokenType.CurlyBracketOpen:
+                    RaiseErrorOccurred(ParseError.InvalidBlockStart, token.Position);
+                    MoveToRuleEnd(ref token);
+                    return null;
+
+                case TokenType.String:
+                case TokenType.Url:
+                case TokenType.CurlyBracketClose:
+                case TokenType.RoundBracketClose:
+                case TokenType.SquareBracketClose:
+                    RaiseErrorOccurred(ParseError.InvalidToken, token.Position);
+                    MoveToRuleEnd(ref token);
+                    return null;
+
+                default:
+                    return CreateStyle(token);
+            }
+        }
+
+        public Rule CreateCharset(Token current)
+        {
+            var rule = new CharsetRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.String) rule.CharacterSet = token.Data;
+
+            JumpToEnd(ref token);
+            rule.StylesheetText = CreateView(start, token.Position);
+            _nodes.Pop();
+            return rule;
+        }
+
+        public Rule CreateDocument(Token current)
+        {
+            var rule = new DocumentRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            FillFunctions(function => rule.AppendChild(function), ref token);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillRules(rule);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateViewport(Token current)
+        {
+            var rule = new ViewportRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillDeclarations(rule, PropertyFactory.Instance.CreateViewport);
+
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateFontFace(Token current)
+        {
+            var rule = new FontFaceRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillDeclarations(rule, PropertyFactory.Instance.CreateFont);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateProperty(Token current)
+        {
+            var rule = new PropertyRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            rule.Name = GetRuleName(ref token);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillDeclarations(rule, PropertyFactory.Instance.CreatePropertyDescriptor);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateFontPaletteValues(Token current)
+        {
+            var rule = new FontPaletteValuesRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            rule.Name = GetRuleName(ref token);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillDeclarations(rule, PropertyFactory.Instance.CreateFontPaletteDescriptor);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateImport(Token current)
+        {
+            var rule = new ImportRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+
+            if (token.Is(TokenType.String, TokenType.Url))
+            {
+                rule.Href = token.Data;
+                token = NextToken();
+                ParseComments(ref token);
+                FillMediaList(rule.Media, TokenType.Semicolon, ref token);
+            }
+
+            ParseComments(ref token);
+            JumpToEnd(ref token);
+            rule.StylesheetText = CreateView(start, token.Position);
+            _nodes.Pop();
+            return rule;
+        }
+
+        public Rule CreateKeyframes(Token current)
+        {
+            var rule = new KeyframesRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            rule.Name = GetRuleName(ref token);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillKeyframeRules(rule);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateMedia(Token current)
+        {
+            var rule = new MediaRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            FillMediaList(rule.Media, TokenType.CurlyBracketOpen, ref token);
+            ParseComments(ref token);
+
+            if (token.Type != TokenType.CurlyBracketOpen)
+                while (token.Type != TokenType.EndOfFile)
+                {
+                    if (token.Type == TokenType.Semicolon)
+                    {
+                        _nodes.Pop();
+                        return null;
+                    }
+
+                    if (token.Type == TokenType.CurlyBracketOpen) break;
+
+                    token = NextToken();
+                }
+
+            var end = FillRules(rule);
+            rule.StylesheetText = CreateView(start, end);
+            _nodes.Pop();
+            return rule;
+        }
+
+        public Rule CreateContainer(Token current)
+        {
+            var rule = new ContainerRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            rule.Name = GetRuleName(ref token);
+            ParseComments(ref token);
+            FillMediaList(rule.Media, TokenType.CurlyBracketOpen, ref token);
+            ParseComments(ref token);
+
+            if (token.Type != TokenType.CurlyBracketOpen)
+                while (token.Type != TokenType.EndOfFile)
+                {
+                    if (token.Type == TokenType.Semicolon)
+                    {
+                        _nodes.Pop();
+                        return null;
+                    }
+
+                    if (token.Type == TokenType.CurlyBracketOpen) break;
+
+                    token = NextToken();
+                }
+
+            var end = FillRules(rule);
+            rule.StylesheetText = CreateView(start, end);
+            _nodes.Pop();
+            return rule;
+
+            //ParseComments(ref token);
+            //rule.Condition = AggregateCondition(ref token);
+            //ParseComments(ref token);
+
+            //if (token.Type != TokenType.CurlyBracketOpen)
+            //    while (token.Type != TokenType.EndOfFile)
+            //    {
+            //        if (token.Type == TokenType.Semicolon)
+            //        {
+            //            _nodes.Pop();
+            //            return null;
+            //        }
+
+            //        if (token.Type == TokenType.CurlyBracketOpen) break;
+
+            //        token = NextToken();
+            //    }
+
+            //var end = FillRules(rule);
+            //rule.StylesheetText = CreateView(start, end);
+            //_nodes.Pop();
+            //return rule;
+        }
+        public Rule CreateLayer(Token current)
+        {
+            var start = current.Position;
+            var token = NextToken();
+            ParseComments(ref token);
+
+            // Read the (optional) comma-separated layer name list, stopping at '{' (block form) or
+            // ';'/EOF (statement form).
+            var names = ReadLayerNames(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                // Block form: `@layer name { rules }` (at most one name; anonymous if none).
+                var rule = new LayerRule(_parser)
+                {
+                    Name = names.Count > 0 ? names[0] : string.Empty
+                };
+                _nodes.Push(rule);
+                var end = FillRules(rule);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            // Statement form: `@layer a, b, c;` — declares layer order only, no rules. token is at ';'/EOF.
+            var statement = new LayerStatementRule(_parser);
+            statement.Names.AddRange(names);
+            statement.StylesheetText = CreateView(start, token.Position);
+            return statement;
+        }
+
+        /// <summary>
+        /// Reads a <c>@layer</c> prelude: zero or more comma-separated layer names, each a dotted
+        /// ident sequence (e.g. <c>framework.utilities</c>). Advances <paramref name="token"/> up to
+        /// (but not past) the terminating <c>{</c>, <c>;</c>, or end of file.
+        /// </summary>
+        private List<string> ReadLayerNames(ref Token token)
+        {
+            var names = new List<string>();
+            var current = new System.Text.StringBuilder();
+
+            void Flush()
+            {
+                if (current.Length <= 0) return;
+                names.Add(current.ToString());
+                current.Clear();
+            }
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketOpen, TokenType.Semicolon))
+            {
+                switch (token.Type)
+                {
+                    case TokenType.Ident:
+                        current.Append(token.Data);
+                        break;
+                    case TokenType.Delim when token.Data == ".":
+                        current.Append('.');
+                        break;
+                    case TokenType.Comma:
+                        Flush();
+                        break;
+                    // Whitespace/comments and anything else separating names are ignored.
+                }
+
+                token = NextToken();
+                ParseComments(ref token);
+            }
+
+            Flush();
+            return names;
+        }
+
+        public Rule CreateNamespace(Token current)
+        {
+            var rule = new NamespaceRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            rule.Prefix = GetRuleName(ref token);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.Url) rule.NamespaceUri = token.Data;
+
+            JumpToEnd(ref token);
+            rule.StylesheetText = CreateView(start, token.Position);
+            _nodes.Pop();
+            return rule;
+        }
+
+        public Rule CreatePage(Token current)
+        {
+            var rule = new PageRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+
+            if (token.Type != TokenType.CurlyBracketOpen)
+            {
+                // A pseudo-selector exists.  Parse it prior
+                // to declarations
+                // e.g. @page :left{...}
+                rule.Selector = CreatePageSelector(ref token);
+                ParseComments(ref token);
+            }
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillDeclarations(rule.Style);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateSupports(Token current)
+        {
+            var rule = new SupportsRule(_parser);
+            var start = current.Position;
+            var token = NextToken();
+            _nodes.Push(rule);
+            ParseComments(ref token);
+            rule.Condition = AggregateCondition(ref token);
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.CurlyBracketOpen)
+            {
+                var end = FillRules(rule);
+                rule.StylesheetText = CreateView(start, end);
+                _nodes.Pop();
+                return rule;
+            }
+
+            _nodes.Pop();
+            return SkipDeclarations(token);
+        }
+
+        public Rule CreateStyle(Token current)
+        {
+            var rule = new StyleRule(_parser);
+            var start = current.Position;
+            _nodes.Push(rule);
+            ParseComments(ref current);
+            rule.Selector = CreateSelector(ref current);
+            var end = FillDeclarations(rule.Style);
+            rule.StylesheetText = CreateView(start, end);
+            _nodes.Pop();
+            return rule.Selector != null ? rule : null;
+        }
+
+        public Rule CreateMarginStyle(ref Token current)
+        {
+            var rule = new MarginStyleRule(_parser);
+            var start = current.Position;
+            _nodes.Push(rule);
+            ParseComments(ref current);
+            rule.Selector = CreateMarginSelector(ref current);
+            var end = FillDeclarations(rule.Style);
+            rule.StylesheetText = CreateView(start, end);
+            _nodes.Pop();
+            return rule.Selector != null ? rule : null;
+        }
+
+        public KeyframeRule CreateKeyframeRule(Token current)
+        {
+            var rule = new KeyframeRule(_parser);
+            var start = current.Position;
+            _nodes.Push(rule);
+            ParseComments(ref current);
+            rule.Key = CreateKeyframeSelector(ref current);
+            var end = FillDeclarations(rule.Style);
+            rule.StylesheetText = CreateView(start, end);
+            _nodes.Pop();
+            return rule.Key != null ? rule : null;
+        }
+
+        public Rule CreateUnknown(Token current)
+        {
+            var start = current.Position;
+
+            if (_parser.Options.IncludeUnknownRules)
+            {
+                var token = NextToken();
+                var rule = new UnknownRule(current.Data, _parser);
+                _nodes.Push(rule);
+
+                while (token.IsNot(TokenType.CurlyBracketOpen, TokenType.Semicolon, TokenType.EndOfFile))
+                    token = NextToken();
+
+                if (token.Type == TokenType.CurlyBracketOpen)
+                {
+                    var curly = 1;
+
+                    do
+                    {
+                        token = NextToken();
+
+                        switch (token.Type)
+                        {
+                            case TokenType.CurlyBracketOpen:
+                                curly++;
+                                break;
+                            case TokenType.CurlyBracketClose:
+                                curly--;
+                                break;
+                            case TokenType.EndOfFile:
+                                curly = 0;
+                                break;
+                        }
+                    } while (curly != 0);
+                }
+
+                rule.StylesheetText = CreateView(start, token.Position);
+                _nodes.Pop();
+                return rule;
+            }
+
+            RaiseErrorOccurred(ParseError.UnknownAtRule, start);
+            MoveToRuleEnd(ref current);
+            return default(UnknownRule);
+        }
+
+        public TokenValue CreateValue(ref Token token)
+        {
+            return CreateValue(TokenType.CurlyBracketClose, ref token, out _);
+        }
+
+        public List<Medium> CreateMedia(ref Token token)
+        {
+            var list = new List<Medium>();
+            ParseComments(ref token);
+
+            while (token.Type != TokenType.EndOfFile)
+            {
+                var medium = CreateMedium(ref token);
+
+                if (medium == null || token.IsNot(TokenType.Comma, TokenType.EndOfFile))
+                    throw new ParseException("Unable to create medium or end of file reached unexpectedly");
+
+                token = NextToken();
+                ParseComments(ref token);
+                list.Add(medium);
+            }
+
+            return list;
+        }
+
+        public TextPosition CreateRules(Stylesheet sheet)
+        {
+            var token = NextToken();
+            _nodes.Push(sheet);
+            ParseComments(ref token);
+
+            while (token.Type != TokenType.EndOfFile)
+            {
+                var rule = CreateRule(token);
+                token = NextToken();
+                ParseComments(ref token);
+                sheet.Rules.Add(rule);
+            }
+
+            _nodes.Pop();
+            return token.Position;
+        }
+
+        public IConditionFunction CreateCondition(ref Token token)
+        {
+            ParseComments(ref token);
+            return AggregateCondition(ref token);
+        }
+
+        public KeyframeSelector CreateKeyframeSelector(ref Token token)
+        {
+            var keys = new List<Percent>();
+            var valid = true;
+            var start = token.Position;
+            ParseComments(ref token);
+
+            while (token.Type != TokenType.EndOfFile)
+            {
+                if (keys.Count > 0)
+                {
+                    if (token.Type == TokenType.CurlyBracketOpen) break;
+                    if (token.Type != TokenType.Comma)
+                        valid = false;
+                    else
+                        token = NextToken();
+
+                    ParseComments(ref token);
+                }
+
+                switch (token.Type)
+                {
+                    case TokenType.Percentage:
+                        keys.Add(new Percent(((UnitToken)token).Value));
+                        break;
+                    case TokenType.Ident when token.Data.Is(Keywords.From):
+                        keys.Add(Percent.Zero);
+                        break;
+                    case TokenType.Ident when token.Data.Is(Keywords.To):
+                        keys.Add(Percent.Hundred);
+                        break;
+                    default:
+                        valid = false;
+                        break;
+                }
+
+                token = NextToken();
+                ParseComments(ref token);
+            }
+
+            if (!valid) RaiseErrorOccurred(ParseError.InvalidSelector, start);
+
+            return new KeyframeSelector(keys);
+        }
+
+        private PageSelector CreatePageSelector(ref Token token)
+        {
+            // Parses the CSS Paged Media selector grammar per comma-separated entry: an optional
+            // <ident> page name followed by an optional :<ident> pseudo-class, e.g.
+            // "@page chapter1:left, chapter2:left { ... }" (name+pseudo), "@page chapter { ... }"
+            // (name only), "@page :first { ... }" (pseudo only). Page names are case-sensitive
+            // custom-idents; pseudo-class keywords (first/left/right) are matched case-insensitively
+            // by the caller. Chaining multiple pseudo-classes on one entry (e.g. ":first:left") isn't
+            // supported — out of scope, not used by any known real-world stylesheet.
+            var entries = new List<PageSelectorEntry>();
+
+            while (true)
+            {
+                string name = null;
+                string pseudo = null;
+
+                if (token.Type == TokenType.Ident)
+                {
+                    name = token.Data;
+                    token = NextToken();
+                }
+
+                if (token.Type == TokenType.Colon)
+                {
+                    token = NextToken();
+                    if (token.Type == TokenType.Ident)
+                    {
+                        pseudo = token.Data;
+                        token = NextToken();
+                    }
+                }
+
+                if (name != null || pseudo != null)
+                    entries.Add(new PageSelectorEntry(name, pseudo));
+
+                ParseComments(ref token);
+
+                if (token.Type != TokenType.Comma) break;
+
+                token = NextToken();
+                ParseComments(ref token);
+            }
+
+            var selector = new PageSelector(entries);
+
+            //var start = token.Position;
+
+            //while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketOpen, TokenType.CurlyBracketClose))
+            //{
+            //    var a = 1;
+            //    token = NextToken();
+            //}
+
+            //var result = selector.ToPool();
+
+            //if (result is StylesheetNode node)
+            //{
+            //    var end = token.Position.Shift(-1);
+            //node.StylesheetText = CreateView(start, end);
+            //}
+
+            //if (!selectorIsValid && !_parser.Options.AllowInvalidValues)
+            //{
+            //    RaiseErrorOccurred(ParseError.InvalidSelector, start);
+            //    result = null;
+            //}
+
+            //return result;
+
+            return selector;
+        }
+
+        public List<DocumentFunction> CreateFunctions(ref Token token)
+        {
+            var functions = new List<DocumentFunction>();
+            ParseComments(ref token);
+            FillFunctions(function => functions.Add(function), ref token);
+            return functions;
+        }
+
+        public TextPosition FillDeclarations(StyleDeclaration style)
+        {
+            var finalProperties = new Dictionary<string, IProperty>(StringComparer.OrdinalIgnoreCase);
+            var token = NextToken();
+            _nodes.Push(style);
+            ParseComments(ref token);
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketClose))
+            {
+                // @page selectors support declaration blocks in the form of at rules.  This 
+                // conditional accounts for the nested at with a page parent
+                //
+                // @page {
+                //   @top-left { ... /* document name */ }
+                //   @bottom-center { ... /* page number */}
+                // }
+                if (token.Is(TokenType.AtKeyword))
+                {
+                    var parentPageRule = _nodes.FirstOrDefault(parent => parent is PageRule);
+                    if (parentPageRule != null)
+                    {
+                        //var genericAtRule = CreateMarginRule(ref token);
+                        //parentPageRule.AppendChild(genericAtRule);
+                        // Rewind to capture the margin's @ symbol
+
+                        var marginToken = new Token(TokenType.Ident, token.Data, token.Position);
+                        var marginStyle = CreateMarginStyle(ref marginToken);
+                        parentPageRule.AppendChild(marginStyle);
+                        // FillDeclarations inside CreateMarginStyle consumed through the closing }
+                        // of the margin box. Advance past it to pick up the next token in @page {}.
+                        token = NextToken();
+                    }
+                    else
+                    {
+                        // Advance to the next token or this is an endless loop
+                        token = NextToken();
+                    }
+                }
+                else if (TryCreateNestedRule(ref token))
+                {
+                    // CSS Nesting: a nested style rule was parsed and attached to the enclosing rule.
+                }
+                else
+                {
+                    var sourceProperty = CreateDeclarationWith(PropertyFactory.Instance.Create, ref token);
+                    var resolvedProperties = new[] { sourceProperty };
+
+                    if (sourceProperty != null && sourceProperty.HasValue)
+                    {
+                        // For shorthand properties we need to first find out what alternate set of properties they will
+                        // end up resolving into so that we can compare them with their previously parsed counterparts (if any)
+                        // and determine which one takes priority over the other.
+                        // Example 1: "margin-left: 5px !important; text-align:center; margin: 3px;";
+                        // Example 2: "margin: 5px !important; text-align:center; margin-left: 3px;";
+                        if (sourceProperty is ShorthandProperty shorthandProperty)
+                        {
+                            if (shorthandProperty.DeclaredValue.Original.ContainsFunction(FunctionNames.Var))
+                            {
+                                // A var() reference can't be split into per-longhand slices at parse time —
+                                // the referenced custom property's value is only known per-element, at cascade
+                                // time. Keep the shorthand declaration whole so cascade-time substitution +
+                                // shorthand expansion (CssUtils.SetPropertyValue) can handle it once resolved.
+                                resolvedProperties = new Property[] { shorthandProperty };
+                            }
+                            else
+                            {
+                                resolvedProperties = PropertyFactory.Instance.CreateLonghandsFor(shorthandProperty.Name);
+                                shorthandProperty.Export(resolvedProperties);
+                            }
+                        }
+
+                        foreach (var resolvedProperty in resolvedProperties)
+                        {
+                            // The following relies on the fact that the tokens are processed in 
+                            // top-to-bottom order of how they are defined in the parsed style declaration.
+                            // This handles exposing the correct value for a property when it appears multiple 
+                            // times in the same style declaration.
+                            // Example: "background-color:green !important; text-align:center; background-color:yellow;";
+                            // In this example even though background-color yellow is defined last, the previous value
+                            // of green should be the one exposed given it is tagged as important.
+                            // ------------------------------------------------------------------------------------------
+                            // Only set this property if one of the following conditions is true:
+                            // a) It was not previously added or...
+                            // b) The previously added property is not tagged as important or ...
+                            // c) The previously added property is tagged as important but so is this new one.
+                            var shouldSetProperty =
+                                !finalProperties.TryGetValue(resolvedProperty.Name, out var previousProperty)
+                                || !previousProperty.IsImportant
+                                || resolvedProperty.IsImportant;
+
+                            if (shouldSetProperty)
+                            {
+                                style.SetProperty(resolvedProperty);
+                                finalProperties[resolvedProperty.Name] = resolvedProperty;
+                            }
+                        }
+                    }
+                }
+
+                ParseComments(ref token);
+            }
+
+            _nodes.Pop();
+            return token.Position;
+        }
+
+        /// <summary>
+        /// CSS Nesting ([CSS Nesting 1](https://www.w3.org/TR/css-nesting-1/)): if the current construct
+        /// in a declaration block is a nested style rule (a selector prelude followed by a <c>{ }</c>
+        /// block) rather than a declaration, parses it, resolves its selector against the enclosing rule,
+        /// attaches it, and returns true (with <paramref name="token"/> advanced past the block). Returns
+        /// false for an ordinary declaration, having rewound the lexer so the caller re-reads it.
+        /// </summary>
+        private bool TryCreateNestedRule(ref Token token)
+        {
+            // Raw source index just before the current (first) token — the construct start, captured by
+            // NextToken. Faithful across \r\n normalization, unlike deriving it from token.Position.
+            var preludeStart = _markBeforeLastToken;
+
+            if (!IsNestedRuleAhead(ref token, out var braceStart))
+                return false;
+
+            CreateNestedStyleRule(preludeStart, braceStart);
+            token = NextToken();
+            return true;
+        }
+
+        /// <summary>
+        /// Looks ahead (bracket-aware) to classify the construct starting at <paramref name="token"/> as a
+        /// nested style rule vs a declaration: the first top-level <c>{</c> means a nested rule (the stream
+        /// is left just after it and its source index returned via <paramref name="braceStart"/>); a
+        /// top-level <c>;</c>/<c>}</c>/EOF means a declaration, in which case the lexer is rewound to the
+        /// construct start and <paramref name="token"/> re-read so the unchanged declaration path re-lexes
+        /// it in value mode (avoiding the <c>#</c> value-mode tokenization hazard a token buffer would hit).
+        /// Custom properties (<c>--x</c>) are always declarations, even with a <c>{</c> in their value.
+        /// Function tokens (e.g. <c>url(…)</c>) are opaque — the lexer already consumed their parentheses —
+        /// so only bare round/square brackets contribute to depth.
+        /// </summary>
+        private bool IsNestedRuleAhead(ref Token token, out int braceStart)
+        {
+            braceStart = 0;
+
+            if (token.Type == TokenType.Ident && token.Data != null &&
+                token.Data.StartsWith("--", StringComparison.Ordinal))
+                return false;
+
+            var rewindMark = _markBeforeLastToken;   // raw source index before `token` (the first token)
+            var depth = 0;
+            var scan = token;
+            var scanStart = rewindMark;              // raw source index before `scan`
+
+            while (scan.Type != TokenType.EndOfFile)
+            {
+                switch (scan.Type)
+                {
+                    case TokenType.RoundBracketOpen:
+                    case TokenType.SquareBracketOpen:
+                        depth++;
+                        break;
+                    case TokenType.RoundBracketClose:
+                    case TokenType.SquareBracketClose:
+                        if (depth > 0) depth--;
+                        break;
+                    case TokenType.CurlyBracketOpen when depth == 0:
+                        braceStart = scanStart;
+                        token = scan;
+                        return true;
+                    case TokenType.CurlyBracketClose when depth == 0:
+                    case TokenType.Semicolon when depth == 0:
+                        _lexer.RewindTo(rewindMark);
+                        token = NextToken();
+                        return false;
+                }
+
+                scanStart = _lexer.InsertionPoint;   // raw index just before the next token
+                scan = _lexer.Get();
+            }
+
+            _lexer.RewindTo(rewindMark);
+            token = NextToken();
+            return false;
+        }
+
+        /// <summary>
+        /// Builds a <see cref="StyleRule"/> from a nested prelude (source span
+        /// <c>[preludeStart, bracePosition)</c>) resolved against the enclosing rule's selector, consumes
+        /// its declaration block from the live stream, and attaches it to the parent rule via
+        /// <see cref="StyleRule.AddNestedRule"/>. The resolved selector is absolute (<c>&amp;</c> →
+        /// <c>:is(parent)</c>) so the cascade/matcher need no nesting awareness.
+        /// </summary>
+        private void CreateNestedStyleRule(int preludeStart, int braceStart)
+        {
+            var parent = _nodes.OfType<StyleRule>().FirstOrDefault();
+            var preludeText = _lexer.Source.Text.Substring(preludeStart, braceStart - preludeStart);
+
+            var selector = parent is null
+                ? null
+                : _parser.ParseSelector(ResolveNestedSelector(preludeText, parent.SelectorText));
+
+            // Always consume the block (via a rule pushed on _nodes so nested-within-nested resolves) to
+            // keep the parser in sync; only attach it when the selector actually resolved.
+            var rule = new StyleRule(_parser);
+
+            if (selector != null)
+                rule.Selector = selector;
+
+            _nodes.Push(rule);
+            FillDeclarations(rule.Style);
+            _nodes.Pop();
+
+            if (parent != null && selector != null)
+                parent.AddNestedRule(rule);
+        }
+
+        /// <summary>
+        /// Resolves a nested selector's prelude text against its parent's selector text per CSS Nesting:
+        /// each <c>&amp;</c> becomes <c>:is(parent)</c> (giving <c>&amp;</c> the parent's specificity); a
+        /// prelude with no <c>&amp;</c> is made relative to the parent (<c>:is(parent) &lt;prelude&gt;</c>),
+        /// which correctly yields both the implicit-descendant (<c>.b</c> → <c>:is(parent) .b</c>) and the
+        /// leading-combinator (<c>&gt; .b</c> → <c>:is(parent) &gt; .b</c>) forms.
+        /// </summary>
+        private static string ResolveNestedSelector(string prelude, string parentText)
+        {
+            var trimmed = prelude.Trim();
+            var parentIs = ":is(" + (string.IsNullOrEmpty(parentText) ? "*" : parentText) + ")";
+
+            // Substitute `&` token-aware: only a `&` that is a real nesting selector is replaced, never a
+            // `&` inside a string/attribute value (e.g. `[data-x="a&b"]`), which must be preserved. This
+            // also decides the "has &" branch correctly, so a prelude whose only `&` is inside a string is
+            // still scoped under the parent (:is(parent) <prelude>) rather than mis-taking the replace path.
+            var sb = Pool.NewStringBuilder();
+            var hasNestingSelector = false;
+            var quote = '\0';
+
+            for (var i = 0; i < trimmed.Length; i++)
+            {
+                var c = trimmed[i];
+
+                if (quote != '\0')
+                {
+                    sb.Append(c);
+                    if (c == '\\' && i + 1 < trimmed.Length)
+                        sb.Append(trimmed[++i]);   // escaped char inside a string — copy verbatim
+                    else if (c == quote)
+                        quote = '\0';
+                    continue;
+                }
+
+                switch (c)
+                {
+                    case '"':
+                    case '\'':
+                        quote = c;
+                        sb.Append(c);
+                        break;
+                    case '&':
+                        hasNestingSelector = true;
+                        sb.Append(parentIs);
+                        break;
+                    default:
+                        sb.Append(c);
+                        break;
+                }
+            }
+
+            return hasNestingSelector ? sb.ToPool() : parentIs + " " + sb.ToPool();
+        }
+
+        public Property CreateDeclarationWith(Func<string, Property> createProperty, ref Token token)
+        {
+            var property = default(Property);
+
+            var sb = Pool.NewStringBuilder();
+            var start = token.Position;
+
+            while (token.IsDeclarationName())
+            {
+                sb.Append(token.ToValue());
+                token = NextToken();
+            }
+
+            var propertyName = sb.ToPool();
+
+            if (propertyName.Length > 0)
+            {
+                property = createProperty(propertyName);
+
+                if (property == null && _parser.Options.IncludeUnknownDeclarations)
+                {
+                    property = new UnknownProperty(propertyName);
+                }
+
+                if (property == null)
+                    RaiseErrorOccurred(ParseError.UnknownDeclarationName, start);
+                else
+                    _nodes.Push(property);
+
+                ParseComments(ref token);
+
+                if (token.Type == TokenType.Colon)
+                {
+                    var value = CreateValue(TokenType.CurlyBracketClose, ref token, out var important);
+
+                    if (value == null)
+                        RaiseErrorOccurred(ParseError.ValueMissing, token.Position);
+                    else if (property != null)
+                    {
+                        if (property.TrySetValue(value))
+                            property.IsImportant = important;
+                        else if (_parser.Options.AllowInvalidValues)
+                        {
+                            _nodes.Pop();
+
+                            property = new UnknownProperty(propertyName);
+                            property.TrySetValue(value);
+                            property.IsImportant = important;
+                            _nodes.Push(property);
+                        }
+                    }
+
+
+                    ParseComments(ref token);
+                }
+                else
+                {
+                    RaiseErrorOccurred(ParseError.ColonMissing, token.Position);
+                }
+
+                JumpToDeclEnd(ref token);
+
+                if (property != null) _nodes.Pop();
+            }
+            else if (token.Type != TokenType.EndOfFile)
+            {
+                RaiseErrorOccurred(ParseError.IdentExpected, start);
+                JumpToDeclEnd(ref token);
+            }
+
+            if (token.Type == TokenType.Semicolon) token = NextToken();
+
+            return property;
+        }
+
+        public Property CreateDeclaration(ref Token token)
+        {
+            ParseComments(ref token);
+            return CreateDeclarationWith(PropertyFactory.Instance.Create, ref token);
+        }
+
+        public Medium CreateMedium(ref Token token)
+        {
+            var medium = new Medium();
+            ParseComments(ref token);
+
+            if (token.Type == TokenType.Ident)
+            {
+                var identifier = token.Data;
+
+                if (identifier.Isi(Keywords.Not))
+                {
+                    medium.IsInverse = true;
+                    token = NextToken();
+                    ParseComments(ref token);
+                }
+                else if (identifier.Isi(Keywords.Only))
+                {
+                    medium.IsExclusive = true;
+                    token = NextToken();
+                    ParseComments(ref token);
+                }
+            }
+
+            if (token.Type == TokenType.Ident)
+            {
+                medium.Type = token.Data;
+                token = NextToken();
+                ParseComments(ref token);
+
+                if (token.Type != TokenType.Ident || !token.Data.Isi(Keywords.And)) return medium;
+
+                token = NextToken();
+                ParseComments(ref token);
+            }
+
+            do
+            {
+                if (token.Type != TokenType.RoundBracketOpen) return null;
+
+                token = NextToken();
+                ParseComments(ref token);
+                var feature = CreateFeature(ref token);
+
+                if (feature != null) medium.AppendChild(feature);
+
+                if (token.Type != TokenType.RoundBracketClose) return null;
+
+                token = NextToken();
+                ParseComments(ref token);
+
+                if (feature == null) return null;
+
+                if (token.Type != TokenType.Ident || !token.Data.Isi(Keywords.And)) break;
+
+                token = NextToken();
+                ParseComments(ref token);
+            } while (token.Type != TokenType.EndOfFile);
+
+            return medium;
+        }
+
+        private void JumpToEnd(ref Token current)
+        {
+            while (current.IsNot(TokenType.EndOfFile, TokenType.Semicolon)) current = NextToken();
+        }
+
+        private void MoveToRuleEnd(ref Token current)
+        {
+            var scopes = 0;
+
+            while (current.Type != TokenType.EndOfFile)
+            {
+                if (current.Type == TokenType.CurlyBracketOpen)
+                    scopes++;
+                else if (current.Type == TokenType.CurlyBracketClose) scopes--;
+
+                if (scopes <= 0 && current.Is(TokenType.CurlyBracketClose, TokenType.Semicolon)) break;
+
+                current = NextToken();
+            }
+        }
+
+        private void JumpToArgEnd(ref Token current)
+        {
+            var arguments = 0;
+
+            while (current.Type != TokenType.EndOfFile)
+            {
+                if (current.Type == TokenType.RoundBracketOpen)
+                    arguments++;
+                else if (arguments <= 0 && current.Type == TokenType.RoundBracketClose)
+                    break;
+                else if (current.Type == TokenType.RoundBracketClose) arguments--;
+
+                current = NextToken();
+            }
+        }
+
+        private void JumpToDeclEnd(ref Token current)
+        {
+            var scopes = 0;
+
+            while (current.Type != TokenType.EndOfFile)
+            {
+                if (current.Type == TokenType.CurlyBracketOpen)
+                    scopes++;
+                else if (scopes <= 0 && current.Is(TokenType.CurlyBracketClose, TokenType.Semicolon))
+                    break;
+                else if (current.Type == TokenType.CurlyBracketClose) scopes--;
+
+                current = NextToken();
+            }
+        }
+
+        private Token NextToken()
+        {
+            _markBeforeLastToken = _lexer.InsertionPoint;
+            return _lexer.Get();
+        }
+
+        private StylesheetText CreateView(TextPosition start, TextPosition end)
+        {
+            var range = new TextRange(start, end);
+            return new StylesheetText(range, _lexer.Source);
+        }
+
+        private void ParseComments(ref Token token)
+        {
+            var preserveComments = _parser.Options.PreserveComments;
+
+            while (token.Type == TokenType.Whitespace || token.Type == TokenType.Comment ||
+                   token.Type == TokenType.Cdc || token.Type == TokenType.Cdo)
+            {
+                if (preserveComments && token.Type == TokenType.Comment)
+                {
+                    var current = _nodes.Peek();
+                    var comment = new Comment(token.Data);
+                    var start = token.Position;
+                    var end = start.After(token.ToValue());
+                    comment.StylesheetText = CreateView(start, end);
+                    current.AppendChild(comment);
+                }
+
+                token = NextToken();
+            }
+        }
+
+        private Rule SkipDeclarations(Token token)
+        {
+            RaiseErrorOccurred(ParseError.InvalidToken, token.Position);
+            MoveToRuleEnd(ref token);
+            return default;
+        }
+
+        private void RaiseErrorOccurred(ParseError code, TextPosition position)
+        {
+            _lexer.RaiseErrorOccurred(code, position);
+        }
+
+        private IConditionFunction AggregateCondition(ref Token token)
+        {
+            var condition = ExtractCondition(ref token);
+
+            if (condition == null) return null;
+
+            ParseComments(ref token);
+            var conjunction = token.Data;
+            var creator = conjunction.GetCreator();
+
+            if (creator != null)
+            {
+                token = NextToken();
+                ParseComments(ref token);
+                var conditions = MultipleConditions(condition, conjunction, ref token);
+                condition = creator.Invoke(conditions);
+            }
+
+            return condition;
+        }
+
+        private IConditionFunction ExtractCondition(ref Token token)
+        {
+            if (token.Type == TokenType.RoundBracketOpen)
+            {
+                token = NextToken();
+                ParseComments(ref token);
+                var condition = AggregateCondition(ref token);
+
+                if (condition != null)
+                {
+                    var group = new GroupCondition
+                    {
+                        Content = condition
+                    };
+                    condition = group;
+                }
+                else if (token.Type == TokenType.Ident)
+                {
+                    condition = DeclarationCondition(ref token);
+                }
+
+                if (token.Type != TokenType.RoundBracketClose) return condition;
+                token = NextToken();
+                ParseComments(ref token);
+
+                return condition;
+            }
+
+            if (token.Data.Isi(Keywords.Not))
+            {
+                var condition = new NotCondition();
+                token = NextToken();
+                ParseComments(ref token);
+                condition.Content = ExtractCondition(ref token);
+                return condition;
+            }
+
+            return null;
+        }
+
+        private IConditionFunction DeclarationCondition(ref Token token)
+        {
+            var property = PropertyFactory.Instance.Create(token.Data) ?? new UnknownProperty(token.Data);
+            var declaration = default(DeclarationCondition);
+            token = NextToken();
+            ParseComments(ref token);
+
+            if (token.Type != TokenType.Colon) return null;
+
+            var result = CreateValue(TokenType.RoundBracketClose, ref token, out var important);
+            property.IsImportant = important;
+
+            if (result != null) declaration = new DeclarationCondition(property, result);
+
+            return declaration;
+        }
+
+        private List<IConditionFunction> MultipleConditions(IConditionFunction condition, string connector, ref Token token)
+        {
+            var list = new List<IConditionFunction>();
+            ParseComments(ref token);
+            list.Add(condition);
+
+            while (token.Type != TokenType.EndOfFile)
+            {
+                condition = ExtractCondition(ref token);
+
+                if (condition == null) break;
+
+                list.Add(condition);
+
+                if (!token.Data.Isi(connector)) break;
+
+                token = NextToken();
+                ParseComments(ref token);
+            }
+
+            return list;
+        }
+
+        private void FillFunctions(Action<DocumentFunction> add, ref Token token)
+        {
+            do
+            {
+                var function = token.ToDocumentFunction();
+
+                if (function == null) break;
+
+                token = NextToken();
+                ParseComments(ref token);
+                add(function);
+
+                if (token.Type != TokenType.Comma) break;
+
+                token = NextToken();
+                ParseComments(ref token);
+            } while (token.Type != TokenType.EndOfFile);
+        }
+
+        private TextPosition FillKeyframeRules(KeyframesRule parentRule)
+        {
+            var token = NextToken();
+            ParseComments(ref token);
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketClose))
+            {
+                var rule = CreateKeyframeRule(token);
+                token = NextToken();
+                ParseComments(ref token);
+                parentRule.Rules.Add(rule);
+            }
+
+            return token.Position;
+        }
+
+        private TextPosition FillDeclarations(DeclarationRule rule, Func<string, Property> createProperty)
+        {
+            var token = NextToken();
+            ParseComments(ref token);
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketClose))
+            {
+                var property = CreateDeclarationWith(createProperty, ref token);
+
+                if (property != null && property.HasValue)
+                {
+                    rule.SetProperty(property);
+                }
+
+                ParseComments(ref token);
+            }
+
+            return token.Position;
+        }
+
+        private TextPosition FillRules(GroupingRule group)
+        {
+            var token = NextToken();
+            ParseComments(ref token);
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketClose))
+            {
+                // "Consume a block's contents" discards a <semicolon-token> outright, exactly as it does a
+                // <whitespace-token> (CSS Syntax 3 §5.5.5). Passing it on to CreateStyle instead feeds it to
+                // SelectorConstructor, which has no recovery for an unexpected semicolon: it folds the token
+                // into the next rule's selector and invalidates it, and because the run-on rule keeps
+                // consuming, the block's own closing brace is swallowed and the following sibling rule is
+                // lost with it.
+                //
+                // Deliberately NOT done in CreateRules: "consume a stylesheet's contents" (§5.5.1) has no
+                // <semicolon-token> case, so a stray semicolon at the top level falls to "anything else" and
+                // is consumed into the next qualified rule's prelude, invalidating it. Only a block passes
+                // <semicolon-token> as the stop token to "consume a qualified rule" (§5.5.3). The Acid2
+                // parser-torture block relies on that: its ".parser { m\argin: 2em; };" is followed by
+                // ".parser { height: 3em; }", which must NOT apply.
+                if (token.Type == TokenType.Semicolon)
+                {
+                    token = NextToken();
+                    ParseComments(ref token);
+                    continue;
+                }
+
+                var rule = CreateRule(token);
+                token = NextToken();
+                ParseComments(ref token);
+                group.Rules.Add(rule);
+            }
+
+            return token.Position;
+        }
+
+        private void FillMediaList(MediaList list, TokenType end, ref Token token)
+        {
+            _nodes.Push(list);
+
+            if (token.Type != end)
+            {
+                while (token.Type != TokenType.EndOfFile)
+                {
+                    var medium = CreateMedium(ref token);
+
+                    if (medium != null) list.AppendChild(medium);
+
+                    if (token.Type != TokenType.Comma) break;
+
+                    token = NextToken();
+                    ParseComments(ref token);
+                }
+
+                if (token.Type != end || list.Length == 0)
+                {
+                    list.Clear();
+                    list.AppendChild(new Medium
+                    {
+                        IsInverse = true,
+                        Type = Keywords.All
+                    });
+                }
+            }
+
+            _nodes.Pop();
+        }
+
+        private ISelector CreateSelector(ref Token token)
+        {
+            var selector = _parser.GetSelectorCreator();
+            var start = token.Position;
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketOpen, TokenType.CurlyBracketClose))
+            {
+                selector.Apply(token);
+                token = NextToken();
+            }
+
+            var selectorIsValid = selector.IsValid;
+            var result = selector.ToPool();
+
+            if (result is StylesheetNode node)
+            {
+                var end = token.Position.Shift(-1);
+                node.StylesheetText = CreateView(start, end);
+            }
+
+            if (!selectorIsValid && !_parser.Options.AllowInvalidValues)
+            {
+                RaiseErrorOccurred(ParseError.InvalidSelector, start);
+                result = null;
+            }
+
+            return result;
+        }
+
+        private ISelector CreateMarginSelector(ref Token token)
+        {
+            var selector = _parser.GetSelectorCreator();
+            var start = token.Position;
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.CurlyBracketOpen, TokenType.CurlyBracketClose))
+            {
+                selector.Apply(token);
+                token = NextToken();
+            }
+
+            var selectorIsValid = selector.IsValid;
+            var result = selector.ToPool();
+
+            if (result is StylesheetNode node)
+            {
+                var end = token.Position.Shift(-1);
+                node.StylesheetText = CreateView(start, end);
+            }
+
+            if (!selectorIsValid && !_parser.Options.AllowInvalidValues)
+            {
+                RaiseErrorOccurred(ParseError.InvalidSelector, start);
+                result = null;
+            }
+
+            return result;
+        }
+
+        private TokenValue CreateValue(TokenType closing, ref Token token, out bool important)
+        {
+            var value = Pool.NewValueBuilder();
+            _lexer.IsInValue = true;
+            token = NextToken();
+            var start = token.Position;
+
+            while (token.IsNot(TokenType.EndOfFile, TokenType.Semicolon, closing))
+            {
+                value.Apply(token);
+                token = NextToken();
+            }
+
+            important = value.IsImportant;
+            _lexer.IsInValue = false;
+            var valueIsValid = value.IsValid;
+            var result = value.ToPool();
+
+            //var node = result as StylesheetNode;
+            var node = (StylesheetNode)result;
+
+            if (node != null)
+            {
+                var end = token.Position.Shift(-1);
+                node.StylesheetText = CreateView(start, end);
+            }
+
+            if (!valueIsValid && !_parser.Options.AllowInvalidValues)
+            {
+                RaiseErrorOccurred(ParseError.InvalidValue, start);
+                result = null;
+            }
+
+            return result;
+        }
+
+        private string GetRuleName(ref Token token)
+        {
+            var name = string.Empty;
+
+            if (token.Type == TokenType.Ident)
+            {
+                name = token.Data;
+                token = NextToken();
+            }
+
+            return name;
+        }
+
+        private MediaFeature CreateFeature(ref Token token)
+        {
+            if (token.Type == TokenType.Ident)
+            {
+                var start = token.Position;
+                var val = TokenValue.Empty;
+                var feature = _parser.Options.AllowInvalidConstraints
+                    ? new UnknownMediaFeature(token.Data)
+                    : MediaFeatureFactory.Instance.Create(token.Data);
+
+                token = NextToken();
+                ParseComments(ref token);
+                var tokenDelimiter = TokenType.Colon;
+                if (token.Type == TokenType.Colon ||
+                    token.Type == TokenType.GreaterThan || token.Type == TokenType.LessThan ||
+                    token.Type == TokenType.GreaterThanOrEqual || token.Type == TokenType.LessThanOrEqual)
+                {
+                    tokenDelimiter = token.Type;
+                    var value = Pool.NewValueBuilder();
+                    token = NextToken();
+
+                    while (token.IsNot(TokenType.RoundBracketClose, TokenType.EndOfFile) || !value.IsReady)
+                    {
+                        value.Apply(token);
+                        token = NextToken();
+                    }
+
+                    val = value.ToPool();
+                }
+                else if (token.Type == TokenType.EndOfFile)
+                {
+                    return null;
+                }
+
+                if (feature != null && feature.TrySetValue(val, tokenDelimiter))
+                {
+                    if (feature is StylesheetNode node)
+                    {
+                        var end = token.Position.Shift(-1);
+                        node.StylesheetText = CreateView(start, end);
+                    }
+
+                    return feature;
+                }
+            }
+            else
+            {
+                JumpToArgEnd(ref token);
+            }
+
+            return null;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Parser/StylesheetParser.cs b/Source/HtmlRenderer/Core/CssEngine/Parser/StylesheetParser.cs
new file mode 100644
index 000000000..fa60a6f57
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Parser/StylesheetParser.cs
@@ -0,0 +1,213 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal class StylesheetParser
+    {
+        internal static readonly StylesheetParser Default = new StylesheetParser();
+
+        public StylesheetParser(
+            bool includeUnknownRules = false,
+            bool includeUnknownDeclarations = false,
+            bool tolerateInvalidSelectors = false,
+            bool tolerateInvalidValues = false,
+            bool tolerateInvalidConstraints = false,
+            bool preserveComments = false,
+            bool preserveDuplicateProperties = false
+        )
+        {
+            Options = new ParserOptions
+            {
+                IncludeUnknownRules = includeUnknownRules,
+                IncludeUnknownDeclarations = includeUnknownDeclarations,
+                AllowInvalidSelectors = tolerateInvalidSelectors,
+                AllowInvalidValues = tolerateInvalidValues,
+                AllowInvalidConstraints = tolerateInvalidConstraints,
+                PreserveComments = preserveComments,
+                PreserveDuplicateProperties = preserveDuplicateProperties,
+            };
+        }
+
+        internal ParserOptions Options { get; }
+
+        public Stylesheet Parse(string content)
+        {
+            var source = new TextSource(content);
+            return Parse(source);
+        }
+
+        public Stylesheet Parse(Stream content)
+        {
+            var source = new TextSource(content);
+            return Parse(source);
+        }
+
+        public Task<Stylesheet> ParseAsync(string content)
+        {
+            return ParseAsync(content, CancellationToken.None);
+        }
+
+        public async Task<Stylesheet> ParseAsync(string content, CancellationToken cancelToken)
+        {
+            var source = new TextSource(content);
+            await source.PrefetchAllAsync(cancelToken).ConfigureAwait(false);
+            return Parse(source);
+        }
+
+        public Task<Stylesheet> ParseAsync(Stream content)
+        {
+            return ParseAsync(content, CancellationToken.None);
+        }
+
+        public async Task<Stylesheet> ParseAsync(Stream content, CancellationToken cancelToken)
+        {
+            var source = new TextSource(content);
+            await source.PrefetchAllAsync(cancelToken).ConfigureAwait(false);
+            return Parse(source);
+        }
+
+        public ISelector ParseSelector(string selectorText)
+        {
+            var tokenizer = CreateTokenizer(selectorText);
+            var token = tokenizer.Get();
+            var creator = GetSelectorCreator();
+            while (token.Type != TokenType.EndOfFile)
+            {
+                creator.Apply(token);
+                token = tokenizer.Get();
+            }
+
+            var valid = creator.IsValid;
+            var result = creator.ToPool();
+
+            return valid || Options.AllowInvalidSelectors ? result : null;
+        }
+
+        internal KeyframeSelector ParseKeyframeSelector(string keyText)
+        {
+            return Parse(keyText, (b, t) => Tuple.Create(b.CreateKeyframeSelector(ref t), t));
+        }
+
+        internal SelectorConstructor GetSelectorCreator()
+        {
+            var attributeSelector = AttributeSelectorFactory.Instance;
+            var pseudoClassSelector = PseudoClassSelectorFactory.Instance;
+            var pseudoElementSelector = new PseudoElementSelectorFactory(this);
+            return Pool.NewSelectorConstructor(attributeSelector, pseudoClassSelector, pseudoElementSelector);
+        }
+
+        internal Stylesheet Parse(TextSource source)
+        {
+            var sheet = new Stylesheet(this);
+            var tokenizer = new Lexer(source);
+            var start = tokenizer.GetCurrentPosition();
+            var builder = new StylesheetComposer(tokenizer, this);
+            var end = builder.CreateRules(sheet);
+            var range = new TextRange(start, end);
+            sheet.StylesheetText = new StylesheetText(range, source);
+            return sheet;
+        }
+
+        internal async Task<Stylesheet> ParseAsync(Stylesheet sheet, TextSource source)
+        {
+            await source.PrefetchAllAsync(CancellationToken.None).ConfigureAwait(false);
+            var tokenizer = new Lexer(source);
+            var start = tokenizer.GetCurrentPosition();
+            var builder = new StylesheetComposer(tokenizer, this);
+            //var tasks = new List<Task>();
+            var end = builder.CreateRules(sheet);
+            var range = new TextRange(start, end);
+            sheet.StylesheetText = new StylesheetText(range, source);
+
+            foreach (var rule in sheet.Rules)
+            {
+                if (rule.Type == RuleType.Charset) continue;
+                if (rule.Type != RuleType.Import) break;
+            }
+
+            //await TaskEx.WhenAll(tasks).ConfigureAwait(false);
+            return sheet;
+        }
+
+        internal TokenValue ParseValue(string valueText)
+        {
+            var tokenizer = CreateTokenizer(valueText);
+            var token = default(Token);
+            var builder = new StylesheetComposer(tokenizer, this);
+            var value = builder.CreateValue(ref token);
+            return token.Type == TokenType.EndOfFile ? value : null;
+        }
+
+        internal Rule ParseRule(string ruleText)
+        {
+            return Parse(ruleText, (b, t) => b.CreateRule(t));
+        }
+
+        internal Property ParseDeclaration(string declarationText)
+        {
+            return Parse(declarationText, (b, t) => Tuple.Create(b.CreateDeclaration(ref t), t));
+        }
+
+        internal List<Medium> ParseMediaList(string mediaText)
+        {
+            return Parse(mediaText, (b, t) => Tuple.Create(b.CreateMedia(ref t), t));
+        }
+
+        internal IConditionFunction ParseCondition(string conditionText)
+        {
+            return Parse(conditionText, (b, t) => Tuple.Create(b.CreateCondition(ref t), t));
+        }
+
+        internal List<DocumentFunction> ParseDocumentRules(string documentText)
+        {
+            return Parse(documentText, (b, t) => Tuple.Create(b.CreateFunctions(ref t), t));
+        }
+
+        internal Medium ParseMedium(string mediumText)
+        {
+            return Parse(mediumText, (b, t) => Tuple.Create(b.CreateMedium(ref t), t));
+        }
+
+        internal KeyframeRule ParseKeyframeRule(string ruleText)
+        {
+            return Parse(ruleText, (b, t) => b.CreateKeyframeRule(t));
+        }
+
+        internal void AppendDeclarations(StyleDeclaration style, string declarations)
+        {
+            var tokenizer = CreateTokenizer(declarations);
+            var builder = new StylesheetComposer(tokenizer, this);
+            builder.FillDeclarations(style);
+        }
+
+        private T Parse<T>(string source, Func<StylesheetComposer, Token, T> create)
+        {
+            var tokenizer = CreateTokenizer(source);
+            var token = tokenizer.Get();
+            var builder = new StylesheetComposer(tokenizer, this);
+            var rule = create(builder, token);
+            return tokenizer.Get().Type == TokenType.EndOfFile ? rule : default;
+        }
+
+        private T Parse<T>(string source, Func<StylesheetComposer, Token, Tuple<T, Token>> create)
+        {
+            var tokenizer = CreateTokenizer(source);
+            var token = tokenizer.Get();
+            var builder = new StylesheetComposer(tokenizer, this);
+            var pair = create(builder, token);
+            return pair.Item2.Type == TokenType.EndOfFile ? pair.Item1 : default;
+        }
+
+        private static Lexer CreateTokenizer(string sourceCode)
+        {
+            var source = new TextSource(sourceCode);
+            return new Lexer(source);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Parser/TokenizerError.cs b/Source/HtmlRenderer/Core/CssEngine/Parser/TokenizerError.cs
new file mode 100644
index 000000000..d19b0792c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Parser/TokenizerError.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal class TokenizerError
+    {
+        private readonly ParseError _code;
+
+        public TokenizerError(ParseError code, TextPosition position)
+        {
+            _code = code;
+            Position = position;
+        }
+
+        public TextPosition Position { get; }
+        public int Code => _code.GetCode();
+        public string Message => "An unknown error occurred.";
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/CharsetRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/CharsetRule.cs
new file mode 100644
index 000000000..a11ca0279
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/CharsetRule.cs
@@ -0,0 +1,26 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class CharsetRule : Rule, ICharsetRule
+    {
+        internal CharsetRule(StylesheetParser parser)
+            : base(RuleType.Charset, parser)
+        {
+        }
+
+        public string CharacterSet { get; set; }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Rule("@charset", CharacterSet.StylesheetString()));
+        }
+
+        protected override void ReplaceWith(IRule rule)
+        {
+            var newRule = rule as CharsetRule;
+            CharacterSet = newRule?.CharacterSet;
+            base.ReplaceWith(rule);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/ConditionRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/ConditionRule.cs
new file mode 100644
index 000000000..623aebd85
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/ConditionRule.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class ConditionRule : GroupingRule
+    {
+        internal ConditionRule(RuleType type, StylesheetParser parser)
+            : base(type, parser)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/ContainerRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/ContainerRule.cs
new file mode 100644
index 000000000..abf4041f0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/ContainerRule.cs
@@ -0,0 +1,32 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ContainerRule : ConditionRule, IContainerRule
+    {
+        internal ContainerRule(StylesheetParser parser) : base(RuleType.Container, parser)
+        {
+            AppendChild(new MediaList(parser));
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var rules = formatter.Block(Rules);
+            var name = "@container";
+            if (!string.IsNullOrEmpty(Name))
+                name = $"{name} {Name}";
+            writer.Write(formatter.Rule(name, ConditionText, rules));
+        }
+
+        public MediaList Media => Children.OfType<MediaList>().FirstOrDefault();
+
+        public string Name { get; set; }
+
+        public string ConditionText
+        {
+            get => Media.MediaText;
+            set => Media.MediaText = value;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/DeclarationRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/DeclarationRule.cs
new file mode 100644
index 000000000..75d2f64da
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/DeclarationRule.cs
@@ -0,0 +1,130 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class DeclarationRule : Rule, IProperties
+    {
+        private readonly string _name;
+
+        internal DeclarationRule(RuleType type, string name, StylesheetParser parser)
+            : base(type, parser)
+        {
+            _name = name;
+        }
+
+        internal void SetProperty(Property property)
+        {
+            foreach (var declaration in Declarations)
+            {
+                if (!declaration.Name.Is(property.Name)) continue;
+
+                ReplaceChild(declaration, property);
+                return;
+            }
+
+            AppendChild(property);
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var rules = new FormatTransporter(Declarations);
+            var content = formatter.Style("@" + _name, rules);
+            writer.Write(content);
+        }
+
+        public string this[string propertyName] => GetValue(propertyName);
+        public IEnumerable<Property> Declarations => Children.OfType<Property>();
+        public int Length => Declarations.Count();
+
+        public string GetPropertyValue(string propertyName)
+        {
+            return GetValue(propertyName);
+        }
+
+        public string GetPropertyPriority(string propertyName)
+        {
+            return null;
+        }
+
+        public void SetProperty(string propertyName, string propertyValue, string priority = null)
+        {
+            SetValue(propertyName, propertyValue);
+        }
+
+        public string RemoveProperty(string propertyName)
+        {
+            foreach (var declaration in Declarations)
+            {
+                if (!declaration.HasValue || !declaration.Name.Is(propertyName)) continue;
+
+                var value = declaration.Value;
+                RemoveChild(declaration);
+                return value;
+            }
+
+            return null;
+        }
+
+        public IEnumerator<IProperty> GetEnumerator()
+        {
+            return Declarations.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        private struct FormatTransporter : IStyleFormattable
+        {
+            private readonly IEnumerable<Property> _properties;
+
+            public FormatTransporter(IEnumerable<Property> properties)
+            {
+                _properties = properties.Where(m => m.HasValue);
+            }
+
+            public void ToCss(TextWriter writer, IStyleFormatter formatter)
+            {
+                var properties = _properties.Select(m => m.ToCss(formatter));
+                var content = formatter.Declarations(properties);
+                writer.Write(content);
+            }
+        }
+
+        protected abstract Property CreateNewProperty(string name);
+
+        protected string GetValue(string propertyName)
+        {
+            foreach (var declaration in Declarations)
+                if (declaration.HasValue && declaration.Name.Is(propertyName))
+                    return declaration.Value;
+
+            return string.Empty;
+        }
+
+        protected void SetValue(string propertyName, string valueText)
+        {
+            foreach (var declaration in Declarations)
+            {
+                if (!declaration.Name.Is(propertyName)) continue;
+
+                var value = Parser.ParseValue(valueText);
+                declaration.TrySetValue(value);
+                return;
+            }
+
+            var property = CreateNewProperty(propertyName);
+
+            if (property == null) return;
+            {
+                var value = Parser.ParseValue(valueText);
+                property.TrySetValue(value);
+                AppendChild(property);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/DocumentRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/DocumentRule.cs
new file mode 100644
index 000000000..1c553f96d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/DocumentRule.cs
@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DocumentRule : GroupingRule
+    {
+        internal DocumentRule(StylesheetParser parser)
+            : base(RuleType.Document, parser)
+        {
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var rules = formatter.Block(Rules);
+            writer.Write(formatter.Rule("@document", ConditionText, rules));
+        }
+
+        public string ConditionText
+        {
+            get
+            {
+                var entries = Conditions.Select(m => m.ToCss());
+                return string.Join(", ", entries);
+            }
+            set
+            {
+                var conditions = Parser.ParseDocumentRules(value);
+
+                if (conditions == null) throw new ParseException("Unable to parse document rules");
+
+                Clear();
+
+                foreach (var condition in conditions) AppendChild(condition);
+            }
+        }
+
+        public IEnumerable<IDocumentFunction> Conditions => Children.OfType<IDocumentFunction>();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/FontFaceRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/FontFaceRule.cs
new file mode 100644
index 000000000..6c4c2d338
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/FontFaceRule.cs
@@ -0,0 +1,63 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FontFaceRule : DeclarationRule, IFontFaceRule
+    {
+        internal FontFaceRule(StylesheetParser parser)
+            : base(RuleType.FontFace, RuleNames.FontFace, parser)
+        {
+        }
+
+        protected override Property CreateNewProperty(string name)
+        {
+            return PropertyFactory.Instance.CreateFont(name);
+        }
+
+        string IFontFaceRule.Family
+        {
+            get => GetValue(PropertyNames.FontFamily);
+            set => SetValue(PropertyNames.FontFamily, value);
+        }
+
+        string IFontFaceRule.Source
+        {
+            get => GetValue(PropertyNames.Src);
+            set => SetValue(PropertyNames.Src, value);
+        }
+
+        string IFontFaceRule.Style
+        {
+            get => GetValue(PropertyNames.FontStyle);
+            set => SetValue(PropertyNames.FontStyle, value);
+        }
+
+        string IFontFaceRule.Weight
+        {
+            get => GetValue(PropertyNames.FontWeight);
+            set => SetValue(PropertyNames.FontWeight, value);
+        }
+
+        string IFontFaceRule.Stretch
+        {
+            get => GetValue(PropertyNames.FontStretch);
+            set => SetValue(PropertyNames.FontStretch, value);
+        }
+
+        string IFontFaceRule.Range
+        {
+            get => GetValue(PropertyNames.UnicodeRange);
+            set => SetValue(PropertyNames.UnicodeRange, value);
+        }
+
+        string IFontFaceRule.Variant
+        {
+            get => GetValue(PropertyNames.FontVariant);
+            set => SetValue(PropertyNames.FontVariant, value);
+        }
+
+        string IFontFaceRule.Features
+        {
+            get => string.Empty;
+            set { }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/FontPaletteValuesRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/FontPaletteValuesRule.cs
new file mode 100644
index 000000000..0ba5ef8f1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/FontPaletteValuesRule.cs
@@ -0,0 +1,56 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// A <c>@font-palette-values</c> at-rule (CSS Fonts Module Level 4): associates a named palette override
+    /// (a dashed-ident such as <c>--my-palette</c>) with a font family, selecting a <c>base-palette</c> and
+    /// optionally overriding individual colors (<c>override-colors</c>). The descriptor block is stored like
+    /// <see cref="PropertyRule"/>; the name is captured from the prelude like <see cref="KeyframesRule.Name"/>.
+    /// </summary>
+    internal sealed class FontPaletteValuesRule : DeclarationRule, IFontPaletteValuesRule
+    {
+        internal FontPaletteValuesRule(StylesheetParser parser)
+            : base(RuleType.FontPaletteValues, RuleNames.FontPaletteValues, parser)
+        {
+        }
+
+        protected override Property CreateNewProperty(string name)
+        {
+            return PropertyFactory.Instance.CreateFontPaletteDescriptor(name);
+        }
+
+        protected override void ReplaceWith(IRule rule)
+        {
+            if (rule is FontPaletteValuesRule other) Name = other.Name;
+            base.ReplaceWith(rule);
+        }
+
+        public string Name { get; set; }
+
+        public string Family
+        {
+            get => GetValue(PropertyNames.FontFamily);
+            set => SetValue(PropertyNames.FontFamily, value);
+        }
+
+        public string BasePalette
+        {
+            get => GetValue(PropertyNames.BasePalette);
+            set => SetValue(PropertyNames.BasePalette, value);
+        }
+
+        public string OverrideColors
+        {
+            get => GetValue(PropertyNames.OverrideColors);
+            set => SetValue(PropertyNames.OverrideColors, value);
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var declarations = formatter.Declarations(Declarations.Where(d => d.HasValue).Select(d => d.ToCss(formatter)));
+            writer.Write(string.Concat("@font-palette-values ", Name, " { ", declarations, " }"));
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/GroupingRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/GroupingRule.cs
new file mode 100644
index 000000000..092e5174f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/GroupingRule.cs
@@ -0,0 +1,34 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class GroupingRule : Rule, IGroupingRule
+    {
+        internal GroupingRule(RuleType type, StylesheetParser parser)
+            : base(type, parser)
+        {
+            Rules = new RuleList(this);
+        }
+
+        public RuleList Rules { get; }
+
+        IRuleList IGroupingRule.Rules => Rules;
+
+        public IRule AddNewRule(RuleType ruleType)
+        {
+            var rule = Parser.CreateRule(ruleType);
+            Rules.Add(rule);
+            return rule;
+        }
+
+        public int Insert(string ruleText, int index)
+        {
+            var rule = Parser.ParseRule(ruleText);
+            Rules.Insert(index, rule);
+            return index;
+        }
+
+        public void RemoveAt(int index)
+        {
+            Rules.RemoveAt(index);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/ICharsetRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/ICharsetRule.cs
new file mode 100644
index 000000000..8d6334589
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/ICharsetRule.cs
@@ -0,0 +1,7 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface ICharsetRule : IRule
+    {
+        string CharacterSet { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IConditionRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IConditionRule.cs
new file mode 100644
index 000000000..ffe6793fd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IConditionRule.cs
@@ -0,0 +1,7 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IConditionRule : IGroupingRule
+    {
+        string ConditionText { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IContainer.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IContainer.cs
new file mode 100644
index 000000000..51cf7441d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IContainer.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IContainerRule : IConditionRule
+    {
+        string Name { get; set; }
+        MediaList Media { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IFontFaceRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IFontFaceRule.cs
new file mode 100644
index 000000000..b917b1e50
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IFontFaceRule.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IFontFaceRule : IRule, IProperties
+    {
+        string Family { get; set; }
+        string Source { get; set; }
+        string Style { get; set; }
+        string Weight { get; set; }
+        string Stretch { get; set; }
+        string Range { get; set; }
+        string Variant { get; set; }
+        string Features { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IFontPaletteValuesRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IFontPaletteValuesRule.cs
new file mode 100644
index 000000000..0c4499933
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IFontPaletteValuesRule.cs
@@ -0,0 +1,21 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// A palette override declared with a <c>@font-palette-values</c> at-rule (CSS Fonts Module Level 4).
+    /// Exposes the prelude name and the three descriptors.
+    /// </summary>
+    internal interface IFontPaletteValuesRule : IRule, IProperties
+    {
+        /// <summary>The palette name, a dashed-ident referenced by <c>font-palette: &lt;dashed-ident&gt;</c>, e.g. <c>--my-palette</c>.</summary>
+        string Name { get; set; }
+
+        /// <summary>The raw <c>font-family</c> descriptor value (the family this palette applies to).</summary>
+        string Family { get; set; }
+
+        /// <summary>The raw <c>base-palette</c> descriptor value (<c>&lt;integer&gt; | light | dark</c>).</summary>
+        string BasePalette { get; set; }
+
+        /// <summary>The raw <c>override-colors</c> descriptor value (a comma list of <c>&lt;index&gt; &lt;color&gt;</c> pairs).</summary>
+        string OverrideColors { get; set; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IGroupingRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IGroupingRule.cs
new file mode 100644
index 000000000..c7aded657
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IGroupingRule.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IGroupingRule : IRule, IRuleCreator
+    {
+        IRuleList Rules { get; }
+        int Insert(string rule, int index);
+        void RemoveAt(int index);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IImportRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IImportRule.cs
new file mode 100644
index 000000000..5d7c3ba9d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IImportRule.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IImportRule : IRule
+    {
+        string Href { get; set; }
+        MediaList Media { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IKeyframeRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IKeyframeRule.cs
new file mode 100644
index 000000000..338ab4cf6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IKeyframeRule.cs
@@ -0,0 +1,9 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IKeyframeRule : IRule
+    {
+        string KeyText { get; set; }
+        StyleDeclaration Style { get; }
+        KeyframeSelector Key { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IKeyframesRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IKeyframesRule.cs
new file mode 100644
index 000000000..9e2fe9df6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IKeyframesRule.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IKeyframesRule : IRule
+    {
+        string Name { get; set; }
+        IRuleList Rules { get; }
+        void Add(string rule);
+        void Remove(string key);
+        IKeyframeRule Find(string key);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/ILayerRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/ILayerRule.cs
new file mode 100644
index 000000000..97b76aaa4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/ILayerRule.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The block form of the <c>@layer</c> cascade-layer at-rule (<c>@layer name { … }</c>, or an
+    /// anonymous <c>@layer { … }</c>). Groups the style rules that belong to a named cascade layer,
+    /// per <see href="https://www.w3.org/TR/css-cascade-5/#layering">CSS Cascade 5</see>.
+    /// </summary>
+    internal interface ILayerRule : IGroupingRule
+    {
+        /// <summary>The layer's (optionally dotted) name; empty for an anonymous layer.</summary>
+        string Name { get; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IMarginRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IMarginRule.cs
new file mode 100644
index 000000000..df47dbc25
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IMarginRule.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IMarginRule : IRule
+    {
+        string Name { get; }
+        StyleDeclaration Style { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IMediaRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IMediaRule.cs
new file mode 100644
index 000000000..e21622de2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IMediaRule.cs
@@ -0,0 +1,7 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IMediaRule : IConditionRule
+    {
+        MediaList Media { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/INamespaceRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/INamespaceRule.cs
new file mode 100644
index 000000000..b18a34ce3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/INamespaceRule.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface INamespaceRule : IRule
+    {
+        string NamespaceUri { get; set; }
+        string Prefix { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IPageRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IPageRule.cs
new file mode 100644
index 000000000..72a5d8b44
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IPageRule.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IPageRule : IRule
+    {
+        string SelectorText { get; set; }
+        StyleDeclaration Style { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IPropertyRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IPropertyRule.cs
new file mode 100644
index 000000000..c7d7d4f58
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IPropertyRule.cs
@@ -0,0 +1,21 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// A registered custom property declared with an <c>@property</c> at-rule
+    /// (CSS Properties &amp; Values API Level 1 §3). Exposes the three descriptors.
+    /// </summary>
+    internal interface IPropertyRule : IRule, IProperties
+    {
+        /// <summary>The registered custom property name, e.g. <c>--my-color</c>.</summary>
+        string Name { get; set; }
+
+        /// <summary>The raw <c>syntax</c> descriptor value (a string, e.g. <c>&lt;color&gt;</c> or <c>*</c>).</summary>
+        string Syntax { get; set; }
+
+        /// <summary>The raw <c>initial-value</c> descriptor value.</summary>
+        string InitialValue { get; set; }
+
+        /// <summary>The raw <c>inherits</c> descriptor value (<c>true</c> or <c>false</c>).</summary>
+        string Inherits { get; set; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IRule.cs
new file mode 100644
index 000000000..2f005ee28
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IRule.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IRule : IStylesheetNode
+    {
+        RuleType Type { get; }
+        string Text { get; set; }
+        IRule Parent { get; }
+        Stylesheet Owner { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IRuleCreator.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IRuleCreator.cs
new file mode 100644
index 000000000..4561db149
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IRuleCreator.cs
@@ -0,0 +1,7 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IRuleCreator
+    {
+        IRule AddNewRule(RuleType ruleType);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IRuleList.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IRuleList.cs
new file mode 100644
index 000000000..c81cb5bac
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IRuleList.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IRuleList : IEnumerable<IRule>
+    {
+        IRule this[int index] { get; }
+        int Length { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/IStyleRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/IStyleRule.cs
new file mode 100644
index 000000000..53a8d5592
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/IStyleRule.cs
@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IStyleRule : IRule
+    {
+        string SelectorText { get; set; }
+        StyleDeclaration Style { get; }
+        ISelector Selector { get; set; }
+
+        /// <summary>
+        /// CSS Nesting: style rules nested inside this rule's block, each already resolved to an
+        /// absolute selector against this (parent) rule. Empty for a non-nesting rule.
+        /// </summary>
+        IReadOnlyList<IStyleRule> NestedRules { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/ISupportsRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/ISupportsRule.cs
new file mode 100644
index 000000000..dcf6a63fe
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/ISupportsRule.cs
@@ -0,0 +1,7 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface ISupportsRule : IConditionRule
+    {
+        IConditionFunction Condition { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/ImportRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/ImportRule.cs
new file mode 100644
index 000000000..9ba116878
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/ImportRule.cs
@@ -0,0 +1,36 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ImportRule : Rule, IImportRule
+    {
+        private Stylesheet _stylesheet;
+
+        internal ImportRule(StylesheetParser parser) : base(RuleType.Import, parser)
+        {
+            AppendChild(new MediaList(parser));
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var media = Media.MediaText;
+            var space = string.IsNullOrEmpty(media) ? string.Empty : " ";
+            var value = string.Concat(Href.StylesheetUrl(), space, media);
+            writer.Write(formatter.Rule("@import", value));
+        }
+
+        protected override void ReplaceWith(IRule rule)
+        {
+            var newRule = rule as ImportRule;
+            Href = newRule?.Href;
+            _stylesheet = null;
+            base.ReplaceWith(rule);
+        }
+
+
+        public string Href { get; set; }
+        public MediaList Media => Children.OfType<MediaList>().FirstOrDefault();
+        public Stylesheet Sheet => _stylesheet;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/KeyframeRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/KeyframeRule.cs
new file mode 100644
index 000000000..da080927c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/KeyframeRule.cs
@@ -0,0 +1,37 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class KeyframeRule : Rule, IKeyframeRule
+    {
+        internal KeyframeRule(StylesheetParser parser)
+            : base(RuleType.Keyframe, parser)
+        {
+            AppendChild(new StyleDeclaration(this));
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Style(KeyText, Style));
+        }
+
+        public string KeyText
+        {
+            get => Key.Text;
+            set
+            {
+                var selector = Parser.ParseKeyframeSelector(value);
+                Key = selector ?? throw new ParseException("Unable to parse keyframe selector");
+            }
+        }
+
+        public KeyframeSelector Key
+        {
+            get => Children.OfType<KeyframeSelector>().FirstOrDefault();
+            set => ReplaceSingle(Key, value);
+        }
+
+        public StyleDeclaration Style => Children.OfType<StyleDeclaration>().FirstOrDefault();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/KeyframesRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/KeyframesRule.cs
new file mode 100644
index 000000000..e01623418
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/KeyframesRule.cs
@@ -0,0 +1,53 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class KeyframesRule : Rule, IKeyframesRule
+    {
+        internal KeyframesRule(StylesheetParser parser)
+            : base(RuleType.Keyframes, parser)
+        {
+            Rules = new RuleList(this);
+        }
+
+        protected override void ReplaceWith(IRule rule)
+        {
+            var newRule = rule as KeyframesRule;
+            Name = newRule?.Name;
+            base.ReplaceWith(rule);
+        }
+
+        public string Name { get; set; }
+        public RuleList Rules { get; }
+        IRuleList IKeyframesRule.Rules => Rules;
+
+        public void Add(string ruleText)
+        {
+            var rule = Parser.ParseKeyframeRule(ruleText);
+            Rules.Add(rule);
+        }
+
+        public void Remove(string key)
+        {
+            var element = Find(key);
+            Rules.Remove(element);
+        }
+
+        public KeyframeRule Find(string key)
+        {
+            return Rules.OfType<KeyframeRule>().FirstOrDefault(m => key.Isi(m.KeyText));
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var rules = formatter.Block(Rules);
+            writer.Write(formatter.Rule("@keyframes", Name, rules));
+        }
+
+        IKeyframeRule IKeyframesRule.Find(string key)
+        {
+            return Find(key);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/LayerRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/LayerRule.cs
new file mode 100644
index 000000000..7957e4d24
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/LayerRule.cs
@@ -0,0 +1,26 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The block form of <c>@layer</c> (<c>@layer name { rules }</c> or anonymous <c>@layer { rules }</c>).
+    /// A grouping rule holding the style rules assigned to a cascade layer; cascade precedence between
+    /// layers is resolved when the rules are indexed (see <c>CssData</c>), not here.
+    /// </summary>
+    internal sealed class LayerRule : GroupingRule, ILayerRule
+    {
+        internal LayerRule(StylesheetParser parser)
+            : base(RuleType.Layer, parser)
+        {
+        }
+
+        public string Name { get; set; } = string.Empty;
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var rules = formatter.Block(Rules);
+            var name = string.IsNullOrEmpty(Name) ? "@layer" : $"@layer {Name}";
+            writer.Write(formatter.Rule(name, null, rules));
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/LayerStatementRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/LayerStatementRule.cs
new file mode 100644
index 000000000..e0bc077f9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/LayerStatementRule.cs
@@ -0,0 +1,26 @@
+using System.Collections.Generic;
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The statement form of <c>@layer</c> (<c>@layer a, b, c;</c>). It declares the relative order of
+    /// one or more named cascade layers without providing any rules; a later block-form
+    /// <see cref="LayerRule"/> attaches rules to a layer already ordered by this statement, per
+    /// <see href="https://www.w3.org/TR/css-cascade-5/#layer-empty">CSS Cascade 5</see>.
+    /// </summary>
+    internal sealed class LayerStatementRule : Rule
+    {
+        internal LayerStatementRule(StylesheetParser parser)
+            : base(RuleType.LayerStatement, parser)
+        {
+        }
+
+        public List<string> Names { get; } = new List<string>();
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Rule("@layer", string.Join(", ", Names)));
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/MarginStyleRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/MarginStyleRule.cs
new file mode 100644
index 000000000..92a91b981
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/MarginStyleRule.cs
@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginStyleRule : Rule, IStyleRule
+    {
+        // @page margin boxes don't participate in CSS Nesting.
+        public IReadOnlyList<IStyleRule> NestedRules
+        {
+            get { return new IStyleRule[0]; }
+        }
+
+        public MarginStyleRule(StylesheetParser parser) : base(RuleType.Style, parser)
+        {
+            AppendChild(new StyleDeclaration(this));
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Style(SelectorText, Style));
+        }
+
+        public ISelector Selector
+        {
+            get => Children.OfType<ISelector>().FirstOrDefault();
+            set => ReplaceSingle(Selector, value);
+        }
+
+        public string SelectorText
+        {
+            get => $"@{Selector.Text}";
+            set => Selector = Parser.ParseSelector(value);
+        }
+
+        public StyleDeclaration Style => Children.OfType<StyleDeclaration>().FirstOrDefault();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/MediaRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/MediaRule.cs
new file mode 100644
index 000000000..4f431c494
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/MediaRule.cs
@@ -0,0 +1,27 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MediaRule : ConditionRule, IMediaRule
+    {
+        internal MediaRule(StylesheetParser parser) : base(RuleType.Media, parser)
+        {
+            AppendChild(new MediaList(parser));
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var rules = formatter.Block(Rules);
+            writer.Write(formatter.Rule("@media", Media.MediaText, rules));
+        }
+
+        public string ConditionText
+        {
+            get => Media.MediaText;
+            set => Media.MediaText = value;
+        }
+
+        public MediaList Media => Children.OfType<MediaList>().FirstOrDefault();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/NamespaceRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/NamespaceRule.cs
new file mode 100644
index 000000000..dbd443009
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/NamespaceRule.cs
@@ -0,0 +1,66 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class NamespaceRule : Rule, INamespaceRule
+    {
+        private string _namespaceUri;
+        private string _prefix;
+
+        internal NamespaceRule(StylesheetParser parser)
+            : base(RuleType.Namespace, parser)
+        {
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var space = string.IsNullOrEmpty(_prefix) ? string.Empty : " ";
+            var value = string.Concat(_prefix, space, _namespaceUri.StylesheetUrl());
+            writer.Write(formatter.Rule("@namespace", value));
+        }
+
+        protected override void ReplaceWith(IRule rule)
+        {
+            var newRule = rule as NamespaceRule;
+            _namespaceUri = newRule?._namespaceUri;
+            _prefix = newRule?._prefix;
+            base.ReplaceWith(rule);
+        }
+
+        public string NamespaceUri
+        {
+            get => _namespaceUri;
+            set
+            {
+                CheckValidity();
+                _namespaceUri = value ?? string.Empty;
+            }
+        }
+
+        public string Prefix
+        {
+            get => _prefix;
+            set
+            {
+                CheckValidity();
+                _prefix = value ?? string.Empty;
+            }
+        }
+
+        private static bool IsNotSupported(RuleType type)
+        {
+            return type != RuleType.Charset && type != RuleType.Import && type != RuleType.Namespace;
+        }
+
+        private void CheckValidity()
+        {
+            var parent = Owner;
+            var list = parent?.Rules;
+
+            if (list == null) return;
+
+            if (list.Any(entry => IsNotSupported(entry.Type))) throw new ParseException("Rule is not supported");
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/PageRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/PageRule.cs
new file mode 100644
index 000000000..061f4b70e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/PageRule.cs
@@ -0,0 +1,47 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PageRule : Rule, IPageRule
+    {
+        internal PageRule(StylesheetParser parser)
+            : base(RuleType.Page, parser)
+        {
+            //AppendChild(SimpleSelector.All);
+            AppendChild(new StyleDeclaration(this));
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Rule("@page", Selector == null ? "" : SelectorText, "{"));
+
+            Style.ToCss(writer, formatter);
+
+            if (Style.Any())
+            {
+                writer.Write("; ");
+                foreach (var margin in Margins) margin.ToCss(writer, formatter);
+            }
+
+            writer.Write("}");
+        }
+
+        public string SelectorText
+        {
+            get => Selector.Text;
+            set => Selector = Parser.ParseSelector(value);
+        }
+
+        public ISelector Selector
+        {
+            get => Children.OfType<ISelector>().FirstOrDefault();
+            set => ReplaceSingle(Selector, value);
+        }
+
+        public StyleDeclaration Style => Children.OfType<StyleDeclaration>().FirstOrDefault();
+        public IEnumerable<MarginStyleRule> Margins => Children.OfType<MarginStyleRule>();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/PropertyRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/PropertyRule.cs
new file mode 100644
index 000000000..a7675f8ae
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/PropertyRule.cs
@@ -0,0 +1,57 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// An <c>@property</c> at-rule (CSS Properties &amp; Values API Level 1 §3): registers a typed custom
+    /// property with a <c>syntax</c>, <c>initial-value</c>, and <c>inherits</c> descriptor. The descriptor
+    /// block is stored like <see cref="FontFaceRule"/>; the registered name (a dashed-ident such as
+    /// <c>--my-color</c>) is captured from the prelude like <see cref="KeyframesRule.Name"/>.
+    /// </summary>
+    internal sealed class PropertyRule : DeclarationRule, IPropertyRule
+    {
+        internal PropertyRule(StylesheetParser parser)
+            : base(RuleType.Property, RuleNames.Property, parser)
+        {
+        }
+
+        protected override Property CreateNewProperty(string name)
+        {
+            return PropertyFactory.Instance.CreatePropertyDescriptor(name);
+        }
+
+        protected override void ReplaceWith(IRule rule)
+        {
+            var other = rule as PropertyRule;
+            if (other != null) Name = other.Name;
+            base.ReplaceWith(rule);
+        }
+
+        public string Name { get; set; }
+
+        public string Syntax
+        {
+            get { return GetValue(PropertyNames.Syntax); }
+            set { SetValue(PropertyNames.Syntax, value); }
+        }
+
+        public string InitialValue
+        {
+            get { return GetValue(PropertyNames.InitialValue); }
+            set { SetValue(PropertyNames.InitialValue, value); }
+        }
+
+        public string Inherits
+        {
+            get { return GetValue(PropertyNames.Inherits); }
+            set { SetValue(PropertyNames.Inherits, value); }
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var declarations = formatter.Declarations(Declarations.Where(d => d.HasValue).Select(d => d.ToCss(formatter)));
+            writer.Write(string.Concat("@property ", Name, " { ", declarations, " }"));
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/Rule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/Rule.cs
new file mode 100644
index 000000000..009d4cee7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/Rule.cs
@@ -0,0 +1,65 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class Rule : StylesheetNode, IRule
+    {
+        private IRule _parentRule;
+
+        internal Rule(RuleType type, StylesheetParser parser)
+        {
+            Type = type;
+            Parser = parser;
+        }
+
+        internal StylesheetParser Parser { get; }
+        public Stylesheet Owner { get; internal set; }
+        public RuleType Type { get; }
+
+        public string Text
+        {
+            get => this.ToCss();
+            set
+            {
+                var rule = Parser.ParseRule(value);
+
+                if (rule == null) throw new ParseException("Unable to parse rule");
+                if (rule.Type != Type) throw new ParseException("Invalid rule type");
+                ReplaceWith(rule);
+            }
+        }
+
+        public IRule Parent
+        {
+            get => _parentRule;
+            internal set
+            {
+                _parentRule = value;
+
+                if (value != null) Owner = _parentRule.Owner;
+            }
+        }
+
+        protected virtual void ReplaceWith(IRule rule)
+        {
+            ReplaceAll(rule);
+        }
+
+        protected void ReplaceSingle(IStylesheetNode oldNode, IStylesheetNode newNode)
+        {
+            if (oldNode != null)
+            {
+                if (newNode != null)
+                {
+                    ReplaceChild(oldNode, newNode);
+                }
+                else
+                {
+                    RemoveChild(oldNode);
+                }
+            }
+            else if (newNode != null)
+            {
+                AppendChild(newNode);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/RuleList.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/RuleList.cs
new file mode 100644
index 000000000..f6c7f6a41
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/RuleList.cs
@@ -0,0 +1,78 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RuleList : IRuleList
+    {
+        private readonly StylesheetNode _parent;
+
+        internal RuleList(StylesheetNode parent)
+        {
+            _parent = parent;
+        }
+
+        public Rule this[int index] => Nodes.GetItemByIndex(index);
+        IRule IRuleList.this[int index] => this[index];
+        public bool HasDeclarativeRules => Nodes.Any(IsDeclarativeRule);
+        public IEnumerable<Rule> Nodes => _parent.Children.OfType<Rule>();
+        public int Length => Nodes.Count();
+
+        private static bool IsDeclarativeRule(Rule rule)
+        {
+            var type = rule.Type;
+            return type != RuleType.Import && type != RuleType.Charset && type != RuleType.Namespace;
+        }
+
+        internal void RemoveAt(int index)
+        {
+            if (index < 0 || index >= Length) throw new ParseException("Invalid index");
+
+            var rule = this[index];
+
+            if (rule.Type == RuleType.Namespace && HasDeclarativeRules)
+                throw new ParseException("Cannot remove namespace or declarative rules");
+
+            Remove(rule);
+        }
+
+        internal void Remove(Rule rule)
+        {
+            if (rule != null)
+                _parent.RemoveChild(rule);
+        }
+
+        internal void Insert(int index, Rule rule)
+        {
+            if (rule == null) throw new ParseException("Rule argument cannot be null");
+
+            if (rule.Type == RuleType.Charset) throw new ParseException("Cannot insert Charset rule");
+
+            if (index > Length || index < 0) throw new ParseException("Invalid index");
+
+            if (rule.Type == RuleType.Namespace && HasDeclarativeRules)
+                throw new ParseException("Cannot insert namespace or declarative rules");
+
+            if (index == Length)
+                _parent.AppendChild(rule);
+            else
+                _parent.InsertBefore(this[index], rule);
+        }
+
+        internal void Add(Rule rule)
+        {
+            if (rule != null) _parent.AppendChild(rule);
+        }
+
+        public IEnumerator<IRule> GetEnumerator()
+        {
+            return Nodes.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/StyleRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/StyleRule.cs
new file mode 100644
index 000000000..7e38cbda2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/StyleRule.cs
@@ -0,0 +1,43 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StyleRule : Rule, IStyleRule
+    {
+        // CSS Nesting: rules written inside this rule's block, resolved to absolute selectors against
+        // this parent. Kept in a dedicated list (not Children) so Selector/Style lookups and ToCss are
+        // unaffected. Populated by StylesheetComposer.FillDeclarations.
+        private readonly List<IStyleRule> _nestedRules = new List<IStyleRule>();
+
+        public StyleRule(StylesheetParser parser) : base(RuleType.Style, parser)
+        {
+            AppendChild(AllSelector.Create());
+            AppendChild(new StyleDeclaration(this));
+        }
+
+        public IReadOnlyList<IStyleRule> NestedRules => _nestedRules;
+
+        public void AddNestedRule(IStyleRule rule) => _nestedRules.Add(rule);
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Style(SelectorText, Style));
+        }
+
+        public ISelector Selector
+        {
+            get => Children.OfType<ISelector>().FirstOrDefault();
+            set => ReplaceSingle(Selector, value);
+        }
+
+        public string SelectorText
+        {
+            get => Selector.Text;
+            set => Selector = Parser.ParseSelector(value);
+        }
+
+        public StyleDeclaration Style => Children.OfType<StyleDeclaration>().FirstOrDefault();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/SupportsRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/SupportsRule.cs
new file mode 100644
index 000000000..b872a2cc4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/SupportsRule.cs
@@ -0,0 +1,43 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class SupportsRule : ConditionRule, ISupportsRule
+    {
+        internal SupportsRule(StylesheetParser parser)
+            : base(RuleType.Supports, parser)
+        {
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var rules = formatter.Block(Rules);
+            writer.Write(formatter.Rule("@supports", ConditionText, rules));
+        }
+
+
+        public string ConditionText
+        {
+            get => Condition.ToCss();
+            set
+            {
+                var condition = Parser.ParseCondition(value);
+
+                Condition = condition ?? throw new ParseException("Unable to parse condition");
+            }
+        }
+
+        public IConditionFunction Condition
+        {
+            get => Children.OfType<IConditionFunction>().FirstOrDefault() ?? new EmptyCondition();
+            set
+            {
+                if (value == null) return;
+
+                RemoveChild(Condition);
+                AppendChild(value);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/UnknownRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/UnknownRule.cs
new file mode 100644
index 000000000..e99b37eb7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/UnknownRule.cs
@@ -0,0 +1,20 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnknownRule : Rule
+    {
+        public UnknownRule(string name, StylesheetParser parser)
+            : base(RuleType.Unknown, parser)
+        {
+            Name = name;
+        }
+
+        public string Name { get; }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(StylesheetText?.Text);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Rules/ViewportRule.cs b/Source/HtmlRenderer/Core/CssEngine/Rules/ViewportRule.cs
new file mode 100644
index 000000000..5e61cf876
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Rules/ViewportRule.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ViewportRule : DeclarationRule
+    {
+        internal ViewportRule(StylesheetParser parser)
+            : base(RuleType.Viewport, RuleNames.ViewPort, parser)
+        {
+        }
+
+        protected override Property CreateNewProperty(string name)
+        {
+            return PropertyFactory.Instance.CreateViewport(name);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AllSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AllSelector.cs
new file mode 100644
index 000000000..cb0b63257
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AllSelector.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AllSelector : SelectorBase
+    {
+        public static AllSelector Create()
+        {
+            return new AllSelector();
+        }
+
+        private AllSelector() : base(Priority.Zero, "*")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrAvailableSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrAvailableSelector.cs
new file mode 100644
index 000000000..f02aaa37a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrAvailableSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrAvailableSelector : AttrSelectorBase
+    {
+        public AttrAvailableSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrBeginsSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrBeginsSelector.cs
new file mode 100644
index 000000000..92d44e022
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrBeginsSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrBeginsSelector : AttrSelectorBase
+    {
+        public AttrBeginsSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}^={value.StylesheetString()}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrContainsSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrContainsSelector.cs
new file mode 100644
index 000000000..f5131014e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrContainsSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrContainsSelector : AttrSelectorBase
+    {
+        public AttrContainsSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}*={value.StylesheetString()}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrEndsSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrEndsSelector.cs
new file mode 100644
index 000000000..2464bfdc9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrEndsSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrEndsSelector : AttrSelectorBase
+    {
+        public AttrEndsSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}$={value.StylesheetString()}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrHyphenSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrHyphenSelector.cs
new file mode 100644
index 000000000..35f8ccd06
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrHyphenSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrHyphenSelector : AttrSelectorBase
+    {
+        public AttrHyphenSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}|={value.StylesheetString()}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrListSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrListSelector.cs
new file mode 100644
index 000000000..2b1a89131
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrListSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrListSelector : AttrSelectorBase
+    {
+        public AttrListSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}~={value.StylesheetString()}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrMatchSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrMatchSelector.cs
new file mode 100644
index 000000000..9ea5d39b7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrMatchSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrMatchSelector : AttrSelectorBase
+    {
+        public AttrMatchSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}={value.StylesheetString()}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrNotMatchSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrNotMatchSelector.cs
new file mode 100644
index 000000000..85a8cfbf1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrNotMatchSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AttrNotMatchSelector : AttrSelectorBase
+    {
+        public AttrNotMatchSelector(string attribute, string value)
+            : base(attribute, value, $"[{attribute}!={value.StylesheetString()}]")
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrSelectorBase.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrSelectorBase.cs
new file mode 100644
index 000000000..29557eb37
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/AttrSelectorBase.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class AttrSelectorBase : SelectorBase, IAttrSelector
+    {
+        protected AttrSelectorBase(string attribute, string value, string text) : base(Priority.OneClass, text)
+        {
+            Attribute = attribute;
+            Value = value;
+        }
+        public string Attribute { get; }
+        public string Value { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/ChildSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/ChildSelector.cs
new file mode 100644
index 000000000..4e7d74007
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/ChildSelector.cs
@@ -0,0 +1,49 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class ChildSelector : StylesheetNode, ISelector
+    {
+        private readonly string _name;
+        public int Step { get; private set; }
+        public int Offset { get; private set; }
+        internal ISelector Kind { get; private set; }
+
+        protected ChildSelector(string name)
+        {
+            _name = name;
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            var a = Step.ToString();
+
+            string b;
+            if (Offset > 0)
+            {
+                b = "+" + Offset;
+            }
+            else if (Offset < 0)
+            {
+                b = Offset.ToString();
+            }
+            else
+            {
+                b = string.Empty;
+            }
+
+            writer.Write(":{0}({1}n{2})", _name, a, b);
+        }
+
+        public Priority Specificity => Priority.OneClass;
+        public string Text => this.ToCss();
+
+        internal ChildSelector With(int step, int offset, ISelector kind)
+        {
+            Step = step;
+            Offset = offset;
+            Kind = kind;
+            return this;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/ClassSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/ClassSelector.cs
new file mode 100644
index 000000000..c504b78d9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/ClassSelector.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ClassSelector : SelectorBase
+    {
+        private ClassSelector(string name) : base(Priority.OneClass, $".{name}")
+        {
+            Class = name;
+        }
+
+        public string Class { get; }
+
+        public static ClassSelector Create(string name)
+        {
+            return new ClassSelector(name);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/CombinatorSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/CombinatorSelector.cs
new file mode 100644
index 000000000..babda6b2b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/CombinatorSelector.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct CombinatorSelector
+    {
+        public string Delimiter { get; internal set; }
+        public ISelector Selector { get; internal set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/ComplexSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/ComplexSelector.cs
new file mode 100644
index 000000000..1aba835a7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/ComplexSelector.cs
@@ -0,0 +1,80 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ComplexSelector : StylesheetNode, ISelector, IEnumerable<CombinatorSelector>
+    {
+        private readonly List<CombinatorSelector> _selectors;
+
+        public ComplexSelector()
+        {
+            _selectors = new List<CombinatorSelector>();
+        }
+
+        public string Text => this.ToCss();
+        public int Length => _selectors.Count;
+        public bool IsReady { get; private set; }
+
+        public Priority Specificity
+        {
+            get
+            {
+                var sum = new Priority();
+                var n = _selectors.Count;
+
+                for (var i = 0; i < n; i++) sum += _selectors[i].Selector.Specificity;
+
+                return sum;
+            }
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            if (_selectors.Count <= 0) return;
+
+            var n = _selectors.Count - 1;
+
+            for (var i = 0; i < n; i++)
+            {
+                writer.Write(_selectors[i].Selector.Text);
+                writer.Write(_selectors[i].Delimiter);
+            }
+
+            writer.Write(_selectors[n].Selector.Text);
+        }
+
+        public void ConcludeSelector(ISelector selector)
+        {
+            if (IsReady) return;
+
+            _selectors.Add(new CombinatorSelector
+            {
+                Selector = selector,
+                Delimiter = null
+            });
+            IsReady = true;
+        }
+
+        public void AppendSelector(ISelector selector, Combinator combinator)
+        {
+            if (!IsReady)
+                _selectors.Add(new CombinatorSelector
+                {
+                    Selector = combinator.Change(selector),
+                    Delimiter = combinator.Delimiter,
+                });
+        }
+
+        public IEnumerator<CombinatorSelector> GetEnumerator()
+        {
+            return _selectors.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/CompoundSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/CompoundSelector.cs
new file mode 100644
index 000000000..0899786cb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/CompoundSelector.cs
@@ -0,0 +1,12 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class CompoundSelector : Selectors, ISelector
+    {
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            foreach (var selector in _selectors) writer.Write(selector.Text);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstChildSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstChildSelector.cs
new file mode 100644
index 000000000..59fab7cee
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstChildSelector.cs
@@ -0,0 +1,11 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+
+{
+    internal sealed class FirstChildSelector : ChildSelector
+    {
+        public FirstChildSelector()
+            : base(PseudoClassNames.NthChild)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstColumnSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstColumnSelector.cs
new file mode 100644
index 000000000..bdbd93437
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstColumnSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FirstColumnSelector : ChildSelector
+    {
+        public FirstColumnSelector()
+            : base(PseudoClassNames.NthColumn)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstTypeSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstTypeSelector.cs
new file mode 100644
index 000000000..bddedaae5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/FirstTypeSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FirstTypeSelector : ChildSelector
+    {
+        public FirstTypeSelector()
+            : base(PseudoClassNames.NthOfType)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/HasSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/HasSelector.cs
new file mode 100644
index 000000000..19be53893
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/HasSelector.cs
@@ -0,0 +1,33 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The relational pseudo-class ":has(S)" - matches an element that has a descendant matching S.
+    /// v1 only supports the default (descendant) relative-selector form; leading-combinator forms
+    /// like ":has(&gt; S)"/":has(+ S)"/":has(~ S)" are not supported (the parser silently discards a
+    /// leading combinator today - see SelectorConstructor.Insert(ISelector) - and fixing that touches
+    /// shared parsing code well beyond :has() itself, so it's an explicit, documented follow-up).
+    /// </summary>
+    internal sealed class HasSelector : StylesheetNode, ISelector
+    {
+        public HasSelector(ISelector inner)
+        {
+            Inner = inner;
+        }
+
+        public ISelector Inner { get; }
+
+        // Per spec, :has() takes the specificity of its most specific argument, same as :is()/:not().
+        public Priority Specificity => Inner.Specificity;
+
+        public string Text => this.ToCss();
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(":has(");
+            writer.Write(Inner.Text);
+            writer.Write(')');
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/IAttrSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/IAttrSelector.cs
new file mode 100644
index 000000000..86d2fef09
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/IAttrSelector.cs
@@ -0,0 +1,8 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IAttrSelector : ISelector
+    {
+        string Attribute { get; }
+        string Value { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/IdSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/IdSelector.cs
new file mode 100644
index 000000000..bcad28ea2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/IdSelector.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class IdSelector : SelectorBase
+    {
+        private IdSelector(string name) : base(Priority.OneId, $"#{name}")
+        {
+            Id = name;
+        }
+
+        public string Id { get; }
+
+        public static IdSelector Create(string name)
+        {
+            return new IdSelector(name);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/KeyframeSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/KeyframeSelector.cs
new file mode 100644
index 000000000..b947efff4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/KeyframeSelector.cs
@@ -0,0 +1,75 @@
+using System.Collections.Generic;
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class KeyframeSelector : StylesheetNode
+    {
+        private readonly List<Percent> _stops;
+
+        public KeyframeSelector(IEnumerable<Percent> stops)
+        {
+            _stops = new List<Percent>(stops);
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            if (_stops.Count <= 0) return;
+
+            writer.Write(_stops[0].ToString());
+            for (var i = 1; i < _stops.Count; i++)
+            {
+                writer.Write(", ");
+                writer.Write(_stops[i].ToString());
+            }
+        }
+
+        public IEnumerable<Percent> Stops => _stops;
+        public string Text => this.ToCss();
+    }
+
+    /// <summary>
+    /// One comma-separated entry of an <c>@page</c> selector list, e.g. the two entries of
+    /// <c>@page chapter1:left, chapter2:left</c> are <c>(Name: "chapter1", Pseudo: "left")</c> and
+    /// <c>(Name: "chapter2", Pseudo: "left")</c>. Either part may be absent: <c>@page chapter</c> has
+    /// <c>Pseudo: null</c>; <c>@page :first</c> has <c>Name: null</c>.
+    /// </summary>
+    internal readonly struct PageSelectorEntry
+    {
+        public PageSelectorEntry(string name, string pseudo)
+        {
+            Name = name;
+            Pseudo = pseudo;
+        }
+
+        public string Name { get; }
+        public string Pseudo { get; }
+    }
+
+    internal sealed class PageSelector : StylesheetNode, ISelector
+    {
+        private readonly List<PageSelectorEntry> _entries;
+
+        public PageSelector(IEnumerable<PageSelectorEntry> entries)
+        {
+            _entries = new List<PageSelectorEntry>(entries);
+        }
+
+        public IReadOnlyList<PageSelectorEntry> Entries => _entries;
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            for (var i = 0; i < _entries.Count; i++)
+            {
+                if (i > 0) writer.Write(", ");
+
+                var entry = _entries[i];
+                if (entry.Name != null) writer.Write(entry.Name);
+                if (entry.Pseudo != null) writer.Write($":{entry.Pseudo}");
+            }
+        }
+
+        public Priority Specificity => Priority.Inline;
+        public string Text => this.ToCss();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/LastChildSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/LastChildSelector.cs
new file mode 100644
index 000000000..759aaa471
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/LastChildSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class LastChildSelector : ChildSelector
+    {
+        public LastChildSelector()
+            : base(PseudoClassNames.NthLastChild)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/LastColumnSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/LastColumnSelector.cs
new file mode 100644
index 000000000..61614a3d8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/LastColumnSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class LastColumnSelector : ChildSelector
+    {
+        public LastColumnSelector()
+            : base(PseudoClassNames.NthLastColumn)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/LastTypeSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/LastTypeSelector.cs
new file mode 100644
index 000000000..d69a469ce
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/LastTypeSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class LastTypeSelector : ChildSelector
+    {
+        public LastTypeSelector()
+            : base(PseudoClassNames.NthLastOfType)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/ListSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/ListSelector.cs
new file mode 100644
index 000000000..d93549ac9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/ListSelector.cs
@@ -0,0 +1,34 @@
+using System.IO;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ListSelector : Selectors, ISelector
+    {
+        public bool IsInvalid { get; internal set; }
+
+        // A comma-separated selector list's specificity is NOT the sum of its alternatives (that's
+        // only correct for a CompoundSelector, whose members all apply to the SAME element at once).
+        // Per spec, when used as the "forgiving selector list" argument to :is()/:not()/:has(), it's
+        // the static max across all alternatives - regardless of which one (if any) actually matches
+        // a given element. When a ListSelector is a style rule's own top-level selector instead
+        // (".a, .b { }"), the spec treats it as shorthand for separate rules, so the specificity that
+        // matters there is whichever ONE alternative matched a given box - that per-match resolution
+        // is handled separately by CssData.GetMatchedSpecificity, which deliberately does not use this
+        // property for that case.
+        public override Priority Specificity =>
+            _selectors.Count == 0 ? Priority.Zero : _selectors.Max(s => s.Specificity);
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            if (_selectors.Count <= 0) return;
+            writer.Write(_selectors[0].Text);
+
+            for (var i = 1; i < _selectors.Count; i++)
+            {
+                writer.Write(Symbols.Comma);
+                writer.Write(_selectors[i].Text);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/MatchesSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/MatchesSelector.cs
new file mode 100644
index 000000000..fe5403c58
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/MatchesSelector.cs
@@ -0,0 +1,43 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The ":matches(S)"/":is(S)"/":where(S)" pseudo-class - matches an element that matches ANY
+    /// selector in S. All three keywords share this same class (":is()" is the modern name,
+    /// ":matches()" the legacy alias, ":where()" the zero-specificity variant); <see cref="Keyword"/>
+    /// controls how it round-trips back to CSS text and, for ":where()", drops its specificity to zero.
+    /// </summary>
+    internal sealed class MatchesSelector : StylesheetNode, ISelector
+    {
+        public MatchesSelector(ISelector inner, string keyword)
+        {
+            Inner = inner;
+            Keyword = keyword;
+        }
+
+        public ISelector Inner { get; }
+
+        public string Keyword { get; }
+
+        // Per CSS Selectors 4 §16: :is()/:matches() take the specificity of their most specific
+        // argument (the static max, via ListSelector's own Specificity, when Inner is a
+        // comma-separated list), while :where() always contributes zero specificity - this is what
+        // lets a utility-framework reset authored in :where(...) be overridden by any real selector.
+        public Priority Specificity =>
+            string.Equals(Keyword, PseudoClassNames.Where, System.StringComparison.OrdinalIgnoreCase)
+                ? Priority.Zero
+                : Inner.Specificity;
+
+        public string Text => this.ToCss();
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(':');
+            writer.Write(Keyword);
+            writer.Write('(');
+            writer.Write(Inner.Text);
+            writer.Write(')');
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/NamespaceSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/NamespaceSelector.cs
new file mode 100644
index 000000000..0af365d3f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/NamespaceSelector.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class NamespaceSelector : SelectorBase
+    {
+        private NamespaceSelector(string prefix) : base(Priority.Zero, prefix)
+        {
+        }
+
+        public static NamespaceSelector Create(string prefix)
+        {
+            return new NamespaceSelector(prefix);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/NotSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/NotSelector.cs
new file mode 100644
index 000000000..551558773
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/NotSelector.cs
@@ -0,0 +1,30 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The negation pseudo-class ":not(S)" - matches an element that does NOT match S.
+    /// </summary>
+    internal sealed class NotSelector : StylesheetNode, ISelector
+    {
+        public NotSelector(ISelector inner)
+        {
+            Inner = inner;
+        }
+
+        public ISelector Inner { get; }
+
+        // Per spec, :not() takes the specificity of its argument (the most specific selector in a
+        // comma-separated argument, via ListSelector's own static-max Specificity).
+        public Priority Specificity => Inner.Specificity;
+
+        public string Text => this.ToCss();
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(":not(");
+            writer.Write(Inner.Text);
+            writer.Write(')');
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/OnlyChildSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/OnlyChildSelector.cs
new file mode 100644
index 000000000..acf99e8a1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/OnlyChildSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OnlyChildSelector : SelectorBase
+    {
+        public OnlyChildSelector()
+            : base(Priority.OneClass, $"{PseudoClassNames.Separator}{PseudoClassNames.OnlyChild}")
+        {
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/OnlyOfTypeSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/OnlyOfTypeSelector.cs
new file mode 100644
index 000000000..d1ed238b8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/OnlyOfTypeSelector.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OnlyOfTypeSelector : SelectorBase
+    {
+        public OnlyOfTypeSelector()
+            : base(Priority.OneClass, $"{PseudoClassNames.Separator}{PseudoClassNames.OnlyType}")
+        {
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/PseudoClassSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/PseudoClassSelector.cs
new file mode 100644
index 000000000..22ee85682
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/PseudoClassSelector.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PseudoClassSelector : SelectorBase
+    {
+        private PseudoClassSelector(string name) : base(Priority.OneClass, $"{PseudoClassNames.Separator}{name}")
+        {
+            Class = name;
+        }
+
+        public string Class { get; }
+
+        public static ISelector Create(string name)
+        {
+            return new PseudoClassSelector(name);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/PseudoElementSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/PseudoElementSelector.cs
new file mode 100644
index 000000000..07e7393d2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/PseudoElementSelector.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PseudoElementSelector : SelectorBase
+    {
+        private PseudoElementSelector(string name) : base(Priority.OneTag, $"{PseudoElementNames.Separator}{name}")
+        {
+            Name = name;
+        }
+
+        public string Name { get; }
+
+        public static ISelector Create(string name)
+        {
+            return new PseudoElementSelector(name);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/SelectorBase.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/SelectorBase.cs
new file mode 100644
index 000000000..0977d9d88
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/SelectorBase.cs
@@ -0,0 +1,21 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class SelectorBase : StylesheetNode, ISelector
+    {
+        protected SelectorBase(Priority specificity, string text)
+        {
+            Specificity = specificity;
+            Text = text;
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(Text);
+        }
+
+        public Priority Specificity { get; }
+        public string Text { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/Selectors.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/Selectors.cs
new file mode 100644
index 000000000..6010b032c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/Selectors.cs
@@ -0,0 +1,55 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class Selectors : StylesheetNode, IEnumerable<ISelector>
+    {
+        protected readonly List<ISelector> _selectors;
+
+        protected Selectors()
+        {
+            _selectors = new List<ISelector>();
+        }
+
+        public virtual Priority Specificity
+        {
+            get
+            {
+                var sum = new Priority();
+
+                return _selectors.Aggregate(sum, (current, t) => current + t.Specificity);
+            }
+        }
+
+        public string Text => this.ToCss();
+        public int Length => _selectors.Count;
+
+        public ISelector this[int index]
+        {
+            get => _selectors[index];
+            set => _selectors[index] = value;
+        }
+
+        public void Add(ISelector selector)
+        {
+            _selectors.Add(selector);
+        }
+
+        public void Remove(ISelector selector)
+        {
+            _selectors.Remove(selector);
+        }
+
+        public IEnumerator<ISelector> GetEnumerator()
+        {
+            return _selectors.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/TypeSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/TypeSelector.cs
new file mode 100644
index 000000000..22876e62a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/TypeSelector.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TypeSelector : SelectorBase
+    {
+        private TypeSelector(string name) : base(Priority.OneTag, name)
+        {
+            Name = name;
+        }
+
+        public string Name { get; }
+
+        public static TypeSelector Create(string name)
+        {
+            return new TypeSelector(name);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Selectors/UnknownSelector.cs b/Source/HtmlRenderer/Core/CssEngine/Selectors/UnknownSelector.cs
new file mode 100644
index 000000000..148e31983
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Selectors/UnknownSelector.cs
@@ -0,0 +1,16 @@
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnknownSelector : StylesheetNode, ISelector
+    {
+        public Priority Specificity => Priority.Zero;
+
+        public string Text => this.ToCss();
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(StylesheetText?.Text);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDelayProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDelayProperty.cs
new file mode 100644
index 000000000..e479c3fee
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDelayProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationDelayProperty : Property
+    {
+        private static readonly IValueConverter
+            ListConverter = Converters.TimeConverter.FromList().OrDefault(Time.Zero);
+
+        internal AnimationDelayProperty()
+            : base(PropertyNames.AnimationDelay)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDirectionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDirectionProperty.cs
new file mode 100644
index 000000000..efa54f187
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDirectionProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationDirectionProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.AnimationDirectionConverter.FromList().OrDefault(AnimationDirection.Normal);
+
+        internal AnimationDirectionProperty()
+            : base(PropertyNames.AnimationDirection)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDurationProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDurationProperty.cs
new file mode 100644
index 000000000..bd7d8383d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationDurationProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationDurationProperty : Property
+    {
+        private static readonly IValueConverter
+            ListConverter = Converters.TimeConverter.FromList().OrDefault(Time.Zero);
+
+        internal AnimationDurationProperty() : base(PropertyNames.AnimationDuration)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationFillModeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationFillModeProperty.cs
new file mode 100644
index 000000000..50fc30df6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationFillModeProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationFillModeProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.AnimationFillStyleConverter.FromList().OrDefault(AnimationFillStyle.None);
+
+        internal AnimationFillModeProperty()
+            : base(PropertyNames.AnimationFillMode)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationIterationCountProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationIterationCountProperty.cs
new file mode 100644
index 000000000..6b7d08236
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationIterationCountProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationIterationCountProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.PositiveOrInfiniteNumberConverter.FromList().OrDefault(1f);
+
+        internal AnimationIterationCountProperty()
+            : base(PropertyNames.AnimationIterationCount)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationNameProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationNameProperty.cs
new file mode 100644
index 000000000..5fad16516
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationNameProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationNameProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.IdentifierConverter.FromList().OrNone().OrDefault();
+
+        internal AnimationNameProperty()
+            : base(PropertyNames.AnimationName)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationPlayStateProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationPlayStateProperty.cs
new file mode 100644
index 000000000..48780bbab
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationPlayStateProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationPlayStateProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.PlayStateConverter.FromList().OrDefault(PlayState.Running);
+
+        internal AnimationPlayStateProperty()
+            : base(PropertyNames.AnimationPlayState)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationProperty.cs
new file mode 100644
index 000000000..3420ad191
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationProperty.cs
@@ -0,0 +1,26 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class AnimationProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter ListConverter = new TimeBasedShorthandConverter(
+            0, // duration index
+            2, // delay index  
+            TimeConverter.Option().For(PropertyNames.AnimationDuration),           // 0
+            TransitionConverter.Option().For(PropertyNames.AnimationTimingFunction), // 1
+            TimeConverter.Option().For(PropertyNames.AnimationDelay),      // 2
+            PositiveOrInfiniteNumberConverter.Option().For(PropertyNames.AnimationIterationCount), // 3
+            AnimationDirectionConverter.Option().For(PropertyNames.AnimationDirection), // 4
+            AnimationFillStyleConverter.Option().For(PropertyNames.AnimationFillMode), // 5
+            PlayStateConverter.Option().For(PropertyNames.AnimationPlayState), // 6
+            IdentifierConverter.Option().For(PropertyNames.AnimationName) // 7
+        ).FromList().OrDefault();
+
+        internal AnimationProperty() : base(PropertyNames.Animation)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationTimingFunctionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationTimingFunctionProperty.cs
new file mode 100644
index 000000000..91a33b2c8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Animation/AnimationTimingFunctionProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnimationTimingFunctionProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.TransitionConverter.FromList().OrDefault(Map.TimingFunctions[Keywords.Ease]);
+
+        internal AnimationTimingFunctionProperty()
+            : base(PropertyNames.AnimationTimingFunction)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundAttachmentProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundAttachmentProperty.cs
new file mode 100644
index 000000000..af47595d0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundAttachmentProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundAttachmentProperty : Property
+    {
+        private static readonly IValueConverter AttachmentConverter =
+            Converters.BackgroundAttachmentConverter.FromList().OrDefault(BackgroundAttachment.Scroll);
+
+        internal BackgroundAttachmentProperty()
+            : base(PropertyNames.BackgroundAttachment)
+        {
+        }
+
+        internal override IValueConverter Converter => AttachmentConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundClipProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundClipProperty.cs
new file mode 100644
index 000000000..5f2374fb0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundClipProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundClipProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.BoxModelConverter.FromList().OrDefault(BoxModel.BorderBox);
+
+        internal BackgroundClipProperty()
+            : base(PropertyNames.BackgroundClip)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundColorProperty.cs
new file mode 100644
index 000000000..e917bcd26
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundColorProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.CurrentColorConverter.OrDefault();
+
+        internal BackgroundColorProperty()
+            : base(PropertyNames.BackgroundColor, PropertyFlags.Hashless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundImageProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundImageProperty.cs
new file mode 100644
index 000000000..97edd558e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundImageProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundImageProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.MultipleImageSourceConverter.OrDefault();
+
+        internal BackgroundImageProperty()
+            : base(PropertyNames.BackgroundImage)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundOriginProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundOriginProperty.cs
new file mode 100644
index 000000000..190933ed7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundOriginProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundOriginProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.BoxModelConverter.FromList().OrDefault(BoxModel.PaddingBox);
+
+        internal BackgroundOriginProperty()
+            : base(PropertyNames.BackgroundOrigin)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundPositionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundPositionProperty.cs
new file mode 100644
index 000000000..e5143f1bb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundPositionProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundPositionProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.PointConverter.FromList().OrDefault(Point.Center);
+
+        internal BackgroundPositionProperty()
+            : base(PropertyNames.BackgroundPosition, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundProperty.cs
new file mode 100644
index 000000000..8eefb71b7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundProperty.cs
@@ -0,0 +1,38 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BackgroundProperty : ShorthandProperty
+    {
+        internal BackgroundProperty()
+            : base(PropertyNames.Background, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+
+        private static readonly IValueConverter NormalLayerConverter = WithAny(
+            OptionalImageSourceConverter.Option().For(PropertyNames.BackgroundImage),
+            WithOrder(
+                PointConverter.Option().For(PropertyNames.BackgroundPosition),
+                BackgroundSizeConverter.StartsWithDelimiter().Option().For(PropertyNames.BackgroundSize)),
+            BackgroundRepeatsConverter.Option().For(PropertyNames.BackgroundRepeat),
+            BackgroundAttachmentConverter.Option().For(PropertyNames.BackgroundAttachment),
+            BoxModelConverter.Option().For(PropertyNames.BackgroundOrigin),
+            BoxModelConverter.Option().For(PropertyNames.BackgroundClip));
+
+        private static readonly IValueConverter FinalLayerConverter = WithAny(
+            OptionalImageSourceConverter.Option().For(PropertyNames.BackgroundImage),
+            WithOrder(
+                PointConverter.Option().For(PropertyNames.BackgroundPosition),
+                BackgroundSizeConverter.StartsWithDelimiter().Option().For(PropertyNames.BackgroundSize)),
+            BackgroundRepeatsConverter.Option().For(PropertyNames.BackgroundRepeat),
+            BackgroundAttachmentConverter.Option().For(PropertyNames.BackgroundAttachment),
+            BoxModelConverter.Option().For(PropertyNames.BackgroundOrigin),
+            BoxModelConverter.Option().For(PropertyNames.BackgroundClip),
+            CurrentColorConverter.Option().For(PropertyNames.BackgroundColor));
+
+        private static readonly IValueConverter StyleConverter =
+            NormalLayerConverter.RequiresEnd(FinalLayerConverter).OrDefault();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundRepeatProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundRepeatProperty.cs
new file mode 100644
index 000000000..fea8d2abf
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundRepeatProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundRepeatProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.BackgroundRepeatsConverter.FromList().OrDefault(BackgroundRepeat.Repeat);
+
+        internal BackgroundRepeatProperty()
+            : base(PropertyNames.BackgroundRepeat)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundSizeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundSizeProperty.cs
new file mode 100644
index 000000000..acf4e9590
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Background/BackgroundSizeProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackgroundSizeProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.BackgroundSizeConverter.FromList().OrDefault();
+
+        internal BackgroundSizeProperty()
+            : base(PropertyNames.BackgroundSize, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomColorProperty.cs
new file mode 100644
index 000000000..6399bc440
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomColorProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBottomColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.CurrentColorConverter.OrDefault(Color.Transparent);
+
+        internal BorderBottomColorProperty()
+            : base(PropertyNames.BorderBottomColor)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomProperty.cs
new file mode 100644
index 000000000..4f0184de8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomProperty.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderBottomProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option().For(PropertyNames.BorderBottomWidth),
+            LineStyleConverter.Option().For(PropertyNames.BorderBottomStyle),
+            CurrentColorConverter.Option().For(PropertyNames.BorderBottomColor)
+        ).OrDefault();
+
+        internal BorderBottomProperty()
+            : base(PropertyNames.BorderBottom, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomStyleProperty.cs
new file mode 100644
index 000000000..fbe356507
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBottomStyleProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.LineStyleConverter.OrDefault(LineStyle.None);
+
+        internal BorderBottomStyleProperty()
+            : base(PropertyNames.BorderBottomStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomWidthProperty.cs
new file mode 100644
index 000000000..3d193444d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderBottomWidthProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBottomWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.OrDefault(Length.Medium);
+
+        internal BorderBottomWidthProperty()
+            : base(PropertyNames.BorderBottomWidth, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderCollapseProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderCollapseProperty.cs
new file mode 100644
index 000000000..57660bf38
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderCollapseProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderCollapseProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.BorderCollapseConverter.OrDefault(true);
+
+        internal BorderCollapseProperty()
+            : base(PropertyNames.BorderCollapse, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderColorProperty.cs
new file mode 100644
index 000000000..296a17069
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderColorProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderColorProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.CurrentColorConverter.Periodic(
+            PropertyNames.BorderTopColor, PropertyNames.BorderRightColor, PropertyNames.BorderBottomColor,
+            PropertyNames.BorderLeftColor).OrDefault();
+
+        internal BorderColorProperty()
+            : base(PropertyNames.BorderColor, PropertyFlags.Hashless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftColorProperty.cs
new file mode 100644
index 000000000..928225cac
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftColorProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderLeftColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.CurrentColorConverter.OrDefault(Color.Transparent);
+
+        internal BorderLeftColorProperty()
+            : base(PropertyNames.BorderLeftColor)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftProperty.cs
new file mode 100644
index 000000000..80c1ca0b6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftProperty.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderLeftProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option().For(PropertyNames.BorderLeftWidth),
+            LineStyleConverter.Option().For(PropertyNames.BorderLeftStyle),
+            CurrentColorConverter.Option().For(PropertyNames.BorderLeftColor)
+        ).OrDefault();
+
+        internal BorderLeftProperty()
+            : base(PropertyNames.BorderLeft, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftStyleProperty.cs
new file mode 100644
index 000000000..9d65bc4f6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderLeftStyleProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.LineStyleConverter.OrDefault(LineStyle.None);
+
+        internal BorderLeftStyleProperty()
+            : base(PropertyNames.BorderLeftStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftWidthProperty.cs
new file mode 100644
index 000000000..063dc64d4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderLeftWidthProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderLeftWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.OrDefault(Length.Medium);
+
+        internal BorderLeftWidthProperty()
+            : base(PropertyNames.BorderLeftWidth, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderProperty.cs
new file mode 100644
index 000000000..4d0bb4939
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderProperty.cs
@@ -0,0 +1,26 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option()
+                .For(PropertyNames.BorderTopWidth, PropertyNames.BorderRightWidth, PropertyNames.BorderBottomWidth,
+                    PropertyNames.BorderLeftWidth),
+            LineStyleConverter.Option()
+                .For(PropertyNames.BorderTopStyle, PropertyNames.BorderRightStyle, PropertyNames.BorderBottomStyle,
+                    PropertyNames.BorderLeftStyle),
+            CurrentColorConverter.Option()
+                .For(PropertyNames.BorderTopColor, PropertyNames.BorderRightColor, PropertyNames.BorderBottomColor,
+                    PropertyNames.BorderLeftColor)
+        ).OrDefault();
+
+        internal BorderProperty()
+            : base(PropertyNames.Border, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightColorProperty.cs
new file mode 100644
index 000000000..bee6b51d3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightColorProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderRightColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.CurrentColorConverter.OrDefault(Color.Transparent);
+
+        internal BorderRightColorProperty()
+            : base(PropertyNames.BorderRightColor)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightProperty.cs
new file mode 100644
index 000000000..52ac87006
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightProperty.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderRightProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option().For(PropertyNames.BorderRightWidth),
+            LineStyleConverter.Option().For(PropertyNames.BorderRightStyle),
+            CurrentColorConverter.Option().For(PropertyNames.BorderRightColor)
+        ).OrDefault();
+
+        internal BorderRightProperty()
+            : base(PropertyNames.BorderRight, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightStyleProperty.cs
new file mode 100644
index 000000000..bf131e8a0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderRightStyleProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.LineStyleConverter.OrDefault(LineStyle.None);
+
+        internal BorderRightStyleProperty()
+            : base(PropertyNames.BorderRightStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightWidthProperty.cs
new file mode 100644
index 000000000..d41efd9ec
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderRightWidthProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderRightWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.OrDefault(Length.Medium);
+
+        internal BorderRightWidthProperty()
+            : base(PropertyNames.BorderRightWidth, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderSpacingProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderSpacingProperty.cs
new file mode 100644
index 000000000..d5e3a43cb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderSpacingProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderSpacingProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthConverter.Many(1, 2).OrDefault(Length.Zero);
+
+        internal BorderSpacingProperty()
+            : base(PropertyNames.BorderSpacing, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderStyleProperty.cs
new file mode 100644
index 000000000..9a4b8b0ca
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderStyleProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderStyleProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineStyleConverter.Periodic(
+            PropertyNames.BorderTopStyle, PropertyNames.BorderRightStyle, PropertyNames.BorderBottomStyle,
+            PropertyNames.BorderLeftStyle).OrDefault();
+
+        internal BorderStyleProperty()
+            : base(PropertyNames.BorderStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopColorProperty.cs
new file mode 100644
index 000000000..d1ba21c37
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopColorProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderTopColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.CurrentColorConverter.OrDefault(Color.Transparent);
+
+        internal BorderTopColorProperty()
+            : base(PropertyNames.BorderTopColor)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopProperty.cs
new file mode 100644
index 000000000..b6bcb64a1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopProperty.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderTopProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option().For(PropertyNames.BorderTopWidth),
+            LineStyleConverter.Option().For(PropertyNames.BorderTopStyle),
+            CurrentColorConverter.Option().For(PropertyNames.BorderTopColor)
+        ).OrDefault();
+
+        internal BorderTopProperty()
+            : base(PropertyNames.BorderTop, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopStyleProperty.cs
new file mode 100644
index 000000000..969fcec4d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderTopStyleProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.LineStyleConverter.OrDefault(LineStyle.None);
+
+        internal BorderTopStyleProperty()
+            : base(PropertyNames.BorderTopStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopWidthProperty.cs
new file mode 100644
index 000000000..a4c07c8f7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderTopWidthProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderTopWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.OrDefault(Length.Medium);
+
+        internal BorderTopWidthProperty()
+            : base(PropertyNames.BorderTopWidth, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderWidthProperty.cs
new file mode 100644
index 000000000..da799aeeb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Border/BorderWidthProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderWidthProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.Periodic(
+            PropertyNames.BorderTopWidth, PropertyNames.BorderRightWidth, PropertyNames.BorderBottomWidth,
+            PropertyNames.BorderLeftWidth).OrDefault();
+
+        internal BorderWidthProperty()
+            : base(PropertyNames.BorderWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageOutsetProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageOutsetProperty.cs
new file mode 100644
index 000000000..8a7749d42
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageOutsetProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderImageOutsetProperty : Property
+    {
+        internal static readonly IValueConverter TheConverter = Converters.LengthOrPercentConverter.Periodic();
+        private static readonly IValueConverter StyleConverter = TheConverter.OrDefault(Length.Zero);
+
+        internal BorderImageOutsetProperty()
+            : base(PropertyNames.BorderImageOutset)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageProperty.cs
new file mode 100644
index 000000000..ad42d7e41
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageProperty.cs
@@ -0,0 +1,26 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderImageProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter ImageConverter = WithAny(
+            OptionalImageSourceConverter.Option().For(PropertyNames.BorderImageSource),
+            WithOrder(
+                BorderImageSliceProperty.TheConverter.Option().For(PropertyNames.BorderImageSlice),
+                BorderImageWidthProperty.TheConverter.StartsWithDelimiter()
+                    .Option()
+                    .For(PropertyNames.BorderImageWidth),
+                BorderImageOutsetProperty.TheConverter.StartsWithDelimiter()
+                    .Option()
+                    .For(PropertyNames.BorderImageOutset)),
+            BorderImageRepeatProperty.TheConverter.Option().For(PropertyNames.BorderImageRepeat)).OrDefault();
+
+        internal BorderImageProperty()
+            : base(PropertyNames.BorderImage)
+        {
+        }
+
+        internal override IValueConverter Converter => ImageConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageRepeatProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageRepeatProperty.cs
new file mode 100644
index 000000000..bbbc564fa
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageRepeatProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderImageRepeatProperty : Property
+    {
+        internal static readonly IValueConverter TheConverter = Map.BorderRepeatModes.ToConverter().Many(1, 2);
+        private static readonly IValueConverter StyleConverter = TheConverter.OrDefault(BorderRepeat.Stretch);
+
+        internal BorderImageRepeatProperty()
+            : base(PropertyNames.BorderImageRepeat)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageSliceProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageSliceProperty.cs
new file mode 100644
index 000000000..ae2dac22d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageSliceProperty.cs
@@ -0,0 +1,23 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderImageSliceProperty : Property
+    {
+        internal static readonly IValueConverter TheConverter = WithAny(
+            BorderSliceConverter.Option(new Length(100f, Length.Unit.Percent)),
+            BorderSliceConverter.Option(),
+            BorderSliceConverter.Option(),
+            BorderSliceConverter.Option(),
+            Assign(Keywords.Fill, true).Option(false));
+
+        private static readonly IValueConverter StyleConverter = TheConverter.OrDefault(Length.Full);
+
+        internal BorderImageSliceProperty()
+            : base(PropertyNames.BorderImageSlice)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageSourceProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageSourceProperty.cs
new file mode 100644
index 000000000..30f7fccea
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageSourceProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderImageSourceProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalImageSourceConverter.OrDefault();
+
+        internal BorderImageSourceProperty()
+            : base(PropertyNames.BorderImageSource)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageWidthProperty.cs
new file mode 100644
index 000000000..d3af1a07c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderImage/BorderImageWidthProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderImageWidthProperty : Property
+    {
+        internal static readonly IValueConverter TheConverter = Converters.ImageBorderWidthConverter.Periodic();
+        private static readonly IValueConverter StyleConverter = TheConverter.OrDefault(Length.Full);
+
+        internal BorderImageWidthProperty()
+            : base(PropertyNames.BorderImageWidth)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderBottomLeftRadiusProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderBottomLeftRadiusProperty.cs
new file mode 100644
index 000000000..119dbfaa6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderBottomLeftRadiusProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBottomLeftRadiusProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.BorderRadiusConverter.OrDefault(Length.Zero);
+
+        internal BorderBottomLeftRadiusProperty()
+            : base(PropertyNames.BorderBottomLeftRadius, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderBottomRightRadiusProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderBottomRightRadiusProperty.cs
new file mode 100644
index 000000000..df08fb2ad
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderBottomRightRadiusProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBottomRightRadiusProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.BorderRadiusConverter.OrDefault(Length.Zero);
+
+        internal BorderBottomRightRadiusProperty()
+            : base(PropertyNames.BorderBottomRightRadius, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderRadiusProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderRadiusProperty.cs
new file mode 100644
index 000000000..89f6f75cb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderRadiusProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderRadiusProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.BorderRadiusShorthandConverter.OrDefault();
+
+        internal BorderRadiusProperty()
+            : base(PropertyNames.BorderRadius, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderTopLeftRadiusProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderTopLeftRadiusProperty.cs
new file mode 100644
index 000000000..979d76090
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderTopLeftRadiusProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderTopLeftRadiusProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.BorderRadiusConverter.OrDefault(Length.Zero);
+
+        internal BorderTopLeftRadiusProperty()
+            : base(PropertyNames.BorderTopLeftRadius, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderTopRightRadiusProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderTopRightRadiusProperty.cs
new file mode 100644
index 000000000..e671ff146
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/BorderRadius/BorderTopRightRadiusProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderTopRightRadiusProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.BorderRadiusConverter.OrDefault(Length.Zero);
+
+        internal BorderTopRightRadiusProperty()
+            : base(PropertyNames.BorderTopRightRadius, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/AspectRatioProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/AspectRatioProperty.cs
new file mode 100644
index 000000000..7e0cb5e87
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/AspectRatioProperty.cs
@@ -0,0 +1,19 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>aspect-ratio</c> property (CSS Box Sizing Level 4). The value is validated by the shared
+    /// <see cref="AspectRatioGrammar"/> and the authored text preserved for the layout engine, which computes
+    /// an auto dimension from the definite one.
+    /// </summary>
+    internal sealed class AspectRatioProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new AspectRatioValueConverter().OrDefault();
+
+        internal AspectRatioProperty()
+            : base(PropertyNames.AspectRatio)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxDecorationBreak.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxDecorationBreak.cs
new file mode 100644
index 000000000..ac37e846e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxDecorationBreak.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BoxDecorationBreak : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.BoxDecorationConverter.OrDefault(false);
+
+        internal BoxDecorationBreak()
+            : base(PropertyNames.BoxDecorationBreak)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxShadowProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxShadowProperty.cs
new file mode 100644
index 000000000..6e3c2d7e9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxShadowProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BoxShadowProperty : Property
+    {
+        // The box-shadow grammar (none | [ inset? && <length>{2,4} && <color>? ]#) is validated once by
+        // the shared BoxShadowGrammar via BoxShadowValueConverter; the authored text is preserved so the
+        // paint-time resolver (CssBox.PaintBoxShadows) sees exactly what was written.
+        private static readonly IValueConverter StyleConverter = new BoxShadowValueConverter().OrDefault();
+
+        internal BoxShadowProperty()
+            : base(PropertyNames.BoxShadow, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxSizingProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxSizingProperty.cs
new file mode 100644
index 000000000..d6e4e8683
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/BoxSizingProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal class BoxSizingProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.BoxSizingConverter.OrDefault(Keywords.ContentBox);
+
+        public BoxSizingProperty()
+            : base(PropertyNames.BoxSizing, PropertyFlags.None)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginBottomProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginBottomProperty.cs
new file mode 100644
index 000000000..31edc442c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginBottomProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginBottomProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal MarginBottomProperty()
+            : base(PropertyNames.MarginBottom, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginLeftProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginLeftProperty.cs
new file mode 100644
index 000000000..b6c28d519
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginLeftProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginLeftProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal MarginLeftProperty()
+            : base(PropertyNames.MarginLeft, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginProperty.cs
new file mode 100644
index 000000000..b09616b81
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AutoLengthOrPercentConverter.Periodic(
+                PropertyNames.MarginTop, PropertyNames.MarginRight, PropertyNames.MarginBottom,
+                PropertyNames.MarginLeft)
+            .OrDefault(Length.Zero);
+
+        internal MarginProperty()
+            : base(PropertyNames.Margin)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginRightProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginRightProperty.cs
new file mode 100644
index 000000000..36abfd68c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginRightProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginRightProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal MarginRightProperty()
+            : base(PropertyNames.MarginRight, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginTopProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginTopProperty.cs
new file mode 100644
index 000000000..d246f4fbe
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/MarginTopProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginTopProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal MarginTopProperty()
+            : base(PropertyNames.MarginTop, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingBottomProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingBottomProperty.cs
new file mode 100644
index 000000000..1282b8321
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingBottomProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PaddingBottomProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal PaddingBottomProperty()
+            : base(PropertyNames.PaddingBottom, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingLeftProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingLeftProperty.cs
new file mode 100644
index 000000000..1f8eae9de
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingLeftProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PaddingLeftProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal PaddingLeftProperty()
+            : base(PropertyNames.PaddingLeft, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingProperty.cs
new file mode 100644
index 000000000..ebee727a7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PaddingProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LengthOrPercentConverter.Periodic(
+                PropertyNames.PaddingTop, PropertyNames.PaddingRight, PropertyNames.PaddingBottom,
+                PropertyNames.PaddingLeft)
+            .OrDefault(Length.Zero);
+
+        internal PaddingProperty()
+            : base(PropertyNames.Padding)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingRightProperty .cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingRightProperty .cs
new file mode 100644
index 000000000..ec56be2c1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingRightProperty .cs	
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PaddingRightProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal PaddingRightProperty()
+            : base(PropertyNames.PaddingRight, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingTopProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingTopProperty.cs
new file mode 100644
index 000000000..67bf806a0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Box/PaddingTopProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PaddingTopProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal PaddingTopProperty()
+            : base(PropertyNames.PaddingTop, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakAfterProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakAfterProperty.cs
new file mode 100644
index 000000000..4e1a08c76
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakAfterProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BreakAfterProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.BreakModeConverter.OrDefault(BreakMode.Auto);
+
+        internal BreakAfterProperty()
+            : base(PropertyNames.BreakAfter)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakBeforeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakBeforeProperty.cs
new file mode 100644
index 000000000..6dcfaf82c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakBeforeProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BreakBeforeProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.BreakModeConverter.OrDefault(BreakMode.Auto);
+
+        internal BreakBeforeProperty()
+            : base(PropertyNames.BreakBefore)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakInsideProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakInsideProperty.cs
new file mode 100644
index 000000000..7e70a2376
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/BreakInsideProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BreakInsideProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.BreakInsideModeConverter.OrDefault(BreakMode.Auto);
+
+        internal BreakInsideProperty()
+            : base(PropertyNames.BreakInside)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakAfterProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakAfterProperty.cs
new file mode 100644
index 000000000..dce593486
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakAfterProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PageBreakAfterProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.PageBreakModeConverter.OrDefault(BreakMode.Auto);
+
+        internal PageBreakAfterProperty()
+            : base(PropertyNames.PageBreakAfter)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakBeforeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakBeforeProperty.cs
new file mode 100644
index 000000000..ee93e893d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakBeforeProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PageBreakBeforeProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.PageBreakModeConverter.OrDefault(BreakMode.Auto);
+
+        internal PageBreakBeforeProperty()
+            : base(PropertyNames.PageBreakBefore)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakInsideProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakInsideProperty.cs
new file mode 100644
index 000000000..bd62f3478
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Break/PageBreakInsideProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PageBreakInsideProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.Assign(Keywords.Auto, BreakMode.Auto)
+                .Or(Keywords.Avoid, BreakMode.Avoid)
+                .OrDefault(BreakMode.Auto);
+
+        internal PageBreakInsideProperty()
+            : base(PropertyNames.PageBreakInside)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CaptionSideProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CaptionSideProperty.cs
new file mode 100644
index 000000000..6d28eff76
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CaptionSideProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class CaptionSideProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.CaptionSideConverter.OrDefault(true);
+
+        internal CaptionSideProperty() : base(PropertyNames.CaptionSide)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnCountProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnCountProperty.cs
new file mode 100644
index 000000000..cb77493fa
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnCountProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnCountProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalIntegerConverter.OrDefault();
+
+        internal ColumnCountProperty()
+            : base(PropertyNames.ColumnCount, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnFillProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnFillProperty.cs
new file mode 100644
index 000000000..77dcafb57
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnFillProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnFillProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.ColumnFillConverter.OrDefault(true);
+
+        internal ColumnFillProperty()
+            : base(PropertyNames.ColumnFill)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnGapProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnGapProperty.cs
new file mode 100644
index 000000000..b4fc95832
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnGapProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnGapProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter
+                      .OrGlobalValue()
+                      .OrDefault(new Length(1f, Length.Unit.Em));
+
+        internal ColumnGapProperty()
+            : base(PropertyNames.ColumnGap, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleColorProperty.cs
new file mode 100644
index 000000000..3773f1a24
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleColorProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnRuleColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.ColorConverter.OrDefault(Color.Transparent);
+
+        internal ColumnRuleColorProperty()
+            : base(PropertyNames.ColumnRuleColor, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleProperty.cs
new file mode 100644
index 000000000..c16bbc7dd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleProperty.cs
@@ -0,0 +1,19 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class ColumnRuleProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            ColorConverter.Option().For(PropertyNames.ColumnRuleColor),
+            LineWidthConverter.Option().For(PropertyNames.ColumnRuleWidth),
+            LineStyleConverter.Option().For(PropertyNames.ColumnRuleStyle)).OrDefault();
+
+        internal ColumnRuleProperty()
+            : base(PropertyNames.ColumnRule, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleStyleProperty.cs
new file mode 100644
index 000000000..7a2ab2389
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnRuleStyleProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.LineStyleConverter.OrDefault(LineStyle.None);
+
+        internal ColumnRuleStyleProperty()
+            : base(PropertyNames.ColumnRuleStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleWidthProperty.cs
new file mode 100644
index 000000000..c0df4990b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnRuleWidthProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnRuleWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.OrDefault(Length.Medium);
+
+        internal ColumnRuleWidthProperty()
+            : base(PropertyNames.ColumnRuleWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnSpanProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnSpanProperty.cs
new file mode 100644
index 000000000..6595dc330
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnSpanProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnSpanProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.ColumnSpanConverter.OrDefault(false);
+
+        internal ColumnSpanProperty()
+            : base(PropertyNames.ColumnSpan)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnWidthProperty.cs
new file mode 100644
index 000000000..7f1d0045e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnWidthProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColumnWidthProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.AutoLengthConverter.OrDefault(Keywords.Auto);
+
+        internal ColumnWidthProperty()
+            : base(PropertyNames.ColumnWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnsProperty.cs
new file mode 100644
index 000000000..cf90c3d2a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Columns/ColumnsProperty.cs
@@ -0,0 +1,21 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class ColumnsProperty : ShorthandProperty
+    {
+        // columns is order-independent (CSS Multi-column 1 - "<'column-width'> || <'column-count'>"), and
+        // both longhands accept "auto", so a positional match lets column-width claim "auto" and strand the
+        // length in "columns: auto 12em". Match in any order, like list-style.
+        private static readonly IValueConverter StyleConverter = WithAnyOrderIndependent(
+            AutoLengthConverter.Option().For(PropertyNames.ColumnWidth),
+            OptionalIntegerConverter.Option().For(PropertyNames.ColumnCount)).OrDefault();
+
+        internal ColumnsProperty()
+            : base(PropertyNames.Columns, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Container/ContainerNameProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Container/ContainerNameProperty.cs
new file mode 100644
index 000000000..59b01d3b5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Container/ContainerNameProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ContainerNameProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.StringConverter.OrDefault();
+
+        internal ContainerNameProperty()
+            : base(PropertyNames.ContainerName)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Container/ContainerTypeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Container/ContainerTypeProperty.cs
new file mode 100644
index 000000000..dfb812cf7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Container/ContainerTypeProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ContainerTypeProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.ContainerTypeConverter.OrDefault(Keywords.Normal);
+
+        internal ContainerTypeProperty()
+            : base(PropertyNames.ContainerType)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/ContentProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/ContentProperty.cs
new file mode 100644
index 000000000..eb829da0d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/ContentProperty.cs
@@ -0,0 +1,61 @@
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class ContentProperty : Property
+    {
+        internal ContentProperty() : base(PropertyNames.Content)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+
+        private static readonly Dictionary<string, ContentMode> ContentModes =
+            new Dictionary<string, ContentMode>(StringComparer.OrdinalIgnoreCase)
+            {
+                {Keywords.OpenQuote, new OpenQuoteContentMode()},
+                {Keywords.NoOpenQuote, new NoOpenQuoteContentMode()},
+                {Keywords.CloseQuote, new CloseQuoteContentMode()},
+                {Keywords.NoCloseQuote, new NoCloseQuoteContentMode()}
+            };
+
+        private static readonly ContentMode[] Default = new ContentMode[] { new NormalContentMode() };
+
+        private static readonly IValueConverter StyleConverter = Assign(Keywords.Normal, Default).OrNone().Or(
+            ContentModes.ToConverter().Or(
+                UrlConverter).Or(
+                Converters.GradientConverter).Or(
+                StringConverter).Or(
+                AttrConverter).Or(
+                CounterConverter).Or(
+                new ContentFunctionConverter()).Or(
+                new StringFunctionConverter()).Many()).OrDefault();
+
+        private abstract class ContentMode
+        {
+        }
+
+        private sealed class NormalContentMode : ContentMode
+        {
+        }
+
+        private sealed class OpenQuoteContentMode : ContentMode
+        {
+        }
+
+        private sealed class CloseQuoteContentMode : ContentMode
+        {
+        }
+
+        private sealed class NoOpenQuoteContentMode : ContentMode
+        {
+        }
+
+        private sealed class NoCloseQuoteContentMode : ContentMode
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/BottomProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/BottomProperty.cs
new file mode 100644
index 000000000..04ab02138
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/BottomProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BottomProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Keywords.Auto);
+
+        internal BottomProperty()
+            : base(PropertyNames.Bottom, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/HeightProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/HeightProperty.cs
new file mode 100644
index 000000000..877be5e86
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/HeightProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class HeightProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Keywords.Auto);
+
+        internal HeightProperty()
+            : base(PropertyNames.Height, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/LeftProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/LeftProperty.cs
new file mode 100644
index 000000000..3389dcd87
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/LeftProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class LeftProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Keywords.Auto);
+
+        internal LeftProperty()
+            : base(PropertyNames.Left, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MaxHeightProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MaxHeightProperty.cs
new file mode 100644
index 000000000..6c550b831
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MaxHeightProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MaxHeightProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.OptionalLengthOrPercentConverter.OrDefault();
+
+        internal MaxHeightProperty()
+            : base(PropertyNames.MaxHeight, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MaxWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MaxWidthProperty.cs
new file mode 100644
index 000000000..879a758aa
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MaxWidthProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MaxWidthProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.OptionalLengthOrPercentConverter.OrDefault();
+
+        internal MaxWidthProperty()
+            : base(PropertyNames.MaxWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MinHeightProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MinHeightProperty.cs
new file mode 100644
index 000000000..9595ceb28
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MinHeightProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MinHeightProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal MinHeightProperty()
+            : base(PropertyNames.MinHeight, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MinWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MinWidthProperty.cs
new file mode 100644
index 000000000..499ad94a9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/MinWidthProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MinWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal MinWidthProperty()
+            : base(PropertyNames.MinWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/RightProperty .cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/RightProperty .cs
new file mode 100644
index 000000000..c1040ea9d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/RightProperty .cs	
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RightProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Keywords.Auto);
+
+        internal RightProperty()
+            : base(PropertyNames.Right, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/TopProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/TopProperty.cs
new file mode 100644
index 000000000..7df1327a9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/TopProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TopProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Keywords.Auto);
+
+        internal TopProperty()
+            : base(PropertyNames.Top, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/WidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/WidthProperty.cs
new file mode 100644
index 000000000..1bb840a9d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Coordinate/WidthProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class WidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.AutoLengthOrPercentConverter.OrDefault(Keywords.Auto);
+
+        internal WidthProperty()
+            : base(PropertyNames.Width, PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CursorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CursorProperty.cs
new file mode 100644
index 000000000..7601f1d9f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CursorProperty.cs
@@ -0,0 +1,21 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class CursorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = ImageSourceConverter.Or(
+            WithOrder(
+                ImageSourceConverter.Required(),
+                NumberConverter.Required(),
+                NumberConverter.Required())).RequiresEnd(
+            Map.Cursors.ToConverter()).OrDefault(SystemCursor.Auto);
+
+        internal CursorProperty()
+            : base(PropertyNames.Cursor, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CustomProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CustomProperty.cs
new file mode 100644
index 000000000..45cace094
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/CustomProperty.cs
@@ -0,0 +1,12 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class CustomProperty : Property
+    {
+        internal CustomProperty(string name)
+            : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/EmptyCellsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/EmptyCellsProperty.cs
new file mode 100644
index 000000000..06198974a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/EmptyCellsProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class EmptyCellsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.EmptyCellsConverter.OrDefault(true);
+
+        internal EmptyCellsProperty()
+            : base(PropertyNames.EmptyCells, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/FeatureProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/FeatureProperty.cs
new file mode 100644
index 000000000..e85c249d5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/FeatureProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FeatureProperty : Property
+    {
+        internal FeatureProperty(MediaFeature feature)
+            : base(feature.Name)
+        {
+            Feature = feature;
+        }
+
+
+        internal override IValueConverter Converter => Feature.Converter;
+
+        internal MediaFeature Feature { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillOpacityProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillOpacityProperty.cs
new file mode 100644
index 000000000..f81b55ea0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillOpacityProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FillOpacityProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.NumberConverter.OrDefault(1f);
+
+        internal FillOpacityProperty()
+            : base(PropertyNames.FillOpacity, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillProperty.cs
new file mode 100644
index 000000000..7b2f4f766
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FillProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.PaintConverter.OrGlobalValue();
+
+        internal FillProperty()
+            : base(PropertyNames.Fill, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillRuleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillRuleProperty.cs
new file mode 100644
index 000000000..786adfe83
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Fill/FillRuleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FillRuleProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.FillRuleConverter.OrDefault(FillRule.Nonzero);
+
+        public FillRuleProperty()
+            : base(PropertyNames.FillRule, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignContentProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignContentProperty.cs
new file mode 100644
index 000000000..0d460837f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignContentProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AlignContentProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AlignContentConverter;
+
+        internal AlignContentProperty()
+            : base(PropertyNames.AlignContent)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignItemsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignItemsProperty.cs
new file mode 100644
index 000000000..fe5da4bde
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignItemsProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AlignItemsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AlignItemsConverter
+                                                                           .OrDefault(Keywords.Normal);
+
+        internal AlignItemsProperty()
+            : base(PropertyNames.AlignItems)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignSelfProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignSelfProperty.cs
new file mode 100644
index 000000000..72b07664e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/AlignSelfProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AlignSelfProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AlignSelfConverter;
+
+        internal AlignSelfProperty()
+            : base(PropertyNames.AlignSelf)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexBasisProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexBasisProperty.cs
new file mode 100644
index 000000000..83c3649eb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexBasisProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FlexBasisProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FlexBasisConverter;
+
+        internal FlexBasisProperty()
+            : base(PropertyNames.FlexBasis)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexDirectionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexDirectionProperty.cs
new file mode 100644
index 000000000..c9eaaf3f4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexDirectionProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FlexDirectionProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FlexDirectionConverter;
+
+        internal FlexDirectionProperty()
+            : base(PropertyNames.FlexDirection)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexFlowProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexFlowProperty.cs
new file mode 100644
index 000000000..7f763963d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexFlowProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FlexFlowProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FlexFlowConverter;
+
+        internal FlexFlowProperty()
+            : base(PropertyNames.FlexFlow)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexGrowProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexGrowProperty.cs
new file mode 100644
index 000000000..d3196bad1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexGrowProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FlexGrowProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FlexGrowShrinkConverter;
+
+        internal FlexGrowProperty()
+            : base(PropertyNames.FlexGrow)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexProperty.cs
new file mode 100644
index 000000000..e73bc74d9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FlexProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FlexConverter;
+
+        internal FlexProperty()
+            : base(PropertyNames.Flex)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexShrinkProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexShrinkProperty.cs
new file mode 100644
index 000000000..24f234907
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexShrinkProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FlexShrinkProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FlexGrowShrinkConverter;
+
+        internal FlexShrinkProperty()
+            : base(PropertyNames.FlexShrink)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexWrapProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexWrapProperty.cs
new file mode 100644
index 000000000..a9b4e784a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/FlexWrapProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FlexWrapProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FlexWrapConverter;
+
+        internal FlexWrapProperty()
+            : base(PropertyNames.FlexWrap)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/JustifyContentProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/JustifyContentProperty.cs
new file mode 100644
index 000000000..f9aac5930
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/JustifyContentProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class JustifyContentProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.JustifyContentConverter
+                                                                           .OrDefault(Keywords.Normal);
+
+        internal JustifyContentProperty()
+            : base(PropertyNames.JustifyContent)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/OrderProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/OrderProperty.cs
new file mode 100644
index 000000000..e29e2b9a7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flexbox/OrderProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OrderProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.IntegerConverter
+                                                                           .OrGlobalValue()
+                                                                           .OrDefault(0);
+
+        internal OrderProperty()
+            : base(PropertyNames.Order)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/ClearProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/ClearProperty.cs
new file mode 100644
index 000000000..99889bf4d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/ClearProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ClearProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.ClearModeConverter.OrDefault(ClearMode.None);
+
+        internal ClearProperty()
+            : base(PropertyNames.Clear)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/DisplayProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/DisplayProperty.cs
new file mode 100644
index 000000000..8cc7a1a74
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/DisplayProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DisplayProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.DisplayModeConverter.OrDefault(DisplayMode.Inline);
+
+        internal DisplayProperty()
+            : base(PropertyNames.Display)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/FloatProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/FloatProperty.cs
new file mode 100644
index 000000000..691b03c3c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/FloatProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FloatProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.FloatingConverter.OrDefault(Floating.None);
+
+        internal FloatProperty()
+            : base(PropertyNames.Float)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/OverflowProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/OverflowProperty.cs
new file mode 100644
index 000000000..3a260d160
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/OverflowProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OverflowProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.OverflowModeConverter.OrDefault(Overflow.Visible);
+
+        internal OverflowProperty()
+            : base(PropertyNames.Overflow)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/PositionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/PositionProperty.cs
new file mode 100644
index 000000000..04137baf6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/PositionProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PositionProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.PositionModeConverter.OrDefault(PositionMode.Static);
+
+        internal PositionProperty()
+            : base(PropertyNames.Position)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/ZIndexProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/ZIndexProperty.cs
new file mode 100644
index 000000000..384a6790c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Flow/ZIndexProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ZIndexProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalIntegerConverter.OrDefault();
+
+        internal ZIndexProperty()
+            : base(PropertyNames.ZIndex, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/ColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/ColorProperty.cs
new file mode 100644
index 000000000..ebd2d2eea
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/ColorProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.ColorConverter.OrDefault(Color.Black);
+
+        internal ColorProperty()
+            : base(PropertyNames.Color, PropertyFlags.Inherited | PropertyFlags.Hashless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontFamilyProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontFamilyProperty.cs
new file mode 100644
index 000000000..4c73d0173
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontFamilyProperty.cs
@@ -0,0 +1,48 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FontFamilyProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.FontFamiliesConverter.OrDefault("Times New Roman");
+
+        internal FontFamilyProperty()
+            : base(PropertyNames.FontFamily, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+
+        //private enum SystemFonts : byte
+        //{
+        //    /// <summary>
+        //    ///     Glyphs have finishing strokes, flared or tapering ends, or have actual serifed endings.
+        //    ///     E.g.  Palatino, "Palatino Linotype", Palladio, "URW Palladio", serif
+        //    /// </summary>
+        //    Serif,
+
+        //    /// <summary>
+        //    ///     Glyphs have stroke endings that are plain.
+        //    ///     E.g. 'Trebuchet MS', 'Liberation Sans', 'Nimbus Sans L', sans-serif
+        //    /// </summary>
+        //    SansSerif,
+
+        //    /// <summary>
+        //    ///     All glyphs have the same fixed width.
+        //    ///     E.g. "DejaVu Sans Mono", Menlo, Consolas, "Liberation Mono", Monaco, "Lucida Console", monospace
+        //    /// </summary>
+        //    Monospace,
+
+        //    /// <summary>
+        //    ///     Glyphs in cursive fonts generally have either joining strokes or other cursive characteristics
+        //    ///     beyond those of italic typefaces. The glyphs are partially or completely connected, and the
+        //    ///     result looks more like handwritten pen or brush writing than printed letterwork.
+        //    /// </summary>
+        //    Cursive,
+
+        //    /// <summary>
+        //    ///     Fantasy fonts are primarily decorative fonts that contain playful representations of characters.
+        //    /// </summary>
+        //    Fantasy
+        //}
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontPaletteProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontPaletteProperty.cs
new file mode 100644
index 000000000..d358f75ab
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontPaletteProperty.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>font-palette</c> property (CSS Fonts Module Level 4): selects a color palette for a COLR/CPAL
+    /// color font. Inherited. The value grammar (<c>normal | light | dark | &lt;dashed-ident&gt; | palette-mix()</c>)
+    /// is validated by <see cref="FontPaletteValueConverter"/>; the authored text is preserved for the paint-time
+    /// resolver (<c>CssBoxProperties.ActualFontPalette</c>).
+    /// </summary>
+    internal sealed class FontPaletteProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new FontPaletteValueConverter().OrDefault();
+
+        internal FontPaletteProperty()
+            : base(PropertyNames.FontPalette, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontProperty.cs
new file mode 100644
index 000000000..ef5412bfd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontProperty.cs
@@ -0,0 +1,27 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class FontProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithOrder(
+            WithAny(
+                FontStyleConverter.Option().For(PropertyNames.FontStyle),
+                FontVariantConverter.Option().For(PropertyNames.FontVariant),
+                FontWeightConverter.Or(WeightIntegerConverter).Option().For(PropertyNames.FontWeight),
+                FontStretchConverter.Option().For(PropertyNames.FontStretch)),
+            WithOrder(
+                FontSizeConverter.Required().For(PropertyNames.FontSize),
+                LineHeightConverter.StartsWithDelimiter().Option().For(PropertyNames.LineHeight),
+                FontFamiliesConverter.Required().For(PropertyNames.FontFamily)))
+            .Or(SystemFontConverter)
+            .OrGlobalValue();
+
+        internal FontProperty()
+            : base(PropertyNames.Font, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontSizeAdjustProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontSizeAdjustProperty.cs
new file mode 100644
index 000000000..bd7417b2a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontSizeAdjustProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FontSizeAdjustProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalNumberConverter.OrDefault();
+
+        internal FontSizeAdjustProperty()
+            : base(PropertyNames.FontSizeAdjust, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontSizeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontSizeProperty.cs
new file mode 100644
index 000000000..ff6b61406
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontSizeProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FontSizeProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.FontSizeConverter.OrDefault(FontSize.Medium.ToLength());
+
+        internal FontSizeProperty()
+            : base(PropertyNames.FontSize, PropertyFlags.Inherited | PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontStretchProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontStretchProperty.cs
new file mode 100644
index 000000000..c5bf8f318
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontStretchProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FontStretchProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.FontStretchConverter.OrDefault(FontStretch.Normal);
+
+        internal FontStretchProperty()
+            : base(PropertyNames.FontStretch, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontStyleProperty.cs
new file mode 100644
index 000000000..c9bab1d64
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FontStyleProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.FontStyleConverter.OrDefault(FontStyle.Normal);
+
+        internal FontStyleProperty()
+            : base(PropertyNames.FontStyle, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontVariantProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontVariantProperty.cs
new file mode 100644
index 000000000..e3d01b64b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontVariantProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FontVariantProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.FontVariantConverter.OrDefault(FontVariant.Normal);
+
+        internal FontVariantProperty()
+            : base(PropertyNames.FontVariant, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontWeightProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontWeightProperty.cs
new file mode 100644
index 000000000..7ad4e6d2a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/FontWeightProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class FontWeightProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = FontWeightConverter.Or(
+            WeightIntegerConverter).OrDefault(FontWeight.Normal);
+
+        internal FontWeightProperty()
+            : base(PropertyNames.FontWeight, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/LetterSpacingProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/LetterSpacingProperty.cs
new file mode 100644
index 000000000..fb84e1b24
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/LetterSpacingProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class LetterSpacingProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalLengthConverter.OrDefault();
+
+        internal LetterSpacingProperty()
+            : base(PropertyNames.LetterSpacing, PropertyFlags.Inherited | PropertyFlags.Unitless)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/LineHeightProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/LineHeightProperty.cs
new file mode 100644
index 000000000..88c2d7057
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/LineHeightProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class LineHeightProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LineHeightConverter.OrDefault(new Length(120f, Length.Unit.Percent));
+
+        internal LineHeightProperty()
+            : base(PropertyNames.LineHeight, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/SrcProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/SrcProperty.cs
new file mode 100644
index 000000000..e23d5e39d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/SrcProperty.cs
@@ -0,0 +1,12 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class SrcProperty : Property
+    {
+        public SrcProperty()
+            : base(PropertyNames.Src)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/UnicodeRangeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/UnicodeRangeProperty.cs
new file mode 100644
index 000000000..65b285559
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/UnicodeRangeProperty.cs
@@ -0,0 +1,12 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnicodeRangeProperty : Property
+    {
+        public UnicodeRangeProperty()
+            : base(PropertyNames.UnicodeRange)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/WordSpacingProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/WordSpacingProperty.cs
new file mode 100644
index 000000000..f6fb74a47
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Font/WordSpacingProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class WordSpacingProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalLengthConverter.OrDefault();
+
+        internal WordSpacingProperty()
+            : base(
+                PropertyNames.WordSpacing, PropertyFlags.Inherited | PropertyFlags.Unitless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/GapProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/GapProperty.cs
new file mode 100644
index 000000000..100e0ee9f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/GapProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal class GapProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LengthOrPercentConverter
+                                                                           .OrGlobalValue()
+                                                                           .Periodic(PropertyNames.RowGap, PropertyNames.ColumnGap);
+
+        internal GapProperty()
+            : base(PropertyNames.Gap, PropertyFlags.Animatable)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAreaProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAreaProperty.cs
new file mode 100644
index 000000000..b77b527d5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAreaProperty.cs
@@ -0,0 +1,19 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-area</c> shorthand (CSS Grid §8.3.1): <c>&lt;grid-line&gt; [ / &lt;grid-line&gt; ]{0,3}</c>,
+    /// expanding to <c>grid-row-start</c> / <c>grid-column-start</c> / <c>grid-row-end</c> /
+    /// <c>grid-column-end</c>. The single named-area form is out of v1 scope.
+    /// </summary>
+    internal sealed class GridAreaProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridAreaConverter.OrGlobalValue();
+
+        internal GridAreaProperty()
+            : base(PropertyNames.GridArea)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoColumnsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoColumnsProperty.cs
new file mode 100644
index 000000000..9a6f6105a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoColumnsProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>grid-auto-columns</c> property (CSS Grid §7.6): the size of implicitly-created columns.</summary>
+    internal sealed class GridAutoColumnsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new GridAutoTracksValueConverter().OrDefault();
+
+        internal GridAutoColumnsProperty()
+            : base(PropertyNames.GridAutoColumns)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoFlowProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoFlowProperty.cs
new file mode 100644
index 000000000..da7d1f48f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoFlowProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>grid-auto-flow</c> property (CSS Grid §7.7): the auto-placement direction and packing.</summary>
+    internal sealed class GridAutoFlowProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new GridAutoFlowValueConverter().OrDefault();
+
+        internal GridAutoFlowProperty()
+            : base(PropertyNames.GridAutoFlow)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoRowsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoRowsProperty.cs
new file mode 100644
index 000000000..d558f3a59
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridAutoRowsProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>grid-auto-rows</c> property (CSS Grid §7.6): the size of implicitly-created rows.</summary>
+    internal sealed class GridAutoRowsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new GridAutoTracksValueConverter().OrDefault();
+
+        internal GridAutoRowsProperty()
+            : base(PropertyNames.GridAutoRows)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnEndProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnEndProperty.cs
new file mode 100644
index 000000000..9552efa71
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnEndProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-column-end</c> longhand (CSS Grid §8.3), one edge of a
+    /// grid item's placement. Validated by the shared <see cref="GridLineGrammar"/>.
+    /// </summary>
+    internal sealed class GridColumnEndProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridLineConverter.OrDefault();
+
+        internal GridColumnEndProperty()
+            : base(PropertyNames.GridColumnEnd)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnProperty.cs
new file mode 100644
index 000000000..9a0672ff0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-column</c> shorthand (CSS Grid §8.3.1): <c>&lt;grid-line&gt; [ / &lt;grid-line&gt; ]?</c>,
+    /// expanding to <c>grid-column-start</c> / <c>grid-column-end</c>.
+    /// </summary>
+    internal sealed class GridColumnProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridColumnConverter.OrGlobalValue();
+
+        internal GridColumnProperty()
+            : base(PropertyNames.GridColumn)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnStartProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnStartProperty.cs
new file mode 100644
index 000000000..fee4a1a02
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridColumnStartProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-column-start</c> longhand (CSS Grid §8.3), one edge of a
+    /// grid item's placement. Validated by the shared <see cref="GridLineGrammar"/>.
+    /// </summary>
+    internal sealed class GridColumnStartProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridLineConverter.OrDefault();
+
+        internal GridColumnStartProperty()
+            : base(PropertyNames.GridColumnStart)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridProperty.cs
new file mode 100644
index 000000000..c8b932657
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid</c> shorthand (CSS Grid §7.8): expands to the three <c>grid-template-*</c> longhands plus
+    /// <c>grid-auto-flow</c> / <c>grid-auto-rows</c> / <c>grid-auto-columns</c>.
+    /// </summary>
+    internal sealed class GridProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridConverter.OrGlobalValue();
+
+        internal GridProperty()
+            : base(PropertyNames.Grid)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowEndProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowEndProperty.cs
new file mode 100644
index 000000000..6f3e1986a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowEndProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-row-end</c> longhand (CSS Grid §8.3), one edge of a
+    /// grid item's placement. Validated by the shared <see cref="GridLineGrammar"/>.
+    /// </summary>
+    internal sealed class GridRowEndProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridLineConverter.OrDefault();
+
+        internal GridRowEndProperty()
+            : base(PropertyNames.GridRowEnd)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowProperty.cs
new file mode 100644
index 000000000..55839a80f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-row</c> shorthand (CSS Grid §8.3.1): <c>&lt;grid-line&gt; [ / &lt;grid-line&gt; ]?</c>,
+    /// expanding to <c>grid-row-start</c> / <c>grid-row-end</c>.
+    /// </summary>
+    internal sealed class GridRowProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridRowConverter.OrGlobalValue();
+
+        internal GridRowProperty()
+            : base(PropertyNames.GridRow)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowStartProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowStartProperty.cs
new file mode 100644
index 000000000..6ebbd6256
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridRowStartProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-row-start</c> longhand (CSS Grid §8.3), one edge of a
+    /// grid item's placement. Validated by the shared <see cref="GridLineGrammar"/>.
+    /// </summary>
+    internal sealed class GridRowStartProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridLineConverter.OrDefault();
+
+        internal GridRowStartProperty()
+            : base(PropertyNames.GridRowStart)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateAreasProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateAreasProperty.cs
new file mode 100644
index 000000000..33f1fcf86
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateAreasProperty.cs
@@ -0,0 +1,19 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-template-areas</c> property (CSS Grid §7.3). Validated by the shared
+    /// <see cref="GridTemplateAreasGrammar"/>; the authored text is preserved for the grid layout engine,
+    /// which derives implicit <c>name-start</c>/<c>name-end</c> lines from each named area.
+    /// </summary>
+    internal sealed class GridTemplateAreasProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new GridTemplateAreasValueConverter().OrDefault();
+
+        internal GridTemplateAreasProperty()
+            : base(PropertyNames.GridTemplateAreas)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateColumnsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateColumnsProperty.cs
new file mode 100644
index 000000000..d7e110c79
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateColumnsProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-template-columns</c> property (CSS Grid Layout Module Level 1/2 §7.2). Validated by the
+    /// shared <see cref="GridTrackListGrammar"/>; the authored text is preserved for the grid layout engine.
+    /// </summary>
+    internal sealed class GridTemplateColumnsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new GridTemplateValueConverter().OrDefault();
+
+        internal GridTemplateColumnsProperty()
+            : base(PropertyNames.GridTemplateColumns)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateProperty.cs
new file mode 100644
index 000000000..cea068bdf
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-template</c> shorthand (CSS Grid §7.4): expands to <c>grid-template-rows</c> /
+    /// <c>grid-template-columns</c> / <c>grid-template-areas</c>.
+    /// </summary>
+    internal sealed class GridTemplateProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.GridTemplateConverter.OrGlobalValue();
+
+        internal GridTemplateProperty()
+            : base(PropertyNames.GridTemplate)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateRowsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateRowsProperty.cs
new file mode 100644
index 000000000..754dde2b7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/GridTemplateRowsProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-template-rows</c> property (CSS Grid Layout Module Level 1/2 §7.2). Validated by the
+    /// shared <see cref="GridTrackListGrammar"/>; the authored text is preserved for the grid layout engine.
+    /// </summary>
+    internal sealed class GridTemplateRowsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = new GridTemplateValueConverter().OrDefault();
+
+        internal GridTemplateRowsProperty()
+            : base(PropertyNames.GridTemplateRows)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/JustifyItemsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/JustifyItemsProperty.cs
new file mode 100644
index 000000000..9014a682d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/JustifyItemsProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>justify-items</c> property (CSS Box Alignment): default inline-axis alignment of grid items.</summary>
+    internal sealed class JustifyItemsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.JustifyItemsConverter;
+
+        internal JustifyItemsProperty()
+            : base(PropertyNames.JustifyItems)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/JustifySelfProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/JustifySelfProperty.cs
new file mode 100644
index 000000000..281659998
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/JustifySelfProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>justify-self</c> property (CSS Box Alignment): a grid item's own inline-axis alignment.</summary>
+    internal sealed class JustifySelfProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.JustifySelfConverter;
+
+        internal JustifySelfProperty()
+            : base(PropertyNames.JustifySelf)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceContentProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceContentProperty.cs
new file mode 100644
index 000000000..954b116fe
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceContentProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>place-content</c> shorthand (CSS Box Alignment): <c>&lt;align-content&gt; &lt;justify-content&gt;?</c>.</summary>
+    internal sealed class PlaceContentProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.PlaceContentConverter.OrGlobalValue();
+
+        internal PlaceContentProperty()
+            : base(PropertyNames.PlaceContent)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceItemsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceItemsProperty.cs
new file mode 100644
index 000000000..5ec9dc74c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceItemsProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>place-items</c> shorthand (CSS Box Alignment): <c>&lt;align-items&gt; &lt;justify-items&gt;?</c>.</summary>
+    internal sealed class PlaceItemsProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.PlaceItemsConverter.OrGlobalValue();
+
+        internal PlaceItemsProperty()
+            : base(PropertyNames.PlaceItems)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceSelfProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceSelfProperty.cs
new file mode 100644
index 000000000..149ac0c7c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Grid/PlaceSelfProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>The <c>place-self</c> shorthand (CSS Box Alignment): <c>&lt;align-self&gt; &lt;justify-self&gt;?</c>.</summary>
+    internal sealed class PlaceSelfProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.PlaceSelfConverter.OrGlobalValue();
+
+        internal PlaceSelfProperty()
+            : base(PropertyNames.PlaceSelf)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/HyphensProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/HyphensProperty.cs
new file mode 100644
index 000000000..1d2e57761
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/HyphensProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class HyphensProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.Assign(Keywords.None, Keywords.None)
+                .Or(Keywords.Manual, Keywords.Manual)
+                .Or(Keywords.Auto, Keywords.Auto)
+                .OrDefault(Keywords.Manual);
+
+        internal HyphensProperty()
+            : base(PropertyNames.Hyphens, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IProperties .cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IProperties .cs
new file mode 100644
index 000000000..eb1509277
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IProperties .cs	
@@ -0,0 +1,14 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IProperties : IEnumerable<IProperty>
+    {
+        string this[string propertyName] { get; }
+        int Length { get; }
+        string GetPropertyValue(string propertyName);
+        string GetPropertyPriority(string propertyName);
+        void SetProperty(string propertyName, string propertyValue, string priority = null);
+        string RemoveProperty(string propertyName);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IProperty.cs
new file mode 100644
index 000000000..b73b474d6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IProperty.cs
@@ -0,0 +1,10 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IProperty : IStylesheetNode
+    {
+        string Name { get; }
+        string Value { get; }
+        string Original { get; }
+        bool IsImportant { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IPropertyValue.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IPropertyValue.cs
new file mode 100644
index 000000000..ec9ac30e2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/IPropertyValue.cs
@@ -0,0 +1,41 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IPropertyValue
+    {
+        string CssText { get; }
+        TokenValue Original { get; }
+        TokenValue ExtractFor(string name);
+    }
+
+    /// <summary>
+    /// Implemented by an <see cref="IPropertyValue"/> that carries a <b>parsed</b>, strongly-typed model
+    /// (a <see cref="CssProperty{T}"/>) alongside its text, so the cascade can hand the parsed value straight
+    /// to the box without re-parsing the authored string. The cascade knows the concrete <typeparamref name="T"/>
+    /// from the property name it is applying (its typed setter casts to the matching
+    /// <c>ITypedPropertyValue&lt;T&gt;</c>). Grid templates (<c>T = GridTemplate</c>) are the first adopter.
+    /// </summary>
+    internal interface ITypedPropertyValue<T>
+    {
+        CssProperty<T> GetTypedValue();
+    }
+
+    internal static class PropertyValueExtensions
+    {
+        /// <summary>
+        /// Returns the parsed <see cref="CssProperty{T}"/> this value carries when it is an
+        /// <see cref="ITypedPropertyValue{T}"/> for the requested <typeparamref name="T"/>; otherwise false
+        /// (e.g. a global-keyword value or a value without a typed carrier).
+        /// </summary>
+        public static bool TryGetValue<T>(this IPropertyValue value, out CssProperty<T> typed)
+        {
+            if (value is ITypedPropertyValue<T> carrier)
+            {
+                typed = carrier.GetTypedValue();
+                return true;
+            }
+
+            typed = null;
+            return false;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/CounterIncrementProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/CounterIncrementProperty.cs
new file mode 100644
index 000000000..03d896076
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/CounterIncrementProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class CounterIncrementProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Continuous(
+            WithOrder(IdentifierConverter.Required(), IntegerConverter.Option(1))).OrDefault();
+
+        internal CounterIncrementProperty()
+            : base(PropertyNames.CounterIncrement)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/CounterResetProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/CounterResetProperty.cs
new file mode 100644
index 000000000..a315863e0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/CounterResetProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class CounterResetProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Continuous(
+            WithOrder(IdentifierConverter.Required(), IntegerConverter.Option(0))).OrDefault();
+
+        internal CounterResetProperty()
+            : base(PropertyNames.CounterReset)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleImageProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleImageProperty.cs
new file mode 100644
index 000000000..bdb066284
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleImageProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ListStyleImageProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalImageSourceConverter.OrDefault();
+
+        internal ListStyleImageProperty()
+            : base(PropertyNames.ListStyleImage, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStylePositionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStylePositionProperty.cs
new file mode 100644
index 000000000..ebfe5811f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStylePositionProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ListStylePositionProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.ListPositionConverter.OrDefault(ListPosition.Outside);
+
+        internal ListStylePositionProperty()
+            : base(PropertyNames.ListStylePosition, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleProperty.cs
new file mode 100644
index 000000000..a2039dbf3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleProperty.cs
@@ -0,0 +1,22 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class ListStyleProperty : ShorthandProperty
+    {
+        // list-style's operands are order-independent (CSS Lists 3 - "in any order"), so a token such as
+        // "none" that both list-style-type and list-style-image accept must not be claimed positionally
+        // ("list-style: none square" must parse like "list-style: square none").
+        private static readonly IValueConverter StyleConverter = WithAnyOrderIndependent(
+            ListStyleConverter.Option().For(PropertyNames.ListStyleType),
+            ListPositionConverter.Option().For(PropertyNames.ListStylePosition),
+            OptionalImageSourceConverter.Option().For(PropertyNames.ListStyleImage)).OrDefault();
+
+        internal ListStyleProperty()
+            : base(PropertyNames.ListStyle, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleTypeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleTypeProperty.cs
new file mode 100644
index 000000000..6e73a8585
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/List/ListStyleTypeProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ListStyleTypeProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.ListStyleConverter.OrDefault(ListStyle.Disc);
+
+        internal ListStyleTypeProperty()
+            : base(PropertyNames.ListStyleType, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockColorProperty.cs
new file mode 100644
index 000000000..8c4ce4463
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockColorProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBlockColorProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.CurrentColorConverter.Periodic(
+            PropertyNames.BorderTopColor, PropertyNames.BorderBottomColor).OrDefault();
+
+        internal BorderBlockColorProperty()
+            : base(PropertyNames.BorderBlockColor, PropertyFlags.Hashless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockProperty.cs
new file mode 100644
index 000000000..eedd13847
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockProperty.cs
@@ -0,0 +1,23 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderBlockProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option()
+                .For(PropertyNames.BorderTopWidth, PropertyNames.BorderBottomWidth),
+            LineStyleConverter.Option()
+                .For(PropertyNames.BorderTopStyle, PropertyNames.BorderBottomStyle),
+            CurrentColorConverter.Option()
+                .For(PropertyNames.BorderTopColor, PropertyNames.BorderBottomColor)
+        ).OrDefault();
+
+        internal BorderBlockProperty()
+            : base(PropertyNames.BorderBlock, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockStyleProperty.cs
new file mode 100644
index 000000000..ab14e27a5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBlockStyleProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineStyleConverter.Periodic(
+            PropertyNames.BorderTopStyle, PropertyNames.BorderBottomStyle).OrDefault();
+
+        internal BorderBlockStyleProperty()
+            : base(PropertyNames.BorderBlockStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockWidthProperty.cs
new file mode 100644
index 000000000..37b978e58
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderBlockWidthProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderBlockWidthProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.Periodic(
+            PropertyNames.BorderTopWidth, PropertyNames.BorderBottomWidth).OrDefault();
+
+        internal BorderBlockWidthProperty()
+            : base(PropertyNames.BorderBlockWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineColorProperty.cs
new file mode 100644
index 000000000..8ff8b7dc5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineColorProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderInlineColorProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.CurrentColorConverter.Periodic(
+            PropertyNames.BorderLeftColor, PropertyNames.BorderRightColor).OrDefault();
+
+        internal BorderInlineColorProperty()
+            : base(PropertyNames.BorderInlineColor, PropertyFlags.Hashless | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineProperty.cs
new file mode 100644
index 000000000..c8bfe6d14
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineProperty.cs
@@ -0,0 +1,23 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderInlineProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option()
+                .For(PropertyNames.BorderLeftWidth, PropertyNames.BorderRightWidth),
+            LineStyleConverter.Option()
+                .For(PropertyNames.BorderLeftStyle, PropertyNames.BorderRightStyle),
+            CurrentColorConverter.Option()
+                .For(PropertyNames.BorderLeftColor, PropertyNames.BorderRightColor)
+        ).OrDefault();
+
+        internal BorderInlineProperty()
+            : base(PropertyNames.BorderInline, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineStyleProperty.cs
new file mode 100644
index 000000000..d3b00a08c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderInlineStyleProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineStyleConverter.Periodic(
+            PropertyNames.BorderLeftStyle, PropertyNames.BorderRightStyle).OrDefault();
+
+        internal BorderInlineStyleProperty()
+            : base(PropertyNames.BorderInlineStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineWidthProperty.cs
new file mode 100644
index 000000000..b482f3f9d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/BorderInlineWidthProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BorderInlineWidthProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.Periodic(
+            PropertyNames.BorderLeftWidth, PropertyNames.BorderRightWidth).OrDefault();
+
+        internal BorderInlineWidthProperty()
+            : base(PropertyNames.BorderInlineWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetBlockProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetBlockProperty.cs
new file mode 100644
index 000000000..43ab5835e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetBlockProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class InsetBlockProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AutoLengthOrPercentConverter.Periodic(
+                PropertyNames.Top, PropertyNames.Bottom)
+            .OrDefault(Keywords.Auto);
+
+        internal InsetBlockProperty()
+            : base(PropertyNames.InsetBlock)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetInlineProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetInlineProperty.cs
new file mode 100644
index 000000000..27501ac21
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetInlineProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class InsetInlineProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AutoLengthOrPercentConverter.Periodic(
+                PropertyNames.Left, PropertyNames.Right)
+            .OrDefault(Keywords.Auto);
+
+        internal InsetInlineProperty()
+            : base(PropertyNames.InsetInline)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetProperty.cs
new file mode 100644
index 000000000..f21cc1290
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/InsetProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class InsetProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AutoLengthOrPercentConverter.Periodic(
+                PropertyNames.Top, PropertyNames.Right, PropertyNames.Bottom, PropertyNames.Left)
+            .OrDefault(Keywords.Auto);
+
+        internal InsetProperty()
+            : base(PropertyNames.Inset)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/MarginBlockProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/MarginBlockProperty.cs
new file mode 100644
index 000000000..52b9c5497
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/MarginBlockProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginBlockProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AutoLengthOrPercentConverter.Periodic(
+                PropertyNames.MarginTop, PropertyNames.MarginBottom)
+            .OrDefault(Length.Zero);
+
+        internal MarginBlockProperty()
+            : base(PropertyNames.MarginBlock)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/MarginInlineProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/MarginInlineProperty.cs
new file mode 100644
index 000000000..6d8178815
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/MarginInlineProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MarginInlineProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.AutoLengthOrPercentConverter.Periodic(
+                PropertyNames.MarginLeft, PropertyNames.MarginRight)
+            .OrDefault(Length.Zero);
+
+        internal MarginInlineProperty()
+            : base(PropertyNames.MarginInline)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/PaddingBlockProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/PaddingBlockProperty.cs
new file mode 100644
index 000000000..091d0eed8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/PaddingBlockProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PaddingBlockProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LengthOrPercentConverter.Periodic(
+                PropertyNames.PaddingTop, PropertyNames.PaddingBottom)
+            .OrDefault(Length.Zero);
+
+        internal PaddingBlockProperty()
+            : base(PropertyNames.PaddingBlock)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/PaddingInlineProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/PaddingInlineProperty.cs
new file mode 100644
index 000000000..10e2c2bbc
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Logical/PaddingInlineProperty.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PaddingInlineProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LengthOrPercentConverter.Periodic(
+                PropertyNames.PaddingLeft, PropertyNames.PaddingRight)
+            .OrDefault(Length.Zero);
+
+        internal PaddingInlineProperty()
+            : base(PropertyNames.PaddingInline)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/OrphansProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/OrphansProperty.cs
new file mode 100644
index 000000000..00908c80b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/OrphansProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OrphansProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.NaturalIntegerConverter.OrDefault(2);
+
+        internal OrphansProperty()
+            : base(PropertyNames.Orphans, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineColorProperty.cs
new file mode 100644
index 000000000..d852f9772
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineColorProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OutlineColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.InvertedColorConverter.OrDefault(Color.Transparent);
+
+        internal OutlineColorProperty()
+            : base(PropertyNames.OutlineColor, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineProperty.cs
new file mode 100644
index 000000000..07563ef9d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineProperty.cs
@@ -0,0 +1,19 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class OutlineProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            LineWidthConverter.Option().For(PropertyNames.OutlineWidth),
+            LineStyleConverter.Option().For(PropertyNames.OutlineStyle),
+            InvertedColorConverter.Option().For(PropertyNames.OutlineColor)).OrDefault();
+
+        internal OutlineProperty()
+            : base(PropertyNames.Outline, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineStyleProperty.cs
new file mode 100644
index 000000000..a6a575469
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OutlineStyleProperty : Property
+    {
+        private static readonly IValueConverter
+            StyleConverter = Converters.LineStyleConverter.OrDefault(LineStyle.None);
+
+        internal OutlineStyleProperty()
+            : base(PropertyNames.OutlineStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineWidthProperty.cs
new file mode 100644
index 000000000..8ac3b9fb4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Outline/OutlineWidthProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OutlineWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LineWidthConverter.OrDefault(Length.Medium);
+
+        internal OutlineWidthProperty()
+            : base(PropertyNames.OutlineWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/PageNameProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/PageNameProperty.cs
new file mode 100644
index 000000000..10e5346da
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/PageNameProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class PageNameProperty : Property
+    {
+        internal PageNameProperty() : base(PropertyNames.PageName)
+        {
+        }
+
+        internal override IValueConverter Converter => IdentifierConverter.OrDefault();
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/PageSizeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/PageSizeProperty.cs
new file mode 100644
index 000000000..db022367f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/PageSizeProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class PageSizeProperty : Property
+    {
+        internal PageSizeProperty() : base(PropertyNames.Size)
+        {
+        }
+
+        internal override IValueConverter Converter => IdentifierConverter.Or(LengthConverter).Many(1, 2).OrDefault();
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Property.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Property.cs
new file mode 100644
index 000000000..682611ab3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Property.cs
@@ -0,0 +1,65 @@
+using System.IO;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class Property : StylesheetNode, IProperty
+    {
+        private readonly PropertyFlags _flags;
+
+        internal Property(string name, PropertyFlags flags = PropertyFlags.None)
+        {
+            Name = name;
+            _flags = flags;
+        }
+
+        public override void ToCss(TextWriter writer, IStyleFormatter formatter)
+        {
+            writer.Write(formatter.Declaration(Name, Value, IsImportant));
+        }
+
+
+        internal bool TrySetValue(TokenValue newTokenValue)
+        {
+            var tokenValue = newTokenValue ?? TokenValue.Initial;
+            var converter = tokenValue.ContainsFunction(FunctionNames.Var) ? Converters.Any : Converter;
+            var value = converter.Convert(tokenValue);
+
+            if (value == null) return false;
+            DeclaredValue = value;
+            return true;
+        }
+
+        public string Value => DeclaredValue != null ? DeclaredValue.CssText : Keywords.Initial;
+
+        public string Original => DeclaredValue != null ? DeclaredValue.Original.Text : Keywords.Initial;
+
+        public bool IsInherited => (_flags & PropertyFlags.Inherited) == PropertyFlags.Inherited && IsInitial ||
+                                   DeclaredValue != null && DeclaredValue.CssText.Is(Keywords.Inherit);
+
+        public bool IsAnimatable => (_flags & PropertyFlags.Animatable) == PropertyFlags.Animatable;
+
+        public bool IsInitial => DeclaredValue == null || DeclaredValue.CssText.Is(Keywords.Initial);
+
+        internal bool HasValue => DeclaredValue != null;
+
+        internal bool CanBeHashless => (_flags & PropertyFlags.Hashless) == PropertyFlags.Hashless;
+
+        internal bool CanBeUnitless => (_flags & PropertyFlags.Unitless) == PropertyFlags.Unitless;
+
+        public bool CanBeInherited => (_flags & PropertyFlags.Inherited) == PropertyFlags.Inherited;
+
+        internal bool IsShorthand => (_flags & PropertyFlags.Shorthand) == PropertyFlags.Shorthand;
+
+        public string Name { get; }
+
+        public bool IsImportant { get; set; }
+
+        public string CssText => this.ToCss();
+
+        internal abstract IValueConverter Converter { get; }
+
+        internal IPropertyValue DeclaredValue { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/QuotesProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/QuotesProperty.cs
new file mode 100644
index 000000000..8238000a3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/QuotesProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class QuotesProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.EvenStringsConverter.OrNone().OrDefault(new[] { "«", "»" });
+
+        internal QuotesProperty()
+            : base(PropertyNames.Quotes, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/RowGapProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/RowGapProperty.cs
new file mode 100644
index 000000000..c7c7929fa
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/RowGapProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RowGapProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LengthOrPercentConverter
+                                                                           .OrGlobalValue()
+                                                                           .OrDefault(0);
+
+        internal RowGapProperty()
+            : base(PropertyNames.RowGap, PropertyFlags.Animatable)
+        { }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/ShorthandProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/ShorthandProperty.cs
new file mode 100644
index 000000000..5f7a18b91
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/ShorthandProperty.cs
@@ -0,0 +1,36 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal abstract class ShorthandProperty : Property
+    {
+        protected ShorthandProperty(string name, PropertyFlags flags = PropertyFlags.None)
+            : base(name, flags | PropertyFlags.Shorthand)
+        {
+        }
+
+        public string Stringify(Property[] properties)
+        {
+            return Converter.Construct(properties)?.CssText;
+        }
+
+        public void Export(Property[] properties)
+        {
+            foreach (var property in properties)
+            {
+                var value = DeclaredValue.ExtractFor(property.Name);
+
+                // A longhand this shorthand's grammar didn't actually match any tokens for (e.g.
+                // "background-color" when "background: none" only matched the image slot) must reset
+                // to its initial value, per CSS Cascading - a shorthand declaration always sets every
+                // longhand it covers, explicitly or implicitly. An empty (but non-null) extracted
+                // TokenValue means exactly that "omitted", so it's treated the same as null here to
+                // reach TrySetValue's existing null -> TokenValue.Initial fallback; passing the empty
+                // value through as-is would instead fail conversion silently, leaving the longhand's
+                // previous declaration (from an earlier, lower-priority rule) as the winning cascade
+                // value instead of being properly overridden.
+                var effectiveValue = value != null && value.Count == 0 ? null : value;
+
+                if (property.TrySetValue(effectiveValue)) property.IsImportant = IsImportant;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Sizing/ObjectFitProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Sizing/ObjectFitProperty.cs
new file mode 100644
index 000000000..0ed9f3a69
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Sizing/ObjectFitProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ObjectFitProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.ObjectFittingConverter.OrDefault(ObjectFitting.Fill);
+
+        internal ObjectFitProperty()
+            : base(PropertyNames.ObjectFit)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Sizing/ObjectPositionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Sizing/ObjectPositionProperty.cs
new file mode 100644
index 000000000..c3db40b0a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Sizing/ObjectPositionProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ObjectPositionProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.PointConverter.OrDefault(Point.Center);
+
+        internal ObjectPositionProperty()
+            : base(PropertyNames.ObjectPosition, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/StringSetProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/StringSetProperty.cs
new file mode 100644
index 000000000..121804ee7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/StringSetProperty.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Represents the CSS string-set property from CSS Generated Content for Paged Media Module.
+    /// Syntax: string-set: [ &lt;custom-ident&gt; &lt;content-list&gt; ]# | none
+    /// where &lt;content-list&gt; = [ &lt;string&gt; | &lt;counter()&gt; | &lt;counters()&gt; | &lt;content()&gt; | &lt;attr()&gt; ]+
+    /// </summary>
+    internal sealed class StringSetProperty : Property
+    {
+        private static readonly IValueConverter ValueConverter = new StringSetValueConverter().OrDefault();
+
+        internal StringSetProperty() : base(PropertyNames.StringSet)
+        {
+        }
+
+        internal override IValueConverter Converter => ValueConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeDasharrayProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeDasharrayProperty.cs
new file mode 100644
index 000000000..6a6b52c66
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeDasharrayProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeDasharrayProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.StrokeDasharrayConverter.OrGlobalValue();
+
+        public StrokeDasharrayProperty()
+            : base(PropertyNames.StrokeDasharray, PropertyFlags.Animatable | PropertyFlags.Unitless)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeDashoffsetProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeDashoffsetProperty.cs
new file mode 100644
index 000000000..0d38028fb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeDashoffsetProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeDashoffsetProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LengthOrPercentConverter.OrGlobalValue();
+
+        public StrokeDashoffsetProperty()
+            : base(PropertyNames.StrokeDashoffset, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeLinecapProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeLinecapProperty.cs
new file mode 100644
index 000000000..46a0f9890
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeLinecapProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeLinecapProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.StrokeLinecapConverter.OrDefault(StrokeLinecap.Butt);
+
+        public StrokeLinecapProperty()
+            : base(PropertyNames.StrokeLinecap, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeLinejoinProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeLinejoinProperty.cs
new file mode 100644
index 000000000..0c8200192
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeLinejoinProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeLinejoinProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.StrokeLinejoinConverter.OrGlobalValue();
+
+        public StrokeLinejoinProperty()
+            : base(PropertyNames.StrokeLinejoin, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeMiterlimitProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeMiterlimitProperty.cs
new file mode 100644
index 000000000..711fe2bc7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeMiterlimitProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeMiterlimitProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.StrokeMiterlimitConverter.OrGlobalValue();
+
+        public StrokeMiterlimitProperty()
+            : base(PropertyNames.StrokeMiterlimit, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeOpacityProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeOpacityProperty.cs
new file mode 100644
index 000000000..9f007e4c0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeOpacityProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeOpacityProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.NumberConverter.OrDefault(1f);
+
+        internal StrokeOpacityProperty()
+            : base(PropertyNames.StrokeOpacity, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeProperty.cs
new file mode 100644
index 000000000..882acb346
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.PaintConverter.OrGlobalValue();
+
+        internal StrokeProperty()
+            : base(PropertyNames.Stroke, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeWidthProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeWidthProperty.cs
new file mode 100644
index 000000000..56e7a7f6b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Stroke/StrokeWidthProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StrokeWidthProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.LengthOrPercentConverter.OrGlobalValue();
+
+        internal StrokeWidthProperty()
+            : base(PropertyNames.StrokeWidth, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/TableLayoutProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/TableLayoutProperty.cs
new file mode 100644
index 000000000..9002c5a17
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/TableLayoutProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TableLayoutProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.TableLayoutConverter.OrDefault(false);
+
+        internal TableLayoutProperty()
+            : base(PropertyNames.TableLayout)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/DirectionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/DirectionProperty.cs
new file mode 100644
index 000000000..b398f7edd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/DirectionProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DirectionProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.DirectionModeConverter.OrDefault(DirectionMode.Ltr);
+
+        internal DirectionProperty()
+            : base(PropertyNames.Direction, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/OverflowWrapProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/OverflowWrapProperty.cs
new file mode 100644
index 000000000..19c1a4360
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/OverflowWrapProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OverflowWrapProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OverflowWrapConverter;
+
+        public OverflowWrapProperty()
+            : base(PropertyNames.OverflowWrap)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAlignLastProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAlignLastProperty.cs
new file mode 100644
index 000000000..5f75f6ed2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAlignLastProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextAlignLastProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.TextAlignLastConverter;
+
+        public TextAlignLastProperty()
+            : base(PropertyNames.TextAlignLast)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAlignProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAlignProperty.cs
new file mode 100644
index 000000000..65881ad2e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAlignProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextAlignProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.HorizontalAlignmentConverter.OrDefault(HorizontalAlignment.Left);
+
+        internal TextAlignProperty()
+            : base(PropertyNames.TextAlign, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAnchorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAnchorProperty.cs
new file mode 100644
index 000000000..fb43c4466
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextAnchorProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextAnchorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.TextAnchorConverter;
+
+        public TextAnchorProperty()
+            : base(PropertyNames.TextAnchor)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationColorProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationColorProperty.cs
new file mode 100644
index 000000000..aeb65d255
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationColorProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextDecorationColorProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.ColorConverter.OrDefault(Color.Black);
+
+        internal TextDecorationColorProperty()
+            : base(PropertyNames.TextDecorationColor, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationLineProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationLineProperty.cs
new file mode 100644
index 000000000..7b41ddcfd
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationLineProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextDecorationLineProperty : Property
+    {
+        private static readonly IValueConverter ListConverter = Converters.TextDecorationLinesConverter.OrDefault();
+
+        internal TextDecorationLineProperty()
+            : base(PropertyNames.TextDecorationLine)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationProperty.cs
new file mode 100644
index 000000000..325ce75e5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationProperty.cs
@@ -0,0 +1,19 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class TextDecorationProperty : ShorthandProperty
+    {
+        private static readonly IValueConverter StyleConverter = WithAny(
+            ColorConverter.Option().For(PropertyNames.TextDecorationColor),
+            TextDecorationStyleConverter.Option().For(PropertyNames.TextDecorationStyle),
+            TextDecorationLinesConverter.Option().For(PropertyNames.TextDecorationLine)).OrDefault();
+
+        internal TextDecorationProperty()
+            : base(PropertyNames.TextDecoration, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationStyleProperty.cs
new file mode 100644
index 000000000..44e721887
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextDecorationStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextDecorationStyleProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.TextDecorationStyleConverter.OrDefault(TextDecorationStyle.Solid);
+
+        internal TextDecorationStyleProperty()
+            : base(PropertyNames.TextDecorationStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextIndentProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextIndentProperty.cs
new file mode 100644
index 000000000..079e9447c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextIndentProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextIndentProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthOrPercentConverter.OrDefault(Length.Zero);
+
+        internal TextIndentProperty()
+            : base(PropertyNames.TextIndent, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextJustifyProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextJustifyProperty.cs
new file mode 100644
index 000000000..568ef5024
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextJustifyProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextJustifyProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.TextJustifyConverter;
+
+        public TextJustifyProperty()
+            : base(PropertyNames.TextJustify)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextShadowProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextShadowProperty.cs
new file mode 100644
index 000000000..5a5f182a3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextShadowProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextShadowProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.MultipleShadowConverter.OrDefault();
+
+        internal TextShadowProperty()
+            : base(PropertyNames.TextShadow, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextTransformProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextTransformProperty.cs
new file mode 100644
index 000000000..cb8ee94de
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/TextTransformProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TextTransformProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.TextTransformConverter.OrDefault(TextTransform.None);
+
+        internal TextTransformProperty()
+            : base(PropertyNames.TextTransform, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/VerticalAlignProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/VerticalAlignProperty.cs
new file mode 100644
index 000000000..2ddc91ee4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/VerticalAlignProperty.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class VerticalAlignProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = LengthOrPercentConverter.Or(
+            VerticalAlignmentConverter).OrDefault(VerticalAlignment.Baseline);
+
+        internal VerticalAlignProperty()
+            : base(PropertyNames.VerticalAlign, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/WhiteSpaceProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/WhiteSpaceProperty.cs
new file mode 100644
index 000000000..6ec2a5235
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/WhiteSpaceProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class WhiteSpaceProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.WhitespaceConverter.OrDefault(Whitespace.Normal);
+
+        internal WhiteSpaceProperty()
+            : base(PropertyNames.WhiteSpace, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/WordBreakProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/WordBreakProperty.cs
new file mode 100644
index 000000000..8e1e39acb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Text/WordBreakProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class WordBreakProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.WordBreakConverter;
+
+        public WordBreakProperty()
+            : base(PropertyNames.WordBreak)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/PerspectiveOriginProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/PerspectiveOriginProperty.cs
new file mode 100644
index 000000000..1b2d37dec
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/PerspectiveOriginProperty.cs
@@ -0,0 +1,51 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class PerspectiveOriginProperty : Property
+    {
+        // perspective-origin is a <position> (CSS Transforms 1). As with transform-origin, the two-value
+        // <length-percentage> form is ordered (horizontal then vertical) and only the keyword-only form may
+        // be reordered - so "2px left" / "top 2px" are invalid (a length forces the ordered form and the
+        // other token is a keyword for the wrong axis).
+        private static readonly IValueConverter Horizontal =
+            LengthOrPercentConverter
+                .Or(Keywords.Left, Length.Zero)
+                .Or(Keywords.Right, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        private static readonly IValueConverter Vertical =
+            LengthOrPercentConverter
+                .Or(Keywords.Top, Length.Zero)
+                .Or(Keywords.Bottom, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        private static readonly IValueConverter HorizontalKeyword =
+            Assign(Keywords.Left, Length.Zero)
+                .Or(Keywords.Right, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        private static readonly IValueConverter VerticalKeyword =
+            Assign(Keywords.Top, Length.Zero)
+                .Or(Keywords.Bottom, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        private static readonly IValueConverter PerspectiveConverter = LengthOrPercentConverter.Or(
+            Keywords.Left, new Point(Length.Zero, Length.Half)).Or(
+            Keywords.Center, new Point(Length.Half, Length.Half)).Or(
+            Keywords.Right, new Point(Length.Full, Length.Half)).Or(
+            Keywords.Top, new Point(Length.Half, Length.Zero)).Or(
+            Keywords.Bottom, new Point(Length.Half, Length.Full)).Or(
+            WithOrder(Horizontal.Option(Length.Half), Vertical.Option(Length.Half))).Or(
+            WithAnyOrderIndependent(HorizontalKeyword.Option(Length.Half), VerticalKeyword.Option(Length.Half)))
+            .OrDefault(Point.Center);
+
+
+        internal PerspectiveOriginProperty()
+            : base(PropertyNames.PerspectiveOrigin, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => PerspectiveConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/PerspectiveProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/PerspectiveProperty.cs
new file mode 100644
index 000000000..1e46c67a5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/PerspectiveProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PerspectiveProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.LengthConverter.OrNone().OrDefault(Length.Zero);
+
+        internal PerspectiveProperty()
+            : base(PropertyNames.Perspective, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformOriginProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformOriginProperty.cs
new file mode 100644
index 000000000..244186094
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformOriginProperty.cs
@@ -0,0 +1,69 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class TransformOriginProperty : Property
+    {
+        // CSS Transforms 1 (https://www.w3.org/TR/css-transforms-1/#transform-origin-property):
+        //   [ left | center | right | top | bottom | <length-percentage> ]
+        // | [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] <length>?
+        // | [ [ center | left | right ] && [ center | top | bottom ] ] <length>?
+        //
+        // The two-value <length-percentage> form is ORDERED (horizontal then vertical). Only the keyword-only
+        // form may be reordered ("center left" == "left center"). So "2px left" and "top 2px" are invalid: a
+        // length in one axis forces the ordered form, and the remaining token is a keyword for the wrong axis.
+        private static readonly IValueConverter Horizontal =
+            LengthOrPercentConverter
+                .Or(Keywords.Left, Length.Zero)
+                .Or(Keywords.Right, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        private static readonly IValueConverter Vertical =
+            LengthOrPercentConverter
+                .Or(Keywords.Top, Length.Zero)
+                .Or(Keywords.Bottom, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        private static readonly IValueConverter HorizontalKeyword =
+            Assign(Keywords.Left, Length.Zero)
+                .Or(Keywords.Right, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        private static readonly IValueConverter VerticalKeyword =
+            Assign(Keywords.Top, Length.Zero)
+                .Or(Keywords.Bottom, Length.Full)
+                .Or(Keywords.Center, Length.Half);
+
+        // A one- or two-value <position> with no z-offset (this is exactly the perspective-origin grammar).
+        private static readonly IValueConverter Position =
+            LengthOrPercentConverter.Or(Keywords.Center, Point.Center)
+                // Ordered horizontal-then-vertical (rejects a keyword in the wrong axis position).
+                .Or(WithOrder(Horizontal.Option(Length.Half), Vertical.Option(Length.Half)))
+                // Keyword-only form, any order ("center left"): a token accepted by both axes must not be
+                // claimed positionally, so this needs order-independent matching.
+                .Or(WithAnyOrderIndependent(HorizontalKeyword.Option(Length.Half), VerticalKeyword.Option(Length.Half)));
+
+        // A genuine two-value position: BOTH a horizontal and a vertical component must be present. The axis
+        // converters are bare (not .Option), so each must actually consume a token. The <length> z-offset only
+        // exists in this two-value production, so gating the z-offset behind this (rather than the shared outer
+        // WithOrder) is what makes a single-value position + length such as "top 2px" invalid.
+        private static readonly IValueConverter TwoValuePosition =
+            WithOrder(Horizontal, Vertical)
+                .Or(WithAnyOrderIndependent(HorizontalKeyword, VerticalKeyword));
+
+        private static readonly IValueConverter StyleConverter =
+            // Two-value position followed by a (required) <length> z-offset - this branch only matches when a
+            // third length token is actually present...
+            WithOrder(TwoValuePosition, LengthConverter)
+                // ...otherwise a plain one- or two-value <position> with no z-offset.
+                .Or(Position)
+                .OrDefault(Point.Center);
+
+        internal TransformOriginProperty()
+            : base(PropertyNames.TransformOrigin, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformProperty.cs
new file mode 100644
index 000000000..e98d55267
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TransformProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.TransformConverter.Many().OrNone().OrDefault();
+
+        internal TransformProperty()
+            : base(PropertyNames.Transform, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformStyleProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformStyleProperty.cs
new file mode 100644
index 000000000..b6833813f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transform/TransformStyleProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TransformStyleProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.Toggle(Keywords.Flat, Keywords.Preserve3d).OrDefault(true);
+
+        internal TransformStyleProperty()
+            : base(PropertyNames.TransformStyle)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionDelayProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionDelayProperty.cs
new file mode 100644
index 000000000..9df84af1f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionDelayProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TransitionDelayProperty : Property
+    {
+        private static readonly IValueConverter
+            ListConverter = Converters.TimeConverter.FromList().OrDefault(Time.Zero);
+
+        internal TransitionDelayProperty()
+            : base(PropertyNames.TransitionDelay)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionDurationProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionDurationProperty.cs
new file mode 100644
index 000000000..97fc07be3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionDurationProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TransitionDurationProperty : Property
+    {
+        private static readonly IValueConverter
+            ListConverter = Converters.TimeConverter.FromList().OrDefault(Time.Zero);
+
+        internal TransitionDurationProperty()
+            : base(PropertyNames.TransitionDuration)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionProperty.cs
new file mode 100644
index 000000000..b7a1b753f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionProperty.cs
@@ -0,0 +1,23 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class TransitionProperty : ShorthandProperty
+    {
+        internal static readonly IValueConverter ListConverter = new TimeBasedShorthandConverter(
+            1, // duration index
+            3, // delay index
+            AnimatableConverter.Option().For(PropertyNames.TransitionProperty), // 0
+            TimeConverter.Option().For(PropertyNames.TransitionDuration), // 1
+            TransitionConverter.Option().For(PropertyNames.TransitionTimingFunction), // 2
+            TimeConverter.Option().For(PropertyNames.TransitionDelay) // 3
+        ).FromList().OrDefault();
+
+        internal TransitionProperty()
+            : base(PropertyNames.Transition)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionPropertyProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionPropertyProperty.cs
new file mode 100644
index 000000000..0138a81a1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionPropertyProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TransitionPropertyProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.AnimatableConverter.FromList().OrNone().OrDefault(Keywords.All);
+
+        internal TransitionPropertyProperty()
+            : base(PropertyNames.TransitionProperty)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionTimingFunctionProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionTimingFunctionProperty.cs
new file mode 100644
index 000000000..c54c3d0ab
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Transition/TransitionTimingFunctionProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TransitionTimingFunctionProperty : Property
+    {
+        private static readonly IValueConverter ListConverter =
+            Converters.TransitionConverter.FromList().OrDefault(Map.TimingFunctions[Keywords.Ease]);
+
+        internal TransitionTimingFunctionProperty()
+            : base(PropertyNames.TransitionTimingFunction)
+        {
+        }
+
+        internal override IValueConverter Converter => ListConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/UnicodeBidirectionalProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/UnicodeBidirectionalProperty.cs
new file mode 100644
index 000000000..1620d1714
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/UnicodeBidirectionalProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnicodeBidirectionalProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.UnicodeModeConverter.OrDefault(UnicodeMode.Normal);
+
+        internal UnicodeBidirectionalProperty()
+            : base(PropertyNames.UnicodeBidirectional)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/UnknownProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/UnknownProperty.cs
new file mode 100644
index 000000000..5254c732e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/UnknownProperty.cs
@@ -0,0 +1,12 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnknownProperty : Property
+    {
+        internal UnknownProperty(string name)
+            : base(name)
+        {
+        }
+
+        internal override IValueConverter Converter => Converters.Any;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/BackfaceVisibilityProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/BackfaceVisibilityProperty.cs
new file mode 100644
index 000000000..f1a78a598
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/BackfaceVisibilityProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class BackfaceVisibilityProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.BackfaceVisibilityConverter.OrDefault(true);
+
+        internal BackfaceVisibilityProperty()
+            : base(PropertyNames.BackfaceVisibility)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/ClipPathProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/ClipPathProperty.cs
new file mode 100644
index 000000000..77125131d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/ClipPathProperty.cs
@@ -0,0 +1,22 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>clip-path</c> property (CSS Masking Module Level 1). The basic-shape grammar
+    /// (<c>polygon()</c>/<c>inset()</c>/<c>circle()</c>/<c>ellipse()</c>) is resolved against the box's
+    /// reference box at paint time, so Layer A only needs to accept and preserve the raw value text.
+    /// </summary>
+    internal sealed class ClipPathProperty : Property
+    {
+        // The basic-shape grammar (polygon()/inset()/circle()/ellipse()) plus the "none" keyword is
+        // validated once by the shared BasicShapeGrammar via ClipPathValueConverter; the authored text
+        // is preserved so the paint-time resolver (CssClipPathResolver) sees exactly what was written.
+        private static readonly IValueConverter StyleConverter = new ClipPathValueConverter().OrDefault();
+
+        internal ClipPathProperty()
+            : base(PropertyNames.ClipPath, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/ClipProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/ClipProperty.cs
new file mode 100644
index 000000000..f8c098894
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/ClipProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ClipProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.ShapeConverter.OrDefault();
+
+        internal ClipProperty()
+            : base(PropertyNames.Clip, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/OpacityProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/OpacityProperty.cs
new file mode 100644
index 000000000..fe9f689ae
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/OpacityProperty.cs
@@ -0,0 +1,13 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OpacityProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.OptionalPercentOrNumberConverter;
+
+        internal OpacityProperty() : base(PropertyNames.Opacity, PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/VisibilityProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/VisibilityProperty.cs
new file mode 100644
index 000000000..db4fdf7b8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/Visibility/VisibilityProperty.cs
@@ -0,0 +1,15 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class VisibilityProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter =
+            Converters.VisibilityConverter.OrDefault(Visibility.Visible);
+
+        internal VisibilityProperty()
+            : base(PropertyNames.Visibility, PropertyFlags.Inherited | PropertyFlags.Animatable)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/StyleProperties/WidowsProperty.cs b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/WidowsProperty.cs
new file mode 100644
index 000000000..53e1dd53a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/StyleProperties/WidowsProperty.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class WidowsProperty : Property
+    {
+        private static readonly IValueConverter StyleConverter = Converters.IntegerConverter.OrDefault(2);
+
+        internal WidowsProperty()
+            : base(PropertyNames.Widows, PropertyFlags.Inherited)
+        {
+        }
+
+        internal override IValueConverter Converter => StyleConverter;
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/TextEncoding.cs b/Source/HtmlRenderer/Core/CssEngine/TextEncoding.cs
new file mode 100644
index 000000000..bbb3f2af5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/TextEncoding.cs
@@ -0,0 +1,305 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class TextEncoding
+    {
+        public static HashSet<string> AvailableEncodings = new HashSet<string>(from encoding in Encoding.GetEncodings()
+                                                                            select encoding.Name);
+
+        public static readonly Encoding Utf8 = new UTF8Encoding(false);
+        public static readonly Encoding Utf16Be = new UnicodeEncoding(true, false);
+        public static readonly Encoding Utf16Le = new UnicodeEncoding(false, false);
+        public static readonly Encoding Utf32Le = GetEncoding("UTF-32LE");
+        public static readonly Encoding Utf32Be = GetEncoding("UTF-32BE");
+        public static readonly Encoding Gb18030 = GetEncoding("GB18030");
+        public static readonly Encoding Big5 = GetEncoding("big5");
+        public static readonly Encoding Windows874 = GetEncoding("windows-874");
+        public static readonly Encoding Windows1250 = GetEncoding("windows-1250");
+        public static readonly Encoding Windows1251 = GetEncoding("windows-1251");
+        public static readonly Encoding Windows1252 = GetEncoding("windows-1252");
+        public static readonly Encoding Windows1253 = GetEncoding("windows-1253");
+        public static readonly Encoding Windows1254 = GetEncoding("windows-1254");
+        public static readonly Encoding Windows1255 = GetEncoding("windows-1255");
+        public static readonly Encoding Windows1256 = GetEncoding("windows-1256");
+        public static readonly Encoding Windows1257 = GetEncoding("windows-1257");
+        public static readonly Encoding Windows1258 = GetEncoding("windows-1258");
+        public static readonly Encoding Latin2 = GetEncoding("iso-8859-2");
+        public static readonly Encoding Latin3 = GetEncoding("iso-8859-3");
+        public static readonly Encoding Latin4 = GetEncoding("iso-8859-4");
+        public static readonly Encoding Latin5 = GetEncoding("iso-8859-5");
+        public static readonly Encoding Latin13 = GetEncoding("iso-8859-13");
+        public static readonly Encoding UsAscii = GetEncoding("us-ascii");
+        public static readonly Encoding Korean = GetEncoding("ks_c_5601-1987");
+        private static readonly Dictionary<string, Encoding> Encodings = CreateEncodings();
+
+        public static bool IsUnicode(this Encoding encoding)
+        {
+            return encoding == Utf16Be || encoding == Utf16Le;
+        }
+
+        public static bool IsSupported(string charset)
+        {
+            return Encodings.ContainsKey(charset);
+        }
+
+        public static Encoding Resolve(string charset)
+        {
+            if (charset != null && Encodings.TryGetValue(charset, out var encoding)) return encoding;
+
+            return Utf8;
+        }
+
+        private static Encoding GetEncoding(string name)
+        {
+            try
+            {
+                if (AvailableEncodings.Contains(name)) return Encoding.GetEncoding(name);
+            }
+            catch
+            {
+            }
+
+
+            // Catch all since WP8 does throw a different exception than W*.
+            return Utf8;
+        }
+
+        private static Dictionary<string, Encoding> CreateEncodings()
+        {
+            var encodings = new Dictionary<string, Encoding>(StringComparer.OrdinalIgnoreCase)
+            {
+                {"unicode-1-1-utf-8", Utf8},
+                {"utf-8", Utf8},
+                {"utf8", Utf8},
+                {"utf-16be", Utf16Be},
+                {"utf-16", Utf16Le},
+                {"utf-16le", Utf16Le},
+                {"dos-874", Windows874},
+                {"iso-8859-11", Windows874},
+                {"iso8859-11", Windows874},
+                {"iso885911", Windows874},
+                {"tis-620", Windows874},
+                {"windows-874", Windows874},
+                {"cp1250", Windows1250},
+                {"windows-1250", Windows1250},
+                {"x-cp1250", Windows1250},
+                {"cp1251", Windows1251},
+                {"windows-1251", Windows1251},
+                {"x-cp1251", Windows1251},
+                {"x-user-defined", Windows1252},
+                {"ansi_x3.4-1968", Windows1252},
+                {"ascii", Windows1252},
+                {"cp1252", Windows1252},
+                {"cp819", Windows1252},
+                {"csisolatin1", Windows1252},
+                {"ibm819", Windows1252},
+                {"iso-8859-1", Windows1252},
+                {"iso-ir-100", Windows1252},
+                {"iso8859-1", Windows1252},
+                {"iso88591", Windows1252},
+                {"iso_8859-1", Windows1252},
+                {"iso_8859-1:1987", Windows1252},
+                {"l1", Windows1252},
+                {"latin1", Windows1252},
+                {"us-ascii", Windows1252},
+                {"windows-1252", Windows1252},
+                {"x-cp1252", Windows1252},
+                {"cp1253", Windows1253},
+                {"windows-1253", Windows1253},
+                {"x-cp1253", Windows1253},
+                {"cp1254", Windows1254},
+                {"csisolatin5", Windows1254},
+                {"iso-8859-9", Windows1254},
+                {"iso-ir-148", Windows1254},
+                {"iso8859-9", Windows1254},
+                {"iso88599", Windows1254},
+                {"iso_8859-9", Windows1254},
+                {"iso_8859-9:1989", Windows1254},
+                {"l5", Windows1254},
+                {"latin5", Windows1254},
+                {"windows-1254", Windows1254},
+                {"x-cp1254", Windows1254},
+                {"cp1255", Windows1255},
+                {"windows-1255", Windows1255},
+                {"x-cp1255", Windows1255},
+                {"cp1256", Windows1256},
+                {"windows-1256", Windows1256},
+                {"x-cp1256", Windows1256},
+                {"cp1257", Windows1257},
+                {"windows-1257", Windows1257},
+                {"x-cp1257", Windows1257},
+                {"cp1258", Windows1258},
+                {"windows-1258", Windows1258},
+                {"x-cp1258", Windows1258}
+            };
+
+            var macintosh = GetEncoding("macintosh");
+            encodings.Add("csmacintosh", macintosh);
+            encodings.Add("mac", macintosh);
+            encodings.Add("macintosh", macintosh);
+            encodings.Add("x-mac-roman", macintosh);
+
+            var maccyrillic = GetEncoding("x-mac-cyrillic");
+
+            encodings.Add("x-mac-cyrillic", maccyrillic);
+            encodings.Add("x-mac-ukrainian", maccyrillic);
+
+            var i866 = GetEncoding("cp866");
+            encodings.Add("866", i866);
+            encodings.Add("cp866", i866);
+            encodings.Add("csibm866", i866);
+            encodings.Add("ibm866", i866);
+
+            encodings.Add("csisolatin2", Latin2);
+            encodings.Add("iso-8859-2", Latin2);
+            encodings.Add("iso-ir-101", Latin2);
+            encodings.Add("iso8859-2", Latin2);
+            encodings.Add("iso88592", Latin2);
+            encodings.Add("iso_8859-2", Latin2);
+            encodings.Add("iso_8859-2:1987", Latin2);
+            encodings.Add("l2", Latin2);
+            encodings.Add("latin2", Latin2);
+
+            encodings.Add("csisolatin3", Latin3);
+            encodings.Add("iso-8859-3", Latin3);
+            encodings.Add("iso-ir-109", Latin3);
+            encodings.Add("iso8859-3", Latin3);
+            encodings.Add("iso88593", Latin3);
+            encodings.Add("iso_8859-3", Latin3);
+            encodings.Add("iso_8859-3:1988", Latin3);
+            encodings.Add("l3", Latin3);
+            encodings.Add("latin3", Latin3);
+
+            encodings.Add("csisolatin4", Latin4);
+            encodings.Add("iso-8859-4", Latin4);
+            encodings.Add("iso-ir-110", Latin4);
+            encodings.Add("iso8859-4", Latin4);
+            encodings.Add("iso88594", Latin4);
+            encodings.Add("iso_8859-4", Latin4);
+            encodings.Add("iso_8859-4:1988", Latin4);
+            encodings.Add("l4", Latin4);
+            encodings.Add("latin4", Latin4);
+
+            encodings.Add("csisolatincyrillic", Latin5);
+            encodings.Add("cyrillic", Latin5);
+            encodings.Add("iso-8859-5", Latin5);
+            encodings.Add("iso-ir-144", Latin5);
+            encodings.Add("iso8859-5", Latin5);
+            encodings.Add("iso88595", Latin5);
+            encodings.Add("iso_8859-5", Latin5);
+            encodings.Add("iso_8859-5:1988", Latin5);
+
+            var latin6 = GetEncoding("iso-8859-6");
+            encodings.Add("arabic", latin6);
+            encodings.Add("asmo-708", latin6);
+            encodings.Add("csiso88596e", latin6);
+            encodings.Add("csiso88596i", latin6);
+            encodings.Add("csisolatinarabic", latin6);
+            encodings.Add("ecma-114", latin6);
+            encodings.Add("iso-8859-6", latin6);
+            encodings.Add("iso-8859-6-e", latin6);
+            encodings.Add("iso-8859-6-i", latin6);
+            encodings.Add("iso-ir-127", latin6);
+            encodings.Add("iso8859-6", latin6);
+            encodings.Add("iso88596", latin6);
+            encodings.Add("iso_8859-6", latin6);
+            encodings.Add("iso_8859-6:1987", latin6);
+
+            var latin7 = GetEncoding("iso-8859-7");
+            encodings.Add("csisolatingreek", latin7);
+            encodings.Add("ecma-118", latin7);
+            encodings.Add("elot_928", latin7);
+            encodings.Add("greek", latin7);
+            encodings.Add("greek8", latin7);
+            encodings.Add("iso-8859-7", latin7);
+            encodings.Add("iso-ir-126", latin7);
+            encodings.Add("iso8859-7", latin7);
+            encodings.Add("iso88597", latin7);
+            encodings.Add("iso_8859-7", latin7);
+            encodings.Add("iso_8859-7:1987", latin7);
+            encodings.Add("sun_eu_greek", latin7);
+
+            var latin8 = GetEncoding("iso-8859-8");
+            encodings.Add("csiso88598e", latin8);
+            encodings.Add("csisolatinhebrew", latin8);
+            encodings.Add("hebrew", latin8);
+            encodings.Add("iso-8859-8", latin8);
+            encodings.Add("iso-8859-8-e", latin8);
+            encodings.Add("iso-ir-138", latin8);
+            encodings.Add("iso8859-8", latin8);
+            encodings.Add("iso88598", latin8);
+            encodings.Add("iso_8859-8", latin8);
+            encodings.Add("iso_8859-8:1988", latin8);
+            encodings.Add("visual", latin8);
+
+            var latini = GetEncoding("iso-8859-8-i");
+            encodings.Add("csiso88598i", latini);
+            encodings.Add("iso-8859-8-i", latini);
+            encodings.Add("logical", latini);
+
+            var latin13 = GetEncoding("iso-8859-13");
+            encodings.Add("iso-8859-13", latin13);
+            encodings.Add("iso8859-13", latin13);
+            encodings.Add("iso885913", latin13);
+
+            var latin15 = GetEncoding("iso-8859-15");
+            encodings.Add("csisolatin9", latin15);
+            encodings.Add("iso-8859-15", latin15);
+            encodings.Add("iso8859-15", latin15);
+            encodings.Add("iso885915", latin15);
+            encodings.Add("iso_8859-15", latin15);
+            encodings.Add("l9", latin15);
+
+            var kr = GetEncoding("koi8-r");
+            encodings.Add("cskoi8r", kr);
+            encodings.Add("koi", kr);
+            encodings.Add("koi8", kr);
+            encodings.Add("koi8-r", kr);
+            encodings.Add("koi8_r", kr);
+            encodings.Add("koi8-u", GetEncoding("koi8-u"));
+
+            var chinese = GetEncoding("x-cp20936");
+            encodings.Add("chinese", chinese);
+            encodings.Add("csgb2312", chinese);
+            encodings.Add("csiso58gb231280", chinese);
+            encodings.Add("gb2312", chinese);
+            encodings.Add("gb_2312", chinese);
+            encodings.Add("gb_2312-80", chinese);
+            encodings.Add("gbk", chinese);
+            encodings.Add("iso-ir-58", chinese);
+            encodings.Add("x-gbk", chinese);
+            encodings.Add("hz-gb-2312", GetEncoding("hz-gb-2312"));
+            encodings.Add("gb18030", Gb18030);
+
+            encodings.Add("big5", Big5);
+            encodings.Add("big5-hkscs", Big5);
+            encodings.Add("cn-big5", Big5);
+            encodings.Add("csbig5", Big5);
+            encodings.Add("x-x-big5", Big5);
+
+            var isojp = GetEncoding("iso-2022-jp");
+            encodings.Add("csiso2022jp", isojp);
+            encodings.Add("iso-2022-jp", isojp);
+
+            var isokr = GetEncoding("iso-2022-kr");
+            encodings.Add("csiso2022kr", isokr);
+            encodings.Add("iso-2022-kr", isokr);
+
+            var isocn = GetEncoding("iso-2022-cn");
+            encodings.Add("iso-2022-cn", isocn);
+            encodings.Add("iso-2022-cn-ext", isocn);
+            encodings.Add("shift_jis", GetEncoding("shift_jis"));
+
+            var eucjp = GetEncoding("euc-jp");
+            encodings.Add("euc-jp", eucjp);
+
+            return encodings;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/ColorToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/ColorToken.cs
new file mode 100644
index 000000000..f06d4aa3e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/ColorToken.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ColorToken : Token
+    {
+        public ColorToken(string data, TextPosition position)
+            : base(TokenType.Color, data, position)
+        {
+        }
+
+        public bool IsValid => Data.Length != 3 && Data.Length != 4 && Data.Length != 6 && Data.Length != 8;
+
+        public override string ToValue()
+        {
+            return "#" + Data;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/CommentToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/CommentToken.cs
new file mode 100644
index 000000000..163b6adb6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/CommentToken.cs
@@ -0,0 +1,19 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class CommentToken : Token
+    {
+        public CommentToken(string data, bool valid, TextPosition position)
+            : base(TokenType.Comment, data, position)
+        {
+            IsValid = valid;
+        }
+
+        public bool IsValid { get; }
+
+        public override string ToValue()
+        {
+            var trailing = IsValid ? string.Empty : "*/";
+            return string.Concat("/*", Data, trailing);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/FunctionToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/FunctionToken.cs
new file mode 100644
index 000000000..26f122222
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/FunctionToken.cs
@@ -0,0 +1,49 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FunctionToken : Token, IEnumerable<Token>
+    {
+        private readonly List<Token> _arguments;
+
+        public FunctionToken(string data, TextPosition position)
+            : base(TokenType.Function, data, position)
+        {
+            _arguments = new List<Token>();
+        }
+
+        public IEnumerable<Token> ArgumentTokens
+        {
+            get
+            {
+                var final = _arguments.Count - 1;
+
+                if (final >= 0 && _arguments[final].Type == TokenType.RoundBracketClose) final--;
+
+                return _arguments.Take(1 + final);
+            }
+        }
+
+        public override string ToValue()
+        {
+            return string.Concat(Data, "(", _arguments.ToText());
+        }
+
+        public void AddArgumentToken(Token token)
+        {
+            _arguments.Add(token);
+        }
+
+        public IEnumerator<Token> GetEnumerator()
+        {
+            return _arguments.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/KeywordToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/KeywordToken.cs
new file mode 100644
index 000000000..75f06930f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/KeywordToken.cs
@@ -0,0 +1,25 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class KeywordToken : Token
+    {
+        public KeywordToken(TokenType type, string data, TextPosition position)
+            : base(type, data, position)
+        {
+        }
+
+        public override string ToValue()
+        {
+            switch (Type)
+            {
+                case TokenType.Hash:
+                    return "#" + Data;
+                case TokenType.AtKeyword:
+                    return "@" + Data;
+                case TokenType.Function:
+                    return Data + "(";
+                default:
+                    return Data;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/NumberToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/NumberToken.cs
new file mode 100644
index 000000000..103917030
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/NumberToken.cs
@@ -0,0 +1,39 @@
+using System.Globalization;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class NumberToken : Token
+    {
+        private static readonly char[] FloatIndicators = { '.', 'e', 'E' };
+
+        public NumberToken(string number, TextPosition position)
+            : base(TokenType.Number, number, position)
+        {
+        }
+
+        public bool IsInteger => Data.IndexOfAny(FloatIndicators) == -1;
+
+        public int IntegerValue
+        {
+            get
+            {
+                var parsed = int.TryParse(Data, out var result);
+
+                if (parsed)
+                {
+                    return result;
+                }
+
+                if (Data.All(char.IsDigit))
+                {
+                    return int.MaxValue;
+                }
+
+                throw new ParseException($"Unrecognized integer value '{Data}.'");
+            }
+        }
+
+        public float Value => float.Parse(Data, CultureInfo.InvariantCulture);
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/RangeToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/RangeToken.cs
new file mode 100644
index 000000000..fee373664
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/RangeToken.cs
@@ -0,0 +1,29 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RangeToken : Token
+    {
+        public RangeToken(string range, TextPosition position)
+            : base(TokenType.Range, range, position)
+        {
+            Start = range.Replace(Symbols.QuestionMark, '0');
+            End = range.Replace(Symbols.QuestionMark, 'F');
+        }
+
+        public RangeToken(string start, string end, TextPosition position)
+            : base(TokenType.Range, string.Concat(start, "-", end), position)
+        {
+            Start = start;
+            End = end;
+        }
+
+        // Data holds the range without its "U+" prefix, so serializing it bare would emit "41-5A" - not a
+        // valid <urange> and not what was authored.
+        public override string ToValue()
+        {
+            return string.Concat("U+", Data);
+        }
+
+        public string Start { get; }
+        public string End { get; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/StringToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/StringToken.cs
new file mode 100644
index 000000000..c758d251a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/StringToken.cs
@@ -0,0 +1,20 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StringToken : Token
+    {
+        public StringToken(string data, bool valid, char quote, TextPosition position)
+            : base(TokenType.String, data, position)
+        {
+            IsValid = valid;
+            Quote = quote;
+        }
+
+        public override string ToValue()
+        {
+            return Data.StylesheetString();
+        }
+
+        public bool IsValid { get; }
+        public char Quote { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/Token.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/Token.cs
new file mode 100644
index 000000000..65a850e6d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/Token.cs
@@ -0,0 +1,24 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal class Token
+    {
+        public static readonly Token Whitespace = new Token(TokenType.Whitespace, " ", TextPosition.Empty);
+        public static readonly Token Comma = new Token(TokenType.Comma, ",", TextPosition.Empty);
+
+        public Token(TokenType type, string data, TextPosition position)
+        {
+            Type = type;
+            Data = data;
+            Position = position;
+        }
+
+        public virtual string ToValue()
+        {
+            return Data;
+        }
+
+        public TextPosition Position { get; }
+        public TokenType Type { get; }
+        public string Data { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/UnitToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/UnitToken.cs
new file mode 100644
index 000000000..cba35070e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/UnitToken.cs
@@ -0,0 +1,22 @@
+using System.Globalization;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnitToken : Token
+    {
+        public UnitToken(TokenType type, string value, string dimension, TextPosition position)
+            : base(type, value, position)
+        {
+            Unit = dimension;
+        }
+
+        public override string ToValue()
+        {
+            return Data + Unit;
+        }
+
+        public float Value => float.Parse(Data, CultureInfo.InvariantCulture);
+
+        public string Unit { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Tokens/UrlToken.cs b/Source/HtmlRenderer/Core/CssEngine/Tokens/UrlToken.cs
new file mode 100644
index 000000000..26d013211
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Tokens/UrlToken.cs
@@ -0,0 +1,21 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UrlToken : Token
+    {
+        public UrlToken(string functionName, string data, bool valid, TextPosition position)
+            : base(TokenType.Url, data, position)
+        {
+            IsValid = valid;
+            FunctionName = functionName;
+        }
+
+        public override string ToValue()
+        {
+            var url = Data.StylesheetString();
+            return FunctionName.StylesheetFunction(url);
+        }
+
+        public bool IsValid { get; }
+        public string FunctionName { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/AnyValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/AnyValueConverter.cs
new file mode 100644
index 000000000..b72bf9da3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/AnyValueConverter.cs
@@ -0,0 +1,34 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class AnyValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            return new AnyValue(value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<AnyValue>();
+        }
+
+        private sealed class AnyValue : IPropertyValue
+        {
+            public AnyValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => Original.ToText();
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ArgumentsValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ArgumentsValueConverter.cs
new file mode 100644
index 000000000..c76330e7a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ArgumentsValueConverter.cs
@@ -0,0 +1,67 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ArgumentsValueConverter : IValueConverter
+    {
+        private readonly IValueConverter[] _converters;
+
+        public ArgumentsValueConverter(params IValueConverter[] converters)
+        {
+            _converters = converters;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var items = value.ToList();
+            var length = _converters.Length;
+
+            if (items.Count > length) return null;
+
+            var args = new IPropertyValue[length];
+
+            for (var i = 0; i < length; i++)
+            {
+                var item = i < items.Count ? items[i] : Enumerable.Empty<Token>();
+                args[i] = _converters[i].Convert(item);
+
+                if (args[i] == null) return null;
+            }
+
+            return new ArgumentsValue(args, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<ArgumentsValue>();
+        }
+
+        private sealed class ArgumentsValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] _arguments;
+
+            public ArgumentsValue(IPropertyValue[] arguments, IEnumerable<Token> tokens)
+            {
+                _arguments = arguments;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    var texts = _arguments.Where(m => !string.IsNullOrEmpty(m.CssText)).Select(m => m.CssText);
+                    return string.Join(", ", texts);
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/AspectRatioValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/AspectRatioValueConverter.cs
new file mode 100644
index 000000000..0abcced98
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/AspectRatioValueConverter.cs
@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates an <c>aspect-ratio</c> value through the shared <see cref="AspectRatioGrammar"/> — accepting
+    /// <c>auto</c>, a <c>&lt;ratio&gt;</c>, or <c>auto &amp;&amp; &lt;ratio&gt;</c>, and rejecting everything
+    /// else so an invalid value is dropped at parse time. The authored text is preserved so Layer B
+    /// (<see cref="Html.Core.Dom.CssLayoutEngine"/>) re-parses the same value during layout.
+    /// </summary>
+    internal sealed class AspectRatioValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.ToArray();
+            return AspectRatioGrammar.TryParse(tokens, out _) ? new AspectRatioValue(tokens) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<AspectRatioValue>();
+        }
+
+        private sealed class AspectRatioValue : IPropertyValue
+        {
+            public AspectRatioValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => Original.Text;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BackgroundPositionValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BackgroundPositionValueConverter.cs
new file mode 100644
index 000000000..f254c0901
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BackgroundPositionValueConverter.cs
@@ -0,0 +1,73 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates and serializes a single-layer <c>background-position</c> value via the shared
+    /// <see cref="BackgroundPositionGrammar"/> (see that class for why this isn't a hand-written
+    /// combinator tree like most other converters in this file).
+    /// </summary>
+    internal sealed class BackgroundPositionValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            var parsed = BackgroundPositionGrammar.TryParse(tokens);
+            return parsed != null ? new BackgroundPositionValue(parsed, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<BackgroundPositionValue>();
+        }
+
+        private sealed class BackgroundPositionValue : IPropertyValue
+        {
+            private readonly BackgroundPositionGrammar.ParsedPosition _parsed;
+
+            public BackgroundPositionValue(BackgroundPositionGrammar.ParsedPosition parsed, IEnumerable<Token> tokens)
+            {
+                _parsed = parsed;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => string.Join(" ", _parsed.AuthoredOrder.Select(ComponentText));
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+
+            private static string ComponentText(BackgroundPositionGrammar.Component c)
+            {
+                if (c.Keyword == BackgroundPositionGrammar.AxisKeyword.None)
+                    return LengthText(c.Offset);
+
+                var keyword = KeywordText(c.Keyword);
+                return c.Offset != null ? keyword + " " + LengthText(c.Offset) : keyword;
+            }
+
+            private static string KeywordText(BackgroundPositionGrammar.AxisKeyword keyword)
+            {
+                switch (keyword)
+                {
+                    case BackgroundPositionGrammar.AxisKeyword.Left:
+                        return Keywords.Left;
+                    case BackgroundPositionGrammar.AxisKeyword.Right:
+                        return Keywords.Right;
+                    case BackgroundPositionGrammar.AxisKeyword.Top:
+                        return Keywords.Top;
+                    case BackgroundPositionGrammar.AxisKeyword.Bottom:
+                        return Keywords.Bottom;
+                    case BackgroundPositionGrammar.AxisKeyword.Center:
+                        return Keywords.Center;
+                    default:
+                        return string.Empty;
+                }
+            }
+
+            private static string LengthText(Token token) =>
+                Converters.LengthOrPercentConverter.Convert(new[] { token })?.CssText ?? string.Empty;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BackgroundSizeValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BackgroundSizeValueConverter.cs
new file mode 100644
index 000000000..491c832f4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BackgroundSizeValueConverter.cs
@@ -0,0 +1,54 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates and serializes a single-layer <c>background-size</c> value via the shared
+    /// <see cref="BackgroundSizeGrammar"/>.
+    /// </summary>
+    internal sealed class BackgroundSizeValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            var parsed = BackgroundSizeGrammar.TryParse(tokens);
+            return parsed != null ? new BackgroundSizeValue(parsed, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<BackgroundSizeValue>();
+        }
+
+        private sealed class BackgroundSizeValue : IPropertyValue
+        {
+            private readonly BackgroundSizeGrammar.ParsedSize _parsed;
+
+            public BackgroundSizeValue(BackgroundSizeGrammar.ParsedSize parsed, IEnumerable<Token> tokens)
+            {
+                _parsed = parsed;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    if (_parsed.IsCover) return Keywords.Cover;
+                    if (_parsed.IsContain) return Keywords.Contain;
+
+                    var width = ComponentText(_parsed.Width);
+                    return _parsed.HasExplicitHeight ? width + " " + ComponentText(_parsed.Height) : width;
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+
+            private static string ComponentText(BackgroundSizeGrammar.Component c) =>
+                c.IsAuto ? Keywords.Auto : Converters.LengthOrPercentConverter.Convert(new[] { c.Value })?.CssText ?? string.Empty;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BorderRadiusConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BorderRadiusConverter.cs
new file mode 100644
index 000000000..e71fa933d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BorderRadiusConverter.cs
@@ -0,0 +1,127 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal sealed class BorderRadiusConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter = LengthOrPercentConverter.Periodic(
+            PropertyNames.BorderTopLeftRadius, PropertyNames.BorderTopRightRadius,
+            PropertyNames.BorderBottomRightRadius,
+            PropertyNames.BorderBottomLeftRadius);
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var front = new List<Token>();
+            var back = new List<Token>();
+            var current = front;
+
+            foreach (var token in value)
+                if (token.Type == TokenType.Delim && token.Data.Is("/"))
+                {
+                    if (current == back) return null;
+
+                    current = back;
+                }
+                else
+                {
+                    current.Add(token);
+                }
+
+            var horizontal = _converter.Convert(front);
+
+            if (horizontal == null) return null;
+
+            var vertical = current == back ? _converter.Convert(back) : horizontal;
+
+            if (vertical == null) return null;
+
+            return new BorderRadiusValue(horizontal, vertical, new TokenValue(value));
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            if (properties.Length == 4)
+            {
+                var front = new List<Token>();
+                var back = new List<Token>();
+                var props = new List<Property>
+                {
+                    properties.First(m => m.Name.Is(PropertyNames.BorderTopLeftRadius)),
+                    properties.First(m => m.Name.Is(PropertyNames.BorderTopRightRadius)),
+                    properties.First(
+                        m => m.Name.Is(PropertyNames.BorderBottomRightRadius)),
+                    properties.First(
+                        m => m.Name.Is(PropertyNames.BorderBottomLeftRadius))
+                };
+
+                for (var i = 0; i < props.Count; i++)
+                {
+                    var dpv = props[i].DeclaredValue as IEnumerable<IPropertyValue>;
+
+                    if (dpv == null) return null;
+
+                    var first = dpv.First().Original;
+                    var second = dpv.Last().Original;
+
+                    if (i != 0)
+                    {
+                        front.Add(Token.Whitespace);
+                        back.Add(Token.Whitespace);
+                    }
+
+                    front.AddRange(first);
+                    back.AddRange(second);
+                }
+
+                var h = _converter.Convert(front);
+                var v = _converter.Convert(back);
+                var o = front.Concat(new Token(TokenType.Delim, "/", TextPosition.Empty)).Concat(back);
+
+                return new BorderRadiusValue(h, v, new TokenValue(o));
+            }
+
+            return null;
+        }
+
+        private sealed class BorderRadiusValue : IPropertyValue
+        {
+            private readonly IPropertyValue _horizontal;
+            private readonly IPropertyValue _vertical;
+
+            public BorderRadiusValue(IPropertyValue horizontal, IPropertyValue vertical, TokenValue original)
+            {
+                _horizontal = horizontal;
+                _vertical = vertical;
+                Original = original;
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    var horizontal = _horizontal.CssText;
+
+                    if (_vertical == null) return horizontal;
+
+                    var vertical = _vertical.CssText;
+
+                    return horizontal != vertical
+                        ? string.Concat(horizontal, " / ", vertical)
+                        : horizontal;
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var h = _horizontal.ExtractFor(name);
+                var v = _vertical.ExtractFor(name);
+                return new TokenValue(h.Concat(Token.Whitespace).Concat(v));
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BoxShadowValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BoxShadowValueConverter.cs
new file mode 100644
index 000000000..d67adef47
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/BoxShadowValueConverter.cs
@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a <c>box-shadow</c> value through the shared <see cref="BoxShadowGrammar"/> - accepting
+    /// <c>none</c> or a comma-separated list of <c>[ inset? &amp;&amp; &lt;length&gt;{2,4} &amp;&amp;
+    /// &lt;color&gt;? ]</c> shadow layers, and rejecting everything else so an invalid value (e.g.
+    /// <c>box-shadow: banana</c>) is dropped at parse time. The authored value text is preserved verbatim
+    /// so the paint-time resolver (Layer B, <c>CssBox.PaintBoxShadows</c>) re-tokenizes and resolves the
+    /// same value against the box - a single grammar shared across both layers.
+    /// </summary>
+    internal sealed class BoxShadowValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.ToArray();
+            return BoxShadowGrammar.TryParse(tokens) is null ? null : new BoxShadowValue(tokens);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<BoxShadowValue>();
+        }
+
+        private sealed class BoxShadowValue : IPropertyValue
+        {
+            public BoxShadowValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            // Preserve the authored text verbatim - Layer B re-parses and resolves this string.
+            public string CssText => Original.Text;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ClipPathValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ClipPathValueConverter.cs
new file mode 100644
index 000000000..1e60ffd15
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ClipPathValueConverter.cs
@@ -0,0 +1,47 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a <c>clip-path</c> value: accepts the keyword <c>none</c> or any <c>&lt;basic-shape&gt;</c>
+    /// the shared <see cref="BasicShapeGrammar"/> recognizes (<c>polygon()</c>/<c>inset()</c>/<c>circle()</c>/
+    /// <c>ellipse()</c>), and rejects everything else so an unknown value (e.g. <c>clip-path: banana</c>)
+    /// is dropped at parse time. The authored value text is preserved verbatim (<see cref="ClipPathValue.CssText"/>
+    /// returns the original tokens) so the render-time resolver (Layer B) sees exactly what the author wrote.
+    /// </summary>
+    internal sealed class ClipPathValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            var isNone = tokens.Length == 1 && tokens[0].Type == TokenType.Ident && tokens[0].Data.Isi(Keywords.None);
+
+            if (!isNone && BasicShapeGrammar.TryParse(tokens) == null)
+                return null;
+
+            return new ClipPathValue(value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<ClipPathValue>();
+        }
+
+        private sealed class ClipPathValue : IPropertyValue
+        {
+            public ClipPathValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            // Preserve the authored text verbatim - Layer B re-tokenizes and resolves this string.
+            public string CssText => Original.Text;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ConditionalStartsWithValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ConditionalStartsWithValueConverter.cs
new file mode 100644
index 000000000..215bbfca6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ConditionalStartsWithValueConverter.cs
@@ -0,0 +1,92 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ConditionalStartsWithValueConverter : IValueConverter
+    {
+        private readonly string _when;
+        private readonly string[] _prefixKeywords;
+        private readonly IValueConverter _converter;
+
+        public ConditionalStartsWithValueConverter(string when, IValueConverter converter, params string[] prefixKeywords)
+        {
+            _when = when;
+            _prefixKeywords = prefixKeywords;
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var enumerator = value.GetEnumerator();
+
+            while (enumerator.MoveNext() && enumerator.Current.Type == TokenType.Whitespace)
+            {
+                //Empty on purpose.
+            }
+
+            if (enumerator.Current.Type != TokenType.Ident || !_prefixKeywords.Contains(enumerator.Current.Data))
+                return null;
+
+            var consumedPrefix = enumerator.Current.Data;
+
+            var remainingTokens = new List<Token>();
+
+            while (enumerator.MoveNext())
+            {
+                if (enumerator.Current.Type == TokenType.Whitespace)
+                    continue;
+
+                remainingTokens.Add(enumerator.Current);
+            }
+
+            var result = _converter.Convert(remainingTokens);
+
+            if (result != null && result.CssText != _when)
+                return null;
+
+            return new ConditionalStartValue(consumedPrefix, result, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var value = _converter.Construct(properties);
+            return value != null ? CreateFrom(value, Enumerable.Empty<Token>()) : null;
+        }
+
+        private IPropertyValue CreateFrom(IPropertyValue value, IEnumerable<Token> tokens)
+        {
+            return value != null ? new ConditionalStartValue(string.Empty, value, tokens) : null;
+        }
+
+        private sealed class ConditionalStartValue : IPropertyValue
+        {
+            private readonly string _start;
+            private readonly IPropertyValue _value;
+
+            public ConditionalStartValue(string start, IPropertyValue value, IEnumerable<Token> tokens)
+            {
+                _start = start;
+                _value = value;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    return !string.IsNullOrEmpty(_start)
+                               ? string.Concat(_start, " ", _value.CssText)
+                               : _value.CssText;
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return _value.ExtractFor(name);
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ConstraintValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ConstraintValueConverter.cs
new file mode 100644
index 000000000..cb06898a7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ConstraintValueConverter.cs
@@ -0,0 +1,62 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ConstraintValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+        private readonly string[] _labels;
+
+        public ConstraintValueConverter(IValueConverter converter, string[] labels)
+        {
+            _converter = converter;
+            _labels = labels;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var result = _converter.Convert(value);
+            return result != null ? new TransformationValueConverter(result, _labels) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var filtered = properties.Where(m => _labels.Contains(m.Name));
+            var existing = default(string);
+
+            foreach (var filter in filtered)
+            {
+                var value = filter.Value;
+
+                if (existing != null && value != existing) return null;
+
+                existing = value;
+            }
+
+            var result = _converter.Construct(filtered.Take(1).ToArray());
+            return result != null ? new TransformationValueConverter(result, _labels) : null;
+        }
+
+        private sealed class TransformationValueConverter : IPropertyValue
+        {
+            private readonly string[] _labels;
+            private readonly IPropertyValue _value;
+
+            public TransformationValueConverter(IPropertyValue value, string[] labels)
+            {
+                _value = value;
+                _labels = labels;
+            }
+
+            public string CssText => _value.CssText;
+
+            public TokenValue Original => _value.Original;
+
+            public TokenValue ExtractFor(string name)
+            {
+                return _labels.Contains(name) ? _value.ExtractFor(name) : null;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ContentFunctionConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ContentFunctionConverter.cs
new file mode 100644
index 000000000..b48dbacd9
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ContentFunctionConverter.cs
@@ -0,0 +1,73 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Converter for the content() function used in string-set property.
+    /// Supports: content(text), content(before), content(after), content(first-letter)
+    /// </summary>
+    internal sealed class ContentFunctionConverter : IValueConverter
+    {
+        private static readonly string[] ValidModes = { "text", "before", "after", "first-letter" };
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var first = value.OnlyOrDefault();
+
+            if (!(first is FunctionToken funcToken) || !funcToken.Data.Equals(FunctionNames.Content, System.StringComparison.OrdinalIgnoreCase))
+                return null;
+
+            // Default mode is "text" if no argument provided
+            var mode = "text";
+
+            if (funcToken.ArgumentTokens.Any())
+            {
+                var argToken = funcToken.ArgumentTokens.FirstOrDefault();
+                if (argToken is KeywordToken keywordToken)
+                {
+                    var keyword = keywordToken.Data.ToLowerInvariant();
+                    if (!ValidModes.Contains(keyword))
+                        return null;
+
+                    mode = keyword;
+                }
+                else
+                {
+                    return null;
+                }
+            }
+
+            return new ContentFunctionValue(mode, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<ContentFunctionValue>();
+        }
+
+        private sealed class ContentFunctionValue : IPropertyValue
+        {
+            private readonly string _mode;
+
+            public ContentFunctionValue(string mode, IEnumerable<Token> tokens)
+            {
+                _mode = mode;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => _mode == "text"
+                ? "content()"
+                : $"content({_mode})";
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+
+            public string Mode => _mode;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ContinuousValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ContinuousValueConverter.cs
new file mode 100644
index 000000000..1e409af46
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ContinuousValueConverter.cs
@@ -0,0 +1,79 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ContinuousValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+
+        public ContinuousValueConverter(IValueConverter converter)
+        {
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var list = new List<Token>(value);
+            var options = new List<IPropertyValue>();
+
+            if (list.Count <= 0) return null;
+
+            while (list.Count != 0)
+            {
+                var option = _converter.VaryStart(list);
+
+                if (option == null) return null;
+
+                options.Add(option);
+            }
+
+            return new OptionsValue(options.ToArray(), value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<OptionsValue>();
+        }
+
+        private sealed class OptionsValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] _options;
+
+            public OptionsValue(IPropertyValue[] options, IEnumerable<Token> tokens)
+            {
+                _options = options;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    return string.Join(" ",
+                        _options.Where(m => !string.IsNullOrEmpty(m.CssText)).Select(m => m.CssText));
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var option in _options)
+                {
+                    var extracted = option.ExtractFor(name);
+
+                    if (extracted == null) continue;
+
+                    if (tokens.Count > 0) tokens.Add(Token.Whitespace);
+
+                    tokens.AddRange(extracted);
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/DictionaryValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/DictionaryValueConverter.cs
new file mode 100644
index 000000000..e41d02e6b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/DictionaryValueConverter.cs
@@ -0,0 +1,46 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class DictionaryValueConverter<T> : IValueConverter
+    {
+        private readonly IReadOnlyDictionary<string, T> _values;
+
+        public DictionaryValueConverter(IReadOnlyDictionary<string, T> values)
+        {
+            _values = values;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var identifier = value.ToIdentifier();
+
+            return identifier != null && _values.TryGetValue(identifier, out _)
+                ? new EnumeratedValue(identifier, value)
+                : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<EnumeratedValue>();
+        }
+
+        private sealed class EnumeratedValue : IPropertyValue
+        {
+            public EnumeratedValue(string identifier, IEnumerable<Token> tokens)
+            {
+                CssText = identifier;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText { get; }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/EndListValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/EndListValueConverter.cs
new file mode 100644
index 000000000..acaeabb90
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/EndListValueConverter.cs
@@ -0,0 +1,104 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class EndListValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _endConverter;
+        private readonly IValueConverter _listConverter;
+
+        public EndListValueConverter(IValueConverter listConverter, IValueConverter endConverter)
+        {
+            _listConverter = listConverter;
+            _endConverter = endConverter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var items = value.ToList();
+            var n = items.Count - 1;
+            var values = new IPropertyValue[n + 1];
+
+            for (var i = 0; i < n; i++)
+            {
+                values[i] = _listConverter.Convert(items[i]);
+
+                if (values[i] == null) return null;
+            }
+
+            values[n] = _endConverter.Convert(items[n]);
+            return values[n] != null ? new ListValue(values, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var valueList = new List<List<Token>>[properties.Length];
+            var dummies = new Property[properties.Length];
+            var max = 0;
+
+            for (var i = 0; i < properties.Length; i++)
+            {
+                var value = properties[i].DeclaredValue;
+                valueList[i] = value != null ? value.Original.ToList() : new List<List<Token>>();
+
+                dummies[i] = PropertyFactory.Instance.CreateLonghand(properties[i].Name);
+                max = Math.Max(max, valueList[i].Count);
+            }
+
+            var values = new IPropertyValue[max];
+
+            for (var i = 0; i < max; i++)
+            {
+                for (var j = 0; j < dummies.Length; j++)
+                {
+                    var list = valueList[j];
+                    var tokens = list.Count > i ? list[i] : Enumerable.Empty<Token>();
+                    dummies[j].TrySetValue(new TokenValue(tokens));
+                }
+
+                var converter = i < max - 1 ? _listConverter : _endConverter;
+                values[i] = converter.Construct(dummies);
+            }
+
+            return new ListValue(values, Enumerable.Empty<Token>());
+        }
+
+        private sealed class ListValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] _values;
+
+            public ListValue(IPropertyValue[] values, IEnumerable<Token> tokens)
+            {
+                _values = values;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get { return string.Join(", ", _values.Select(m => m.CssText)); }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var value in _values)
+                {
+                    var extracted = value.ExtractFor(name);
+
+                    if (extracted == null) continue;
+
+                    if (tokens.Count > 0) tokens.Add(Token.Comma);
+
+                    tokens.AddRange(extracted);
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ExtendedImageConverters.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ExtendedImageConverters.cs
new file mode 100644
index 000000000..908e59aea
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ExtendedImageConverters.cs
@@ -0,0 +1,132 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    /// <summary>
+    /// A validated-but-not-rendered image function (<c>image-set()</c>/<c>cross-fade()</c>/<c>element()</c>,
+    /// CSS Images 4 §2/§3). The engine accepts these as syntactically-valid <c>&lt;image&gt;</c> values (so a
+    /// property or <c>@property</c> registration using one is valid, per spec) but paints nothing for them —
+    /// the render path (<c>CssValueParser.ParseImage</c> → <c>CssImagePainter</c>) only handles url()/gradients.
+    /// This value carries the original tokens for serialization only.
+    /// </summary>
+    internal sealed class ImageFunctionValue : IPropertyValue
+    {
+        public ImageFunctionValue(IEnumerable<Token> tokens)
+        {
+            Original = new TokenValue(tokens);
+        }
+
+        public string CssText => Original.Text;
+
+        public TokenValue Original { get; }
+
+        public TokenValue ExtractFor(string name) => Original;
+    }
+
+    /// <summary>The inner <c>&lt;image&gt;</c> of an <c>image-set()</c>/<c>cross-fade()</c> option — a url() or a
+    /// gradient. Nested <c>image-set()</c> isn't modeled (not a real authoring pattern); referencing the two
+    /// base converters directly also avoids a construction cycle with <c>ImageSourceConverter</c>.</summary>
+    internal static class ExtendedImage
+    {
+        // Qualify GradientConverter — the bare name also resolves to the abstract GradientConverter *type*.
+        public static readonly IValueConverter InnerImage = UrlConverter.Or(Converters.GradientConverter);
+    }
+
+    /// <summary><c>element( &lt;id-selector&gt; )</c> — a single <c>#id</c> hash argument.</summary>
+    internal sealed class ElementImageConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            // ToArray (LINQ) — a bare ToList() on IEnumerable<Token> resolves to the CSS comma-group splitter.
+            var tokens = value.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            // An '#id' selector is a single <hash-token> (CSS Syntax §4). A '#f00'-shaped id lexes as a Color
+            // token, any other id as a Hash token; both are the single '#'-prefixed form.
+            return tokens.Length == 1 && (tokens[0].Type == TokenType.Hash || tokens[0].Type == TokenType.Color)
+                ? new ImageFunctionValue(value)
+                : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<ImageFunctionValue>();
+    }
+
+    /// <summary><c>image-set( &lt;image-set-option&gt;# )</c>, option = <c>[ &lt;image&gt; | &lt;string&gt; ] [ &lt;resolution&gt; || type(&lt;string&gt;) ]?</c>.</summary>
+    internal sealed class ImageSetConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var options = value.ToList(); // comma-separated groups
+            if (options.Count == 0 || options.Any(o => !IsOption(o))) return null;
+            return new ImageFunctionValue(value);
+        }
+
+        private static bool IsOption(List<Token> option)
+        {
+            var items = option.ToItems(); // whitespace/function-boundary split
+            if (items.Count == 0) return false;
+
+            // The source: a <string> or a url()/gradient <image>.
+            if (StringConverter.Convert(items[0]) == null && ExtendedImage.InnerImage.Convert(items[0]) == null)
+                return false;
+
+            // Any remaining items are a <resolution> (incl. the `x` dppx alias, modeled by Resolution.GetUnit)
+            // and/or a type(<string>), in either order.
+            for (var i = 1; i < items.Count; i++)
+                if (ResolutionConverter.Convert(items[i]) == null && !IsTypeFunction(items[i]))
+                    return false;
+
+            return true;
+        }
+
+        private static bool IsTypeFunction(List<Token> item)
+        {
+            var fn = item.Count == 1 ? item[0] as FunctionToken : null;
+            if (fn == null || !fn.Data.Equals("type", System.StringComparison.OrdinalIgnoreCase))
+                return false;
+            var inner = fn.Where(t => t.Type != TokenType.Whitespace && t.Type != TokenType.RoundBracketClose).ToArray();
+            return inner.Length == 1 && inner[0].Type == TokenType.String;
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<ImageFunctionValue>();
+    }
+
+    /// <summary><c>cross-fade( &lt;cf-image&gt;# )</c>, <c>&lt;cf-image&gt; = &lt;percentage&gt;? &amp;&amp; [ &lt;image&gt; | &lt;color&gt; ]</c>;
+    /// plus the legacy <c>cross-fade( &lt;image&gt;, &lt;image&gt;, &lt;percentage&gt; )</c> form.</summary>
+    internal sealed class CrossFadeConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var args = value.ToList(); // comma-separated groups
+            if (args.Count == 0) return null;
+
+            if (args.All(IsCrossFadeImage) ||
+                (args.Count == 3 && IsCrossFadeImage(args[0]) && IsCrossFadeImage(args[1]) && PercentConverter.Convert(args[2]) != null))
+                return new ImageFunctionValue(value);
+
+            return null;
+        }
+
+        private static bool IsCrossFadeImage(List<Token> arg)
+        {
+            var hasImageOrColor = false;
+            foreach (var item in arg.ToItems())
+            {
+                if (ExtendedImage.InnerImage.Convert(item) != null || ColorConverter.Convert(item) != null)
+                {
+                    hasImageOrColor = true;
+                }
+                else if (PercentConverter.Convert(item) == null)
+                {
+                    return false;
+                }
+            }
+
+            return hasImageOrColor;
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<ImageFunctionValue>();
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FallbackValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FallbackValueConverter.cs
new file mode 100644
index 000000000..3f1580d1f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FallbackValueConverter.cs
@@ -0,0 +1,44 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FallbackValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+        private readonly TokenValue _defaultValue;
+
+        public FallbackValueConverter(IValueConverter converter, TokenValue defaultValue)
+        {
+            _converter = converter;
+            _defaultValue = defaultValue;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            return value.Any() ? _converter.Convert(value) : new OptionValue(_defaultValue);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return _converter.Construct(properties) ?? new OptionValue(_defaultValue);
+        }
+
+        private sealed class OptionValue : IPropertyValue
+        {
+            public OptionValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => string.Empty;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FontPaletteValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FontPaletteValueConverter.cs
new file mode 100644
index 000000000..163899166
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FontPaletteValueConverter.cs
@@ -0,0 +1,49 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a <c>font-palette</c> value (CSS Fonts Module Level 4): the keywords <c>normal</c>/
+    /// <c>light</c>/<c>dark</c>, a <c>&lt;dashed-ident&gt;</c> naming an <c>@font-palette-values</c> rule, or a
+    /// <c>palette-mix()</c> function (validated through the shared <see cref="PaletteMixGrammar"/>). Anything
+    /// else is dropped at parse time. The authored value text is preserved verbatim (Layer B re-tokenizes and
+    /// resolves it in <c>ActualFontPalette</c>), mirroring <see cref="ClipPathValueConverter"/>.
+    /// </summary>
+    internal sealed class FontPaletteValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            bool valid = tokens.Length == 1 && tokens[0].Type == TokenType.Ident
+                ? IsKeywordOrDashedIdent(tokens[0].Data)
+                : PaletteMixGrammar.TryParse(tokens) != null;
+
+            return valid ? new FontPaletteValue(value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<FontPaletteValue>();
+        }
+
+        private static bool IsKeywordOrDashedIdent(string ident) =>
+            ident.Isi(Keywords.Normal) || ident.Isi("light") || ident.Isi("dark") ||
+            ident.StartsWith("--", System.StringComparison.Ordinal);
+
+        private sealed class FontPaletteValue : IPropertyValue
+        {
+            public FontPaletteValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => Original.Text;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FunctionValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FunctionValueConverter.cs
new file mode 100644
index 000000000..62d72083c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/FunctionValueConverter.cs
@@ -0,0 +1,59 @@
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class FunctionValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _arguments;
+        private readonly string _name;
+
+        public FunctionValueConverter(string name, IValueConverter arguments)
+        {
+            _name = name;
+            _arguments = arguments;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var function = value.OnlyOrDefault() as FunctionToken;
+
+            if (!Check(function)) return null;
+
+            var args = _arguments.Convert(function.ArgumentTokens);
+            return args != null ? new FunctionValue(_name, args, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<FunctionValue>();
+        }
+
+        private bool Check(FunctionToken function)
+        {
+            return function != null && function.Data.Equals(_name, StringComparison.OrdinalIgnoreCase);
+        }
+
+        private sealed class FunctionValue : IPropertyValue
+        {
+            private readonly IPropertyValue _arguments;
+            private readonly string _name;
+
+            public FunctionValue(string name, IPropertyValue arguments, IEnumerable<Token> tokens)
+            {
+                _name = name;
+                _arguments = arguments;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => _name.StylesheetFunction(_arguments.CssText);
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GradientConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GradientConverter.cs
new file mode 100644
index 000000000..4090331f1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GradientConverter.cs
@@ -0,0 +1,346 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    using static Converters;
+
+    internal abstract class GradientConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var args = value.ToList();
+            var initial = args.Count != 0 ? ConvertFirstArgument(args[0]) : null;
+            var offset = initial != null ? 1 : 0;
+            var stops = ToGradientStops(args, offset);
+            return stops != null ? new GradientValue(initial, stops, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<GradientValue>();
+        }
+
+        /// <summary>
+        /// The converter used to validate a colour stop's position. Length/percentage for linear and
+        /// radial gradients (the default); overridden by <see cref="ConicGradientConverter"/>, whose
+        /// angular stops are positioned by an &lt;angle&gt; or &lt;percentage&gt; instead.
+        /// </summary>
+        protected virtual IValueConverter StopPositionConverter => LengthOrPercentConverter;
+
+        private IPropertyValue[] ToGradientStops(List<List<Token>> values, int offset)
+        {
+            var stops = new IPropertyValue[values.Count - offset];
+
+            for (int i = offset, k = 0; i < values.Count; i++, k++)
+            {
+                stops[k] = ToGradientStop(values[i]);
+
+                if (stops[k] == null) return null;
+            }
+
+            return stops;
+        }
+
+        private IPropertyValue ToGradientStop(List<Token> value)
+        {
+            var color = default(IPropertyValue);
+            var firstPosition = default(IPropertyValue);
+            var secondPosition = default(IPropertyValue);
+            var items = value.ToItems();
+
+            if (items.Count != 0)
+            {
+                firstPosition = StopPositionConverter.Convert(items[items.Count - 1]);
+
+                if (firstPosition != null) items.RemoveAt(items.Count - 1);
+            }
+
+            // <color-stop-length> = <length-percentage>{1,2} (CSS Images 4 §3.5.1): a stop may carry two
+            // positions, equivalent to two same-colour stops, one at each position. Parsing right-to-left,
+            // the position taken above is the second (rightmost); a position immediately before it is the
+            // first. Both are kept, in source order, so the value round-trips as authored - the render
+            // layer (CssValueParser.ParseLinearGradient) reads the property's serialized value and already
+            // expands two positions into two stops, so dropping one here collapsed the solid band it draws.
+            // (For conic gradients the same two-position shorthand applies, positioned by <angle>.)
+            if (firstPosition != null && items.Count != 0)
+            {
+                var earlier = StopPositionConverter.Convert(items[items.Count - 1]);
+
+                if (earlier != null)
+                {
+                    secondPosition = firstPosition;
+                    firstPosition = earlier;
+                    items.RemoveAt(items.Count - 1);
+                }
+            }
+
+            if (items.Count != 0)
+            {
+                color = ColorConverter.Convert(items[items.Count - 1]);
+
+                if (color != null) items.RemoveAt(items.Count - 1);
+            }
+
+            // The two-position form is only defined for a <color-stop>; a bare <length-percentage> with no
+            // colour is a <linear-color-hint>, which takes exactly one position.
+            if (secondPosition != null && color == null) return null;
+
+            return items.Count == 0 ? new StopValue(color, firstPosition, secondPosition, value) : null;
+        }
+
+        protected abstract IPropertyValue ConvertFirstArgument(IEnumerable<Token> value);
+
+        private sealed class StopValue : IPropertyValue
+        {
+            private readonly IPropertyValue _color;
+            private readonly IPropertyValue _firstPosition;
+            private readonly IPropertyValue _secondPosition;
+
+            public StopValue(IPropertyValue color, IPropertyValue firstPosition, IPropertyValue secondPosition,
+                IEnumerable<Token> tokens)
+            {
+                _color = color;
+                _firstPosition = firstPosition;
+                _secondPosition = secondPosition;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    var parts = new List<string>(3);
+
+                    if (_color != null) parts.Add(_color.CssText);
+                    if (_firstPosition != null) parts.Add(_firstPosition.CssText);
+                    if (_secondPosition != null) parts.Add(_secondPosition.CssText);
+
+                    return string.Join(" ", parts);
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+
+        // Factory used by derived classes to return an opaque placeholder IPropertyValue that echoes
+        // its tokens back as CssText - for a group whose grammar is accepted but not further modelled
+        // here (e.g. an "in <colorspace>" modifier, or a conic bare-0 / calc() angular stop position).
+        protected static IPropertyValue CreatePlaceholder(IEnumerable<Token> tokens)
+            => new PlaceholderValue(tokens);
+
+        private sealed class PlaceholderValue : IPropertyValue
+        {
+            public PlaceholderValue(IEnumerable<Token> tokens) { Original = new TokenValue(tokens); }
+            public string CssText => Original.Text;
+            public TokenValue Original { get; }
+            public TokenValue ExtractFor(string name) => Original;
+        }
+
+        private sealed class GradientValue : IPropertyValue
+        {
+            private readonly IPropertyValue _initial;
+            private readonly IPropertyValue[] _stops;
+
+            public GradientValue(IPropertyValue initial, IPropertyValue[] stops, IEnumerable<Token> tokens)
+            {
+                _initial = initial;
+                _stops = stops;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    var count = _stops.Length;
+
+                    if (_initial != null) count++;
+
+                    var args = new string[count];
+                    count = 0;
+
+                    if (_initial != null) args[count++] = _initial.CssText;
+
+                    foreach (var propertyValue in _stops) args[count++] = propertyValue.CssText;
+
+                    return string.Join(", ", args);
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+
+    internal sealed class LinearGradientConverter : GradientConverter
+    {
+        private readonly IValueConverter _converter;
+
+        public LinearGradientConverter()
+        {
+            _converter = AngleConverter.Or(
+                SideOrCornerConverter.StartsWithKeyword(Keywords.To));
+        }
+
+        protected override IPropertyValue ConvertFirstArgument(IEnumerable<Token> value)
+        {
+            // "[ <angle> | to <side-or-corner> ] || <color-interpolation-method>" (CSS Images 4). Validate
+            // any "in <colorspace> [<hue-method>]" prelude, then validate what remains as the direction.
+            if (!ColorInterpolationMethodGrammar.TryExtractInterpolationMethod(value, out var remainder, out var hasIn))
+                return null;
+
+            if (hasIn)
+                return remainder.Count == 0 || _converter.Convert(remainder) != null ? CreatePlaceholder(value) : null;
+
+            return _converter.Convert(value);
+        }
+    }
+
+    // Validates conic-gradient() at parse time (mirroring RadialGradientConverter), so a malformed
+    // value is dropped per CSS Cascade §4.1 instead of silently painting nothing at render. The
+    // grammar matches CssValueParser.ParseConicGradient exactly.
+    internal sealed class ConicGradientConverter : GradientConverter
+    {
+        private readonly IValueConverter _prelude;
+
+        public ConicGradientConverter()
+        {
+            // [ from <angle> ]? [ at <position> ]? — same combinator shape RadialGradientConverter
+            // uses for its own prelude, just with conic's from/at keywords.
+            _prelude = WithAny(
+                AngleConverter.StartsWithKeyword(Keywords.From).Option(),
+                PointConverter.StartsWithKeyword(Keywords.At).Option(Point.Center));
+        }
+
+        // A conic <angular-color-stop> is positioned by <angle> | <percentage>, with the same bare-0
+        // and calc()-family acceptance the renderer's TryParseConicAngle allows (AngleConverter already
+        // covers calc()-typed angles; a length such as 5px is correctly rejected).
+        protected override IValueConverter StopPositionConverter { get; } =
+            AngleConverter.Or(PercentConverter).Or(new ZeroOrCalcPositionConverter());
+
+        protected override IPropertyValue ConvertFirstArgument(IEnumerable<Token> value)
+        {
+            // "[ from <angle> ]? [ at <position> ]? || <color-interpolation-method>" — validate any
+            // "in <colorspace> [<hue-method>]" prelude, then validate what remains as from/at.
+            if (!ColorInterpolationMethodGrammar.TryExtractInterpolationMethod(value, out var remainder, out var hasIn))
+                return null;
+
+            if (!hasIn)
+                return ConvertPrelude(value);
+
+            return remainder.Count == 0 || ConvertPrelude(remainder) != null ? CreatePlaceholder(value) : null;
+        }
+
+        private IPropertyValue ConvertPrelude(IEnumerable<Token> value)
+        {
+            // If the first non-whitespace token is an ident that is not a prelude keyword, this comma
+            // group is a color stop, not a prelude — return null so it flows to stop validation.
+            Token first = null;
+            foreach (var t in value)
+            {
+                if (t.Type != TokenType.Whitespace) { first = t; break; }
+            }
+            if (first != null && first.Type == TokenType.Ident)
+            {
+                var id = first.Data;
+                if (!string.Equals(id, Keywords.From, System.StringComparison.OrdinalIgnoreCase) &&
+                    !string.Equals(id, Keywords.At, System.StringComparison.OrdinalIgnoreCase))
+                    return null;
+            }
+
+            return _prelude.Convert(value);
+        }
+
+        // Accepts a bare `0` (the universal zero, which <angle> otherwise requires a unit for) or a
+        // single calc()-family function used as an angular stop position — matching the corresponding
+        // branches of CssValueParser.TryParseConicAngle, using the same primitives.
+        private sealed class ZeroOrCalcPositionConverter : IValueConverter
+        {
+            public IPropertyValue Convert(IEnumerable<Token> value)
+            {
+                var only = value.OnlyOrDefault();
+                if (only == null) return null;
+
+                if (only.Type == TokenType.Number && ((NumberToken)only).Value == 0f)
+                    return CreatePlaceholder(value);
+
+                if (only is FunctionToken function && CalcParser.IsCalcFamily(function.Data))
+                    return CreatePlaceholder(value);
+
+                return null;
+            }
+
+            public IPropertyValue Construct(Property[] properties) => null;
+        }
+    }
+
+    internal sealed class RadialGradientConverter : GradientConverter
+    {
+        private readonly IValueConverter _converter;
+
+        public RadialGradientConverter()
+        {
+            var position = PointConverter.StartsWithKeyword(Keywords.At).Option(Point.Center);
+            var circle = WithOrder(WithAny(Assign(Keywords.Circle, true).Option(true),
+                    LengthConverter.Option()),
+                position);
+
+            var ellipse = WithOrder(WithAny(Assign(Keywords.Ellipse, false).Option(false),
+                    LengthOrPercentConverter.Many(2, 2).Option()),
+                position);
+
+            var extents = WithOrder(WithAny(Toggle(Keywords.Circle, Keywords.Ellipse).Option(false),
+                Map.RadialGradientSizeModes.ToConverter()), position);
+
+            _converter = circle.Or(ellipse.Or(extents));
+        }
+
+        protected override IPropertyValue ConvertFirstArgument(IEnumerable<Token> value)
+        {
+            // "[ <ending-shape> || <size> ]? [ at <position> ]? || <color-interpolation-method>" — validate
+            // any "in <colorspace> [<hue-method>]" prelude, then validate what remains as shape/size/position.
+            if (!ColorInterpolationMethodGrammar.TryExtractInterpolationMethod(value, out var remainder, out var hasIn))
+                return null;
+
+            if (!hasIn)
+                return ConvertShape(value);
+
+            return remainder.Count == 0 || ConvertShape(remainder) != null ? CreatePlaceholder(value) : null;
+        }
+
+        private IPropertyValue ConvertShape(IEnumerable<Token> value)
+        {
+            // If the first non-whitespace token is an ident that is not a known gradient
+            // shape/size keyword, it must be a CSS color name (e.g. "red" in "red 0 8px").
+            // In that case, this comma group is a color stop, not a shape/size modifier.
+            Token first = null;
+            foreach (var t in value)
+            {
+                if (t.Type != TokenType.Whitespace) { first = t; break; }
+            }
+            if (first != null && first.Type == TokenType.Ident)
+            {
+                var id = first.Data;
+                if (!string.Equals(id, "circle", System.StringComparison.OrdinalIgnoreCase) &&
+                    !string.Equals(id, "ellipse", System.StringComparison.OrdinalIgnoreCase) &&
+                    !string.Equals(id, "at", System.StringComparison.OrdinalIgnoreCase) &&
+                    !string.Equals(id, "closest-side", System.StringComparison.OrdinalIgnoreCase) &&
+                    !string.Equals(id, "farthest-corner", System.StringComparison.OrdinalIgnoreCase) &&
+                    !string.Equals(id, "closest-corner", System.StringComparison.OrdinalIgnoreCase) &&
+                    !string.Equals(id, "farthest-side", System.StringComparison.OrdinalIgnoreCase))
+                    return null;
+            }
+
+            return _converter.Convert(value);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAreaShorthandValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAreaShorthandValueConverter.cs
new file mode 100644
index 000000000..e989e5811
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAreaShorthandValueConverter.cs
@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-area</c> shorthand: <c>&lt;grid-line&gt; [ / &lt;grid-line&gt; ]{0,3}</c> in the order
+    /// row-start / column-start / row-end / column-end. Implements the CSS Grid §8.3.1 omitted-value copy
+    /// rule — a bare <c>&lt;custom-ident&gt;</c> propagates to the paired/all edges, so <c>grid-area: main</c>
+    /// fills the whole <c>main</c> area, while <c>grid-area: 2</c> leaves the other edges <c>auto</c>.
+    /// </summary>
+    internal sealed class GridAreaShorthandValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var c = GridPlacementShorthand.Split(value, maxComponents: 4);
+            if (c is null) return null;
+
+            var rowStart = c[0];
+            // column-start omitted → if row-start is a bare custom-ident, all four take it; else auto.
+            var colStart = c.Count > 1 ? c[1]
+                : rowStart.IsBareCustomIdent ? rowStart : (GridPlacementShorthand.Component?)null;
+            // row-end omitted → copy a bare custom-ident row-start, else auto.
+            var rowEnd = c.Count > 2 ? c[2]
+                : rowStart.IsBareCustomIdent ? rowStart : (GridPlacementShorthand.Component?)null;
+            // column-end omitted → copy a bare custom-ident column-start, else auto.
+            var colEnd = c.Count > 3 ? c[3]
+                : colStart.HasValue && colStart.Value.IsBareCustomIdent ? colStart : (GridPlacementShorthand.Component?)null;
+
+            var map = new Dictionary<string, IReadOnlyList<Token>>
+            {
+                [PropertyNames.GridRowStart] = rowStart.Tokens,
+                [PropertyNames.GridColumnStart] = GridPlacementShorthand.Or(colStart),
+                [PropertyNames.GridRowEnd] = GridPlacementShorthand.Or(rowEnd),
+                [PropertyNames.GridColumnEnd] = GridPlacementShorthand.Or(colEnd),
+            };
+            return new MappedShorthandValue(map, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<MappedShorthandValue>();
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAutoFlowValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAutoFlowValueConverter.cs
new file mode 100644
index 000000000..9211cc287
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAutoFlowValueConverter.cs
@@ -0,0 +1,57 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a <c>grid-auto-flow</c> value (CSS Grid §7.7): <c>[ row | column ] || dense</c> — one of
+    /// <c>row</c>/<c>column</c> optionally combined with <c>dense</c>, in either order. The authored text is
+    /// preserved for the grid layout engine.
+    /// </summary>
+    internal sealed class GridAutoFlowValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.ToArray();
+            var idents = tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+            if (idents.Length < 1 || idents.Length > 2 || idents.Any(t => t.Type != TokenType.Ident))
+                return null;
+
+            var hasAxis = false;
+            var hasDense = false;
+            foreach (var t in idents)
+            {
+                if (t.Data.Isi(Keywords.Row) || t.Data.Isi(Keywords.Column))
+                {
+                    if (hasAxis) return null; // row and column are mutually exclusive
+                    hasAxis = true;
+                }
+                else if (t.Data.Isi(Keywords.Dense))
+                {
+                    if (hasDense) return null;
+                    hasDense = true;
+                }
+                else
+                {
+                    return null;
+                }
+            }
+
+            return new GridAutoFlowValue(tokens);
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<GridAutoFlowValue>();
+
+        private sealed class GridAutoFlowValue : IPropertyValue
+        {
+            public GridAutoFlowValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => Original.Text;
+            public TokenValue Original { get; }
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAutoTracksValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAutoTracksValueConverter.cs
new file mode 100644
index 000000000..4003b1d7a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridAutoTracksValueConverter.cs
@@ -0,0 +1,35 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a <c>grid-auto-columns</c>/<c>grid-auto-rows</c> value: a <c>&lt;track-size&gt;+</c> list
+    /// (no <c>repeat()</c>) via the shared <see cref="GridTrackListGrammar"/>. The authored text is preserved
+    /// for the grid layout engine.
+    /// </summary>
+    internal sealed class GridAutoTracksValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.ToArray();
+            return GridTrackListGrammar.TryParseTrackSizeList(tokens.Where(t => t.Type != TokenType.Whitespace).ToArray()) is null
+                ? null
+                : new GridAutoTracksValue(tokens);
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<GridAutoTracksValue>();
+
+        private sealed class GridAutoTracksValue : IPropertyValue
+        {
+            public GridAutoTracksValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => Original.Text;
+            public TokenValue Original { get; }
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridColumnRowShorthandValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridColumnRowShorthandValueConverter.cs
new file mode 100644
index 000000000..8287de6c7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridColumnRowShorthandValueConverter.cs
@@ -0,0 +1,43 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-column</c> / <c>grid-row</c> shorthand: <c>&lt;grid-line&gt; [ / &lt;grid-line&gt; ]?</c>
+    /// expanding to the axis's <c>-start</c>/<c>-end</c> longhands. Implements the CSS Grid §8.3.1
+    /// omitted-value copy rule that the generic <c>WithOrder(...).Option()</c> DSL cannot: when the end is
+    /// omitted, it copies a bare <c>&lt;custom-ident&gt;</c> start (so <c>grid-column: main</c> spans the
+    /// whole <c>main</c> area) but leaves a line number / span as <c>auto</c>.
+    /// </summary>
+    internal sealed class GridColumnRowShorthandValueConverter : IValueConverter
+    {
+        private readonly string _startName;
+        private readonly string _endName;
+
+        public GridColumnRowShorthandValueConverter(string startName, string endName)
+        {
+            _startName = startName;
+            _endName = endName;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var components = GridPlacementShorthand.Split(value, maxComponents: 2);
+            if (components is null) return null;
+
+            var start = components[0];
+            // end omitted → copy a bare custom-ident start, else auto.
+            var end = components.Count > 1 ? components[1]
+                : start.IsBareCustomIdent ? start : (GridPlacementShorthand.Component?)null;
+
+            var map = new Dictionary<string, IReadOnlyList<Token>>
+            {
+                [_startName] = start.Tokens,
+                [_endName] = GridPlacementShorthand.Or(end),
+            };
+            return new MappedShorthandValue(map, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<MappedShorthandValue>();
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridLineValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridLineValueConverter.cs
new file mode 100644
index 000000000..91a845e90
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridLineValueConverter.cs
@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a single grid <c>&lt;grid-line&gt;</c> (<c>grid-column-start</c>/<c>-end</c>,
+    /// <c>grid-row-start</c>/<c>-end</c>) through the shared <see cref="GridLineGrammar"/> — <c>auto</c>, an
+    /// integer line, or <c>span N</c>. The authored text is preserved for the grid placement engine.
+    /// </summary>
+    internal sealed class GridLineValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.ToArray();
+            return GridLineGrammar.TryParse(tokens.Where(t => t.Type != TokenType.Whitespace).ToArray()) is null
+                ? null
+                : new GridLineValue(tokens);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<GridLineValue>();
+        }
+
+        private sealed class GridLineValue : IPropertyValue
+        {
+            public GridLineValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => Original.Text;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridPlacementShorthand.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridPlacementShorthand.cs
new file mode 100644
index 000000000..a50980dd4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridPlacementShorthand.cs
@@ -0,0 +1,88 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>Shared helpers for the grid placement shorthands (<c>grid-column</c>/<c>grid-row</c>/
+    /// <c>grid-area</c>): splitting a value on <c>/</c> into <c>&lt;grid-line&gt;</c> components, validating
+    /// each, and building the omitted-value copy result (CSS Grid §8.3.1).</summary>
+    internal static class GridPlacementShorthand
+    {
+        /// <summary>A parsed <c>&lt;grid-line&gt;</c> component: its authored tokens and whether it is a bare
+        /// <c>&lt;custom-ident&gt;</c> (the only form the omitted-value copy rule propagates).</summary>
+        internal struct Component
+        {
+            public IReadOnlyList<Token> Tokens { get; set; }
+            public bool IsBareCustomIdent { get; set; }
+        }
+
+        private static readonly Token AutoToken = new Token(TokenType.Ident, Keywords.Auto, TextPosition.Empty);
+
+        /// <summary>Splits the value on top-level <c>/</c> delimiters into <c>&lt;grid-line&gt;</c> components,
+        /// validating each via <see cref="GridLineGrammar"/>. Returns null on any invalid component or an
+        /// out-of-range component count.</summary>
+        internal static List<Component> Split(IEnumerable<Token> value, int maxComponents)
+        {
+            var groups = new List<List<Token>> { new List<Token>() };
+            foreach (var token in value)
+            {
+                if (token.Type == TokenType.Whitespace) { groups[groups.Count - 1].Add(token); continue; }
+                if (token.Type == TokenType.Delim && token.Data == "/") { groups.Add(new List<Token>()); continue; }
+                groups[groups.Count - 1].Add(token);
+            }
+
+            var components = new List<Component>(groups.Count);
+            foreach (var group in groups)
+            {
+                var significant = group.Where(t => t.Type != TokenType.Whitespace).ToArray();
+                var parsed = GridLineGrammar.TryParse(significant);
+                if (parsed is null) return null;
+                // Preserve internal whitespace in the stored tokens (only trim the ends) so a two-token
+                // component like "span 2" round-trips as "span 2", not "span2" (which would re-lex as one
+                // ident). A bare <custom-ident> is a single ident token that parsed to a named (non-Nth) line.
+                components.Add(new Component
+                {
+                    Tokens = Trim(group),
+                    IsBareCustomIdent = significant.Length == 1 && significant[0].Type == TokenType.Ident && parsed.Name != null
+                });
+            }
+
+            return components.Count >= 1 && components.Count <= maxComponents ? components : null;
+        }
+
+        /// <summary>The tokens for a longhand: the specified component's tokens, or <c>auto</c> when omitted.</summary>
+        internal static IReadOnlyList<Token> Or(Component? component)
+        {
+            return component.HasValue ? component.Value.Tokens : new[] { AutoToken };
+        }
+
+        /// <summary>Drops leading and trailing whitespace tokens, keeping internal whitespace.</summary>
+        private static IReadOnlyList<Token> Trim(List<Token> group)
+        {
+            var start = 0;
+            var end = group.Count - 1;
+            while (start <= end && group[start].Type == TokenType.Whitespace) start++;
+            while (end >= start && group[end].Type == TokenType.Whitespace) end--;
+            return group.GetRange(start, end - start + 1);
+        }
+    }
+
+    /// <summary>A shorthand <see cref="IPropertyValue"/> that emits a precomputed token stream for each of
+    /// its longhands (via <see cref="ExtractFor"/>), used by the grid placement shorthands.</summary>
+    internal sealed class MappedShorthandValue : IPropertyValue
+    {
+        private readonly IReadOnlyDictionary<string, IReadOnlyList<Token>> _map;
+
+        public MappedShorthandValue(IReadOnlyDictionary<string, IReadOnlyList<Token>> map, IEnumerable<Token> original)
+        {
+            _map = map;
+            Original = new TokenValue(original);
+        }
+
+        public string CssText => Original.Text;
+        public TokenValue Original { get; }
+
+        public TokenValue ExtractFor(string name) =>
+            _map.TryGetValue(name, out var tokens) ? new TokenValue(tokens) : new TokenValue(new Token[0]);
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridShorthandValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridShorthandValueConverter.cs
new file mode 100644
index 000000000..34969d11b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridShorthandValueConverter.cs
@@ -0,0 +1,76 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid</c> shorthand (CSS Grid §7.8): either a <c>&lt;grid-template&gt;</c>, or one of the two
+    /// auto-flow forms
+    /// <c>&lt;grid-template-rows&gt; / [ auto-flow &amp;&amp; dense? ] &lt;grid-auto-columns&gt;?</c> and
+    /// <c>[ auto-flow &amp;&amp; dense? ] &lt;grid-auto-rows&gt;? / &lt;grid-template-columns&gt;</c>. Expands to
+    /// the three <c>grid-template-*</c> longhands plus <c>grid-auto-flow</c>/<c>-rows</c>/<c>-columns</c>;
+    /// every longhand it doesn't set is reset to its initial value (an absent slice — §7.8).
+    /// </summary>
+    internal sealed class GridShorthandValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            // NB: the domain-specific IEnumerable<Token>.ToList() extension splits on commas; materialize the
+            // flat token list explicitly instead.
+            var tokens = new List<Token>(value);
+
+            // Form 1: <grid-template>. The three template longhands are set; grid-auto-flow/-rows/-columns
+            // are omitted here so they reset to their initial values (row / auto / auto).
+            if (GridTemplateShorthand.TryParseTemplate(tokens, out var rows, out var columns, out var areas))
+            {
+                var templateMap = new Dictionary<string, IReadOnlyList<Token>>();
+                if (rows != null) templateMap[PropertyNames.GridTemplateRows] = rows;
+                if (columns != null) templateMap[PropertyNames.GridTemplateColumns] = columns;
+                if (areas != null) templateMap[PropertyNames.GridTemplateAreas] = areas;
+                return new MappedShorthandValue(templateMap, tokens);
+            }
+
+            // Forms 2/3: an auto-flow form — requires exactly one top-level '/'.
+            var groups = GridTemplateShorthand.SplitTopLevelSlash(tokens);
+            if (groups.Count != 2) return null;
+
+            var leftRaw = groups[0];
+            var rightRaw = groups[1];
+            var left = GridTemplateShorthand.Significant(leftRaw);
+            var right = GridTemplateShorthand.Significant(rightRaw);
+
+            var leftHasFlow = left.Any(t => t.Type == TokenType.Ident && t.Data.Isi(Keywords.AutoFlow));
+            var rightHasFlow = right.Any(t => t.Type == TokenType.Ident && t.Data.Isi(Keywords.AutoFlow));
+            if (leftHasFlow == rightHasFlow) return null; // exactly one side carries auto-flow
+
+            var map = new Dictionary<string, IReadOnlyList<Token>>();
+
+            if (rightHasFlow)
+            {
+                // <grid-template-rows> / [ auto-flow && dense? ] <grid-auto-columns>?
+                var rowsSlice = GridTemplateShorthand.TryTemplateAxis(leftRaw);
+                if (rowsSlice is null) return null;
+                if (!GridTemplateShorthand.TryParseAutoFlowSide(rightRaw, out var dense, out var autoColumns)) return null;
+
+                map[PropertyNames.GridTemplateRows] = rowsSlice;
+                map[PropertyNames.GridAutoFlow] = GridTemplateShorthand.BuildAutoFlow(column: true, dense);
+                if (autoColumns != null) map[PropertyNames.GridAutoColumns] = autoColumns;
+            }
+            else
+            {
+                // [ auto-flow && dense? ] <grid-auto-rows>? / <grid-template-columns>
+                var columnsSlice = GridTemplateShorthand.TryTemplateAxis(rightRaw);
+                if (columnsSlice is null) return null;
+                if (!GridTemplateShorthand.TryParseAutoFlowSide(leftRaw, out var dense, out var autoRows)) return null;
+
+                map[PropertyNames.GridTemplateColumns] = columnsSlice;
+                map[PropertyNames.GridAutoFlow] = GridTemplateShorthand.BuildAutoFlow(column: false, dense);
+                if (autoRows != null) map[PropertyNames.GridAutoRows] = autoRows;
+            }
+
+            return new MappedShorthandValue(map, tokens);
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<MappedShorthandValue>();
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateAreasValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateAreasValueConverter.cs
new file mode 100644
index 000000000..491ba7ab8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateAreasValueConverter.cs
@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a <c>grid-template-areas</c> value: the keyword <c>none</c> or a rectangular grid of quoted
+    /// strings accepted by the shared <see cref="GridTemplateAreasGrammar"/> (equal columns per row, each
+    /// named area a single filled rectangle). The authored text is preserved so the grid layout engine
+    /// re-parses the same value.
+    /// </summary>
+    internal sealed class GridTemplateAreasValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            var isNone = tokens.Length == 1 && tokens[0].Type == TokenType.Ident && tokens[0].Data.Isi(Keywords.None);
+
+            if (!isNone && GridTemplateAreasGrammar.TryParse(tokens) == null)
+                return null;
+
+            return new GridTemplateAreasValue(value);
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<GridTemplateAreasValue>();
+
+        private sealed class GridTemplateAreasValue : IPropertyValue
+        {
+            public GridTemplateAreasValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => Original.Text;
+            public TokenValue Original { get; }
+            public TokenValue ExtractFor(string name) => Original;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateShorthand.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateShorthand.cs
new file mode 100644
index 000000000..045d99fe6
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateShorthand.cs
@@ -0,0 +1,263 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Shared parsing for the CSS Grid mega-shorthands <c>grid-template</c> (<a
+    /// href="https://www.w3.org/TR/css-grid-2/#explicit-grid-shorthand">§7.4</a>) and <c>grid</c> (<a
+    /// href="https://www.w3.org/TR/css-grid-2/#grid-shorthand">§7.8</a>): splitting the value on the
+    /// top-level <c>/</c>, running the areas-form row scanner, and validating each partitioned slice
+    /// against the existing longhand grammars (<see cref="GridTrackListGrammar"/>/<see
+    /// cref="GridTemplateAreasGrammar"/>). The two converters stay thin over this helper.
+    /// </summary>
+    internal static class GridTemplateShorthand
+    {
+        internal static readonly Token AutoToken = new Token(TokenType.Ident, Keywords.Auto, TextPosition.Empty);
+        private static readonly Token NoneToken = new Token(TokenType.Ident, Keywords.None, TextPosition.Empty);
+
+        /// <summary>
+        /// Splits the flat token stream on top-level <c>/</c> delimiters, preserving each group's
+        /// whitespace. No bracket/paren depth counter is needed: functions are single <see
+        /// cref="FunctionToken"/>s (their args nested) and <c>[name]</c> groups hold only idents, so a
+        /// <c>/</c> never appears nested at the flat level (same reasoning as
+        /// <see cref="GridPlacementShorthand"/>).
+        /// </summary>
+        internal static List<List<Token>> SplitTopLevelSlash(IEnumerable<Token> value)
+        {
+            var groups = new List<List<Token>> { new List<Token>() };
+
+            foreach (var token in value)
+            {
+                if (token.Type == TokenType.Delim && token.Data == "/") groups.Add(new List<Token>());
+                else groups[groups.Count - 1].Add(token);
+            }
+
+            return groups;
+        }
+
+        internal static Token[] Significant(IEnumerable<Token> tokens) =>
+            tokens.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+        /// <summary>
+        /// Validates one axis of the <c>&lt;rows&gt; / &lt;columns&gt;</c> form — a <c>&lt;track-list&gt;</c> or
+        /// the keyword <c>none</c> (both accepted by the <c>grid-template-rows</c>/<c>-columns</c> longhands) —
+        /// returning the edge-trimmed slice, or <see langword="null"/> if invalid.
+        /// </summary>
+        internal static IReadOnlyList<Token> TryTemplateAxis(IReadOnlyList<Token> raw)
+        {
+            var significant = Significant(raw);
+            if (significant.Length == 0) return null;
+            if (significant.Length == 1 && significant[0].Type == TokenType.Ident && significant[0].Data.Isi(Keywords.None)) return Trim(raw);
+            return GridTrackListGrammar.TryParse(raw) != null ? Trim(raw) : null;
+        }
+
+        private static bool ContainsRepeat(IEnumerable<Token> significant) =>
+            significant.Any(t => t is FunctionToken fn && fn.Data.Isi(FunctionNames.Repeat));
+
+        /// <summary>Drops leading/trailing whitespace tokens, keeping internal whitespace.</summary>
+        internal static IReadOnlyList<Token> Trim(IReadOnlyList<Token> tokens)
+        {
+            var start = 0;
+            var end = tokens.Count - 1;
+            while (start <= end && tokens[start].Type == TokenType.Whitespace) start++;
+            while (end >= start && tokens[end].Type == TokenType.Whitespace) end--;
+
+            var result = new List<Token>(end - start + 1);
+            for (var i = start; i <= end; i++) result.Add(tokens[i]);
+            return result;
+        }
+
+        /// <summary>The <c>grid-auto-flow</c> token slice for the <c>grid</c> auto-flow forms.</summary>
+        internal static IReadOnlyList<Token> BuildAutoFlow(bool column, bool dense)
+        {
+            var flow = new List<Token> { new Token(TokenType.Ident, column ? Keywords.Column : Keywords.Row, TextPosition.Empty) };
+            if (dense)
+            {
+                flow.Add(Token.Whitespace);
+                flow.Add(new Token(TokenType.Ident, Keywords.Dense, TextPosition.Empty));
+            }
+            return flow;
+        }
+
+        /// <summary>
+        /// Parses a <c>grid-template</c> value (§7.4) into the three longhand slices. A <see langword="null"/>
+        /// out-slice means "omit it" (the longhand resets to its initial value). Returns <see langword="false"/>
+        /// for an invalid value (the whole declaration is then dropped).
+        /// </summary>
+        internal static bool TryParseTemplate(IEnumerable<Token> value,
+            out IReadOnlyList<Token> rows, out IReadOnlyList<Token> columns, out IReadOnlyList<Token> areas)
+        {
+            rows = columns = areas = null;
+
+            var groups = SplitTopLevelSlash(value);
+            if (groups.Count > 2) return false; // at most one top-level '/'
+
+            var leftRaw = groups[0];
+            var rightRaw = groups.Count == 2 ? groups[1] : null;
+            var left = Significant(leftRaw);
+            var right = rightRaw is null ? null : Significant(rightRaw);
+
+            // grid-template: none  →  all three longhands none.
+            if (right == null && left.Length == 1 && left[0].Type == TokenType.Ident && left[0].Data.Isi(Keywords.None))
+            {
+                rows = columns = areas = new[] { NoneToken };
+                return true;
+            }
+
+            if (left.Length == 0) return false;
+
+            if (left.Any(t => t.Type == TokenType.String))
+            {
+                // Areas form: [ <line-names>? <string> <track-size>? <line-names>? ]+ [ / <explicit-track-list> ]?
+                if (!TryScanAreasForm(left, out var rowsTokens, out var areaTokens)) return false;
+                if (GridTemplateAreasGrammar.TryParse(areaTokens) is null) return false;
+                if (GridTrackListGrammar.TryParse(rowsTokens) is null) return false;
+
+                rows = rowsTokens;
+                areas = areaTokens;
+
+                if (rightRaw != null)
+                {
+                    // The trailing columns are an <explicit-track-list> — a <track-list> with no repeat().
+                    if (right.Length == 0 || ContainsRepeat(right) || GridTrackListGrammar.TryParse(rightRaw) is null)
+                        return false;
+                    columns = Trim(rightRaw);
+                }
+
+                return true;
+            }
+
+            // rows / columns form: requires the slash; each side is a <track-list> or `none`.
+            if (rightRaw is null) return false;
+            var rowsSlice = TryTemplateAxis(leftRaw);
+            var columnsSlice = TryTemplateAxis(rightRaw);
+            if (rowsSlice is null || columnsSlice is null) return false;
+
+            rows = rowsSlice;
+            columns = columnsSlice;
+            return true;
+        }
+
+        /// <summary>
+        /// Scans the areas-form left side, synthesizing the <c>grid-template-rows</c> track list
+        /// (<paramref name="rowsOut"/>) and collecting the ordered <c>&lt;string&gt;</c> area tokens
+        /// (<paramref name="areaStrings"/>). Every emitted token is whitespace-separated so both round-trip
+        /// serialization (via <c>ToText</c>) and re-parsing are valid.
+        /// </summary>
+        private static bool TryScanAreasForm(Token[] toks, out List<Token> rowsOut, out List<Token> areaStrings)
+        {
+            rowsOut = new List<Token>();
+            areaStrings = new List<Token>();
+            var sawString = false;
+
+            var i = 0;
+            while (i < toks.Length)
+            {
+                var t = toks[i];
+
+                if (t.Type == TokenType.SquareBracketOpen)
+                {
+                    // Copy the [ name … ] line-name group (idents only) at the current line position, kept
+                    // compact as `[a b]` (edge spaces omitted, single space between names).
+                    if (rowsOut.Count > 0) rowsOut.Add(Token.Whitespace);
+                    rowsOut.Add(t);
+                    i++;
+                    var firstName = true;
+                    while (i < toks.Length && toks[i].Type != TokenType.SquareBracketClose)
+                    {
+                        if (toks[i].Type != TokenType.Ident) return false;
+                        if (!firstName) rowsOut.Add(Token.Whitespace);
+                        rowsOut.Add(toks[i]);
+                        firstName = false;
+                        i++;
+                    }
+                    if (i >= toks.Length) return false; // unclosed '['
+                    rowsOut.Add(toks[i]); // ']'
+                    i++;
+                    continue;
+                }
+
+                if (t.Type == TokenType.String)
+                {
+                    Emit(areaStrings, t);
+                    sawString = true;
+                    i++;
+
+                    // Optional single-token <track-size> for this row (else the row track is `auto`).
+                    if (i < toks.Length && toks[i].Type != TokenType.SquareBracketOpen && toks[i].Type != TokenType.String)
+                    {
+                        if (GridTrackListGrammar.TryParseTrackSizeList(new[] { toks[i] }) is null) return false;
+                        Emit(rowsOut, toks[i]);
+                        i++;
+                    }
+                    else
+                    {
+                        Emit(rowsOut, AutoToken);
+                    }
+
+                    continue;
+                }
+
+                // A track-size or stray token with no preceding string at this position is invalid.
+                return false;
+            }
+
+            return sawString;
+        }
+
+        private static void Emit(List<Token> tokens, Token token)
+        {
+            if (tokens.Count > 0) tokens.Add(Token.Whitespace);
+            tokens.Add(token);
+        }
+
+        /// <summary>
+        /// Parses the <c>[ auto-flow &amp;&amp; dense? ] &lt;track-size&gt;*</c> side of a <c>grid</c> auto-flow
+        /// form. Returns <see langword="false"/> when <c>auto-flow</c> is absent or the value is malformed;
+        /// <paramref name="autoTracks"/> is null when the optional track-size list is omitted (reset to initial).
+        /// </summary>
+        internal static bool TryParseAutoFlowSide(IReadOnlyList<Token> raw, out bool dense, out IReadOnlyList<Token> autoTracks)
+        {
+            dense = false;
+            autoTracks = null;
+            var hasAutoFlow = false;
+
+            var i = 0;
+            while (i < raw.Count)
+            {
+                var t = raw[i];
+                if (t.Type == TokenType.Whitespace) { i++; continue; }
+                if (t.Type == TokenType.Ident && t.Data.Isi(Keywords.AutoFlow))
+                {
+                    if (hasAutoFlow) return false;
+                    hasAutoFlow = true;
+                    i++;
+                    continue;
+                }
+                if (t.Type == TokenType.Ident && t.Data.Isi(Keywords.Dense))
+                {
+                    if (dense) return false;
+                    dense = true;
+                    i++;
+                    continue;
+                }
+                break;
+            }
+
+            if (!hasAutoFlow) return false;
+
+            var rest = new List<Token>();
+            for (; i < raw.Count; i++) rest.Add(raw[i]);
+            var trimmed = Trim(rest);
+
+            if (trimmed.Count > 0)
+            {
+                if (GridTrackListGrammar.TryParseTrackSizeList(trimmed) is null) return false;
+                autoTracks = trimmed;
+            }
+
+            return true;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateShorthandValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateShorthandValueConverter.cs
new file mode 100644
index 000000000..82537bac0
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateShorthandValueConverter.cs
@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The <c>grid-template</c> shorthand (CSS Grid §7.4), expanding to <c>grid-template-rows</c> /
+    /// <c>grid-template-columns</c> / <c>grid-template-areas</c>. An omitted axis is reset to its initial
+    /// value (<c>none</c>) by <see cref="ShorthandProperty.Export"/> when its slice is absent.
+    /// </summary>
+    internal sealed class GridTemplateShorthandValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            if (!GridTemplateShorthand.TryParseTemplate(value, out var rows, out var columns, out var areas))
+                return null;
+
+            var map = new Dictionary<string, IReadOnlyList<Token>>();
+            if (rows != null) map[PropertyNames.GridTemplateRows] = rows;
+            if (columns != null) map[PropertyNames.GridTemplateColumns] = columns;
+            if (areas != null) map[PropertyNames.GridTemplateAreas] = areas;
+
+            return new MappedShorthandValue(map, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties) => properties.Guard<MappedShorthandValue>();
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateValueConverter.cs
new file mode 100644
index 000000000..a2abf5c83
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/GridTemplateValueConverter.cs
@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Validates a <c>grid-template-columns</c>/<c>grid-template-rows</c> value: accepts the keyword
+    /// <c>none</c>, the <c>subgrid</c> keyword, or any <c>&lt;track-list&gt;</c> the shared
+    /// <see cref="GridTrackListGrammar"/> recognizes (lengths, %, <c>fr</c>, <c>auto</c>,
+    /// <c>min-content</c>/<c>max-content</c>, <c>minmax()</c>, <c>fit-content()</c>, <c>repeat()</c>),
+    /// rejecting everything else so an invalid template is dropped at parse time. The parse produced here to
+    /// validate is <b>kept</b> and exposed as a <see cref="CssProperty{T}"/> via
+    /// <see cref="ITypedPropertyValue{T}"/>, so the grid layout engine (Layer B) reads the already-parsed
+    /// template instead of re-parsing the same string.
+    /// </summary>
+    internal sealed class GridTemplateValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var tokens = value.Where(t => t.Type != TokenType.Whitespace).ToArray();
+
+            var isNone = tokens.Length == 1 && tokens[0].Type == TokenType.Ident && tokens[0].Data.Isi(Keywords.None);
+
+            GridTemplate template = null;
+            if (!isNone)
+            {
+                template = GridTrackListGrammar.TryParse(tokens);
+                if (template is null) return null;
+            }
+
+            return new GridTemplateValue(value, template);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<GridTemplateValue>();
+        }
+
+        /// <summary>
+        /// Builds the box-side <see cref="CssProperty{T}"/> for a grid-template value directly from its authored
+        /// string, for the cascade paths that apply a plain string rather than a Layer A parse result (the
+        /// initial-value seed, a resolved global keyword, an inherited copy, a var()-resolved string). A CSS-wide
+        /// keyword becomes a global value; a string still containing <c>var(</c> stays unresolved (never parsed
+        /// into a bogus template); otherwise the track list is parsed by the same <see cref="GridTrackListGrammar"/>
+        /// the converter uses — keeping all <see cref="CssProperty{T}"/> construction in the CSS-OM layer.
+        /// </summary>
+        internal static CssProperty<GridTemplate> FromCssText(string value)
+        {
+            if (CssGlobalKeywords.TryParse(value, out var keyword))
+                return CssProperty<GridTemplate>.Global(keyword);
+            if (value.IndexOf("var(", StringComparison.OrdinalIgnoreCase) >= 0)
+                return CssProperty<GridTemplate>.Unresolved(value);
+            var template = GridTrackListGrammar.TryParse(Tokenize(value));
+            return CssProperty<GridTemplate>.FromValue(value, template);
+        }
+
+        /// <summary>Tokenizes an authored value string with the CSS-OM <see cref="Lexer"/> (whitespace/EOF
+        /// stripped) — the CSS-OM equivalent of the Html-layer <c>CssValueParser.GetCssTokens</c>, so this
+        /// Layer A factory has no upward dependency on <c>Html.Core.Parse</c>.</summary>
+        private static List<Token> Tokenize(string value)
+        {
+            using (var lexer = new Lexer(value) { IsInValue = false })
+            {
+                var tokens = new List<Token>();
+                Token token;
+                do
+                {
+                    token = lexer.Get();
+                    if (token.Type != TokenType.EndOfFile && token.Type != TokenType.Whitespace)
+                        tokens.Add(token);
+                } while (token.Type != TokenType.EndOfFile);
+                return tokens;
+            }
+        }
+
+        private sealed class GridTemplateValue : IPropertyValue, ITypedPropertyValue<GridTemplate>
+        {
+            private readonly CssProperty<GridTemplate> _typed;
+
+            public GridTemplateValue(IEnumerable<Token> tokens, GridTemplate template)
+            {
+                Original = new TokenValue(tokens);
+                // template is null for the `none` keyword — a resolved value with a null GridTemplate, which
+                // the engine treats as an empty (no explicit tracks) grid, exactly like the string path.
+                _typed = CssProperty<GridTemplate>.FromValue(Original.Text, template);
+            }
+
+            public string CssText => Original.Text;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name) => Original;
+
+            public CssProperty<GridTemplate> GetTypedValue() => _typed;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/IdentifierValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/IdentifierValueConverter.cs
new file mode 100644
index 000000000..4f5e86b68
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/IdentifierValueConverter.cs
@@ -0,0 +1,84 @@
+using System;
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class IdentifierValueConverter : IValueConverter
+    {
+        private readonly Func<IEnumerable<Token>, string> _converter;
+
+        public IdentifierValueConverter(Func<IEnumerable<Token>, string> converter)
+        {
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var result = _converter(value);
+            return result != null ? new IdentifierValue(result, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<IdentifierValue>();
+        }
+
+        private sealed class IdentifierValue : IPropertyValue
+        {
+            public IdentifierValue(string identifier, IEnumerable<Token> tokens)
+            {
+                CssText = identifier;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText { get; }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+
+    internal sealed class IdentifierValueConverter<T> : IValueConverter
+    {
+        private readonly string _identifier;
+        private readonly T _result;
+
+        public IdentifierValueConverter(string identifier, T result)
+        {
+            _identifier = identifier;
+            _result = result;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            return value.Is(_identifier) ? new IdentifierValue(_identifier, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<IdentifierValue>();
+        }
+
+        private sealed class IdentifierValue : IPropertyValue
+        {
+            public IdentifierValue(string identifier, IEnumerable<Token> tokens)
+            {
+                CssText = identifier;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText { get; }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ListValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ListValueConverter.cs
new file mode 100644
index 000000000..d1218a127
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/ListValueConverter.cs
@@ -0,0 +1,107 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ListValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+
+        public ListValueConverter(IValueConverter converter)
+        {
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var items = value.ToList();
+            var values = new IPropertyValue[items.Count];
+
+            for (var i = 0; i < items.Count; i++)
+            {
+                values[i] = _converter.Convert(items[i]);
+
+                if (values[i] == null) return null;
+            }
+
+            return values.Length != 1 ? new ListValue(values, value) : values[0];
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var result = properties.Guard<ListValue>();
+
+            if (result == null)
+            {
+                var valueList = new List<List<Token>>[properties.Length];
+                var dummies = new Property[properties.Length];
+                var max = 0;
+
+                for (var i = 0; i < properties.Length; i++)
+                {
+                    var value = properties[i].DeclaredValue;
+                    valueList[i] = value != null ? value.Original.ToList() : new List<List<Token>>();
+
+                    dummies[i] = PropertyFactory.Instance.CreateLonghand(properties[i].Name);
+                    max = Math.Max(max, valueList[i].Count);
+                }
+
+                var values = new IPropertyValue[max];
+
+                for (var i = 0; i < max; i++)
+                {
+                    for (var j = 0; j < dummies.Length; j++)
+                    {
+                        var list = valueList[j];
+                        var tokens = list.Count > i ? list[i] : Enumerable.Empty<Token>();
+                        dummies[j].TrySetValue(new TokenValue(tokens));
+                    }
+
+                    values[i] = _converter.Construct(dummies);
+                }
+
+                result = new ListValue(values, Enumerable.Empty<Token>());
+            }
+
+            return result;
+        }
+
+        private sealed class ListValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] _values;
+
+            public ListValue(IPropertyValue[] values, IEnumerable<Token> tokens)
+            {
+                _values = values;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get { return string.Join(", ", _values.Select(m => m.CssText)); }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var value in _values)
+                {
+                    var extracted = value.ExtractFor(name);
+
+                    if (extracted != null)
+                    {
+                        if (tokens.Count > 0) tokens.Add(Token.Comma);
+
+                        tokens.AddRange(extracted);
+                    }
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OneOrMoreValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OneOrMoreValueConverter.cs
new file mode 100644
index 000000000..5c064edd7
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OneOrMoreValueConverter.cs
@@ -0,0 +1,101 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OneOrMoreValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+        private readonly int _maximum;
+        private readonly int _minimum;
+
+        public OneOrMoreValueConverter(IValueConverter converter, int minimum, int maximum)
+        {
+            _converter = converter;
+            _minimum = minimum;
+            _maximum = maximum;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var items = value.ToItems();
+            var n = items.Count;
+
+            if (n < _minimum || n > _maximum) return null;
+            var values = new IPropertyValue[items.Count];
+
+            for (var i = 0; i < n; i++)
+            {
+                values[i] = _converter.Convert(items[i]);
+
+                if (values[i] == null) return null;
+            }
+
+            return new MultipleValue(values, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var result = properties.Guard<MultipleValue>();
+
+            if (result == null)
+            {
+                var values = new IPropertyValue[properties.Length];
+
+                for (var i = 0; i < properties.Length; i++)
+                {
+                    var value = _converter.Construct(new[] { properties[i] });
+
+                    if (value == null) return null;
+
+                    values[i] = value;
+                }
+
+                result = new MultipleValue(values, Enumerable.Empty<Token>());
+            }
+
+            return result;
+        }
+
+        private sealed class MultipleValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] _values;
+
+            public MultipleValue(IPropertyValue[] values, IEnumerable<Token> tokens)
+            {
+                _values = values;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    return string.Join(" ",
+                        _values.Where(m => !string.IsNullOrEmpty(m.CssText)).Select(m => m.CssText));
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var value in _values)
+                {
+                    var extracted = value.ExtractFor(name);
+
+                    if (extracted != null)
+                    {
+                        if (tokens.Count > 0) tokens.Add(Token.Whitespace);
+
+                        tokens.AddRange(extracted);
+                    }
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OptionValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OptionValueConverter.cs
new file mode 100644
index 000000000..847bdc116
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OptionValueConverter.cs
@@ -0,0 +1,89 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OptionValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+
+        public OptionValueConverter(IValueConverter converter)
+        {
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            return value.Any() ? _converter.Convert(value) : new OptionValue(value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var value = _converter.Construct(properties);
+            // A longhand this optional shorthand slot maps to may carry the literal "initial"
+            // sentinel (see ShorthandProperty.Export) when the original shorthand text omitted it -
+            // that's correct for cascade purposes, but re-serializing the shorthand must omit it
+            // entirely (matching real browser serialization of e.g. "border: 1px outset" - the never-
+            // specified color must not round-trip as "1px outset initial"), the same as if this slot
+            // had never been set at all.
+            return value is null || value.CssText == Keywords.Initial ? new OptionValue(Enumerable.Empty<Token>()) : value;
+        }
+
+        private sealed class OptionValue : IPropertyValue
+        {
+            public OptionValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => string.Empty;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return null;
+            }
+        }
+    }
+
+    internal sealed class OptionValueConverter<T> : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+
+        public OptionValueConverter(IValueConverter converter)
+        {
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            return value.Any() ? _converter.Convert(value) : new OptionValue(value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var value = _converter.Construct(properties);
+            // See OptionValueConverter.Construct above for why the "initial" sentinel must be
+            // suppressed here rather than serialized literally.
+            return value is null || value.CssText == Keywords.Initial ? new OptionValue(Enumerable.Empty<Token>()) : value;
+        }
+
+        private sealed class OptionValue : IPropertyValue
+        {
+            public OptionValue(IEnumerable<Token> tokens)
+            {
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => string.Empty;
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return null;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrValueConverter.cs
new file mode 100644
index 000000000..f00791e28
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrValueConverter.cs
@@ -0,0 +1,26 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OrValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _next;
+        private readonly IValueConverter _previous;
+
+        public OrValueConverter(IValueConverter previous, IValueConverter next)
+        {
+            _previous = previous;
+            _next = next;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            return _previous.Convert(value) ?? _next.Convert(value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return _previous.Construct(properties) ?? _next.Construct(properties);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrderIndependentOptionsConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrderIndependentOptionsConverter.cs
new file mode 100644
index 000000000..43bd775e3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrderIndependentOptionsConverter.cs
@@ -0,0 +1,173 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    // Like UnorderedOptionsConverter (the WithAny combinator), but matches the operands in any order rather
+    // than only in declaration order. WithAny matches greedily left-to-right, which fails whenever an
+    // earlier converter claims a token a later one also accepts - e.g. "list-style: none square", where
+    // list-style-type takes "none" before list-style-image can.
+    //
+    // Use this ONLY for shorthands whose operands are order-independent with no positional tie-break. Some
+    // "||" (any-order) shorthands still assign longhands by position and so must NOT be reordered: animation's
+    // first <time> is animation-duration and the second is animation-delay (CSS Animations 1 3), background's
+    // first <visual-box> is background-origin and the second is background-clip (CSS Backgrounds 3 2.10), and
+    // transform-origin keeps its length form axis-ordered. The declaration-order matcher (WithAny) already
+    // satisfies those positional rules, so those shorthands stay on it; list-style (CSS Lists 3) and columns
+    // (CSS Multi-column 1) have no such rule and genuinely need order-independent matching.
+    internal sealed class OrderIndependentOptionsConverter : IValueConverter
+    {
+        // The reorder search is O(n!); every shorthand that uses this converter has only a few operands, so
+        // cap it well below the large "||" shorthands (background has 7-8 operands) as a safety net.
+        private const int MaxReorderableConverters = 6;
+
+        private readonly IValueConverter[] _converters;
+
+        public OrderIndependentOptionsConverter(params IValueConverter[] converters)
+        {
+            _converters = converters;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            // Fast path: match the operands in declaration order, identical to WithAny. This covers every
+            // already-ordered value and keeps its serialization byte-for-byte the same.
+            var list = new List<Token>(value);
+            var options = new IPropertyValue[_converters.Length];
+            var matched = true;
+
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                options[i] = _converters[i].VaryAll(list);
+
+                if (options[i] == null)
+                {
+                    matched = false;
+                    break;
+                }
+            }
+
+            if (matched && list.Count == 0) return new OptionsValue(options, value);
+
+            // Fallback: search converter orderings until one consumes every token, then keep the results in
+            // canonical converter order so ExtractFor still resolves each longhand.
+            if (_converters.Length > MaxReorderableConverters) return null;
+
+            var reordered = new IPropertyValue[_converters.Length];
+            var used = new bool[_converters.Length];
+            var remaining = new List<Token>(value);
+
+            return TryReorder(remaining, used, reordered)
+                ? new OptionsValue(reordered, value)
+                : null;
+        }
+
+        // Depth-first search over converter orderings: each step lets an unused converter consume a leading
+        // run of tokens and recurses on the rest; once every token is consumed, any converter left unused is
+        // assigned its empty default (non-null only for optional operands).
+        private bool TryReorder(List<Token> remaining, bool[] used, IPropertyValue[] options)
+        {
+            if (remaining.Count == 0)
+            {
+                for (var i = 0; i < _converters.Length; i++)
+                {
+                    if (used[i]) continue;
+
+                    var empty = _converters[i].ConvertDefault();
+
+                    if (empty == null) return false;
+
+                    options[i] = empty;
+                }
+
+                return true;
+            }
+
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                if (used[i]) continue;
+
+                var snapshot = new List<Token>(remaining);
+                var value = _converters[i].VaryStart(remaining);
+
+                if (value != null && remaining.Count < snapshot.Count)
+                {
+                    used[i] = true;
+                    options[i] = value;
+
+                    if (TryReorder(remaining, used, options)) return true;
+
+                    used[i] = false;
+                }
+
+                remaining.Clear();
+                remaining.AddRange(snapshot);
+            }
+
+            return false;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var result = properties.Guard<OptionsValue>();
+
+            if (result != null) return result;
+
+            var values = new IPropertyValue[_converters.Length];
+
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                var value = _converters[i].Construct(properties);
+
+                if (value == null) return null;
+
+                values[i] = value;
+            }
+
+            result = new OptionsValue(values, Enumerable.Empty<Token>());
+
+            return result;
+        }
+
+        private sealed class OptionsValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] _options;
+
+            public OptionsValue(IPropertyValue[] options, IEnumerable<Token> tokens)
+            {
+                _options = options;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    return string.Join(" ",
+                        _options.Where(m => !string.IsNullOrEmpty(m.CssText)).Select(m => m.CssText));
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var option in _options)
+                {
+                    var extracted = option.ExtractFor(name);
+
+                    if (extracted != null && extracted.Count > 0)
+                    {
+                        if (tokens.Count > 0) tokens.Add(Token.Whitespace);
+
+                        tokens.AddRange(extracted);
+                    }
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrderedOptionsConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrderedOptionsConverter.cs
new file mode 100644
index 000000000..5ed015cb1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/OrderedOptionsConverter.cs
@@ -0,0 +1,105 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class OrderedOptionsConverter : IValueConverter
+    {
+        private readonly IValueConverter[] _converters;
+
+        public OrderedOptionsConverter(params IValueConverter[] converters)
+        {
+            _converters = converters;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var list = new List<Token>(value);
+            var options = new IPropertyValue[_converters.Length];
+
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                options[i] = _converters[i].VaryStart(list);
+
+                if (options[i] == null) return null;
+            }
+
+            return list.Count == 0 ? new OptionsValue(options, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var result = properties.Guard<OptionsValue>();
+
+            if (result == null)
+            {
+                var values = new IPropertyValue[_converters.Length];
+
+                for (var i = 0; i < _converters.Length; i++)
+                {
+                    var value = _converters[i].Construct(properties);
+
+                    if (value == null) return null;
+
+                    values[i] = value;
+                }
+
+                result = new OptionsValue(values, Enumerable.Empty<Token>());
+            }
+
+            return result;
+        }
+
+        private sealed class OptionsValue : IPropertyValue, IEnumerable<IPropertyValue>
+        {
+            private readonly IPropertyValue[] _options;
+
+            public OptionsValue(IPropertyValue[] options, IEnumerable<Token> tokens)
+            {
+                _options = options;
+                Original = new TokenValue(tokens);
+            }
+
+            IEnumerator<IPropertyValue> IEnumerable<IPropertyValue>.GetEnumerator()
+            {
+                return ((IEnumerable<IPropertyValue>)_options).GetEnumerator();
+            }
+
+            IEnumerator IEnumerable.GetEnumerator()
+            {
+                return _options.GetEnumerator();
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    return string.Join(" ",
+                        _options.Where(m => !string.IsNullOrEmpty(m.CssText)).Select(m => m.CssText));
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var option in _options)
+                {
+                    var extracted = option.ExtractFor(name);
+
+                    if (extracted != null && extracted.Count > 0)
+                    {
+                        if (tokens.Count > 0) tokens.Add(Token.Whitespace);
+
+                        tokens.AddRange(extracted);
+                    }
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/PeriodicValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/PeriodicValueConverter.cs
new file mode 100644
index 000000000..e9c234bb3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/PeriodicValueConverter.cs
@@ -0,0 +1,132 @@
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PeriodicValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+        private readonly string[] _labels;
+
+        public PeriodicValueConverter(IValueConverter converter, string[] labels)
+        {
+            Debug.Assert(labels.Length == 0 || labels.Length == 4 || labels.Length == 2);
+
+            _converter = converter;
+            _labels = labels;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var list = new List<Token>(value);
+            var options = new IPropertyValue[_labels.Length == 0 ? 4 : _labels.Length];
+
+            if (list.Count == 0) return null;
+
+            for (var i = 0; i < options.Length && list.Count != 0; i++)
+            {
+                options[i] = _converter.VaryStart(list);
+
+                if (options[i] == null) return null;
+            }
+
+            return list.Count == 0 ? new PeriodicValue(options, value, _labels) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var options = new IPropertyValue[_labels.Length];
+
+            for (var i = 0; i < _labels.Length; i++)
+                options[i] = _converter.Construct(properties.Where(m => m.Name == _labels[i]).ToArray());
+
+            return options.All(opt => opt != null)
+                ? new PeriodicValue(options, Enumerable.Empty<Token>(), _labels)
+                : null;
+        }
+
+        private sealed class PeriodicValue : IPropertyValue
+        {
+            private readonly string[] _labels;
+            private readonly IPropertyValue[] _values;
+
+            public PeriodicValue(IPropertyValue[] options, IEnumerable<Token> tokens, string[] labels)
+            {
+                Debug.Assert(labels.Length == 0 || labels.Length == 2 || labels.Length == 4);
+
+                _values = new IPropertyValue[labels.Length == 0 ? 4 : labels.Length];
+
+                if (_values.Length == 0 || _values.Length == 4)
+                {
+                    //Top, right, bottom, left
+                    _values[0] = options[0];
+                    _values[1] = options[1] ?? _values[0];
+                    _values[2] = options[2] ?? _values[0];
+                    _values[3] = options[3] ?? _values[1];
+                }
+                else
+                {
+                    _values[0] = options[0];
+                    _values[1] = options[1] ?? _values[0];
+                }
+
+                Original = new TokenValue(tokens);
+                _labels = labels;
+            }
+
+            private string[] Values
+            {
+                get
+                {
+                    if (_values.Length == 0 || _values.Length == 4)
+                    {
+                        var top = _values[0].CssText;
+                        var right = _values[1].CssText;
+                        var bottom = _values[2].CssText;
+                        var left = _values[3].CssText;
+
+                        if (!right.Is(left))
+                            return new[] { top, right, bottom, left };
+
+                        if (!top.Is(bottom))
+                            return new[] { top, right, bottom };
+
+                        return right.Is(top)
+                                   ? new[] { top }
+                                   : new[] { top, right };
+                    }
+
+                    var first = _values[0].CssText;
+                    var second = _values[1].CssText;
+
+                    return first.Is(second)
+                               ? new[] { first }
+                               : new[] { first, second };
+                }
+            }
+
+            public string CssText => string.Join(" ", Values);
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                if (name.Is(_labels[0])) return _values[0].Original;
+
+                if (name.Is(_labels[1])) return _values[1].Original;
+
+                if (_labels.Length == 4)
+                {
+                    if (name.Is(_labels[2]))
+                        return _values[2].Original;
+
+                    if (name.Is(_labels[3]))
+                        return _values[3].Original;
+                }
+
+                return null;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/RequiredValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/RequiredValueConverter.cs
new file mode 100644
index 000000000..0a7371282
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/RequiredValueConverter.cs
@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RequiredValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+
+        public RequiredValueConverter(IValueConverter converter)
+        {
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            return value.Any() ? _converter.Convert(value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return _converter.Construct(properties);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StartsWithValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StartsWithValueConverter.cs
new file mode 100644
index 000000000..9f379f99a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StartsWithValueConverter.cs
@@ -0,0 +1,84 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StartsWithValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _converter;
+        private readonly string _data;
+        private readonly TokenType _type;
+
+        public StartsWithValueConverter(TokenType type, string data, IValueConverter converter)
+        {
+            _type = type;
+            _data = data;
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var rest = Transform(value);
+            return rest != null ? CreateFrom(_converter.Convert(rest), value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var value = _converter.Construct(properties);
+            return value != null ? CreateFrom(value, Enumerable.Empty<Token>()) : null;
+        }
+
+        private IPropertyValue CreateFrom(IPropertyValue value, IEnumerable<Token> tokens)
+        {
+            return value != null ? new StartValue(_data, value, tokens) : null;
+        }
+
+        private List<Token> Transform(IEnumerable<Token> values)
+        {
+            using (var enumerator = values.GetEnumerator())
+            {
+                bool hasCurrent;
+                while ((hasCurrent = enumerator.MoveNext()) && enumerator.Current.Type == TokenType.Whitespace)
+                {
+                    //Empty on purpose.
+                }
+
+                // An empty (or whitespace-only) input - e.g. ConvertDefault()'s Enumerable.Empty<Token>() -
+                // must resolve to "no match", not throw, exactly like every other converter's empty-input
+                // behavior (e.g. DictionaryValueConverter's ToIdentifier() returning null).
+                if (!hasCurrent) return null;
+
+                if (enumerator.Current.Type != _type || !enumerator.Current.Data.Isi(_data)) return null;
+                var list = new List<Token>();
+
+                while (enumerator.MoveNext())
+                    if (enumerator.Current.Type != TokenType.Whitespace || list.Count != 0)
+                        list.Add(enumerator.Current);
+
+                return list;
+            }
+        }
+
+        private sealed class StartValue : IPropertyValue
+        {
+            private readonly string _start;
+            private readonly IPropertyValue _value;
+
+            public StartValue(string start, IPropertyValue value, IEnumerable<Token> tokens)
+            {
+                _start = start;
+                _value = value;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => string.Concat(_start, " ", _value.CssText);
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return _value.ExtractFor(name);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringFunctionConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringFunctionConverter.cs
new file mode 100644
index 000000000..38472be8d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringFunctionConverter.cs
@@ -0,0 +1,88 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Converter for the string() function used in content and string-set properties.
+    /// Supports: string(name), string(name, first), string(name, last), string(name, start), string(name, first-except)
+    /// </summary>
+    internal sealed class StringFunctionConverter : IValueConverter
+    {
+        private static readonly string[] ValidKeywords = { "first", "last", "start", "first-except" };
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var first = value.OnlyOrDefault();
+
+            if (!(first is FunctionToken funcToken) || !funcToken.Data.Equals("string", System.StringComparison.OrdinalIgnoreCase))
+                return null;
+
+            // First argument must be the string name (identifier)
+            var argToken = funcToken.ArgumentTokens.FirstOrDefault();
+
+            if (!(argToken is KeywordToken nameToken))
+                return null;
+
+            var name = nameToken.Data;
+
+            // Default keyword is "first" if not specified
+            var keyword = "first";
+
+            // Check for optional second argument (keyword)
+            var args = funcToken.ArgumentTokens
+ .Where(t => t.Type != TokenType.Comma && t.Type != TokenType.Whitespace)
+.ToArray();
+
+            if (args.Length > 1)
+            {
+                if (args[1] is KeywordToken keywordToken)
+                {
+                    var kw = keywordToken.Data.ToLowerInvariant();
+                    if (!ValidKeywords.Contains(kw))
+                        return null;
+
+                    keyword = kw;
+                }
+                else
+                {
+                    return null;
+                }
+            }
+
+            return new StringFunctionValue(name, keyword, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<StringFunctionValue>();
+        }
+
+        private sealed class StringFunctionValue : IPropertyValue
+        {
+            private readonly string _name;
+            private readonly string _keyword;
+
+            public StringFunctionValue(string name, string keyword, IEnumerable<Token> tokens)
+            {
+                _name = name;
+                _keyword = keyword;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => _keyword == "first"
+             ? $"string({_name})"
+           : $"string({_name}, {_keyword})";
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+
+            public string Name => _name;
+            public string Keyword => _keyword;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringSetValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringSetValueConverter.cs
new file mode 100644
index 000000000..595bc2db8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringSetValueConverter.cs
@@ -0,0 +1,136 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Converter for the string-set property.
+    /// Syntax: string-set: [ &lt;custom-ident&gt; &lt;content-list&gt; ]# | none
+    /// where &lt;content-list&gt; = [ &lt;string&gt; | &lt;counter()&gt; | &lt;counters()&gt; | &lt;content()&gt; | &lt;attr()&gt; ]+
+    /// </summary>
+    internal sealed class StringSetValueConverter : IValueConverter
+    {
+        private readonly IValueConverter _contentListItemConverter;
+
+        public StringSetValueConverter()
+        {
+            // Content list can contain: strings, counter(), counters(), content(), attr(), string()
+            _contentListItemConverter = Converters.StringConverter
+                .Or(Converters.CounterConverter)
+                .Or(new ContentFunctionConverter())
+                .Or(new StringFunctionConverter())
+                .Or(Converters.AttrConverter);
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var first = value.OnlyOrDefault();
+
+            // Check for "none" keyword
+            if (first is KeywordToken keyword && keyword.Data.Isi(Keywords.None))
+            {
+                return new StringSetValue(null, value);
+            }
+
+            // Parse comma-separated list of name/content-list pairs using ToList()
+            var items = value.ToList(); // This splits by commas, returns List<List<Token>>
+            var pairs = new List<StringSetPair>();
+
+            foreach (var item in items)
+            {
+                var pair = ParsePair(item);
+                if (pair == null)
+                    return null;
+
+                pairs.Add(pair);
+            }
+
+            if (pairs.Count == 0)
+                return null;
+
+            return new StringSetValue(pairs, value);
+        }
+
+        private StringSetPair ParsePair(List<Token> tokens)
+        {
+            if (tokens.Count < 2)
+                return null;
+
+            // First token should be an identifier (the name)
+            if (!(tokens[0] is KeywordToken nameToken) || nameToken.Type != TokenType.Ident)
+                return null;
+
+            var name = nameToken.Data;
+
+            // Remaining tokens form the content-list - split by whitespace
+            var contentItems = tokens.Skip(1).ToItems();
+            var values = new List<IPropertyValue>();
+
+            foreach (var item in contentItems)
+            {
+                var converted = _contentListItemConverter.Convert(item);
+                if (converted == null)
+                    return null;
+
+                values.Add(converted);
+            }
+
+            if (values.Count == 0)
+                return null;
+
+            return new StringSetPair(name, values);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<StringSetValue>();
+        }
+
+        private sealed class StringSetPair
+        {
+            public StringSetPair(string name, List<IPropertyValue> contentList)
+            {
+                Name = name;
+                ContentList = contentList;
+            }
+
+            public string Name { get; }
+            public List<IPropertyValue> ContentList { get; }
+        }
+
+        private sealed class StringSetValue : IPropertyValue
+        {
+            private readonly List<StringSetPair> _pairs;
+
+            public StringSetValue(List<StringSetPair> pairs, IEnumerable<Token> tokens)
+            {
+                _pairs = pairs;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    if (_pairs == null || _pairs.Count == 0)
+                        return Keywords.None;
+
+                    var pairStrings = _pairs.Select(pair =>
+                         {
+                             var contentStr = string.Join(" ", pair.ContentList.Select(c => c.CssText));
+                             return $"{pair.Name} {contentStr}";
+                         });
+
+                    return string.Join(", ", pairStrings);
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringValueConverter.cs
new file mode 100644
index 000000000..77f15d532
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringValueConverter.cs
@@ -0,0 +1,38 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StringValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var str = value.ToCssString();
+            return str != null ? new StringValue(str, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<StringValue>();
+        }
+
+        private sealed class StringValue : IPropertyValue
+        {
+            private readonly string _value;
+
+            public StringValue(string value, IEnumerable<Token> tokens)
+            {
+                _value = value;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => _value.StylesheetString();
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringsValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringsValueConverter.cs
new file mode 100644
index 000000000..e54f52d61
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StringsValueConverter.cs
@@ -0,0 +1,55 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StringsValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var items = value.ToItems();
+            var n = items.Count;
+
+            if (n % 2 != 0) return null;
+
+            var values = new string[items.Count];
+
+            for (var i = 0; i < n; i++)
+            {
+                values[i] = items[i].ToCssString();
+
+                if (values[i] == null) return null;
+            }
+
+            return new StringsValue(values, value);
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<StringsValue>();
+        }
+
+        private sealed class StringsValue : IPropertyValue
+        {
+            private readonly string[] _values;
+
+            public StringsValue(string[] values, IEnumerable<Token> tokens)
+            {
+                _values = values;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get { return string.Join(" ", _values.Select(m => m.StylesheetString())); }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StructValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StructValueConverter.cs
new file mode 100644
index 000000000..356ab935d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/StructValueConverter.cs
@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StructValueConverter<T> : IValueConverter
+        where T : struct, IFormattable
+    {
+        private readonly Func<IEnumerable<Token>, T?> _converter;
+
+        public StructValueConverter(Func<IEnumerable<Token>, T?> converter)
+        {
+            _converter = converter;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var val = _converter(value);
+            return val.HasValue ? new StructValue(val.Value, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<StructValue>();
+        }
+
+        private sealed class StructValue : IPropertyValue
+        {
+            private readonly T _value;
+
+            public StructValue(T value, IEnumerable<Token> tokens)
+            {
+                _value = value;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => _value.ToString(null, CultureInfo.InvariantCulture);
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/TimeBasedShorthandConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/TimeBasedShorthandConverter.cs
new file mode 100644
index 000000000..01504d044
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/TimeBasedShorthandConverter.cs
@@ -0,0 +1,209 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// Specialized converter for CSS properties with time-based disambiguation rules.
+    /// Handles animation and transition shorthands where two time values must be
+    /// interpreted as duration (first) and delay (second) per CSS spec.
+    /// </summary>
+    internal sealed class TimeBasedShorthandConverter : IValueConverter
+    {
+        private readonly IValueConverter[] _converters;
+        private readonly int _durationIndex;
+        private readonly int _delayIndex;
+
+        public TimeBasedShorthandConverter(int durationIndex, int delayIndex, params IValueConverter[] converters)
+        {
+            _converters = converters;
+            _durationIndex = durationIndex;
+            _delayIndex = delayIndex;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var list = new List<Token>(value);
+            if (list.Count == 0)
+            {
+                return null;
+            }
+
+            var options = new IPropertyValue[_converters.Length];
+            var timeValuesFound = 0;
+
+            // Track which converters have been matched
+            var matched = new bool[_converters.Length];
+
+            // Parse tokens, applying special logic for time values
+            while (list.Count > 0)
+            {
+                var foundMatch = false;
+
+                // Try each unmatched converter
+                for (var i = 0; i < _converters.Length; i++)
+                {
+                    if (matched[i])
+                    {
+                        continue;
+                    }
+
+                    // Special handling for time converters
+                    var isTimeConverter = i == _durationIndex || i == _delayIndex;
+
+                    if (isTimeConverter)
+                    {
+                        // Try to match a time value (without consuming)
+                        var testList = new List<Token>(list);
+                        if (TryMatchTime(testList, out var timeValue))
+                        {
+                            // We found a time value
+                            // Assign to duration if it's the first time value, delay if it's the second
+                            var targetIndex = timeValuesFound == 0 ? _durationIndex : _delayIndex;
+
+                            if (targetIndex == i)
+                            {
+                                // This is the right slot for this time value - actually consume it
+                                TryMatchTime(list, out timeValue);
+                                options[i] = timeValue;
+                                matched[i] = true;
+                                timeValuesFound++;
+                                foundMatch = true;
+                                break;
+                            }
+                            // else: This time value belongs to a different slot, skip this converter for now
+                        }
+                        // else: Not a time value at all, continue to try other converters
+                    }
+                    else
+                    {
+                        // Non-time converter: try normal matching
+                        var beforeCount = list.Count;
+                        var testList = new List<Token>(list);
+                        var result = _converters[i].VaryStart(testList);
+
+                        if (result != null)
+                        {
+                            // Check if it actually consumed tokens (not just a default value)
+                            var consumed = beforeCount - testList.Count;
+                            if (consumed > 0)
+                            {
+                                options[i] = result;
+                                matched[i] = true;
+                                list = testList;
+                                foundMatch = true;
+                                break;
+                            }
+                        }
+                    }
+                }
+
+                if (!foundMatch)
+                {
+                    // No converter matched the current position
+                    break;
+                }
+            }
+
+            // Fill in defaults for unmatched optional converters
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                if (options[i] == null)
+                {
+                    options[i] = _converters[i].ConvertDefault();
+                }
+            }
+
+            // Success if all tokens were consumed
+            if (list.Count == 0)
+            {
+                return new OptionsValue(options, value);
+            }
+
+            return null;
+        }
+        private bool TryMatchTime(List<Token> list, out IPropertyValue timeValue)
+        {
+            // Use the TimeConverter to try to match a time value
+            var testList = new List<Token>(list);
+            var beforeCount = testList.Count;
+            var result = Converters.TimeConverter.VaryStart(testList);
+
+            if (result != null && testList.Count < beforeCount)
+            {
+                // Successfully matched and consumed tokens
+                timeValue = result;
+                // Update the original list
+                list.Clear();
+                list.AddRange(testList);
+                return true;
+            }
+
+            timeValue = null;
+            return false;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var result = properties.Guard<OptionsValue>();
+
+            if (result != null) return result;
+
+            var values = new IPropertyValue[_converters.Length];
+
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                var value = _converters[i].Construct(properties);
+
+                if (value == null) return null;
+
+                values[i] = value;
+            }
+
+            result = new OptionsValue(values, new Token[0]);
+
+            return result;
+        }
+
+        private sealed class OptionsValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] options;
+
+            public OptionsValue(IPropertyValue[] options, IEnumerable<Token> tokens)
+            {
+                this.options = options;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    // Output in canonical converter order
+                    return string.Join(" ",
+                     options.Where(m => !string.IsNullOrEmpty(m == null ? null : m.CssText)).Select(m => m.CssText));
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var option in options)
+                {
+                    if (option == null) continue;
+
+                    var extracted = option.ExtractFor(name);
+
+                    if (extracted == null || extracted.Count == 0) continue;
+                    if (tokens.Count > 0) tokens.Add(Token.Whitespace);
+                    tokens.AddRange(extracted);
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/UnorderedOptionsConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/UnorderedOptionsConverter.cs
new file mode 100644
index 000000000..841fa0fbf
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/UnorderedOptionsConverter.cs
@@ -0,0 +1,93 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UnorderedOptionsConverter : IValueConverter
+    {
+        private readonly IValueConverter[] _converters;
+
+        public UnorderedOptionsConverter(params IValueConverter[] converters)
+        {
+            _converters = converters;
+        }
+
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var list = new List<Token>(value);
+            var options = new IPropertyValue[_converters.Length];
+
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                options[i] = _converters[i].VaryAll(list);
+
+                if (options[i] == null) return null;
+            }
+
+            return list.Count == 0 ? new OptionsValue(options, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            var result = properties.Guard<OptionsValue>();
+
+            if (result != null) return result;
+
+            var values = new IPropertyValue[_converters.Length];
+
+            for (var i = 0; i < _converters.Length; i++)
+            {
+                var value = _converters[i].Construct(properties);
+
+                if (value == null) return null;
+
+                values[i] = value;
+            }
+
+            result = new OptionsValue(values, Enumerable.Empty<Token>());
+
+            return result;
+        }
+
+        private sealed class OptionsValue : IPropertyValue
+        {
+            private readonly IPropertyValue[] _options;
+
+            public OptionsValue(IPropertyValue[] options, IEnumerable<Token> tokens)
+            {
+                _options = options;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText
+            {
+                get
+                {
+                    return string.Join(" ",
+                        _options.Where(m => !string.IsNullOrEmpty(m.CssText)).Select(m => m.CssText));
+                }
+            }
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                var tokens = new List<Token>();
+
+                foreach (var option in _options)
+                {
+                    var extracted = option.ExtractFor(name);
+
+                    if (extracted != null && extracted.Count > 0)
+                    {
+                        if (tokens.Count > 0) tokens.Add(Token.Whitespace);
+
+                        tokens.AddRange(extracted);
+                    }
+                }
+
+                return new TokenValue(tokens);
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/ValueConverters/UrlValueConverter.cs b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/UrlValueConverter.cs
new file mode 100644
index 000000000..ad38c438d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/ValueConverters/UrlValueConverter.cs
@@ -0,0 +1,38 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class UrlValueConverter : IValueConverter
+    {
+        public IPropertyValue Convert(IEnumerable<Token> value)
+        {
+            var str = value.ToUri();
+            return str != null ? new UrlValue(str, value) : null;
+        }
+
+        public IPropertyValue Construct(Property[] properties)
+        {
+            return properties.Guard<UrlValue>();
+        }
+
+        private sealed class UrlValue : IPropertyValue
+        {
+            private readonly string _value;
+
+            public UrlValue(string value, IEnumerable<Token> tokens)
+            {
+                _value = value;
+                Original = new TokenValue(tokens);
+            }
+
+            public string CssText => _value.StylesheetUrl();
+
+            public TokenValue Original { get; }
+
+            public TokenValue ExtractFor(string name)
+            {
+                return Original;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Angle.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Angle.cs
new file mode 100644
index 000000000..3d6caf565
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Angle.cs
@@ -0,0 +1,217 @@
+using System;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Angle : IEquatable<Angle>, IComparable<Angle>, IFormattable
+    {
+        public static readonly Angle Zero = new Angle(0f, Unit.Rad);
+        public static readonly Angle HalfQuarter = new Angle(45f, Unit.Deg);
+        public static readonly Angle Quarter = new Angle(90f, Unit.Deg);
+        public static readonly Angle TripleHalfQuarter = new Angle(135f, Unit.Deg);
+        public static readonly Angle Half = new Angle(180f, Unit.Deg);
+
+        public Angle(float value, Unit unit)
+        {
+            Value = value;
+            Type = unit;
+        }
+
+        public float Value { get; }
+        public Unit Type { get; }
+
+        public string UnitString
+        {
+            get
+            {
+                switch (Type)
+                {
+                    case Unit.Deg:
+                        return UnitNames.Deg;
+
+                    case Unit.Grad:
+                        return UnitNames.Grad;
+
+                    case Unit.Turn:
+                        return UnitNames.Turn;
+
+                    case Unit.Rad:
+                        return UnitNames.Rad;
+
+                    default:
+                        return string.Empty;
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two angles.
+        /// </summary>
+        public static bool operator >=(Angle a, Angle b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == 1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two angles.
+        /// </summary>
+        public static bool operator >(Angle a, Angle b)
+        {
+            return a.CompareTo(b) == 1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two angles.
+        /// </summary>
+        public static bool operator <=(Angle a, Angle b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == -1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two angles.
+        /// </summary>
+        public static bool operator <(Angle a, Angle b)
+        {
+            return a.CompareTo(b) == -1;
+        }
+
+        /// <summary>
+        ///     Compares the current angle against the given one.
+        /// </summary>
+        /// <param name="other">The angle to compare to.</param>
+        /// <returns>The result of the comparison.</returns>
+        public int CompareTo(Angle other)
+        {
+            return ToRadian().CompareTo(other.ToRadian());
+        }
+
+        public static bool TryParse(string s, out Angle result)
+        {
+            var unit = GetUnit(s.StylesheetUnit(out var value));
+
+            if (unit != Unit.None)
+            {
+                result = new Angle(value, unit);
+                return true;
+            }
+
+            result = default;
+            return false;
+        }
+
+        public static Unit GetUnit(string s)
+        {
+            switch (s)
+            {
+                case "deg":
+                    return Unit.Deg;
+                case "grad":
+                    return Unit.Grad;
+                case "turn":
+                    return Unit.Turn;
+                case "rad":
+                    return Unit.Rad;
+                default:
+                    return Unit.None;
+            }
+        }
+
+        public float ToRadian()
+        {
+            switch (Type)
+            {
+                case Unit.Deg:
+                    return (float)(Math.PI / 180.0 * Value);
+                case Unit.Grad:
+                    return (float)(Math.PI / 200.0 * Value);
+                case Unit.Turn:
+                    return (float)(2.0 * Math.PI * Value);
+                default:
+                    return Value;
+            }
+        }
+
+        public float ToTurns()
+        {
+            switch (Type)
+            {
+                case Unit.Deg:
+                    return (float)(Value / 360.0);
+                case Unit.Grad:
+                    return (float)(Value / 400.0);
+                case Unit.Rad:
+                    return (float)(Value / (2.0 * Math.PI));
+                default:
+                    return Value;
+            }
+        }
+
+        public bool Equals(Angle other)
+        {
+            return ToRadian() == other.ToRadian();
+        }
+
+        /// <summary>
+        ///     An enumeration of angle representations.
+        /// </summary>
+        internal enum Unit : byte
+        {
+            None,
+            Deg,
+            Rad,
+            Grad,
+            Turn
+        }
+
+        /// <summary>
+        ///     Checks for equality of two angles.
+        /// </summary>
+        public static bool operator ==(Angle a, Angle b)
+        {
+            return a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Checks for inequality of two angles.
+        /// </summary>
+        public static bool operator !=(Angle a, Angle b)
+        {
+            return !a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Tests if another object is equal to this object.
+        /// </summary>
+        /// <param name="obj">The object to test with.</param>
+        /// <returns>True if the two objects are equal, otherwise false.</returns>
+        public override bool Equals(object obj)
+        {
+            var other = obj as Angle?;
+
+            return other != null && Equals(other.Value);
+        }
+
+        /// <summary>
+        ///     Returns a hash code that defines the current angle.
+        /// </summary>
+        /// <returns>The integer value of the hashcode.</returns>
+        public override int GetHashCode()
+        {
+            return (int)Value;
+        }
+
+        public override string ToString()
+        {
+            return string.Concat(Value.ToString(), UnitString);
+        }
+
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            return string.Concat(Value.ToString(format, formatProvider), UnitString);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Color.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Color.cs
new file mode 100644
index 000000000..06b326524
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Color.cs
@@ -0,0 +1,461 @@
+using System;
+using System.Runtime.InteropServices;
+
+// ReSharper disable UnusedMember.Global
+
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    [StructLayout(LayoutKind.Explicit, Pack = 1, CharSet = CharSet.Unicode)]
+    internal struct Color : IEquatable<Color>, IComparable<Color>, IFormattable
+    {
+        [FieldOffset(0)] private readonly byte _alpha;
+        [FieldOffset(1)] private readonly byte _red;
+        [FieldOffset(2)] private readonly byte _green;
+        [FieldOffset(3)] private readonly byte _blue;
+        [FieldOffset(0)] private readonly int _hashcode;
+
+
+        #region Basic colors
+
+        /// <summary>
+        ///      #000000.
+        /// </summary>
+        public static readonly Color Black = new Color(0, 0, 0);
+
+        /// <summary>
+        ///      #FFFFFF.
+        /// </summary>
+        public static readonly Color White = new Color(255, 255, 255);
+
+        /// <summary>
+        ///      #FF0000.
+        /// </summary>
+        public static readonly Color Red = new Color(255, 0, 0);
+
+        /// <summary>
+        ///      #FF00FF.
+        /// </summary>
+        public static readonly Color Magenta = new Color(255, 0, 255);
+
+        /// <summary>
+        ///      #008000.
+        /// </summary>
+        public static readonly Color Green = new Color(0, 128, 0);
+
+        /// <summary>
+        ///      #00FF00.
+        /// </summary>
+        public static readonly Color PureGreen = new Color(0, 255, 0);
+
+        /// <summary>
+        ///      #0000FF.
+        /// </summary>
+        public static readonly Color Blue = new Color(0, 0, 255);
+
+        /// <summary>
+        ///      #00000000.
+        /// </summary>
+        public static readonly Color Transparent = new Color(0, 0, 0, 0);
+
+        #endregion
+
+        public Color(byte r, byte g, byte b)
+        {
+            _hashcode = 0;
+            _alpha = 255;
+            _red = r;
+            _blue = b;
+            _green = g;
+        }
+
+        public Color(byte red, byte green, byte blue, byte alpha)
+        {
+            _hashcode = 0;
+            _alpha = alpha;
+            _red = red;
+            _blue = blue;
+            _green = green;
+        }
+
+        public static Color FromRgba(byte red, byte green, byte blue, float alpha)
+        {
+            return new Color(red, green, blue, Normalize(alpha));
+        }
+
+        public static Color FromRgba(float red, float green, float blue, float alpha)
+        {
+            return new Color(Normalize(red), Normalize(green), Normalize(blue), Normalize(alpha));
+        }
+
+        public static Color FromGray(byte number, float alpha = 1f)
+        {
+            return new Color(number, number, number, Normalize(alpha));
+        }
+
+        public static Color FromGray(float value, float alpha = 1f)
+        {
+            return FromGray(Normalize(value), alpha);
+        }
+
+        public static Color? FromName(string name)
+        {
+            return Colors.GetColor(name);
+        }
+
+        public static Color FromRgb(byte red, byte green, byte blue)
+        {
+            return new Color(red, green, blue);
+        }
+
+        public static Color FromHex(string color)
+        {
+            int r = 0, g = 0, b = 0, a = 255;
+
+            switch (color.Length)
+            {
+                case 4:
+                    a = 17 * color[3].FromHex();
+                    goto case 3;
+                case 3:
+                    r = 17 * color[0].FromHex();
+                    g = 17 * color[1].FromHex();
+                    b = 17 * color[2].FromHex();
+                    break;
+                case 8:
+                    a = 16 * color[6].FromHex() + color[7].FromHex();
+                    goto case 6;
+                case 6:
+                    r = 16 * color[0].FromHex() + color[1].FromHex();
+                    g = 16 * color[2].FromHex() + color[3].FromHex();
+                    b = 16 * color[4].FromHex() + color[5].FromHex();
+                    break;
+            }
+
+            return new Color((byte)r, (byte)g, (byte)b, (byte)a);
+        }
+
+        public static bool TryFromHex(string color, out Color value)
+        {
+            if (color.Length == 6 || color.Length == 3 || color.Length == 8 || color.Length == 4)
+            {
+                for (var i = 0; i < color.Length; i++)
+                    if (!color[i].IsHex())
+                        goto fail;
+
+                value = FromHex(color);
+                return true;
+            }
+
+            fail:
+            value = new Color();
+            return false;
+        }
+
+        public static Color FromFlexHex(string color)
+        {
+            var length = Math.Max(color.Length, 3);
+            var remaining = length % 3;
+
+            if (remaining != 0) length += 3 - remaining;
+
+            var n = length / 3;
+            var d = Math.Min(2, n);
+            var s = Math.Max(n - 8, 0);
+            var chars = new char[length];
+
+            for (var i = 0; i < color.Length; i++) chars[i] = color[i].IsHex() ? color[i] : '0';
+
+            for (var i = color.Length; i < length; i++) chars[i] = '0';
+
+            if (d == 1)
+            {
+                var r = chars[0 * n + s].FromHex();
+                var g = chars[1 * n + s].FromHex();
+                var b = chars[2 * n + s].FromHex();
+                return new Color((byte)r, (byte)g, (byte)b);
+            }
+            else
+            {
+                var r = 16 * chars[0 * n + s].FromHex() + chars[0 * n + s + 1].FromHex();
+                var g = 16 * chars[1 * n + s].FromHex() + chars[1 * n + s + 1].FromHex();
+                var b = 16 * chars[2 * n + s].FromHex() + chars[2 * n + s + 1].FromHex();
+                return new Color((byte)r, (byte)g, (byte)b);
+            }
+        }
+
+        public static Color FromHsl(float hue, float saturation, float luminosity)
+        {
+            return FromHsla(hue, saturation, luminosity, 1f);
+        }
+
+        public static Color FromHsla(float hue, float saturation, float luminosity, float alpha)
+        {
+            const float third = 1f / 3f;
+
+            var m2 = luminosity <= 0.5f
+                ? luminosity * (saturation + 1f)
+                : luminosity + saturation - luminosity * saturation;
+
+            var m1 = 2f * luminosity - m2;
+            var r = Convert(HueToRgb(m1, m2, hue + third));
+            var g = Convert(HueToRgb(m1, m2, hue));
+            var b = Convert(HueToRgb(m1, m2, hue - third));
+            return new Color(r, g, b, Normalize(alpha));
+        }
+
+        public static Color FromHwb(float hue, float whiteness, float blackness)
+        {
+            return FromHwba(hue, whiteness, blackness, 1f);
+        }
+
+        public static Color FromHwba(float hue, float whiteness, float blackness, float alpha)
+        {
+            var ratio = 1f / (whiteness + blackness);
+            if (ratio < 1f)
+            {
+                whiteness *= ratio;
+                blackness *= ratio;
+            }
+
+            var p = (int)(6 * hue);
+            var f = 6 * hue - p;
+
+            if ((p & 0x01) != 0) f = 1 - f;
+
+            var v = 1 - blackness;
+            var n = whiteness + f * (v - whiteness);
+
+            float red;
+            float green;
+            float blue;
+            switch (p)
+            {
+                default:
+                case 6:
+                case 0:
+                    red = v;
+                    green = n;
+                    blue = whiteness;
+                    break;
+                case 1:
+                    red = n;
+                    green = v;
+                    blue = whiteness;
+                    break;
+                case 2:
+                    red = whiteness;
+                    green = v;
+                    blue = n;
+                    break;
+                case 3:
+                    red = whiteness;
+                    green = n;
+                    blue = v;
+                    break;
+                case 4:
+                    red = n;
+                    green = whiteness;
+                    blue = v;
+                    break;
+                case 5:
+                    red = v;
+                    green = whiteness;
+                    blue = n;
+                    break;
+            }
+
+            return FromRgba(red, green, blue, alpha);
+        }
+
+        // CSS Color 4/5 spaces (lab/oklab/lch/oklch) and color-mix().
+        // Components are in each space's native units (L: lab/lch 0..100, oklab/oklch 0..1; a/b and C
+        // in native chroma units; H in degrees). The conversion math is shared with gradient
+        // interpolation via ColorSpaceMath so there is a single implementation of the color science.
+
+        public static Color FromLab(double l, double a, double b, float alpha = 1f)
+        {
+            return FromSpaceComponents(new[] { l, a, b }, ColorSpaceMath.Space.Lab, alpha);
+        }
+
+        public static Color FromOklab(double l, double a, double b, float alpha = 1f)
+        {
+            return FromSpaceComponents(new[] { l, a, b }, ColorSpaceMath.Space.Oklab, alpha);
+        }
+
+        public static Color FromLch(double l, double c, double h, float alpha = 1f)
+        {
+            return FromSpaceComponents(new[] { l, c, h }, ColorSpaceMath.Space.Lch, alpha);
+        }
+
+        public static Color FromOklch(double l, double c, double h, float alpha = 1f)
+        {
+            return FromSpaceComponents(new[] { l, c, h }, ColorSpaceMath.Space.Oklch, alpha);
+        }
+
+        private static Color FromSpaceComponents(double[] v, ColorSpaceMath.Space cs, float alpha)
+        {
+            var rgb = ColorSpaceMath.FromSpace(v, cs);
+            return new Color(ToByte(rgb.Item1), ToByte(rgb.Item2), ToByte(rgb.Item3), Normalize(alpha));
+        }
+
+        /// <summary>
+        /// <see href="https://www.w3.org/TR/css-color-5/#color-mix">CSS Color 5 <c>color-mix()</c></see>:
+        /// premultiplied-alpha interpolation in <paramref name="cs"/> with weight <paramref name="t"/>
+        /// toward <paramref name="c2"/>, the result alpha then scaled by <paramref name="alphaMultiplier"/>
+        /// (below 1 only when the two percentages summed to under 100%).
+        /// </summary>
+        public static Color Mix(Color c1, Color c2, double t, ColorSpaceMath.Space cs, ColorSpaceMath.HueMethod hue, double alphaMultiplier)
+        {
+            t = Math.Min(Math.Max(t, 0.0), 1.0);
+            double a1 = c1.A / 255.0, a2 = c2.A / 255.0;
+
+            var v1 = ColorSpaceMath.ToSpace(c1.R / 255.0, c1.G / 255.0, c1.B / 255.0, cs);
+            var v2 = ColorSpaceMath.ToSpace(c2.R / 255.0, c2.G / 255.0, c2.B / 255.0, cs);
+            var hueIndex = ColorSpaceMath.HueIndex(cs);
+
+            for (var i = 0; i < 3; i++)
+            {
+                if (i == hueIndex) continue;
+                v1[i] *= a1;
+                v2[i] *= a2;
+            }
+
+            var mixedAlpha = a1 + t * (a2 - a1);
+            var v = new double[3];
+            for (var i = 0; i < 3; i++)
+            {
+                if (i == hueIndex)
+                {
+                    v[i] = ColorSpaceMath.InterpolateHue(v1[i], v2[i], t, hue);
+                    continue;
+                }
+
+                var mixed = v1[i] + t * (v2[i] - v1[i]);
+                v[i] = mixedAlpha > 1e-10 ? mixed / mixedAlpha : 0;
+            }
+
+            var rgb = ColorSpaceMath.FromSpace(v, cs);
+            var outAlpha = (byte)Math.Round(Math.Min(Math.Max(mixedAlpha * alphaMultiplier, 0), 1) * 255);
+            return new Color(ToByte(rgb.Item1), ToByte(rgb.Item2), ToByte(rgb.Item3), outAlpha);
+        }
+
+        private static byte ToByte(double v)
+        {
+            return (byte)Math.Round(Math.Min(Math.Max(v, 0), 1) * 255);
+        }
+
+        public int Value => _hashcode;
+        public byte A => _alpha;
+        public double Alpha => Math.Round(_alpha / 255.0, 2);
+        public byte R => _red;
+        public byte G => _green;
+        public byte B => _blue;
+
+        public static bool operator ==(Color a, Color b)
+        {
+            return a._hashcode == b._hashcode;
+        }
+
+        public static bool operator !=(Color a, Color b)
+        {
+            return a._hashcode != b._hashcode;
+        }
+
+        public bool Equals(Color other)
+        {
+            return _hashcode == other._hashcode;
+        }
+
+        public override bool Equals(object obj)
+        {
+            var other = obj as Color?;
+
+            if (other != null) return Equals(other.Value);
+
+            return false;
+        }
+
+        int IComparable<Color>.CompareTo(Color other)
+        {
+            return _hashcode - other._hashcode;
+        }
+
+        public override int GetHashCode()
+        {
+            return _hashcode;
+        }
+
+        public static Color Mix(Color above, Color below)
+        {
+            return Mix(above.Alpha, above, below);
+        }
+
+        public static Color Mix(double alpha, Color above, Color below)
+        {
+            var gamma = 1.0 - alpha;
+            var r = gamma * below.R + alpha * above.R;
+            var g = gamma * below.G + alpha * above.G;
+            var b = gamma * below.B + alpha * above.B;
+            return new Color((byte)r, (byte)g, (byte)b);
+        }
+
+        private static byte Normalize(float value)
+        {
+            return (byte)Math.Max(Math.Min(Math.Round(255 * value), 255), 0);
+        }
+
+        private static byte Convert(float value)
+        {
+            return (byte)Math.Round(255f * value);
+        }
+
+        private static float HueToRgb(float m1, float m2, float h)
+        {
+            const float oneSixth = 1f / 6f;
+            const float twoThird = 2f / 3f;
+
+            if (h < 0f)
+                h += 1f;
+            else if (h > 1f) h -= 1f;
+
+            if (h < oneSixth) return m1 + (m2 - m1) * h * 6f;
+            if (h < 0.5) return m2;
+            if (h < twoThird) return m1 + (m2 - m1) * (twoThird - h) * 6f;
+
+            return m1;
+        }
+
+        public override string ToString()
+        {
+            if (_alpha == 255)
+            {
+                var arguments = string.Join(", ", R.ToString(), G.ToString(), B.ToString());
+                return FunctionNames.Rgb.StylesheetFunction(arguments);
+            }
+            else
+            {
+                var arguments = string.Join(", ", R.ToString(), G.ToString(), B.ToString(), Alpha.ToString());
+                return FunctionNames.Rgba.StylesheetFunction(arguments);
+            }
+        }
+
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            if (_alpha == 255)
+            {
+                var arguments = string.Join(", ", R.ToString(format, formatProvider),
+                    G.ToString(format, formatProvider),
+                    B.ToString(format, formatProvider));
+                return FunctionNames.Rgb.StylesheetFunction(arguments);
+            }
+            else
+            {
+                var arguments = string.Join(", ", R.ToString(format, formatProvider),
+                    G.ToString(format, formatProvider),
+                    B.ToString(format, formatProvider), Alpha.ToString(format, formatProvider));
+                return FunctionNames.Rgba.StylesheetFunction(arguments);
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/ColorSpaceMath.cs b/Source/HtmlRenderer/Core/CssEngine/Values/ColorSpaceMath.cs
new file mode 100644
index 000000000..452e53ce2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/ColorSpaceMath.cs
@@ -0,0 +1,436 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    /// <summary>
+    /// The single home for CSS color-space conversion math (CSS Color 4/5): forward/reverse transforms
+    /// between gamma-encoded sRGB and every interpolation space, plus polar-hue interpolation. Kept in
+    /// the CSS-OM (rather than the render layer) so that solid-color resolution (<see cref="Color"/>'s
+    /// <c>oklch()</c>/<c>lab()</c>/<c>color-mix()</c> factories) and any gradient interpolation that
+    /// needs a non-sRGB space share one implementation.
+    /// </summary>
+    internal static class ColorSpaceMath
+    {
+        internal enum Space { Srgb, SrgbLinear, DisplayP3, Lab, Oklab, XyzD65, XyzD50, Hsl, Hwb, Lch, Oklch }
+
+        internal enum HueMethod { Shorter, Longer, Increasing, Decreasing }
+
+        public static bool IsPolar(Space cs)
+        {
+            return cs == Space.Hsl || cs == Space.Hwb || cs == Space.Lch || cs == Space.Oklch;
+        }
+
+        // The index of the hue coordinate in a space's ToSpace/FromSpace layout, or -1 if rectangular.
+        // HSL/HWB carry hue first ([h, s/w, l/bk]); LCH/OKLch carry it last ([L, C, H]).
+        public static int HueIndex(Space cs)
+        {
+            switch (cs)
+            {
+                case Space.Hsl:
+                case Space.Hwb:
+                    return 0;
+                case Space.Lch:
+                case Space.Oklch:
+                    return 2;
+                default:
+                    return -1;
+            }
+        }
+
+        public static double NormalizeHue(double h)
+        {
+            return ((h % 360) + 360) % 360;
+        }
+
+        public static double InterpolateHue(double h1, double h2, double t, HueMethod hue)
+        {
+            h1 = NormalizeHue(h1);
+            h2 = NormalizeHue(h2);
+            var diff = h2 - h1;
+            switch (hue)
+            {
+                case HueMethod.Longer:
+                    if (diff > 0 && diff < 180) diff -= 360;
+                    else if (diff < 0 && diff > -180) diff += 360;
+                    break;
+                case HueMethod.Increasing:
+                    if (diff < 0) diff += 360;
+                    break;
+                case HueMethod.Decreasing:
+                    if (diff > 0) diff -= 360;
+                    break;
+                default: // Shorter
+                    if (diff > 180) diff -= 360;
+                    else if (diff < -180) diff += 360;
+                    break;
+            }
+            return h1 + t * diff;
+        }
+
+        private static double Clamp01(double v)
+        {
+            return v < 0 ? 0 : (v > 1 ? 1 : v);
+        }
+
+        // Cube root that accepts negative input, for targets whose Math has no Cbrt.
+        private static double Cbrt(double v)
+        {
+            return v < 0 ? -Math.Pow(-v, 1.0 / 3.0) : Math.Pow(v, 1.0 / 3.0);
+        }
+
+        // sRGB gamma
+
+        private static double Linearize(double c)
+        {
+            c = Clamp01(c);
+            return c <= 0.04045 ? c / 12.92 : Math.Pow((c + 0.055) / 1.055, 2.4);
+        }
+
+        private static double Delinearize(double c)
+        {
+            c = Clamp01(c);
+            return c <= 0.0031308 ? c * 12.92 : 1.055 * Math.Pow(c, 1.0 / 2.4) - 0.055;
+        }
+
+        // Linear sRGB <-> XYZ-D65 (IEC 61966-2-1)
+
+        private static (double X, double Y, double Z) LinSrgbToXyzD65(double r, double g, double b)
+        {
+            return (0.4124564 * r + 0.3575761 * g + 0.1804375 * b,
+                    0.2126729 * r + 0.7151522 * g + 0.0721750 * b,
+                    0.0193339 * r + 0.1191920 * g + 0.9503041 * b);
+        }
+
+        private static (double R, double G, double B) XyzD65ToLinSrgb(double x, double y, double z)
+        {
+            return ( 3.2404542 * x - 1.5371385 * y - 0.4985314 * z,
+                    -0.9692660 * x + 1.8760108 * y + 0.0415560 * z,
+                     0.0556434 * x - 0.2040259 * y + 1.0572252 * z);
+        }
+
+        // XYZ-D65 <-> XYZ-D50 (Bradford)
+
+        private static (double X, double Y, double Z) XyzD65ToXyzD50(double x, double y, double z)
+        {
+            return ( 1.0478112 * x + 0.0228866 * y - 0.0501270 * z,
+                     0.0295424 * x + 0.9904844 * y - 0.0170491 * z,
+                    -0.0092345 * x + 0.0150436 * y + 0.7521316 * z);
+        }
+
+        private static (double X, double Y, double Z) XyzD50ToXyzD65(double x, double y, double z)
+        {
+            return ( 0.9554734 * x - 0.0230393 * y + 0.0631636 * z,
+                    -0.0282895 * x + 1.0099416 * y + 0.0210077 * z,
+                     0.0122982 * x - 0.0204830 * y + 1.3299098 * z);
+        }
+
+        // Display-P3 <-> XYZ-D65 (P3 uses sRGB gamma)
+
+        private static (double X, double Y, double Z) LinP3ToXyzD65(double r, double g, double b)
+        {
+            return (0.4865709 * r + 0.2656677 * g + 0.1982173 * b,
+                    0.2289746 * r + 0.6917386 * g + 0.0792869 * b,
+                    0.0000000 * r + 0.0451134 * g + 1.0439444 * b);
+        }
+
+        private static (double R, double G, double B) XyzD65ToLinP3(double x, double y, double z)
+        {
+            return ( 2.4934969 * x - 0.9313836 * y - 0.4027108 * z,
+                    -0.8294890 * x + 1.7626641 * y + 0.0236247 * z,
+                     0.0358458 * x - 0.0761724 * y + 0.9568845 * z);
+        }
+
+        // CIE L*a*b*
+
+        private const double Xn50 = 0.96422, Yn50 = 1.0, Zn50 = 0.82521;
+
+        private static double LabF(double t)
+        {
+            const double d = 6.0 / 29.0;
+            return t > d * d * d ? Cbrt(t) : t / (3 * d * d) + 4.0 / 29.0;
+        }
+
+        private static double LabFInv(double t)
+        {
+            const double d = 6.0 / 29.0;
+            return t > d ? t * t * t : 3 * d * d * (t - 4.0 / 29.0);
+        }
+
+        private static (double L, double a, double b) XyzD50ToLab(double x, double y, double z)
+        {
+            double fx = LabF(x / Xn50), fy = LabF(y / Yn50), fz = LabF(z / Zn50);
+            return (116 * fy - 16, 500 * (fx - fy), 200 * (fy - fz));
+        }
+
+        private static (double X, double Y, double Z) LabToXyzD50(double L, double a, double b)
+        {
+            var fy = (L + 16) / 116;
+            return (Xn50 * LabFInv(a / 500 + fy), Yn50 * LabFInv(fy), Zn50 * LabFInv(fy - b / 200));
+        }
+
+        // OKLab (Björn Ottosson)
+
+        private static (double L, double a, double b) XyzD65ToOkLab(double x, double y, double z)
+        {
+            var l = Cbrt(0.8189330101 * x + 0.3618667424 * y - 0.1288597137 * z);
+            var m = Cbrt(0.0329845436 * x + 0.9293118715 * y + 0.0361456387 * z);
+            var s = Cbrt(0.0482003018 * x + 0.2643662691 * y + 0.6338517070 * z);
+            return (0.2104542553 * l + 0.7936177850 * m - 0.0040720468 * s,
+                    1.9779984951 * l - 2.4285922050 * m + 0.4505937099 * s,
+                    0.0259040371 * l + 0.7827717662 * m - 0.8086757660 * s);
+        }
+
+        private static (double X, double Y, double Z) OkLabToXyzD65(double L, double a, double b)
+        {
+            double l = L + 0.3963377774 * a + 0.2158037573 * b; l = l * l * l;
+            double m = L - 0.1055613458 * a - 0.0638541728 * b; m = m * m * m;
+            double s = L - 0.0894841775 * a - 1.2914855480 * b; s = s * s * s;
+            return ( 1.2270138511 * l - 0.5577999807 * m + 0.2812561490 * s,
+                    -0.0405801784 * l + 1.1122568696 * m - 0.0716766787 * s,
+                    -0.0763812845 * l - 0.4214819784 * m + 1.5861632204 * s);
+        }
+
+        // HSL
+
+        private static (double H, double S, double L) SrgbToHsl(double r, double g, double b)
+        {
+            double max = Math.Max(r, Math.Max(g, b));
+            double min = Math.Min(r, Math.Min(g, b));
+            double d = max - min;
+            double l = (max + min) / 2;
+            if (d < 1e-10) return (0, 0, l * 100);
+            double s = d / (1 - Math.Abs(2 * l - 1));
+            double h;
+            if (max == r)      h = 60 * (((g - b) / d) % 6);
+            else if (max == g) h = 60 * ((b - r) / d + 2);
+            else               h = 60 * ((r - g) / d + 4);
+            if (h < 0) h += 360;
+            return (h, s * 100, l * 100);
+        }
+
+        private static (double R, double G, double B) HslToSrgb(double h, double s, double l)
+        {
+            s /= 100; l /= 100;
+            double c = (1 - Math.Abs(2 * l - 1)) * s;
+            double x = c * (1 - Math.Abs(h / 60 % 2 - 1));
+            double m = l - c / 2;
+            double r = 0, g = 0, b = 0;
+            switch ((int)(h / 60) % 6)
+            {
+                case 0: r = c; g = x; break;
+                case 1: r = x; g = c; break;
+                case 2: g = c; b = x; break;
+                case 3: g = x; b = c; break;
+                case 4: r = x; b = c; break;
+                case 5: r = c; b = x; break;
+            }
+            return (r + m, g + m, b + m);
+        }
+
+        // HWB
+
+        private static (double H, double W, double Bk) SrgbToHwb(double r, double g, double b)
+        {
+            var hsl = SrgbToHsl(r, g, b);
+            return (hsl.H,
+                    Math.Min(r, Math.Min(g, b)) * 100,
+                    (1 - Math.Max(r, Math.Max(g, b))) * 100);
+        }
+
+        private static (double R, double G, double B) HwbToSrgb(double h, double w, double bk)
+        {
+            w /= 100; bk /= 100;
+            if (w + bk >= 1) { double grey = w / (w + bk); return (grey, grey, grey); }
+            var rgb = HslToSrgb(h, 100, 50);
+            double f = 1 - w - bk;
+            return (rgb.R * f + w, rgb.G * f + w, rgb.B * f + w);
+        }
+
+        // LCH / OKLch (rectangular <-> polar)
+
+        private static (double L, double C, double H) RectToPolar(double L, double a, double b)
+        {
+            double c = Math.Sqrt(a * a + b * b);
+            double h = Math.Atan2(b, a) * (180.0 / Math.PI);
+            if (h < 0) h += 360;
+            return (L, c, h);
+        }
+
+        private static (double L, double a, double b) PolarToRect(double L, double c, double h)
+        {
+            double rad = h * (Math.PI / 180.0);
+            return (L, c * Math.Cos(rad), c * Math.Sin(rad));
+        }
+
+        // Forward: gamma-sRGB (0..1) -> color-space coordinates
+
+        public static double[] ToSpace(double r, double g, double b, Space cs)
+        {
+            switch (cs)
+            {
+                case Space.SrgbLinear:
+                    return new[] { Linearize(r), Linearize(g), Linearize(b) };
+
+                case Space.DisplayP3:
+                {
+                    var xyz = LinSrgbToXyzD65(Linearize(r), Linearize(g), Linearize(b));
+                    var p3 = XyzD65ToLinP3(xyz.X, xyz.Y, xyz.Z);
+                    return new[] { Delinearize(p3.R), Delinearize(p3.G), Delinearize(p3.B) };
+                }
+
+                case Space.Lab:
+                {
+                    var xyz = LinSrgbToXyzD65(Linearize(r), Linearize(g), Linearize(b));
+                    var xyz50 = XyzD65ToXyzD50(xyz.X, xyz.Y, xyz.Z);
+                    var lab = XyzD50ToLab(xyz50.X, xyz50.Y, xyz50.Z);
+                    return new[] { lab.L, lab.a, lab.b };
+                }
+
+                case Space.Oklab:
+                {
+                    var xyz = LinSrgbToXyzD65(Linearize(r), Linearize(g), Linearize(b));
+                    var lab = XyzD65ToOkLab(xyz.X, xyz.Y, xyz.Z);
+                    return new[] { lab.L, lab.a, lab.b };
+                }
+
+                case Space.XyzD65:
+                {
+                    var xyz = LinSrgbToXyzD65(Linearize(r), Linearize(g), Linearize(b));
+                    return new[] { xyz.X, xyz.Y, xyz.Z };
+                }
+
+                case Space.XyzD50:
+                {
+                    var xyz = LinSrgbToXyzD65(Linearize(r), Linearize(g), Linearize(b));
+                    var xyz50 = XyzD65ToXyzD50(xyz.X, xyz.Y, xyz.Z);
+                    return new[] { xyz50.X, xyz50.Y, xyz50.Z };
+                }
+
+                case Space.Hsl:
+                {
+                    var hsl = SrgbToHsl(r, g, b);
+                    return new[] { hsl.H, hsl.S, hsl.L };
+                }
+
+                case Space.Hwb:
+                {
+                    var hwb = SrgbToHwb(r, g, b);
+                    return new[] { hwb.H, hwb.W, hwb.Bk };
+                }
+
+                case Space.Lch:
+                {
+                    var xyz = LinSrgbToXyzD65(Linearize(r), Linearize(g), Linearize(b));
+                    var xyz50 = XyzD65ToXyzD50(xyz.X, xyz.Y, xyz.Z);
+                    var lab = XyzD50ToLab(xyz50.X, xyz50.Y, xyz50.Z);
+                    var lch = RectToPolar(lab.L, lab.a, lab.b);
+                    return new[] { lch.L, lch.C, lch.H };
+                }
+
+                case Space.Oklch:
+                {
+                    var xyz = LinSrgbToXyzD65(Linearize(r), Linearize(g), Linearize(b));
+                    var lab = XyzD65ToOkLab(xyz.X, xyz.Y, xyz.Z);
+                    var lch = RectToPolar(lab.L, lab.a, lab.b);
+                    return new[] { lch.L, lch.C, lch.H };
+                }
+
+                default: // Srgb
+                    return new[] { r, g, b };
+            }
+        }
+
+        // Reverse: color-space coordinates -> gamut-mapped sRGB (0..1)
+
+        public static (double R, double G, double B) FromSpace(double[] v, Space cs)
+        {
+            double r, g, b;
+
+            switch (cs)
+            {
+                case Space.SrgbLinear:
+                    r = Delinearize(v[0]); g = Delinearize(v[1]); b = Delinearize(v[2]);
+                    break;
+
+                case Space.DisplayP3:
+                {
+                    var xyz = LinP3ToXyzD65(Linearize(v[0]), Linearize(v[1]), Linearize(v[2]));
+                    var lin = XyzD65ToLinSrgb(xyz.X, xyz.Y, xyz.Z);
+                    r = Delinearize(lin.R); g = Delinearize(lin.G); b = Delinearize(lin.B);
+                    break;
+                }
+
+                case Space.Lab:
+                {
+                    var xyz50 = LabToXyzD50(v[0], v[1], v[2]);
+                    var xyz = XyzD50ToXyzD65(xyz50.X, xyz50.Y, xyz50.Z);
+                    var lin = XyzD65ToLinSrgb(xyz.X, xyz.Y, xyz.Z);
+                    r = Delinearize(lin.R); g = Delinearize(lin.G); b = Delinearize(lin.B);
+                    break;
+                }
+
+                case Space.Oklab:
+                {
+                    var xyz = OkLabToXyzD65(v[0], v[1], v[2]);
+                    var lin = XyzD65ToLinSrgb(xyz.X, xyz.Y, xyz.Z);
+                    r = Delinearize(lin.R); g = Delinearize(lin.G); b = Delinearize(lin.B);
+                    break;
+                }
+
+                case Space.XyzD65:
+                {
+                    var lin = XyzD65ToLinSrgb(v[0], v[1], v[2]);
+                    r = Delinearize(lin.R); g = Delinearize(lin.G); b = Delinearize(lin.B);
+                    break;
+                }
+
+                case Space.XyzD50:
+                {
+                    var xyz = XyzD50ToXyzD65(v[0], v[1], v[2]);
+                    var lin = XyzD65ToLinSrgb(xyz.X, xyz.Y, xyz.Z);
+                    r = Delinearize(lin.R); g = Delinearize(lin.G); b = Delinearize(lin.B);
+                    break;
+                }
+
+                case Space.Hsl:
+                {
+                    var rgb = HslToSrgb(v[0], v[1], v[2]);
+                    r = rgb.R; g = rgb.G; b = rgb.B;
+                    break;
+                }
+
+                case Space.Hwb:
+                {
+                    var rgb = HwbToSrgb(v[0], v[1], v[2]);
+                    r = rgb.R; g = rgb.G; b = rgb.B;
+                    break;
+                }
+
+                case Space.Lch:
+                {
+                    var lab = PolarToRect(v[0], v[1], v[2]);
+                    var xyz50 = LabToXyzD50(lab.L, lab.a, lab.b);
+                    var xyz = XyzD50ToXyzD65(xyz50.X, xyz50.Y, xyz50.Z);
+                    var lin = XyzD65ToLinSrgb(xyz.X, xyz.Y, xyz.Z);
+                    r = Delinearize(lin.R); g = Delinearize(lin.G); b = Delinearize(lin.B);
+                    break;
+                }
+
+                case Space.Oklch:
+                {
+                    var lab = PolarToRect(v[0], v[1], v[2]);
+                    var xyz = OkLabToXyzD65(lab.L, lab.a, lab.b);
+                    var lin = XyzD65ToLinSrgb(xyz.X, xyz.Y, xyz.Z);
+                    r = Delinearize(lin.R); g = Delinearize(lin.G); b = Delinearize(lin.B);
+                    break;
+                }
+
+                default: // Srgb
+                    r = v[0]; g = v[1]; b = v[2];
+                    break;
+            }
+
+            return (Clamp01(r), Clamp01(g), Clamp01(b));
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Counter.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Counter.cs
new file mode 100644
index 000000000..c561e1943
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Counter.cs
@@ -0,0 +1,16 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class Counter
+    {
+        public Counter(string identifier, string listStyle, string separator)
+        {
+            CounterIdentifier = identifier;
+            ListStyle = listStyle;
+            DefinedSeparator = separator;
+        }
+
+        public string CounterIdentifier { get; }
+        public string ListStyle { get; }
+        public string DefinedSeparator { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/CubicBezierTimingFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Values/CubicBezierTimingFunction.cs
new file mode 100644
index 000000000..ae826259c
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/CubicBezierTimingFunction.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class CubicBezierTimingFunction : ITimingFunction
+    {
+        public CubicBezierTimingFunction(float x1, float y1, float x2, float y2)
+        {
+            X1 = x1;
+            Y1 = y1;
+            X2 = x2;
+            Y2 = y2;
+        }
+
+        public float X1 { get; }
+        public float Y1 { get; }
+        public float X2 { get; }
+        public float Y2 { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Frequency.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Frequency.cs
new file mode 100644
index 000000000..be29f6f9d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Frequency.cs
@@ -0,0 +1,139 @@
+using System;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Frequency : IEquatable<Frequency>, IComparable<Frequency>, IFormattable
+    {
+        public Frequency(float value, Unit unit)
+        {
+            Value = value;
+            Type = unit;
+        }
+
+        public float Value { get; }
+        public Unit Type { get; }
+
+        public string UnitString
+        {
+            get
+            {
+                switch (Type)
+                {
+                    case Unit.Khz:
+                        return UnitNames.Khz;
+
+                    case Unit.Hz:
+                        return UnitNames.Hz;
+
+                    default:
+                        return string.Empty;
+                }
+            }
+        }
+
+        public static bool operator >=(Frequency a, Frequency b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == 1;
+        }
+
+        public static bool operator >(Frequency a, Frequency b)
+        {
+            return a.CompareTo(b) == 1;
+        }
+
+        public static bool operator <=(Frequency a, Frequency b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == -1;
+        }
+
+        public static bool operator <(Frequency a, Frequency b)
+        {
+            return a.CompareTo(b) == -1;
+        }
+
+        public int CompareTo(Frequency other)
+        {
+            return ToHertz().CompareTo(other.ToHertz());
+        }
+
+        public static bool TryParse(string s, out Frequency result)
+        {
+            var unit = GetUnit(s.StylesheetUnit(out var value));
+
+            if (unit != Unit.None)
+            {
+                result = new Frequency(value, unit);
+                return true;
+            }
+
+            result = default;
+            return false;
+        }
+
+        public static Unit GetUnit(string s)
+        {
+            switch (s)
+            {
+                case "hz":
+                    return Unit.Hz;
+                case "khz":
+                    return Unit.Khz;
+                default:
+                    return Unit.None;
+            }
+        }
+
+        public float ToHertz()
+        {
+            return Type == Unit.Khz ? Value * 1000f : Value;
+        }
+
+        public bool Equals(Frequency other)
+        {
+            return Value == other.Value && Type == other.Type;
+        }
+
+        internal enum Unit : byte
+        {
+            None,
+            Hz,
+            Khz
+        }
+
+        public static bool operator ==(Frequency a, Frequency b)
+        {
+            return a.Equals(b);
+        }
+
+        public static bool operator !=(Frequency a, Frequency b)
+        {
+            return !a.Equals(b);
+        }
+
+        public override bool Equals(object obj)
+        {
+            var other = obj as Frequency?;
+
+            return other != null && Equals(other.Value);
+        }
+
+        public override int GetHashCode()
+        {
+            return Value.GetHashCode();
+        }
+
+        public override string ToString()
+        {
+            return string.Concat(Value.ToString(), UnitString);
+        }
+
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            return string.Concat(Value.ToString(format, formatProvider), UnitString);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/GradientStop.cs b/Source/HtmlRenderer/Core/CssEngine/Values/GradientStop.cs
new file mode 100644
index 000000000..366d5ef07
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/GradientStop.cs
@@ -0,0 +1,14 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct GradientStop
+    {
+        public GradientStop(Color color, Length location)
+        {
+            Color = color;
+            Location = location;
+        }
+
+        public Color Color { get; }
+        public Length Location { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/IGradient.cs b/Source/HtmlRenderer/Core/CssEngine/Values/IGradient.cs
new file mode 100644
index 000000000..9787278ac
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/IGradient.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IGradient : IImageSource
+    {
+        IEnumerable<GradientStop> Stops { get; }
+        bool IsRepeating { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/IImageSource.cs b/Source/HtmlRenderer/Core/CssEngine/Values/IImageSource.cs
new file mode 100644
index 000000000..c910654b5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/IImageSource.cs
@@ -0,0 +1,6 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface IImageSource
+    {
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/ITimingFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Values/ITimingFunction.cs
new file mode 100644
index 000000000..1637ddc94
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/ITimingFunction.cs
@@ -0,0 +1,6 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface ITimingFunction
+    {
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/ITransform.cs b/Source/HtmlRenderer/Core/CssEngine/Values/ITransform.cs
new file mode 100644
index 000000000..967945bda
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/ITransform.cs
@@ -0,0 +1,7 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal interface ITransform
+    {
+        TransformMatrix ComputeMatrix();
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Length.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Length.cs
new file mode 100644
index 000000000..6b8e05466
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Length.cs
@@ -0,0 +1,368 @@
+using System;
+
+// ReSharper disable UnusedMember.Global
+
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Length : IEquatable<Length>, IComparable<Length>, IFormattable
+    {
+        /// <summary>
+        ///     Gets a zero pixel length value.
+        /// </summary>
+        public static readonly Length Zero = new Length(0f, Unit.Px);
+
+        /// <summary>
+        ///     Gets the half relative length, i.e. 50%.
+        /// </summary>
+        public static readonly Length Half = new Length(50f, Unit.Percent);
+
+        /// <summary>
+        ///     Gets the full relative length, i.e. 100%.
+        /// </summary>
+        public static readonly Length Full = new Length(100f, Unit.Percent);
+
+        /// <summary>
+        ///     Gets a thin length value.
+        /// </summary>
+        public static readonly Length Thin = new Length(1f, Unit.Px);
+
+        /// <summary>
+        ///     Gets a medium length value.
+        /// </summary>
+        public static readonly Length Medium = new Length(3f, Unit.Px);
+
+        /// <summary>
+        ///     Gets a thick length value.
+        /// </summary>
+        public static readonly Length Thick = new Length(5f, Unit.Px);
+
+        /// <summary>
+        ///     Gets the missing value.
+        /// </summary>
+        public static readonly Length Missing = new Length(-1f, Unit.Ch);
+
+        public Length(float value, Unit unit)
+        {
+            Value = value;
+            Type = unit;
+        }
+
+        /// <summary>
+        ///     Gets if the length is given in absolute units.
+        ///     Such a length may be converted to pixels.
+        /// </summary>
+        public bool IsAbsolute =>
+            Type == Unit.In || Type == Unit.Mm || Type == Unit.Pc || Type == Unit.Px ||
+            Type == Unit.Pt || Type == Unit.Cm;
+
+        /// <summary>
+        ///     Gets if the length is given in relative units.
+        ///     Such a length cannot be converted to pixels.
+        /// </summary>
+        public bool IsRelative => !IsAbsolute;
+
+        /// <summary>
+        ///     Gets the type of the length.
+        /// </summary>
+        public Unit Type { get; }
+
+        /// <summary>
+        ///     Gets the value of the length.
+        /// </summary>
+        public float Value { get; }
+
+        /// <summary>
+        ///     Gets the representation of the unit as a string.
+        /// </summary>
+        public string UnitString
+        {
+            get
+            {
+                switch (Type)
+                {
+                    case Unit.Px:
+                        return UnitNames.Px;
+                    case Unit.Em:
+                        return UnitNames.Em;
+                    case Unit.Ex:
+                        return UnitNames.Ex;
+                    case Unit.Cm:
+                        return UnitNames.Cm;
+                    case Unit.Mm:
+                        return UnitNames.Mm;
+                    case Unit.In:
+                        return UnitNames.In;
+                    case Unit.Pt:
+                        return UnitNames.Pt;
+                    case Unit.Pc:
+                        return UnitNames.Pc;
+                    case Unit.Ch:
+                        return UnitNames.Ch;
+                    case Unit.Rem:
+                        return UnitNames.Rem;
+                    case Unit.Vw:
+                        return UnitNames.Vw;
+                    case Unit.Vh:
+                        return UnitNames.Vh;
+                    case Unit.Vmin:
+                        return UnitNames.Vmin;
+                    case Unit.Vmax:
+                        return UnitNames.Vmax;
+                    case Unit.Percent:
+                        return UnitNames.Percent;
+                    default:
+                        return string.Empty;
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two lengths.
+        /// </summary>
+        public static bool operator >=(Length a, Length b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == 1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two lengths.
+        /// </summary>
+        public static bool operator >(Length a, Length b)
+        {
+            return a.CompareTo(b) == 1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two lengths.
+        /// </summary>
+        public static bool operator <=(Length a, Length b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == -1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two lengths.
+        /// </summary>
+        public static bool operator <(Length a, Length b)
+        {
+            return a.CompareTo(b) == -1;
+        }
+
+        /// <summary>
+        ///     Compares the current length against the given one.
+        /// </summary>
+        /// <param name="other">The length to compare to.</param>
+        /// <returns>The result of the comparison.</returns>
+        public int CompareTo(Length other)
+        {
+            if (Type == other.Type) return Value.CompareTo(other.Value);
+
+            if (IsAbsolute && other.IsAbsolute) return ToPixel().CompareTo(other.ToPixel());
+
+            return 0;
+        }
+
+        public static bool TryParse(string s, out Length result)
+        {
+            var unitString = s.StylesheetUnit(out var value);
+            var unit = GetUnit(unitString);
+
+            if (unit != Unit.None)
+            {
+                result = new Length(value, unit);
+                return true;
+            }
+
+            // Only a genuinely parsed bare "0" may omit its unit (CSS Values & Units §5.1) -
+            // StylesheetUnit returns an empty unit string for a plain number but null when it
+            // couldn't tokenize a number at all, and both leave value at 0, so the unit string
+            // must be checked to avoid accepting arbitrary non-length input as zero.
+            if (unitString != null && unitString.Length == 0 && value == 0f)
+            {
+                result = Zero;
+                return true;
+            }
+
+            result = default;
+            return false;
+        }
+
+        public static Unit GetUnit(string s)
+        {
+            switch (s)
+            {
+                case "ch": return Unit.Ch;
+                case "cm": return Unit.Cm;
+                case "em": return Unit.Em;
+                case "ex": return Unit.Ex;
+                case "in": return Unit.In;
+                case "mm": return Unit.Mm;
+                case "pc": return Unit.Pc;
+                case "pt": return Unit.Pt;
+                case "px": return Unit.Px;
+                case "rem": return Unit.Rem;
+                case "vh": return Unit.Vh;
+                case "vmax": return Unit.Vmax;
+                case "vmin": return Unit.Vmin;
+                case "vw": return Unit.Vw;
+                case "%": return Unit.Percent;
+                default: return Unit.None;
+            }
+        }
+
+        public float ToPixel()
+        {
+            if (IsRelative)
+                throw new InvalidOperationException("A relative unit cannot be converted.");
+
+            return (float)ToPixels(0, 0, 0);
+        }
+
+        /// <summary>
+        ///     Resolves this length to pixels, given the context needed for relative units
+        ///     (<c>em</c>/<c>rem</c>/<c>ex</c>/<c>%</c>). This is the single source of truth for
+        ///     "unit + context -> pixels" — <see cref="ToPixel"/> delegates to it for absolute units,
+        ///     and layout-time consumers (e.g. calc() evaluation) use it directly for the relative case.
+        /// </summary>
+        /// <param name="emFactor">Pixels per 1em, i.e. the relevant font size in pixels.</param>
+        /// <param name="remFactor">Pixels per 1rem, i.e. the root element's font size in pixels.</param>
+        /// <param name="hundredPercent">The pixel value equivalent to 100%.</param>
+        /// <param name="fontAdjust">If the length is in pixels and font related, apply the 72/96 factor.</param>
+        internal double ToPixels(double emFactor, double remFactor, double hundredPercent, bool fontAdjust = false)
+        {
+            // The layout unit here is the CSS pixel, so absolute units resolve against 96dpi
+            // (CSS Values & Units §5.2: 1in = 96px, 1pt = 1/72in, 1pc = 12pt). These factors must
+            // stay identical to the ones CssValueParser.ParseLength applies to non-calc() lengths,
+            // otherwise `calc(1in)` and `width: 1in` would disagree.
+            switch (Type)
+            {
+                case Unit.Em: return emFactor * Value;
+                case Unit.Rem: return remFactor * Value;
+                case Unit.Ex: return emFactor / 2 * Value;
+                case Unit.Px: return (fontAdjust ? 72d / 96d : 1d) * Value; //TODO: a check support for hi dpi
+                case Unit.In: // 1 in = 96 px
+                    return 96d * Value;
+                case Unit.Mm: // 1 mm = 96/25.4 px
+                    return (96d / 25.4d) * Value;
+                case Unit.Pc: // 1 pc = 12 pt = 16 px
+                    return 16d * Value;
+                case Unit.Pt: // 1 pt = 1/72 in = 96/72 px
+                    return (96d / 72d) * Value;
+                case Unit.Cm: // 1 cm = 96/2.54 px
+                    return (96d / 2.54d) * Value;
+                case Unit.Percent: return hundredPercent / 100d * Value;
+                default: return 0d;
+            }
+        }
+
+        public float To(Unit unit)
+        {
+            var value = ToPixel();
+
+            // Inverse of ToPixels' absolute-unit factors: `value` is in CSS pixels.
+            switch (unit)
+            {
+                case Unit.In: // 1 in = 96 px
+                    return value / 96f;
+                case Unit.Mm: // 1 mm = 96/25.4 px
+                    return value * 25.4f / 96f;
+                case Unit.Pc: // 1 pc = 16 px
+                    return value / 16f;
+                case Unit.Pt: // 1 pt = 96/72 px
+                    return value * 72f / 96f;
+                case Unit.Cm: // 1 cm = 96/2.54 px
+                    return value * 2.54f / 96f;
+                case Unit.Px: // px is the layout unit
+                    return value;
+                default:
+                    throw new InvalidOperationException("An absolute unit cannot be converted to a relative one.");
+            }
+        }
+
+        public bool Equals(Length other)
+        {
+            return Value == other.Value && Type == other.Type;
+        }
+
+        internal enum Unit : byte
+        {
+            None,
+            Px,
+            Em,
+            Ex,
+            Cm,
+            Mm,
+            In,
+            Pt,
+            Pc,
+            Ch,
+            Rem,
+            Vw,
+            Vh,
+            Vmin,
+            Vmax,
+            Percent
+        }
+
+        /// <summary>
+        ///     Checks the equality of the two given lengths.
+        /// </summary>
+        /// <param name="a">The left length.</param>
+        /// <param name="b">The right length.</param>
+        /// <returns>True if both lengths are equal, otherwise false.</returns>
+        public static bool operator ==(Length a, Length b)
+        {
+            return a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Checks the inequality of the two given lengths.
+        /// </summary>
+        /// <param name="a">The left length.</param>
+        /// <param name="b">The right length.</param>
+        /// <returns>True if both lengths are not equal, otherwise false.</returns>
+        public static bool operator !=(Length a, Length b)
+        {
+            return !a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Tests if another object is equal to this object.
+        /// </summary>
+        /// <param name="obj">The object to test with.</param>
+        /// <returns>True if the two objects are equal, otherwise false.</returns>
+        public override bool Equals(object obj)
+        {
+            var other = obj as Length?;
+
+            if (other != null)
+                return Equals(other.Value);
+
+            return false;
+        }
+
+        /// <summary>
+        ///     Returns a hash code that defines the current length.
+        /// </summary>
+        /// <returns>The integer value of the hashcode.</returns>
+        public override int GetHashCode()
+        {
+            return Value.GetHashCode();
+        }
+
+        public override string ToString()
+        {
+            var unit = Value == 0f ? string.Empty : UnitString;
+            return string.Concat(Value.ToString(), unit);
+        }
+
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            var unit = Value == 0f ? string.Empty : UnitString;
+            return string.Concat(Value.ToString(format, formatProvider), unit);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/LinearGradient.cs b/Source/HtmlRenderer/Core/CssEngine/Values/LinearGradient.cs
new file mode 100644
index 000000000..e487b0e84
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/LinearGradient.cs
@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class LinearGradient : IGradient
+    {
+        public LinearGradient(Angle angle, GradientStop[] stops, bool repeating = false)
+        {
+            _stops = stops;
+            Angle = angle;
+            IsRepeating = repeating;
+        }
+
+        private readonly GradientStop[] _stops;
+
+        public Angle Angle { get; }
+        public IEnumerable<GradientStop> Stops => _stops.AsEnumerable();
+        public bool IsRepeating { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/MatrixTransform.cs b/Source/HtmlRenderer/Core/CssEngine/Values/MatrixTransform.cs
new file mode 100644
index 000000000..6872e4a92
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/MatrixTransform.cs
@@ -0,0 +1,17 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class MatrixTransform : ITransform
+    {
+        private readonly float[] _values;
+
+        internal MatrixTransform(float[] values)
+        {
+            _values = values;
+        }
+
+        public TransformMatrix ComputeMatrix()
+        {
+            return new TransformMatrix(_values);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Number.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Number.cs
new file mode 100644
index 000000000..5261235d1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Number.cs
@@ -0,0 +1,102 @@
+using System;
+
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Number : IEquatable<Number>, IComparable<Number>, IFormattable
+    {
+        /// <summary>
+        ///     Gets a zero value.
+        /// </summary>
+        public static readonly Number Zero = new Number(0f, Unit.Integer);
+
+        /// <summary>
+        ///     Gets the positive infinite value.
+        /// </summary>
+        public static readonly Number Infinite = new Number(float.PositiveInfinity, Unit.Float);
+
+        /// <summary>
+        ///     Gets the neutral element.
+        /// </summary>
+        public static readonly Number One = new Number(1f, Unit.Integer);
+
+        private readonly Unit _unit;
+
+        public Number(float value, Unit unit)
+        {
+            Value = value;
+            _unit = unit;
+        }
+
+        public float Value { get; }
+        public bool IsInteger => _unit == Unit.Integer;
+
+        public static bool operator >=(Number a, Number b)
+        {
+            return a.Value >= b.Value;
+        }
+
+        public static bool operator >(Number a, Number b)
+        {
+            return a.Value > b.Value;
+        }
+
+        public static bool operator <=(Number a, Number b)
+        {
+            return a.Value <= b.Value;
+        }
+
+        public static bool operator <(Number a, Number b)
+        {
+            return a.Value < b.Value;
+        }
+
+        public int CompareTo(Number other)
+        {
+            return Value.CompareTo(other.Value);
+        }
+
+        public bool Equals(Number other)
+        {
+            return Value == other.Value && _unit == other._unit;
+        }
+
+        internal enum Unit : byte
+        {
+            Integer,
+            Float,
+            Percent
+        }
+
+        public static bool operator ==(Number a, Number b)
+        {
+            return a.Value == b.Value;
+        }
+
+        public static bool operator !=(Number a, Number b)
+        {
+            return a.Value != b.Value;
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is Number other && Equals(other);
+        }
+
+        public override int GetHashCode()
+        {
+            return Value.GetHashCode();
+        }
+
+        public override string ToString()
+        {
+            return Value.ToString() + (_unit == Unit.Percent ? "%" : string.Empty);
+        }
+
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            return Value.ToString(format, formatProvider) + (_unit == Unit.Percent ? "%" : string.Empty);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Percent.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Percent.cs
new file mode 100644
index 000000000..7efa0358b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Percent.cs
@@ -0,0 +1,125 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Percent : IEquatable<Percent>, IComparable<Percent>, IFormattable
+    {
+        /// <summary>
+        ///     Gets a zero percent value.
+        /// </summary>
+        public static readonly Percent Zero = new Percent(0f);
+
+        /// <summary>
+        ///     Gets a fifty percent value.
+        /// </summary>
+        public static readonly Percent Fifty = new Percent(50f);
+
+        /// <summary>
+        ///     Gets a hundred percent value.
+        /// </summary>
+        public static readonly Percent Hundred = new Percent(100f);
+
+        public Percent(float value)
+        {
+            Value = value;
+        }
+
+        public float NormalizedValue => Value * 0.01f;
+        public float Value { get; }
+
+        /// <summary>
+        ///     Compares the magnitude of two percents.
+        /// </summary>
+        public static bool operator >=(Percent a, Percent b)
+        {
+            return a.Value >= b.Value;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two percents.
+        /// </summary>
+        public static bool operator >(Percent a, Percent b)
+        {
+            return a.Value > b.Value;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two percents.
+        /// </summary>
+        public static bool operator <=(Percent a, Percent b)
+        {
+            return a.Value <= b.Value;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two percents.
+        /// </summary>
+        public static bool operator <(Percent a, Percent b)
+        {
+            return a.Value < b.Value;
+        }
+
+        /// <summary>
+        ///     Compares the current percentage against the given one.
+        /// </summary>
+        /// <param name="other">The percentage to compare to.</param>
+        /// <returns>The result of the comparison.</returns>
+        public int CompareTo(Percent other)
+        {
+            return Value.CompareTo(other.Value);
+        }
+
+        /// <summary>
+        ///     Checks if the given percent value is equal to the current one.
+        /// </summary>
+        /// <param name="other">The other percent value.</param>
+        /// <returns>True if both have the same value.</returns>
+        public bool Equals(Percent other)
+        {
+            return Value == other.Value;
+        }
+
+        /// <summary>
+        ///     Checks for equality of two percents.
+        /// </summary>
+        public static bool operator ==(Percent a, Percent b)
+        {
+            return a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Checks for inequality of two percents.
+        /// </summary>
+        public static bool operator !=(Percent a, Percent b)
+        {
+            return !a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Tests if another object is equal to this object.
+        /// </summary>
+        /// <param name="obj">The object to test with.</param>
+        /// <returns>True if the two objects are equal, otherwise false.</returns>
+        public override bool Equals(object obj)
+        {
+            if (obj is Percent other) return Equals(other);
+
+            return false;
+        }
+
+        public override int GetHashCode()
+        {
+            return Value.GetHashCode();
+        }
+
+        public override string ToString()
+        {
+            return Value + "%";
+        }
+
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            return Value.ToString(format, formatProvider) + "%";
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/PerspectiveTransform.cs b/Source/HtmlRenderer/Core/CssEngine/Values/PerspectiveTransform.cs
new file mode 100644
index 000000000..8134744cb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/PerspectiveTransform.cs
@@ -0,0 +1,32 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class PerspectiveTransform : ITransform
+    {
+        private readonly Length _distance;
+
+        internal PerspectiveTransform(Length distance)
+        {
+            _distance = distance;
+        }
+
+        public TransformMatrix ComputeMatrix()
+        {
+            return new TransformMatrix(
+                1f,
+                0f,
+                0f,
+                0f,
+                1f,
+                0f,
+                0f,
+                0f,
+                1f,
+                0f,
+                0f,
+                0f,
+                0f,
+                0f,
+                -1f / _distance.ToPixel());
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Point.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Point.cs
new file mode 100644
index 000000000..ee8bad8d4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Point.cs
@@ -0,0 +1,41 @@
+// ReSharper disable UnusedMember.Global
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Point
+    {
+        /// <summary>
+        ///     Gets the (50%, 50%) point.
+        /// </summary>
+        public static readonly Point Center = new Point(Length.Half, Length.Half);
+
+        /// <summary>
+        ///     Gets the (0, 0) point.
+        /// </summary>
+        public static readonly Point LeftTop = new Point(Length.Zero, Length.Zero);
+
+        /// <summary>
+        ///     Gets the (100%, 0) point.
+        /// </summary>
+        public static readonly Point RightTop = new Point(Length.Full, Length.Zero);
+
+        /// <summary>
+        ///     Gets the (100%, 100%) point.
+        /// </summary>
+        public static readonly Point RightBottom = new Point(Length.Full, Length.Full);
+
+        /// <summary>
+        ///     Gets the (0, 100%) point.
+        /// </summary>
+        public static readonly Point LeftBottom = new Point(Length.Zero, Length.Full);
+
+        public Point(Length x, Length y)
+        {
+            X = x;
+            Y = y;
+        }
+
+        public Length X { get; }
+        public Length Y { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/PortNumbers.cs b/Source/HtmlRenderer/Core/CssEngine/Values/PortNumbers.cs
new file mode 100644
index 000000000..5ac5b2924
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/PortNumbers.cs
@@ -0,0 +1,26 @@
+using System.Collections.Generic;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class PortNumbers
+    {
+        private static readonly Dictionary<string, string> Ports = new Dictionary<string, string>
+        {
+            {ProtocolNames.Http, "80"},
+            {ProtocolNames.Https, "443"},
+            {ProtocolNames.Ftp, "21"},
+            {ProtocolNames.File, ""},
+            {ProtocolNames.Ws, "80"},
+            {ProtocolNames.Wss, "443"},
+            {ProtocolNames.Gopher, "70"},
+            {ProtocolNames.Telnet, "23"},
+            {ProtocolNames.Ssh, "22"}
+        };
+
+        public static string GetDefaultPort(string protocol)
+        {
+            Ports.TryGetValue(protocol, out var value);
+            return value;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/ProtocolNames.cs b/Source/HtmlRenderer/Core/CssEngine/Values/ProtocolNames.cs
new file mode 100644
index 000000000..6c544a482
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/ProtocolNames.cs
@@ -0,0 +1,50 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal static class ProtocolNames
+    {
+        public static readonly string Http = "http";
+        public static readonly string Https = "https";
+        public static readonly string Ftp = "ftp";
+        public static readonly string JavaScript = "javascript";
+        public static readonly string Data = "data";
+        public static readonly string Mailto = "mailto";
+        public static readonly string File = "file";
+        public static readonly string Ws = "ws";
+        public static readonly string Wss = "wss";
+        public static readonly string Telnet = "telnet";
+        public static readonly string Ssh = "ssh";
+        public static readonly string Gopher = "gopher";
+        public static readonly string Blob = "blob";
+
+        private static readonly string[] RelativeProtocols =
+        {
+            Http,
+            Https,
+            Ftp,
+            File,
+            Ws,
+            Wss,
+            Gopher
+        };
+
+        private static readonly string[] OriginalableProtocols =
+        {
+            Http,
+            Https,
+            Ftp,
+            Ws,
+            Wss,
+            Gopher
+        };
+
+        public static bool IsRelative(string protocol)
+        {
+            return RelativeProtocols.Contains(protocol);
+        }
+
+        public static bool IsOriginable(string protocol)
+        {
+            return OriginalableProtocols.Contains(protocol);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/RadialGradient.cs b/Source/HtmlRenderer/Core/CssEngine/Values/RadialGradient.cs
new file mode 100644
index 000000000..55f026bb1
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/RadialGradient.cs
@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RadialGradient : IImageSource
+    {
+        internal enum SizeMode : byte
+        {
+            None,
+            ClosestCorner,
+            ClosestSide,
+            FarthestCorner,
+            FarthestSide
+        }
+
+        public RadialGradient(bool circle, Point pt, Length width, Length height, SizeMode sizeMode,
+            GradientStop[] stops, bool repeating = false)
+        {
+            _stops = stops;
+            Position = pt;
+            MajorRadius = width;
+            MinorRadius = height;
+            IsRepeating = repeating;
+            IsCircle = circle;
+            Mode = sizeMode;
+        }
+
+        private readonly GradientStop[] _stops;
+
+        public bool IsCircle { get; }
+
+        public SizeMode Mode { get; }
+        public Point Position { get; }
+        public Length MajorRadius { get; }
+        public Length MinorRadius { get; }
+        public IEnumerable<GradientStop> Stops => _stops.AsEnumerable();
+        public bool IsRepeating { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Resolution.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Resolution.cs
new file mode 100644
index 000000000..9355bac2e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Resolution.cs
@@ -0,0 +1,123 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Resolution : IEquatable<Resolution>, IComparable<Resolution>, IFormattable
+    {
+        public Resolution(float value, Unit unit)
+        {
+            Value = value;
+            Type = unit;
+        }
+
+        public float Value { get; }
+        public Unit Type { get; }
+
+        public string UnitString
+        {
+            get
+            {
+                switch (Type)
+                {
+                    case Unit.Dpcm:
+                        return UnitNames.Dpcm;
+                    case Unit.Dpi:
+                        return UnitNames.Dpi;
+                    case Unit.Dppx:
+                        return UnitNames.Dppx;
+                    default:
+                        return string.Empty;
+                }
+            }
+        }
+
+        public static bool TryParse(string s, out Resolution result)
+        {
+            var unit = GetUnit(s.StylesheetUnit(out var value));
+
+            if (unit != Unit.None)
+            {
+                result = new Resolution(value, unit);
+                return true;
+            }
+
+            result = default;
+            return false;
+        }
+
+        public static Unit GetUnit(string s)
+        {
+            switch (s)
+            {
+                case "dpcm":
+                    return Unit.Dpcm;
+                case "dpi":
+                    return Unit.Dpi;
+                case "dppx":
+                    return Unit.Dppx;
+                case "x": // `x` is the canonical alias for `dppx` (CSS Values 4 §7.4)
+                    return Unit.Dppx;
+                default:
+                    return Unit.None;
+            }
+        }
+
+        public float ToDotsPerPixel()
+        {
+            if (Type == Unit.Dpi) return Value / 96f;
+            if (Type == Unit.Dpcm) return Value * 127f / (50f * 96f);
+
+            return Value;
+        }
+
+        public float To(Unit unit)
+        {
+            var value = ToDotsPerPixel();
+
+            if (unit == Unit.Dpi) return value * 96f;
+            if (unit == Unit.Dpcm) return value * 50f * 96f / 127f;
+
+            return value;
+        }
+
+        public bool Equals(Resolution other)
+        {
+            return Value == other.Value && Type == other.Type;
+        }
+
+        internal enum Unit : byte
+        {
+            None,
+            Dpi,
+            Dpcm,
+            Dppx
+        }
+
+        public int CompareTo(Resolution other)
+        {
+            return ToDotsPerPixel().CompareTo(other.ToDotsPerPixel());
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (obj is Resolution other) return Equals(other);
+
+            return false;
+        }
+
+        public override int GetHashCode()
+        {
+            return Value.GetHashCode();
+        }
+
+        public override string ToString()
+        {
+            return string.Concat(Value.ToString(), UnitString);
+        }
+
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            return string.Concat(Value.ToString(format, formatProvider), UnitString);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/RotateTransform.cs b/Source/HtmlRenderer/Core/CssEngine/Values/RotateTransform.cs
new file mode 100644
index 000000000..0b3abe4c4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/RotateTransform.cs
@@ -0,0 +1,38 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class RotateTransform : ITransform
+    {
+        internal RotateTransform(float x, float y, float z, float angle)
+        {
+            X = x;
+            Y = y;
+            Z = z;
+            Angle = angle;
+        }
+
+        public float X { get; }
+        public float Y { get; }
+        public float Z { get; }
+        public float Angle { get; }
+
+        public TransformMatrix ComputeMatrix()
+        {
+            var norm = 1f / (float)Math.Sqrt(X * X + Y * Y + Z * Z);
+            var sina = (float)Math.Sin(Angle);
+            var cosa = (float)Math.Cos(Angle);
+
+            var l = X * norm;
+            var m = Y * norm;
+            var n = Z * norm;
+            var omc = 1f - cosa;
+
+            return new TransformMatrix(
+                l * l * omc + cosa, m * l * omc - n * sina, n * l * omc + m * sina,
+                l * m * omc + n * sina, m * m * omc + cosa, n * m * omc - l * sina,
+                l * n * omc - m * sina, m * n * omc + l * sina, n * n * omc + cosa,
+                0f, 0f, 0f, 0f, 0f, 0f);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/ScaleTransform.cs b/Source/HtmlRenderer/Core/CssEngine/Values/ScaleTransform.cs
new file mode 100644
index 000000000..4abc4f7d3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/ScaleTransform.cs
@@ -0,0 +1,21 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class ScaleTransform : ITransform
+    {
+        private readonly float _sx;
+        private readonly float _sy;
+        private readonly float _sz;
+
+        internal ScaleTransform(float sx, float sy, float sz)
+        {
+            _sx = sx;
+            _sy = sy;
+            _sz = sz;
+        }
+
+        public TransformMatrix ComputeMatrix()
+        {
+            return new TransformMatrix(_sx, 0f, 0f, 0f, _sy, 0f, 0f, 0f, _sz, 0f, 0f, 0f, 0f, 0f, 0f);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Shadow.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Shadow.cs
new file mode 100644
index 000000000..7b335e334
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Shadow.cs
@@ -0,0 +1,22 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class Shadow
+    {
+        public Shadow(bool inset, Length offsetX, Length offsetY, Length blurRadius, Length spreadRadius, Color color)
+        {
+            IsInset = inset;
+            OffsetX = offsetX;
+            OffsetY = offsetY;
+            BlurRadius = blurRadius;
+            SpreadRadius = spreadRadius;
+            Color = color;
+        }
+
+        public Color Color { get; }
+        public Length OffsetX { get; }
+        public Length OffsetY { get; }
+        public Length BlurRadius { get; }
+        public Length SpreadRadius { get; }
+        public bool IsInset { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Shape.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Shape.cs
new file mode 100644
index 000000000..bf800e69b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Shape.cs
@@ -0,0 +1,18 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class Shape
+    {
+        public Shape(Length top, Length right, Length bottom, Length left)
+        {
+            Top = top;
+            Right = right;
+            Bottom = bottom;
+            Left = left;
+        }
+
+        public Length Top { get; }
+        public Length Right { get; }
+        public Length Bottom { get; }
+        public Length Left { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/SkewTransform.cs b/Source/HtmlRenderer/Core/CssEngine/Values/SkewTransform.cs
new file mode 100644
index 000000000..5448cf3a8
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/SkewTransform.cs
@@ -0,0 +1,23 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class SkewTransform : ITransform
+    {
+        internal SkewTransform(float alpha, float beta)
+        {
+            Alpha = alpha;
+            Beta = beta;
+        }
+
+        public TransformMatrix ComputeMatrix()
+        {
+            var a = (float)Math.Tan(Alpha);
+            var b = (float)Math.Tan(Beta);
+            return new TransformMatrix(1f, a, 0f, b, 1f, 0f, 0f, 0f, 1f, 0f, 0f, 0f, 0f, 0f, 0f);
+        }
+
+        public float Alpha { get; }
+        public float Beta { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/StepsTimingFunction.cs b/Source/HtmlRenderer/Core/CssEngine/Values/StepsTimingFunction.cs
new file mode 100644
index 000000000..10540dbc2
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/StepsTimingFunction.cs
@@ -0,0 +1,16 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class StepsTimingFunction : ITimingFunction
+    {
+        public StepsTimingFunction(int intervals, bool start = false)
+        {
+            Intervals = Math.Max(1, intervals);
+            IsStart = start;
+        }
+
+        public int Intervals { get; }
+        public bool IsStart { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/Time.cs b/Source/HtmlRenderer/Core/CssEngine/Values/Time.cs
new file mode 100644
index 000000000..518789b90
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/Time.cs
@@ -0,0 +1,161 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal struct Time : IEquatable<Time>, IComparable<Time>, IFormattable
+    {
+        public static readonly Time Zero = new Time(0f, Unit.Ms);
+
+        public Time(float value, Unit unit)
+        {
+            Value = value;
+            Type = unit;
+        }
+
+        public float Value { get; }
+        public Unit Type { get; }
+
+        public string UnitString
+        {
+            get
+            {
+                switch (Type)
+                {
+                    case Unit.Ms:
+                        return UnitNames.Ms;
+                    case Unit.S:
+                        return UnitNames.S;
+                    default:
+                        return string.Empty;
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two times.
+        /// </summary>
+        public static bool operator >=(Time a, Time b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == 1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two times.
+        /// </summary>
+        public static bool operator >(Time a, Time b)
+        {
+            return a.CompareTo(b) == 1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two times.
+        /// </summary>
+        public static bool operator <=(Time a, Time b)
+        {
+            var result = a.CompareTo(b);
+            return result == 0 || result == -1;
+        }
+
+        /// <summary>
+        ///     Compares the magnitude of two times.
+        /// </summary>
+        public static bool operator <(Time a, Time b)
+        {
+            return a.CompareTo(b) == -1;
+        }
+
+        public int CompareTo(Time other)
+        {
+            return ToMilliseconds().CompareTo(other.ToMilliseconds());
+        }
+
+
+        public static Unit GetUnit(string s)
+        {
+            switch (s)
+            {
+                case "s":
+                    return Unit.S;
+                case "ms":
+                    return Unit.Ms;
+                default:
+                    return Unit.None;
+            }
+        }
+
+        public float ToMilliseconds()
+        {
+            return Type == Unit.S ? Value * 1000f : Value;
+        }
+
+        public bool Equals(Time other)
+        {
+            return ToMilliseconds() == other.ToMilliseconds();
+        }
+
+        internal enum Unit : byte
+        {
+            None,
+            Ms,
+            S
+        }
+
+        /// <summary>
+        ///     Checks for equality of two times.
+        /// </summary>
+        public static bool operator ==(Time a, Time b)
+        {
+            return a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Checks for inequality of two times.
+        /// </summary>
+        public static bool operator !=(Time a, Time b)
+        {
+            return !a.Equals(b);
+        }
+
+        /// <summary>
+        ///     Tests if another object is equal to this object.
+        /// </summary>
+        /// <param name="obj">The object to test with.</param>
+        /// <returns>True if the two objects are equal, otherwise false.</returns>
+        public override bool Equals(object obj)
+        {
+            if (obj is Time other) return Equals(other);
+
+            return false;
+        }
+
+        /// <summary>
+        ///     Returns a hash code that defines the current time.
+        /// </summary>
+        /// <returns>The integer value of the hashcode.</returns>
+        public override int GetHashCode()
+        {
+            return Value.GetHashCode();
+        }
+
+        /// <summary>
+        ///     Returns a string representing the time.
+        /// </summary>
+        /// <returns>The unit string.</returns>
+        public override string ToString()
+        {
+            return string.Concat(Value.ToString(), UnitString);
+        }
+
+        /// <summary>
+        ///     Returns a formatted string representing the time.
+        /// </summary>
+        /// <param name="format">The format of the number.</param>
+        /// <param name="formatProvider">The provider to use.</param>
+        /// <returns>The unit string.</returns>
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            return string.Concat(Value.ToString(format, formatProvider), UnitString);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/Values/TranslateTransform.cs b/Source/HtmlRenderer/Core/CssEngine/Values/TranslateTransform.cs
new file mode 100644
index 000000000..bd6e3d6bb
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/Values/TranslateTransform.cs
@@ -0,0 +1,24 @@
+namespace TheArtOfDev.HtmlRenderer.Core.CssEngine
+{
+    internal sealed class TranslateTransform : ITransform
+    {
+        internal TranslateTransform(Length x, Length y, Length z)
+        {
+            Dx = x;
+            Dy = y;
+            Dz = z;
+        }
+
+        public TransformMatrix ComputeMatrix()
+        {
+            var dx = Dx.ToPixel();
+            var dy = Dy.ToPixel();
+            var dz = Dz.ToPixel();
+            return new TransformMatrix(1f, 0f, 0f, 0f, 1f, 0f, 0f, 0f, 1f, dx, dy, dz, 0f, 0f, 0f);
+        }
+
+        public Length Dx { get; }
+        public Length Dy { get; }
+        public Length Dz { get; }
+    }
+}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/CssEngine/license.txt b/Source/HtmlRenderer/Core/CssEngine/license.txt
new file mode 100644
index 000000000..5ee26cb76
--- /dev/null
+++ b/Source/HtmlRenderer/Core/CssEngine/license.txt
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2024 Tyler Brinks
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/Dom/CssBox.cs b/Source/HtmlRenderer/Core/Dom/CssBox.cs
index 05ae7f539..4b26a8fd4 100644
--- a/Source/HtmlRenderer/Core/Dom/CssBox.cs
+++ b/Source/HtmlRenderer/Core/Dom/CssBox.cs
@@ -154,6 +154,24 @@ public bool IsTableRowGroupBox
             get { return Display == CssConstants.TableRowGroup || Display == CssConstants.TableHeaderGroup || Display == CssConstants.TableFooterGroup; }
         }
 
+        /// <summary>
+        /// Is this box a synthesized <c>::before</c> pseudo-element (see <see cref="CssData"/>'s selector-matching synthesis).
+        /// </summary>
+        public bool IsBeforePseudoElement { get; set; }
+
+        /// <summary>
+        /// Is this box a synthesized <c>::after</c> pseudo-element (see <see cref="CssData"/>'s selector-matching synthesis).
+        /// </summary>
+        public bool IsAfterPseudoElement { get; set; }
+
+        /// <summary>
+        /// Is this box a synthesized <c>::before</c>/<c>::after</c> pseudo-element.
+        /// </summary>
+        public bool IsPseudoElement
+        {
+            get { return IsBeforePseudoElement || IsAfterPseudoElement; }
+        }
+
         /// <summary>
         /// is the box "Display" is "Inline", is this is an inline box and not block.
         /// </summary>
@@ -171,11 +189,32 @@ public bool IsBlock
         }
 
         /// <summary>
-        /// Is the css box clickable (by default only "a" element is clickable)
+        /// Is this box floated (float: left or float: right).
+        /// </summary>
+        public bool IsFloated
+        {
+            get { return Float == CssConstants.Left || Float == CssConstants.Right; }
+        }
+
+        /// <summary>
+        /// True for a box removed from normal flow: floated, or absolutely/fixed positioned. Ported
+        /// from PeachPDF's CssBox.IsOutOfFlow - used to find a container's last IN-FLOW child (e.g.
+        /// <see cref="MarginBottomCollapse"/>), since an out-of-flow box doesn't contribute to a
+        /// non-BFC-establishing container's own auto-height (CSS 2.1 10.6.3/10.6.7).
+        /// </summary>
+        public bool IsOutOfFlow
+        {
+            get { return IsFloated || Position == CssConstants.Absolute || Position == CssConstants.Fixed; }
+        }
+
+        /// <summary>
+        /// Is the css box clickable (by default only "a" elements that are actual hyperlinks - i.e.
+        /// have an "href" - are clickable; an "a" used only as a named anchor/target has no href and
+        /// is not clickable, matching the same "href" gate CSS uses for the :link pseudo-class).
         /// </summary>
         public virtual bool IsClickable
         {
-            get { return HtmlTag != null && HtmlTag.Name == HtmlConstants.A && !HtmlTag.HasAttribute("id"); }
+            get { return HtmlTag != null && HtmlTag.Name == HtmlConstants.A && HtmlTag.HasAttribute("href"); }
         }
 
         /// <summary>
@@ -613,6 +652,90 @@ public virtual void Dispose()
 
         #region Private Methods
 
+        /// <summary>
+        /// Computes this box's used height, ported from PeachPDF's CssLayoutEngine.GetBoxHeight -
+        /// scoped to the height features this engine supports (no aspect-ratio, no absolutely-
+        /// positioned top+bottom fill, no per-page height: PeachPDF features this engine never had).
+        /// PeachPDF's Size.Height is content-only, so its GetBoxHeight starts from
+        /// ActualBoxSizingHeight (Size.Height + padding/border) as the auto-height baseline and can
+        /// return null for an indeterminate percentage height, leaving ApplyHeight's Math.Max to
+        /// preserve whatever content-driven value is already there. This engine's Size.Height is
+        /// already the border-box measure (see <see cref="ActualRight"/>), so the equivalent baseline
+        /// is Size.Height itself, and there is no null case to thread through - an indeterminate
+        /// percentage height simply falls back to that same baseline directly.
+        /// </summary>
+        private double GetBoxHeight()
+        {
+            double height = Size.Height;
+
+            if (CssValueParser.IsValidLength(Height) && !(Height.EndsWith("%") && !ContainingBlock.IsHeightCalculated))
+            {
+                height = CssValueParser.ParseLength(Height, ContainingBlock.Size.Height, this) + ActualBoxSizeIncludedHeight;
+            }
+
+            if (CssValueParser.IsValidLength(MinHeight) && (ContainingBlock.IsHeightCalculated || !MinHeight.EndsWith("%")))
+            {
+                var minHeight = CssValueParser.ParseLength(MinHeight, ContainingBlock.Size.Height, this) + ActualBoxSizeIncludedHeight;
+                if (minHeight > height)
+                {
+                    height = minHeight;
+                }
+            }
+
+            return height;
+        }
+
+        /// <summary>
+        /// Applies this box's used height (CSS 2.1 10.5/10.6.3/10.7) to <see cref="CssBoxProperties.ActualBottom"/>,
+        /// and computes whether this box counts as height-calculated for a descendant's percentage
+        /// height resolution. Ported from PeachPDF's CssLayoutEngine.ApplyHeight.
+        /// <para>
+        /// The assignment below is unconditional (not the plain <c>Math.Max(ActualBottom, ...)</c>
+        /// this replaced) - a no-op for auto height, since <see cref="GetBoxHeight"/>'s baseline is
+        /// already ActualBottom's own current value, but a real correction for a definite height,
+        /// able to shrink ActualBottom back down, which Math.Max alone never could. That correction is
+        /// what fixes a real bug this exposed: <see cref="CssLayoutEngine.FlowBox"/>'s own "handle
+        /// height setting" step (for a nested atomic inline-block) pushes a block's own maxBottom out
+        /// to the block's full ActualHeight measured from its content top, and CreateLineBoxes then
+        /// adds that same block's bottom padding/border again on top - inflating ActualBottom by one
+        /// extra padding+border box for any floated or block-level box with both an explicit height
+        /// and non-zero padding/border (e.g. every floated box in the W3C ACID1 test). A definite
+        /// height here authoritatively overwrites that inflated value instead of merely preserving it.
+        /// </para>
+        /// </summary>
+        private void ApplyHeight()
+        {
+            var height = GetBoxHeight();
+            ActualBottom = Location.Y + height;
+
+            var isRootWithPageHeight = ParentBox == null && HtmlContainer != null;
+            var isDefiniteHeight = CssValueParser.IsValidLength(Height) && (ContainingBlock.IsHeightCalculated || !Height.EndsWith("%"));
+            IsHeightCalculated = isRootWithPageHeight || isDefiniteHeight;
+
+            if (CssValueParser.IsValidLength(MaxHeight) && MaxHeight != CssConstants.None
+                && (ContainingBlock.IsHeightCalculated || !MaxHeight.EndsWith("%")))
+            {
+                var maxHeight = CssValueParser.ParseLength(MaxHeight, ContainingBlock.Size.Height, this) + ActualBoxSizeIncludedHeight;
+                var maxBottom = Location.Y + maxHeight;
+
+                if (ActualBottom > maxBottom)
+                {
+                    ActualBottom = maxBottom;
+
+                    if (CssValueParser.IsValidLength(MinHeight) && (ContainingBlock.IsHeightCalculated || !MinHeight.EndsWith("%")))
+                    {
+                        var minHeight = CssValueParser.ParseLength(MinHeight, ContainingBlock.Size.Height, this) + ActualBoxSizeIncludedHeight;
+                        var minBottom = Location.Y + minHeight;
+
+                        if (ActualBottom < minBottom)
+                        {
+                            ActualBottom = minBottom;
+                        }
+                    }
+                }
+            }
+        }
+
         /// <summary>
         /// Measures the bounds of box and children, recursively.<br/>
         /// Performs layout of the DOM structure creating lines by set bounds restrictions.<br/>
@@ -631,19 +754,44 @@ protected virtual void PerformLayoutImp(RGraphics g)
                 // Because their width and height are set by CssTable
                 if (Display != CssConstants.TableCell && Display != CssConstants.Table)
                 {
-                    double width = ContainingBlock.Size.Width
+                    double availableWidth = ContainingBlock.Size.Width
                                    - ContainingBlock.ActualPaddingLeft - ContainingBlock.ActualPaddingRight
                                    - ContainingBlock.ActualBorderLeftWidth - ContainingBlock.ActualBorderRightWidth;
+                    double width = availableWidth;
+                    bool explicitWidth = Width != CssConstants.Auto && !string.IsNullOrEmpty(Width);
 
-                    if (Width != CssConstants.Auto && !string.IsNullOrEmpty(Width))
+                    if (explicitWidth)
+                    {
+                        // CSS 2.1 10.2: a percentage/length `width` resolves against the containing block's
+                        // content width. Per CSS Box Sizing 3, that resolved value is this box's CONTENT
+                        // width under the default `box-sizing: content-box` - its border-box width (what
+                        // Size.Width holds throughout this engine) additionally includes this box's own
+                        // padding+border (ActualBoxSizeIncludedWidth is 0 for `box-sizing: border-box`,
+                        // where the resolved value already IS the border-box width).
+                        width = CssValueParser.ParseLength(Width, availableWidth, this) + ActualBoxSizeIncludedWidth;
+                    }
+                    else if (IsFloated)
                     {
-                        width = CssValueParser.ParseLength(Width, width, this);
+                        // CSS 2.1 10.3.5: a floated box with width:auto shrinks to fit its content
+                        // instead of taking the full containing-block width like an ordinary block.
+                        // GetMinMaxWidth already returns border-box-inclusive bounds (its own padding/
+                        // border baked in), so no box-sizing adjustment is needed here.
+                        double minWidth, maxWidth;
+                        GetMinMaxWidth(out minWidth, out maxWidth);
+                        width = Math.Min(Math.Max(minWidth, width), maxWidth);
                     }
 
                     Size = new RSize(width, Size.Height);
 
-                    // must be separate because the margin can be calculated by percentage of the width
-                    Size = new RSize(width - ActualMarginLeft - ActualMarginRight, Size.Height);
+                    if (!explicitWidth && !IsFloated)
+                    {
+                        // CSS 2.1 10.3.3: only a plain (non-floated) width:auto block absorbs its own
+                        // margin into the available fill width to become its used (border-box) width - an
+                        // explicit width, or a floated shrink-to-fit width, is the used width as-is; margin
+                        // is separate space outside the border box (already accounted for via this box's
+                        // Location.X), not a further reduction of Size.Width on top of that.
+                        Size = new RSize(width - ActualMarginLeft - ActualMarginRight, Size.Height);
+                    }
                 }
 
                 if (Display != CssConstants.TableCell)
@@ -663,6 +811,10 @@ protected virtual void PerformLayoutImp(RGraphics g)
                         top = (prevSibling == null && ParentBox != null ? ParentBox.ClientTop : ParentBox == null ? Location.Y : 0) + MarginTopCollapse(prevSibling) + (prevSibling != null ? prevSibling.ActualBottom + prevSibling.ActualBorderBottomWidth : 0);
                         Location = new RPoint(left, top);
                         ActualBottom = top;
+
+                        // static position committed above; float/clear now overwrite Location using that
+                        // static position as input. No-op for boxes that are neither floated nor clearing.
+                        CssLayoutEngine.FloatBox(this);
                     }
                 }
 
@@ -686,7 +838,19 @@ protected virtual void PerformLayoutImp(RGraphics g)
                             childBox.PerformLayout(g);
                         }
                         ActualRight = CalculateActualRight();
-                        ActualBottom = MarginBottomCollapse();
+
+                        // CSS 2.1 10.6.3/10.6.7: a plain (non-BFC-establishing) box's own auto-height
+                        // doesn't contribute from out-of-flow (floated/absolutely-positioned) children
+                        // at all - if EVERY child is out-of-flow (e.g. a <ul> whose only children are
+                        // floated <li>s), there is no in-flow content to measure, so ActualBottom is
+                        // left exactly as the static-position commit above already set it (its own
+                        // top, i.e. zero content height) rather than being pulled down to match a
+                        // floated child's position. Ported from PeachPDF's CssBox.PerformLayoutImp
+                        // (`if (Boxes.Any(b => !b.IsOutOfFlow)) { ActualBottom = MarginBottomCollapse(); }`).
+                        if (Boxes.Exists(b => !b.IsOutOfFlow))
+                        {
+                            ActualBottom = MarginBottomCollapse();
+                        }
                     }
                 }
             }
@@ -700,7 +864,7 @@ protected virtual void PerformLayoutImp(RGraphics g)
                     ActualBottom = prevSibling.ActualBottom;
                 }
             }
-            ActualBottom = Math.Max(ActualBottom, Location.Y + ActualHeight);
+            ApplyHeight();
 
             CreateListItemBox(g);
 
@@ -719,10 +883,10 @@ internal virtual void MeasureWordsSize(RGraphics g)
         {
             if (!_wordsSizeMeasured)
             {
-                if (BackgroundImage != CssConstants.None && _imageLoadHandler == null)
+                if (ActualBackgroundImage is CssImage.Url urlImage && _imageLoadHandler == null)
                 {
                     _imageLoadHandler = new ImageLoadHandler(HtmlContainer, OnImageLoadComplete);
-                    _imageLoadHandler.LoadImage(BackgroundImage, HtmlTag != null ? HtmlTag.Attributes : null);
+                    _imageLoadHandler.LoadImage(urlImage.Href, HtmlTag != null ? HtmlTag.Attributes : null);
                 }
 
                 MeasureWordSpacing(g);
@@ -1173,13 +1337,20 @@ private double CalculateActualRight()
         /// <returns>Resulting bottom margin</returns>
         private double MarginBottomCollapse()
         {
+            // Only called when at least one in-flow child exists (see the caller's IsOutOfFlow gate),
+            // so this is guaranteed to find one - an out-of-flow (floated/absolutely-positioned) child
+            // doesn't contribute to this box's own auto-height (CSS 2.1 10.6.3/10.6.7) and must not be
+            // used as "the last child" here, matching PeachPDF's own MarginBottomCollapse
+            // (`Boxes.Last(b => !b.IsOutOfFlow)`).
+            var lastInFlowBox = _boxes.FindLast(b => !b.IsOutOfFlow);
+
             double margin = 0;
             if (ParentBox != null && ParentBox.Boxes.IndexOf(this) == ParentBox.Boxes.Count - 1 && _parentBox.ActualMarginBottom < 0.1)
             {
-                var lastChildBottomMargin = _boxes[_boxes.Count - 1].ActualMarginBottom;
+                var lastChildBottomMargin = lastInFlowBox.ActualMarginBottom;
                 margin = Height == "auto" ? Math.Max(ActualMarginBottom, lastChildBottomMargin) : lastChildBottomMargin;
             }
-            return Math.Max(ActualBottom, _boxes[_boxes.Count - 1].ActualBottom + margin + ActualPaddingBottom + ActualBorderBottomWidth);
+            return Math.Max(ActualBottom, lastInFlowBox.ActualBottom + margin + ActualPaddingBottom + ActualBorderBottomWidth);
         }
 
         /// <summary>
@@ -1310,15 +1481,18 @@ protected void PaintBackground(RGraphics g, RRect rect, bool isFirst, bool isLas
             {
                 RBrush brush = null;
 
-                if (BackgroundGradient != CssConstants.None)
+                var backgroundImage = ActualBackgroundImage;
+                if (backgroundImage is CssImage.LinearGradient linearGradient)
                 {
-                    brush = g.GetLinearGradientBrush(rect, ActualBackgroundColor, ActualBackgroundGradient, ActualBackgroundGradientAngle);
+                    brush = CssImagePainter.GetLinearGradientBrush(g, rect, linearGradient.Gradient);
                 }
                 else if (RenderUtils.IsColorVisible(ActualBackgroundColor))
                 {
                     brush = g.GetSolidBrush(ActualBackgroundColor);
                 }
 
+                var rad = ComputeRadii(rect);
+
                 if (brush != null)
                 {
                     // TODO:a handle it correctly (tables background)
@@ -1326,13 +1500,13 @@ protected void PaintBackground(RGraphics g, RRect rect, bool isFirst, bool isLas
                     //  rectangle.Width -= ActualWordSpacing + CssUtils.GetWordEndWhitespace(ActualFont);
 
                     RGraphicsPath roundrect = null;
-                    if (IsRounded)
+                    if (rad.IsRounded)
                     {
-                        roundrect = RenderUtils.GetRoundRect(g, rect, ActualCornerNw, ActualCornerNe, ActualCornerSe, ActualCornerSw);
+                        roundrect = RenderUtils.GetRoundRect(g, rect, rad.TLX, rad.TLY, rad.TRX, rad.TRY, rad.BRX, rad.BRY, rad.BLX, rad.BLY);
                     }
 
                     Object prevMode = null;
-                    if (HtmlContainer != null && !HtmlContainer.AvoidGeometryAntialias && IsRounded)
+                    if (HtmlContainer != null && !HtmlContainer.AvoidGeometryAntialias && rad.IsRounded)
                     {
                         prevMode = g.SetAntiAliasSmoothingMode();
                     }
@@ -1430,21 +1604,6 @@ protected void PaintDecoration(RGraphics g, RRect rectangle, bool isFirst, bool
             if (string.IsNullOrEmpty(TextDecoration) || TextDecoration == CssConstants.None)
                 return;
 
-            double y = 0f;
-            if (TextDecoration == CssConstants.Underline)
-            {
-                y = Math.Round(rectangle.Top + ActualFont.UnderlineOffset);
-            }
-            else if (TextDecoration == CssConstants.LineThrough)
-            {
-                y = rectangle.Top + rectangle.Height / 2f;
-            }
-            else if (TextDecoration == CssConstants.Overline)
-            {
-                y = rectangle.Top;
-            }
-            y -= ActualPaddingBottom - ActualBorderBottomWidth;
-
             double x1 = rectangle.X;
             if (isFirst)
                 x1 += ActualPaddingLeft + ActualBorderLeftWidth;
@@ -1453,10 +1612,36 @@ protected void PaintDecoration(RGraphics g, RRect rectangle, bool isFirst, bool
             if (isLast)
                 x2 -= ActualPaddingRight + ActualBorderRightWidth;
 
+            var bottomInset = ActualPaddingBottom - ActualBorderBottomWidth;
             var pen = g.GetPen(ActualColor);
             pen.Width = 1;
             pen.DashStyle = RDashStyle.Solid;
-            g.DrawLine(pen, x1, y, x2, y);
+
+            // text-decoration-line may list several space-separated line keywords (e.g. "underline
+            // overline") - draw each one present rather than only the first/only value.
+            foreach (var line in TextDecoration.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries))
+            {
+                double y;
+                if (line == CssConstants.Underline)
+                {
+                    y = Math.Round(rectangle.Top + ActualFont.UnderlineOffset);
+                }
+                else if (line == CssConstants.LineThrough)
+                {
+                    y = rectangle.Top + rectangle.Height / 2f;
+                }
+                else if (line == CssConstants.Overline)
+                {
+                    y = rectangle.Top;
+                }
+                else
+                {
+                    continue;
+                }
+
+                y -= bottomInset;
+                g.DrawLine(pen, x1, y, x2, y);
+            }
         }
 
         /// <summary>
@@ -1523,9 +1708,29 @@ protected RBrush GetSelectionBackBrush(RGraphics g, bool forceAlpha)
             }
         }
 
-        protected override RFont GetCachedFont(string fontFamily, double fsize, RFontStyle st)
+        protected override RFont GetCachedFont(string fontFamily, double fsize, RFontStyle st, int weight, int stretch, int? codepoint)
+        {
+            return HtmlContainer.Adapter.GetFont(fontFamily, fsize, st, weight, stretch, codepoint);
+        }
+
+        /// <summary>See <see cref="CssBoxProperties.GetFirstNonWhitespaceCodepoint"/>.</summary>
+        protected override int? GetFirstNonWhitespaceCodepoint()
         {
-            return HtmlContainer.Adapter.GetFont(fontFamily, fsize, st);
+            if (string.IsNullOrEmpty(_text))
+                return null;
+
+            for (var i = 0; i < _text.Length; i++)
+            {
+                if (char.IsWhiteSpace(_text[i]))
+                    continue;
+
+                if (char.IsHighSurrogate(_text[i]) && i + 1 < _text.Length && char.IsLowSurrogate(_text[i + 1]))
+                    return char.ConvertToUtf32(_text[i], _text[i + 1]);
+
+                return _text[i];
+            }
+
+            return null;
         }
 
         protected override RColor GetActualColor(string colorStr)
@@ -1533,6 +1738,11 @@ protected override RColor GetActualColor(string colorStr)
             return HtmlContainer.CssParser.ParseColor(colorStr);
         }
 
+        protected override CssImage GetActualBackgroundImageValue(string value)
+        {
+            return HtmlContainer.CssParser.ParseBackgroundImage(value);
+        }
+
         protected override RPoint GetActualLocation(string X, string Y)
         {
             var left = CssValueParser.ParseLength(X, this.HtmlContainer.PageSize.Width, this, null);
diff --git a/Source/HtmlRenderer/Core/Dom/CssBoxFrame.cs b/Source/HtmlRenderer/Core/Dom/CssBoxFrame.cs
index 72104eef1..ecebb9223 100644
--- a/Source/HtmlRenderer/Core/Dom/CssBoxFrame.cs
+++ b/Source/HtmlRenderer/Core/Dom/CssBoxFrame.cs
@@ -11,13 +11,13 @@
 // "The Art of War"
 
 using System;
-using System.Net;
-using System.Text;
-using System.Threading;
+using System.IO;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Handlers;
+using TheArtOfDev.HtmlRenderer.Core.Network;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Dom
@@ -65,6 +65,22 @@ internal sealed class CssBoxFrame : CssBox
         /// </summary>
         private bool _imageLoadingComplete;
 
+        /// <summary>
+        /// the resolved YouTube/Vimeo oEmbed API URI to fetch, set in the constructor but not fetched
+        /// until <see cref="MeasureWordsSize"/> - see its own doc comment for why the fetch can't start
+        /// in the constructor.
+        /// </summary>
+        private RUri _videoApiUri;
+
+        /// <summary>"YouTube" or "Vimeo", for <see cref="FetchVideoApiDataAsync"/>'s error reporting.</summary>
+        private string _videoApiSource;
+
+        /// <summary><see cref="OnDownloadYoutubeApiCompleted"/> or <see cref="OnDownloadVimeoApiCompleted"/>.</summary>
+        private Action<string> _videoApiParseResult;
+
+        /// <summary>Whether <see cref="FetchVideoApiDataAsync"/> has already been kicked off - guards <see cref="MeasureWordsSize"/> so it only starts once.</summary>
+        private bool _videoDataRequested;
+
         #endregion
 
 
@@ -85,12 +101,16 @@ public CssBoxFrame(CssBox parent, HtmlTag tag)
                 if (uri.Host.IndexOf("youtube.com", StringComparison.InvariantCultureIgnoreCase) > -1)
                 {
                     _isVideo = true;
-                    LoadYoutubeDataAsync(uri);
+                    _videoApiUri = new RUri(string.Format("https://www.youtube.com/oembed?url=https://www.youtube.com/watch?v={0}&format=json", uri.Segments[2]));
+                    _videoApiSource = "YouTube";
+                    _videoApiParseResult = OnDownloadYoutubeApiCompleted;
                 }
                 else if (uri.Host.IndexOf("vimeo.com", StringComparison.InvariantCultureIgnoreCase) > -1)
                 {
                     _isVideo = true;
-                    LoadVimeoDataAsync(uri);
+                    _videoApiUri = new RUri(string.Format("https://vimeo.com/api/v2/video/{0}.json", uri.Segments[2]));
+                    _videoApiSource = "Vimeo";
+                    _videoApiParseResult = OnDownloadVimeoApiCompleted;
                 }
             }
 
@@ -138,317 +158,252 @@ public override void Dispose()
         #region Private methods
 
         /// <summary>
-        /// Load YouTube video data (title, image, link) by calling YouTube API.
+        /// Fetch and read <paramref name="apiUri"/> as text, fire-and-forget (matching
+        /// <see cref="ImageLoadHandler"/>'s pattern - nothing here blocks layout/paint), and hand the
+        /// result (or null on failure) to <paramref name="parseResult"/>. A null/unresolvable response is
+        /// reported the same way as any other "video not found" outcome - <see cref="RNetworkResponse"/>
+        /// has no HTTP status code to distinguish a 404 from another failure, matching every other
+        /// resource kind's fail-soft contract through this funnel.
         /// </summary>
-        private void LoadYoutubeDataAsync(Uri uri)
+        private async Task FetchVideoApiDataAsync(RUri apiUri, string source, Action<string> parseResult)
         {
-            ThreadPool.QueueUserWorkItem(state =>
+            try
             {
-                try
-                {
-                    var apiUri = new Uri(string.Format("https://www.youtube.com/oembed?url=https://www.youtube.com/watch?v={0}&format=json", uri.Segments[2]));
+                var networkResponse = await HtmlContainer.Adapter.GetResourceStream(apiUri).ConfigureAwait(false);
 
-                    var client = new WebClient();
-                    client.Encoding = Encoding.UTF8;
-                    client.DownloadStringCompleted += OnDownloadYoutubeApiCompleted;
-                    client.DownloadStringAsync(apiUri);
+                if (networkResponse == null || networkResponse.ResourceStream == null)
+                {
+                    _videoTitle = "The video is not found, possibly removed by the user.";
                 }
-                catch (Exception ex)
+                else
                 {
-                    HtmlContainer.ReportError(HtmlRenderErrorType.Iframe, "Failed to get youtube video data: " + uri, ex);
-                    HtmlContainer.RequestRefresh(false);
+                    string result;
+                    using (var reader = new StreamReader(networkResponse.ResourceStream))
+                    {
+                        result = await reader.ReadToEndAsync().ConfigureAwait(false);
+                    }
+
+                    parseResult(result);
                 }
-            });
+            }
+            catch (Exception ex)
+            {
+                HtmlContainer.ReportError(HtmlRenderErrorType.Iframe, "Failed to get " + source + " video data: " + apiUri.AbsoluteUri, ex);
+            }
+
+            HandlePostApiCall();
         }
 
         /// <summary>
         /// Parse YouTube API response to get video data (title, image, link).
         /// </summary>
-        private void OnDownloadYoutubeApiCompleted(object sender, DownloadStringCompletedEventArgs e)
+        private void OnDownloadYoutubeApiCompleted(string result)
         {
             try
             {
-                if (!e.Cancelled)
+                var idx = result.IndexOf("\"title\"", StringComparison.Ordinal);
+                if (idx > -1)
                 {
-                    if (e.Error == null)
+                    idx = result.IndexOf('"', idx + 7);
+                    if (idx > -1)
                     {
-                        var idx = e.Result.IndexOf("\"title\"", StringComparison.Ordinal);
-                        if (idx > -1)
+                        var endIdx = result.IndexOf('"', idx + 1);
+                        while (endIdx > 0 && result[endIdx - 1] == '\\')
+                            endIdx = result.IndexOf('"', endIdx + 1);
+                        if (endIdx > -1)
                         {
-                            idx = e.Result.IndexOf('"', idx + 7);
-                            if (idx > -1)
-                            {
-                                var endIdx = e.Result.IndexOf('"', idx + 1);
-                                while (endIdx > 0 && e.Result[endIdx - 1] == '\\')
-                                    endIdx = e.Result.IndexOf('"', endIdx + 1);
-                                if (endIdx > -1)
-                                {
-                                    _videoTitle = e.Result.Substring(idx + 1, endIdx - idx - 1).Replace("\\\"", "\"");
-                                }
-                            }
+                            _videoTitle = result.Substring(idx + 1, endIdx - idx - 1).Replace("\\\"", "\"");
                         }
+                    }
+                }
 
-                        idx = e.Result.IndexOf("\"thumbnail_url\"", StringComparison.Ordinal);
-                        if (idx > -1)
+                idx = result.IndexOf("\"thumbnail_url\"", StringComparison.Ordinal);
+                if (idx > -1)
+                {
+                    idx = result.IndexOf('"', idx + 15);
+                    if (idx > -1)
+                    {
+                        var endIdx = result.IndexOf('"', idx + 1);
+                        while (endIdx > 0 && result[endIdx - 1] == '\\')
+                            endIdx = result.IndexOf('"', endIdx + 1);
+                        if (endIdx > -1)
                         {
-                            idx = e.Result.IndexOf('"', idx + 15);
-                            if (idx > -1)
-                            {
-                                var endIdx = e.Result.IndexOf('"', idx + 1);
-                                while (endIdx > 0 && e.Result[endIdx - 1] == '\\')
-                                    endIdx = e.Result.IndexOf('"', endIdx + 1);
-                                if (endIdx > -1)
-                                {
-                                    _videoImageUrl = e.Result.Substring(idx + 1, endIdx - idx - 1).Replace("\\\"", "\"");
-                                }
-                            }
+                            _videoImageUrl = result.Substring(idx + 1, endIdx - idx - 1).Replace("\\\"", "\"");
+                        }
+                    }
 
-                            idx = e.Result.IndexOf("\"thumbnail_width\"", StringComparison.Ordinal);
-                            if (idx > -1)
+                    idx = result.IndexOf("\"thumbnail_width\"", StringComparison.Ordinal);
+                    if (idx > -1)
+                    {
+                        idx = result.IndexOf(':', idx);
+                        if (idx > -1)
+                        {
+                            var endIdx = result.IndexOf(',', idx);
+                            if (endIdx > -1)
                             {
-                                idx = e.Result.IndexOf(':', idx);
-                                if (idx > -1)
+                                var widthStr = result.Substring(idx + 1, endIdx - idx - 1).Trim();
+                                if (int.TryParse(widthStr, out int width))
                                 {
-                                    var endIdx = e.Result.IndexOf(',', idx);
-                                    if (endIdx > -1)
-                                    {
-                                        var widthStr = e.Result.Substring(idx + 1, endIdx - idx - 1).Trim();
-                                        if (int.TryParse(widthStr, out int width))
-                                        {
-                                            if (string.IsNullOrEmpty(Width))
-                                                Width = width + "px";
-                                        }
-                                    }
+                                    if (string.IsNullOrEmpty(Width))
+                                        Width = width + "px";
                                 }
                             }
+                        }
+                    }
 
-                            idx = e.Result.IndexOf("\"thumbnail_height\"", StringComparison.Ordinal);
-                            if (idx > -1)
+                    idx = result.IndexOf("\"thumbnail_height\"", StringComparison.Ordinal);
+                    if (idx > -1)
+                    {
+                        idx = result.IndexOf(':', idx);
+                        if (idx > -1)
+                        {
+                            var endIdx = result.IndexOf(',', idx);
+                            if (endIdx == -1)
+                                endIdx = result.IndexOf('}', idx);
+                            if (endIdx > -1)
                             {
-                                idx = e.Result.IndexOf(':', idx);
-                                if (idx > -1)
+                                var heightStr = result.Substring(idx + 1, endIdx - idx - 1).Trim();
+                                if (int.TryParse(heightStr, out int height))
                                 {
-                                    var endIdx = e.Result.IndexOf(',', idx);
-                                    if (endIdx == -1)
-                                        endIdx = e.Result.IndexOf('}', idx);
-                                    if (endIdx > -1)
-                                    {
-                                        var heightStr = e.Result.Substring(idx + 1, endIdx - idx - 1).Trim();
-                                        if (int.TryParse(heightStr, out int height))
-                                        {
-                                            if (string.IsNullOrEmpty(Height))
-                                                Height = height + "px";
-                                        }
-                                    }
+                                    if (string.IsNullOrEmpty(Height))
+                                        Height = height + "px";
                                 }
                             }
                         }
+                    }
+                }
 
-                        idx = e.Result.IndexOf("\"html\"", StringComparison.Ordinal);
+                idx = result.IndexOf("\"html\"", StringComparison.Ordinal);
+                if (idx > -1)
+                {
+                    idx = result.IndexOf("src=", idx);
+                    if (idx > -1)
+                    {
+                        idx = result.IndexOf("embed/", idx);
                         if (idx > -1)
                         {
-                            idx = e.Result.IndexOf("src=", idx);
-                            if (idx > -1)
+                            var endIdx = result.IndexOf('?', idx);
+                            if (endIdx > -1)
                             {
-                                idx = e.Result.IndexOf("embed/", idx);
-                                if (idx > -1)
-                                {
-                                    var endIdx = e.Result.IndexOf('?', idx);
-                                    if (endIdx > -1)
-                                    {
-                                        var videoId = e.Result.Substring(idx + 6, endIdx - idx - 6);
-                                        _videoLinkUrl = "https://www.youtube.com/watch?v=" + videoId;
-                                    }
-                                }
+                                var videoId = result.Substring(idx + 6, endIdx - idx - 6);
+                                _videoLinkUrl = "https://www.youtube.com/watch?v=" + videoId;
                             }
                         }
                     }
-                    else
-                    {
-                        HandleDataLoadFailure(e.Error, "YouTube");
-                    }
                 }
             }
             catch (Exception ex)
             {
                 HtmlContainer.ReportError(HtmlRenderErrorType.Iframe, "Failed to parse YouTube video response", ex);
             }
-
-            HandlePostApiCall(sender);
-        }
-
-        /// <summary>
-        /// Load Vimeo video data (title, image, link) by calling Vimeo API.
-        /// </summary>
-        private void LoadVimeoDataAsync(Uri uri)
-        {
-            ThreadPool.QueueUserWorkItem(state =>
-            {
-                try
-                {
-                    var apiUri = new Uri(string.Format("https://vimeo.com/api/v2/video/{0}.json", uri.Segments[2]));
-
-                    var client = new WebClient();
-                    client.Encoding = Encoding.UTF8;
-                    client.DownloadStringCompleted += OnDownloadVimeoApiCompleted;
-                    client.DownloadStringAsync(apiUri);
-                }
-                catch (Exception ex)
-                {
-                    _imageLoadingComplete = true;
-                    SetErrorBorder();
-                    HtmlContainer.ReportError(HtmlRenderErrorType.Iframe, "Failed to get vimeo video data: " + uri, ex);
-                    HtmlContainer.RequestRefresh(false);
-                }
-            });
         }
 
         /// <summary>
         /// Parse Vimeo API response to get video data (title, image, link).
         /// </summary>
-        private void OnDownloadVimeoApiCompleted(object sender, DownloadStringCompletedEventArgs e)
+        private void OnDownloadVimeoApiCompleted(string result)
         {
             try
             {
-                if (!e.Cancelled)
+                var idx = result.IndexOf("\"title\"", StringComparison.Ordinal);
+                if (idx > -1)
                 {
-                    if (e.Error == null)
+                    idx = result.IndexOf('"', idx + 7);
+                    if (idx > -1)
                     {
-                        var idx = e.Result.IndexOf("\"title\"", StringComparison.Ordinal);
-                        if (idx > -1)
+                        var endIdx = result.IndexOf('"', idx + 1);
+                        while (endIdx > 0 && result[endIdx - 1] == '\\')
+                            endIdx = result.IndexOf('"', endIdx + 1);
+                        if (endIdx > -1)
                         {
-                            idx = e.Result.IndexOf('"', idx + 7);
-                            if (idx > -1)
-                            {
-                                var endIdx = e.Result.IndexOf('"', idx + 1);
-                                while (endIdx > 0 && e.Result[endIdx - 1] == '\\')
-                                    endIdx = e.Result.IndexOf('"', endIdx + 1);
-                                if (endIdx > -1)
-                                {
-                                    _videoTitle = e.Result.Substring(idx + 1, endIdx - idx - 1).Replace("\\\"", "\"");
-                                }
-                            }
+                            _videoTitle = result.Substring(idx + 1, endIdx - idx - 1).Replace("\\\"", "\"");
                         }
+                    }
+                }
 
-                        idx = e.Result.IndexOf("\"thumbnail_large\"", StringComparison.Ordinal);
+                idx = result.IndexOf("\"thumbnail_large\"", StringComparison.Ordinal);
+                if (idx > -1)
+                {
+                    if (string.IsNullOrEmpty(Width))
+                        Width = "640";
+                    if (string.IsNullOrEmpty(Height))
+                        Height = "360";
+                    var urlIdx = result.IndexOf("\"https:\\/\\/", idx);
+                    if (urlIdx != -1)
+                        idx = urlIdx;
+                }
+                else
+                {
+                    idx = result.IndexOf("\"thumbnail_medium\"", StringComparison.Ordinal);
+                    if (idx > -1)
+                    {
+                        if (string.IsNullOrEmpty(Width))
+                            Width = "200";
+                        if (string.IsNullOrEmpty(Height))
+                            Height = "150";
+                        var urlIdx = result.IndexOf("\"https:\\/\\/", idx);
+                        if (urlIdx != -1)
+                            idx = urlIdx;
+                    }
+                    else
+                    {
+                        idx = result.IndexOf("\"thumbnail_small\"", StringComparison.Ordinal);
                         if (idx > -1)
                         {
                             if (string.IsNullOrEmpty(Width))
-                                Width = "640";
+                                Width = "100";
                             if (string.IsNullOrEmpty(Height))
-                                Height = "360";
-                            var urlIdx = e.Result.IndexOf("\"https:\\/\\/", idx);
+                                Height = "75";
+                            var urlIdx = result.IndexOf("\"https:\\/\\/", idx);
                             if (urlIdx != -1)
                                 idx = urlIdx;
                         }
-                        else
-                        {
-                            idx = e.Result.IndexOf("\"thumbnail_medium\"", StringComparison.Ordinal);
-                            if (idx > -1)
-                            {
-                                if (string.IsNullOrEmpty(Width))
-                                    Width = "200";
-                                if (string.IsNullOrEmpty(Height))
-                                    Height = "150";
-                                var urlIdx = e.Result.IndexOf("\"https:\\/\\/", idx);
-                                if (urlIdx != -1)
-                                    idx = urlIdx;
-                            }
-                            else
-                            {
-                                idx = e.Result.IndexOf("\"thumbnail_small\"", StringComparison.Ordinal);
-                                if (idx > -1)
-                                {
-                                    if (string.IsNullOrEmpty(Width))
-                                        Width = "100";
-                                    if (string.IsNullOrEmpty(Height))
-                                        Height = "75";
-                                    var urlIdx = e.Result.IndexOf("\"https:\\/\\/", idx);
-                                    if (urlIdx != -1)
-                                        idx = urlIdx;
-                                }
-                            }
-                        }
-                        if (idx > -1)
-                        {
-                            idx = idx + 1;
-                            var endIdx = e.Result.IndexOf('"', idx);
-                            if (endIdx > -1)
-                            {
-                                _videoImageUrl = e.Result.Substring(idx, endIdx - idx).Replace("\\/", "/");
-                            }
-                        }
+                    }
+                }
+                if (idx > -1)
+                {
+                    idx = idx + 1;
+                    var endIdx = result.IndexOf('"', idx);
+                    if (endIdx > -1)
+                    {
+                        _videoImageUrl = result.Substring(idx, endIdx - idx).Replace("\\/", "/");
+                    }
+                }
 
-                        idx = e.Result.IndexOf("\"url\"", StringComparison.Ordinal);
-                        if (idx > -1)
+                idx = result.IndexOf("\"url\"", StringComparison.Ordinal);
+                if (idx > -1)
+                {
+                    idx = result.IndexOf("\"https:\\/\\/", idx);
+                    if (idx > -1)
+                    {
+                        idx = idx + 1;
+                        var endIdx = result.IndexOf('"', idx);
+                        if (endIdx > -1)
                         {
-                            idx = e.Result.IndexOf("\"https:\\/\\/", idx);
-                            if (idx > -1)
-                            {
-                                idx = idx + 1;
-                                var endIdx = e.Result.IndexOf('"', idx);
-                                if (endIdx > -1)
-                                {
-                                    _videoLinkUrl = e.Result.Substring(idx, endIdx - idx).Replace("\\/", "/");
-                                }
-                            }
+                            _videoLinkUrl = result.Substring(idx, endIdx - idx).Replace("\\/", "/");
                         }
                     }
-                    else
-                    {
-                        HandleDataLoadFailure(e.Error, "Vimeo");
-                    }
                 }
             }
             catch (Exception ex)
             {
                 HtmlContainer.ReportError(HtmlRenderErrorType.Iframe, "Failed to parse Vimeo video response", ex);
             }
-
-            HandlePostApiCall(sender);
         }
 
         /// <summary>
-        /// Handle error occurred during video data load to handle if the video was not found.
+        /// Update error-border state once the video API call has finished (success, failure, or parse
+        /// error) and request a refresh.
         /// </summary>
-        /// <param name="ex">the exception that occurred during data load web request</param>
-        /// <param name="source">the name of the video source (YouTube/Vimeo/Etc.)</param>
-        private void HandleDataLoadFailure(Exception ex, string source)
+        private void HandlePostApiCall()
         {
-            var webError = ex as WebException;
-            var webResponse = webError != null ? webError.Response as HttpWebResponse : null;
-            if (webResponse != null && webResponse.StatusCode == HttpStatusCode.NotFound)
-            {
-                _videoTitle = "The video is not found, possibly removed by the user.";
-            }
-            else
+            if (_videoImageUrl == null)
             {
-                HtmlContainer.ReportError(HtmlRenderErrorType.Iframe, "Failed to load " + source + " video data", ex);
+                _imageLoadingComplete = true;
+                SetErrorBorder();
             }
-        }
-
-        /// <summary>
-        /// Create image handler for downloading video image if found and release the WebClient instance used for API call.
-        /// </summary>
-        private void HandlePostApiCall(object sender)
-        {
-            try
-            {
-                if (_videoImageUrl == null)
-                {
-                    _imageLoadingComplete = true;
-                    SetErrorBorder();
-                }
 
-                var webClient = (WebClient)sender;
-                webClient.DownloadStringCompleted -= OnDownloadYoutubeApiCompleted;
-                webClient.DownloadStringCompleted -= OnDownloadVimeoApiCompleted;
-                webClient.Dispose();
-
-                HtmlContainer.RequestRefresh(IsLayoutRequired());
-            }
-            catch
-            { }
+            HtmlContainer.RequestRefresh(IsLayoutRequired());
         }
 
         /// <summary>
@@ -570,6 +525,21 @@ private void DrawPlay(RGraphics g, RRect rect)
         /// <param name="g">the device to use</param>
         internal override void MeasureWordsSize(RGraphics g)
         {
+            // Kicks off the YouTube/Vimeo oEmbed API fetch (through the configured
+            // RAdapter.NetworkLoader - the same funnel used for images/stylesheets/fonts, so a consumer's
+            // custom loader applies here too) here rather than from the constructor: HtmlContainer walks
+            // up to the root box's own HtmlContainer, which DomParser.GenerateCssTree only assigns AFTER
+            // the whole box tree (including this one) has already been constructed - so at construction
+            // time it's always null. FetchVideoApiDataAsync dereferences it immediately (before its first
+            // genuine await), so starting the fetch from the constructor throws a NullReferenceException
+            // synchronously out of box-tree construction itself. MeasureWordsSize runs during layout, well
+            // after HtmlContainer is assigned, so it's a safe place to start this instead.
+            if (_isVideo && !_videoDataRequested)
+            {
+                _videoDataRequested = true;
+                _ = FetchVideoApiDataAsync(_videoApiUri, _videoApiSource, _videoApiParseResult);
+            }
+
             if (!_wordsSizeMeasured)
             {
                 MeasureWordSpacing(g);
diff --git a/Source/HtmlRenderer/Core/Dom/CssBoxImage.cs b/Source/HtmlRenderer/Core/Dom/CssBoxImage.cs
index a33627c83..8322416ab 100644
--- a/Source/HtmlRenderer/Core/Dom/CssBoxImage.cs
+++ b/Source/HtmlRenderer/Core/Dom/CssBoxImage.cs
@@ -11,9 +11,12 @@
 // "The Art of War"
 
 using System;
+using System.Linq;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 using TheArtOfDev.HtmlRenderer.Core.Handlers;
+using TheArtOfDev.HtmlRenderer.Core.Parse;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Dom
@@ -73,7 +76,7 @@ protected override void PaintImp(RGraphics g)
             if (_imageLoadHandler == null)
             {
                 _imageLoadHandler = new ImageLoadHandler(HtmlContainer, OnLoadImageComplete);
-                _imageLoadHandler.LoadImage(GetAttribute("src"), HtmlTag != null ? HtmlTag.Attributes : null);
+                _imageLoadHandler.LoadImage(GetImageSource(), HtmlTag != null ? HtmlTag.Attributes : null);
             }
 
             var rect = CommonUtils.GetFirstValueOrDefault(Rectangles);
@@ -142,11 +145,7 @@ internal override void MeasureWordsSize(RGraphics g)
                 if (_imageLoadHandler == null && (HtmlContainer.AvoidAsyncImagesLoading || HtmlContainer.AvoidImagesLateLoading))
                 {
                     _imageLoadHandler = new ImageLoadHandler(HtmlContainer, OnLoadImageComplete);
-
-                    if (this.Content != null && this.Content != CssConstants.Normal)
-                        _imageLoadHandler.LoadImage(this.Content, HtmlTag != null ? HtmlTag.Attributes : null);
-                    else
-                        _imageLoadHandler.LoadImage(GetAttribute("src"), HtmlTag != null ? HtmlTag.Attributes : null);
+                    _imageLoadHandler.LoadImage(GetImageSource(), HtmlTag != null ? HtmlTag.Attributes : null);
                 }
 
                 MeasureWordSpacing(g);
@@ -169,6 +168,28 @@ public override void Dispose()
 
         #region Private methods
 
+        /// <summary>
+        /// Get the image source to load: a resolved <c>content: url(...)</c> value takes precedence
+        /// over the "src" attribute (CSS generated content replacing the element's own rendering, same
+        /// as this engine already gives generated content priority for pseudo-elements), falling back
+        /// to "src" when content is unset/none/normal or isn't a url().<br/>
+        /// <see cref="CssBox.Content"/> holds the literal declared CSS text (e.g. <c>url('data:...')</c>,
+        /// quotes and all) rather than an unwrapped source string, so the url() token's data has to be
+        /// pulled out here - <see cref="ImageLoadHandler.LoadImage"/> only recognizes a bare path or
+        /// "data:image..." URI, not CSS function syntax.
+        /// </summary>
+        private string GetImageSource()
+        {
+            if (!string.IsNullOrEmpty(Content) && Content != CssConstants.Normal && Content != CssConstants.None)
+            {
+                var token = CssValueParser.GetCssTokens(Content).FirstOrDefault();
+                if (token is UrlToken urlToken)
+                    return urlToken.Data;
+            }
+
+            return GetAttribute("src");
+        }
+
         /// <summary>
         /// Set error image border on the image box.
         /// </summary>
diff --git a/Source/HtmlRenderer/Core/Dom/CssBoxProperties.cs b/Source/HtmlRenderer/Core/Dom/CssBoxProperties.cs
index e74671701..79c1e6987 100644
--- a/Source/HtmlRenderer/Core/Dom/CssBoxProperties.cs
+++ b/Source/HtmlRenderer/Core/Dom/CssBoxProperties.cs
@@ -11,10 +11,12 @@
 // "The Art of War"
 
 using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.Text.RegularExpressions;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Parse;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
@@ -32,8 +34,6 @@ internal abstract class CssBoxProperties
         #region CSS Fields
 
         private string _backgroundColor = "transparent";
-        private string _backgroundGradient = "none";
-        private string _backgroundGradientAngle = "90";
         private string _backgroundImage = "none";
         private string _backgroundPosition = "0% 0%";
         private string _backgroundRepeat = "repeat";
@@ -54,11 +54,10 @@ internal abstract class CssBoxProperties
         private string _bottom;
         private string _color = "black";
         private string _content = "normal";
-        private string _cornerNwRadius = "0";
-        private string _cornerNeRadius = "0";
-        private string _cornerSeRadius = "0";
-        private string _cornerSwRadius = "0";
-        private string _cornerRadius = "0";
+        private string _borderTopLeftRadius = "0 0";
+        private string _borderTopRightRadius = "0 0";
+        private string _borderBottomRightRadius = "0 0";
+        private string _borderBottomLeftRadius = "0 0";
         private string _emptyCells = "show";
         private string _direction = "ltr";
         private string _display = "inline";
@@ -67,8 +66,14 @@ internal abstract class CssBoxProperties
         private string _fontStyle = "normal";
         private string _fontVariant = "normal";
         private string _fontWeight = "normal";
+        private string _fontStretch = "normal";
         private string _float = "none";
+        private string _clear = "none";
+        private string _boxSizing = CssConstants.ContentBox;
         private string _height = "auto";
+        private string _minHeight = "0";
+        private string _maxHeight = CssConstants.None;
+        private bool _isHeightCalculated;
         private string _marginBottom = "0";
         private string _marginLeft = "0";
         private string _marginRight = "0";
@@ -99,6 +104,12 @@ internal abstract class CssBoxProperties
         private string _whiteSpace = "normal";
         private string _visibility = "visible";
 
+        /// <summary>
+        /// Specified (not var()-resolved) values of this box's CSS custom properties (--foo), keyed by
+        /// their case-sensitive name. Lazily created; null when no custom property has been declared or inherited.
+        /// </summary>
+        internal Dictionary<string, string> CustomProperties;
+
         #endregion
 
 
@@ -114,12 +125,15 @@ internal abstract class CssBoxProperties
         /// </summary>
         private RSize _size;
 
-        private double _actualCornerNw = double.NaN;
-        private double _actualCornerNe = double.NaN;
-        private double _actualCornerSw = double.NaN;
-        private double _actualCornerSe = double.NaN;
+        private double _actualBorderTopLeftRadiusX = double.NaN;
+        private double _actualBorderTopLeftRadiusY = double.NaN;
+        private double _actualBorderTopRightRadiusX = double.NaN;
+        private double _actualBorderTopRightRadiusY = double.NaN;
+        private double _actualBorderBottomRightRadiusX = double.NaN;
+        private double _actualBorderBottomRightRadiusY = double.NaN;
+        private double _actualBorderBottomLeftRadiusX = double.NaN;
+        private double _actualBorderBottomLeftRadiusY = double.NaN;
         private RColor _actualColor = RColor.Empty;
-        private double _actualBackgroundGradientAngle = double.NaN;
         private double _actualHeight = double.NaN;
         private double _actualWidth = double.NaN;
         private double _actualPaddingTop = double.NaN;
@@ -145,13 +159,15 @@ internal abstract class CssBoxProperties
         private double _actualTextIndent = double.NaN;
         private double _actualBorderSpacingHorizontal = double.NaN;
         private double _actualBorderSpacingVertical = double.NaN;
-        private RColor _actualBackgroundGradient = RColor.Empty;
+        private bool _actualBackgroundImageComputed;
+        private CssImage _actualBackgroundImage;
         private RColor _actualBorderTopColor = RColor.Empty;
         private RColor _actualBorderLeftColor = RColor.Empty;
         private RColor _actualBorderBottomColor = RColor.Empty;
         private RColor _actualBorderRightColor = RColor.Empty;
         private RColor _actualBackgroundColor = RColor.Empty;
         private RFont _actualFont;
+        private int? _actualFontWeight;
 
         #endregion
 
@@ -274,66 +290,96 @@ public string BorderCollapse
             set { _borderCollapse = value; }
         }
 
-        public string CornerRadius
+        /// <summary>
+        /// The "border-radius" shorthand: sets all four corners at once, with an optional "/" separating
+        /// horizontal and vertical radii for elliptical corners (e.g. "10px 5px / 20px 10px"). Each side
+        /// of the "/" independently follows the standard 1/2/3/4-value CSS expansion rule
+        /// (1=all, 2=TL+BR/TR+BL, 3=TL/TR+BL/BR, 4=TL/TR/BR/BL). Write-only, like the other border-*
+        /// shorthands in this class - the four longhand properties below hold the actual state.
+        /// </summary>
+        public string BorderRadius
         {
-            get { return _cornerRadius; }
             set
             {
-                MatchCollection r = RegexParserUtils.Match(RegexParserUtils.CssLength, value);
+                int slash = value.IndexOf('/');
+                string hGroup = (slash >= 0 ? value.Substring(0, slash) : value).Trim();
+                string vGroup = (slash >= 0 ? value.Substring(slash + 1) : hGroup).Trim();
 
-                switch (r.Count)
-                {
-                    case 1:
-                        CornerNeRadius = r[0].Value;
-                        CornerNwRadius = r[0].Value;
-                        CornerSeRadius = r[0].Value;
-                        CornerSwRadius = r[0].Value;
-                        break;
-                    case 2:
-                        CornerNeRadius = r[0].Value;
-                        CornerNwRadius = r[0].Value;
-                        CornerSeRadius = r[1].Value;
-                        CornerSwRadius = r[1].Value;
-                        break;
-                    case 3:
-                        CornerNeRadius = r[0].Value;
-                        CornerNwRadius = r[1].Value;
-                        CornerSeRadius = r[2].Value;
-                        break;
-                    case 4:
-                        CornerNeRadius = r[0].Value;
-                        CornerNwRadius = r[1].Value;
-                        CornerSeRadius = r[2].Value;
-                        CornerSwRadius = r[3].Value;
-                        break;
-                }
+                string[] h = ExpandRadiusShorthand(hGroup);
+                string[] v = ExpandRadiusShorthand(vGroup);
 
-                _cornerRadius = value;
+                BorderTopLeftRadius = h[0] + " " + v[0];
+                BorderTopRightRadius = h[1] + " " + v[1];
+                BorderBottomRightRadius = h[2] + " " + v[2];
+                BorderBottomLeftRadius = h[3] + " " + v[3];
             }
         }
 
-        public string CornerNwRadius
+        /// <summary>
+        /// Expands a 1-4 value length group into [TopLeft, TopRight, BottomRight, BottomLeft] per the
+        /// standard CSS shorthand rule.
+        /// </summary>
+        private static string[] ExpandRadiusShorthand(string group)
         {
-            get { return _cornerNwRadius; }
-            set { _cornerNwRadius = value; }
+            MatchCollection r = RegexParserUtils.Match(RegexParserUtils.CssLength, group);
+
+            switch (r.Count)
+            {
+                case 1:
+                    return new[] { r[0].Value, r[0].Value, r[0].Value, r[0].Value };
+                case 2:
+                    return new[] { r[0].Value, r[1].Value, r[0].Value, r[1].Value };
+                case 3:
+                    return new[] { r[0].Value, r[1].Value, r[2].Value, r[1].Value };
+                case 4:
+                    return new[] { r[0].Value, r[1].Value, r[2].Value, r[3].Value };
+                default:
+                    return new[] { "0", "0", "0", "0" };
+            }
         }
 
-        public string CornerNeRadius
+        public string BorderTopLeftRadius
         {
-            get { return _cornerNeRadius; }
-            set { _cornerNeRadius = value; }
+            get { return _borderTopLeftRadius; }
+            set
+            {
+                _borderTopLeftRadius = value;
+                _actualBorderTopLeftRadiusX = double.NaN;
+                _actualBorderTopLeftRadiusY = double.NaN;
+            }
         }
 
-        public string CornerSeRadius
+        public string BorderTopRightRadius
         {
-            get { return _cornerSeRadius; }
-            set { _cornerSeRadius = value; }
+            get { return _borderTopRightRadius; }
+            set
+            {
+                _borderTopRightRadius = value;
+                _actualBorderTopRightRadiusX = double.NaN;
+                _actualBorderTopRightRadiusY = double.NaN;
+            }
         }
 
-        public string CornerSwRadius
+        public string BorderBottomRightRadius
         {
-            get { return _cornerSwRadius; }
-            set { _cornerSwRadius = value; }
+            get { return _borderBottomRightRadius; }
+            set
+            {
+                _borderBottomRightRadius = value;
+                _actualBorderBottomRightRadiusX = double.NaN;
+                _actualBorderBottomRightRadiusY = double.NaN;
+            }
+        }
+
+        public string BorderBottomLeftRadius
+        {
+            get { return _borderBottomLeftRadius; }
+            set
+            {
+                _borderBottomLeftRadius = value;
+                _actualBorderBottomLeftRadiusX = double.NaN;
+                _actualBorderBottomLeftRadiusY = double.NaN;
+            }
         }
 
         public string MarginBottom
@@ -455,6 +501,34 @@ public string Height
             set { _height = value; }
         }
 
+        public string MinHeight
+        {
+            get { return _minHeight; }
+            set { _minHeight = value; }
+        }
+
+        public string MaxHeight
+        {
+            get { return _maxHeight; }
+            set { _maxHeight = value; }
+        }
+
+        /// <summary>
+        /// Whether this box's own height is "specified explicitly" per CSS 2.1 10.5: a definite
+        /// (non-auto) length, or a percentage against a containing block that is itself
+        /// height-calculated - or this box is the root/initial containing block (whose used height is
+        /// the page height regardless of its own computed `height`). Drives whether a DESCENDANT's
+        /// percentage height/min-height/max-height resolves against this box; computed by
+        /// <see cref="CssBox.ApplyHeight"/> once this box's own height is finalized, not a pure
+        /// computed getter (a descendant's own ApplyHeight needs to read it before this box's parent
+        /// has necessarily finished, so it can't be derived on demand from current state alone).
+        /// </summary>
+        public bool IsHeightCalculated
+        {
+            get { return _isHeightCalculated; }
+            set { _isHeightCalculated = value; }
+        }
+
         public string BackgroundColor
         {
             get { return _backgroundColor; }
@@ -464,7 +538,11 @@ public string BackgroundColor
         public string BackgroundImage
         {
             get { return _backgroundImage; }
-            set { _backgroundImage = value; }
+            set
+            {
+                _backgroundImage = value;
+                _actualBackgroundImageComputed = false;
+            }
         }
 
         public string BackgroundPosition
@@ -479,18 +557,6 @@ public string BackgroundRepeat
             set { _backgroundRepeat = value; }
         }
 
-        public string BackgroundGradient
-        {
-            get { return _backgroundGradient; }
-            set { _backgroundGradient = value; }
-        }
-
-        public string BackgroundGradientAngle
-        {
-            get { return _backgroundGradientAngle; }
-            set { _backgroundGradientAngle = value; }
-        }
-
         public string Color
         {
             get { return _color; }
@@ -531,6 +597,18 @@ public string Float
             set { _float = value; }
         }
 
+        public string Clear
+        {
+            get { return _clear; }
+            set { _clear = value; }
+        }
+
+        public string BoxSizing
+        {
+            get { return _boxSizing; }
+            set { _boxSizing = value; }
+        }
+
         public string Position
         {
             get { return _position; }
@@ -649,6 +727,12 @@ public string FontWeight
             set { _fontWeight = value; }
         }
 
+        public string FontStretch
+        {
+            get { return _fontStretch; }
+            set { _fontStretch = value; }
+        }
+
         public string ListStyle
         {
             get { return _listStyle; }
@@ -726,6 +810,35 @@ public double AvailableWidth
             get { return Size.Width - ActualBorderLeftWidth - ActualPaddingLeft - ActualPaddingRight - ActualBorderRightWidth; }
         }
 
+        /// <summary>
+        /// The padding+border this box's own explicit <see cref="Width"/>/<see cref="Height"/> value needs
+        /// added on top of it to reach the border-box measure - zero for <c>box-sizing: border-box</c>
+        /// (where the declared value already IS the border-box measure), padding+border for the default
+        /// <c>content-box</c> (where the declared value is the content measure alone).
+        /// </summary>
+        public double ActualBoxSizeIncludedWidth
+        {
+            get
+            {
+                return BoxSizing == CssConstants.BorderBox
+                    ? 0
+                    : ActualPaddingLeft + ActualPaddingRight + ActualBorderLeftWidth + ActualBorderRightWidth;
+            }
+        }
+
+        /// <summary>
+        /// See <see cref="ActualBoxSizeIncludedWidth"/>, the vertical counterpart.
+        /// </summary>
+        public double ActualBoxSizeIncludedHeight
+        {
+            get
+            {
+                return BoxSizing == CssConstants.BorderBox
+                    ? 0
+                    : ActualPaddingTop + ActualPaddingBottom + ActualBorderTopWidth + ActualBorderBottomWidth;
+            }
+        }
+
         /// <summary>
         /// Gets the right of the box. When setting, it will affect only the width of the box.
         /// </summary>
@@ -794,7 +907,16 @@ public double ActualHeight
             {
                 if (double.IsNaN(_actualHeight))
                 {
-                    _actualHeight = CssValueParser.ParseLength(Height, Size.Height, this);
+                    var parsedHeight = CssValueParser.ParseLength(Height, Size.Height, this);
+
+                    // An explicit (non-auto) Height is a content-box measure under the default box-sizing
+                    // (CSS Box Sizing 3) - add this box's own padding+border to reach the border-box measure
+                    // this getter's one caller (CssBox.PerformLayoutImp's ActualBottom expansion) expects.
+                    // ActualBoxSizeIncludedHeight is 0 for box-sizing:border-box, where parsedHeight already
+                    // IS the border-box measure.
+                    _actualHeight = Height != null && Height != CssConstants.Auto && !string.IsNullOrEmpty(Height)
+                        ? parsedHeight + ActualBoxSizeIncludedHeight
+                        : parsedHeight;
                 }
                 return _actualHeight;
             }
@@ -809,7 +931,15 @@ public double ActualWidth
             {
                 if (double.IsNaN(_actualWidth))
                 {
-                    _actualWidth = CssValueParser.ParseLength(Width, Size.Width, this);
+                    // A percentage Width was already resolved to an absolute pixel value (against its
+                    // containing block, box-sizing-included) by CssBox.PerformLayoutImp's block-width pass
+                    // and baked into Size.Width - re-parsing it here against Size.Width (already-resolved
+                    // pixels, not a percentage base) would resolve the percentage against itself, squaring
+                    // it. A fixed-unit Width (em/px/pt) is unaffected either way, since ParseLength ignores
+                    // the percentage base for those units - only percentage Width ever hits this path.
+                    _actualWidth = Width != null && Width.EndsWith("%")
+                        ? Size.Width
+                        : CssValueParser.ParseLength(Width, Size.Width, this);
                 }
                 return _actualWidth;
             }
@@ -1059,6 +1189,26 @@ public RColor ActualBorderTopColor
 
         protected abstract RColor GetActualColor(string colorStr);
 
+        protected abstract CssImage GetActualBackgroundImageValue(string value);
+
+        /// <summary>
+        /// Gets the parsed "background-image" value - either a url() reference or a linear-gradient(),
+        /// lazily resolved (needs adapter-dependent named-color lookup for gradient stops, see
+        /// <see cref="GetActualBackgroundImageValue"/>) and cached until <see cref="BackgroundImage"/> is set again.
+        /// </summary>
+        public CssImage ActualBackgroundImage
+        {
+            get
+            {
+                if (!_actualBackgroundImageComputed)
+                {
+                    _actualBackgroundImage = GetActualBackgroundImageValue(BackgroundImage);
+                    _actualBackgroundImageComputed = true;
+                }
+                return _actualBackgroundImage;
+            }
+        }
+
         /// <summary>
         /// Gets the actual Left border Color
         /// </summary>
@@ -1104,72 +1254,147 @@ public RColor ActualBorderRightColor
             }
         }
 
-        /// <summary>
-        /// Gets the actual length of the north west corner
-        /// </summary>
-        public double ActualCornerNw
+        public double ActualBorderTopLeftRadiusX
         {
             get
             {
-                if (double.IsNaN(_actualCornerNw))
-                {
-                    _actualCornerNw = CssValueParser.ParseLength(CornerNwRadius, 0, this);
-                }
-                return _actualCornerNw;
+                if (double.IsNaN(_actualBorderTopLeftRadiusX))
+                    _actualBorderTopLeftRadiusX = CssValueParser.ParseLength(FirstCssValue(BorderTopLeftRadius), Size.Width, this);
+                return _actualBorderTopLeftRadiusX;
             }
         }
 
-        /// <summary>
-        /// Gets the actual length of the north east corner
-        /// </summary>
-        public double ActualCornerNe
+        public double ActualBorderTopLeftRadiusY
         {
             get
             {
-                if (double.IsNaN(_actualCornerNe))
-                {
-                    _actualCornerNe = CssValueParser.ParseLength(CornerNeRadius, 0, this);
-                }
-                return _actualCornerNe;
+                if (double.IsNaN(_actualBorderTopLeftRadiusY))
+                    _actualBorderTopLeftRadiusY = CssValueParser.ParseLength(SecondCssValue(BorderTopLeftRadius), Size.Height, this);
+                return _actualBorderTopLeftRadiusY;
             }
         }
 
-        /// <summary>
-        /// Gets the actual length of the south east corner
-        /// </summary>
-        public double ActualCornerSe
+        public double ActualBorderTopRightRadiusX
         {
             get
             {
-                if (double.IsNaN(_actualCornerSe))
-                {
-                    _actualCornerSe = CssValueParser.ParseLength(CornerSeRadius, 0, this);
-                }
-                return _actualCornerSe;
+                if (double.IsNaN(_actualBorderTopRightRadiusX))
+                    _actualBorderTopRightRadiusX = CssValueParser.ParseLength(FirstCssValue(BorderTopRightRadius), Size.Width, this);
+                return _actualBorderTopRightRadiusX;
             }
         }
 
-        /// <summary>
-        /// Gets the actual length of the south west corner
-        /// </summary>
-        public double ActualCornerSw
+        public double ActualBorderTopRightRadiusY
         {
             get
             {
-                if (double.IsNaN(_actualCornerSw))
-                {
-                    _actualCornerSw = CssValueParser.ParseLength(CornerSwRadius, 0, this);
-                }
-                return _actualCornerSw;
+                if (double.IsNaN(_actualBorderTopRightRadiusY))
+                    _actualBorderTopRightRadiusY = CssValueParser.ParseLength(SecondCssValue(BorderTopRightRadius), Size.Height, this);
+                return _actualBorderTopRightRadiusY;
             }
         }
 
+        public double ActualBorderBottomRightRadiusX
+        {
+            get
+            {
+                if (double.IsNaN(_actualBorderBottomRightRadiusX))
+                    _actualBorderBottomRightRadiusX = CssValueParser.ParseLength(FirstCssValue(BorderBottomRightRadius), Size.Width, this);
+                return _actualBorderBottomRightRadiusX;
+            }
+        }
+
+        public double ActualBorderBottomRightRadiusY
+        {
+            get
+            {
+                if (double.IsNaN(_actualBorderBottomRightRadiusY))
+                    _actualBorderBottomRightRadiusY = CssValueParser.ParseLength(SecondCssValue(BorderBottomRightRadius), Size.Height, this);
+                return _actualBorderBottomRightRadiusY;
+            }
+        }
+
+        public double ActualBorderBottomLeftRadiusX
+        {
+            get
+            {
+                if (double.IsNaN(_actualBorderBottomLeftRadiusX))
+                    _actualBorderBottomLeftRadiusX = CssValueParser.ParseLength(FirstCssValue(BorderBottomLeftRadius), Size.Width, this);
+                return _actualBorderBottomLeftRadiusX;
+            }
+        }
+
+        public double ActualBorderBottomLeftRadiusY
+        {
+            get
+            {
+                if (double.IsNaN(_actualBorderBottomLeftRadiusY))
+                    _actualBorderBottomLeftRadiusY = CssValueParser.ParseLength(SecondCssValue(BorderBottomLeftRadius), Size.Height, this);
+                return _actualBorderBottomLeftRadiusY;
+            }
+        }
+
+        /// <summary>
+        /// Returns the first top-level-whitespace-delimited token in a "border-*-radius" longhand value
+        /// (the horizontal radius).
+        /// </summary>
+        private static string FirstCssValue(string value)
+        {
+            foreach (var token in CssValueParser.SplitTopLevelWhitespace(value))
+                return token;
+            return value;
+        }
+
+        /// <summary>
+        /// Returns the second top-level-whitespace-delimited token in a "border-*-radius" longhand value
+        /// (the vertical radius), or the first if there is no second (spec: omitted v-radius = h-radius).
+        /// </summary>
+        private static string SecondCssValue(string value)
+        {
+            var tokens = new List<string>(CssValueParser.SplitTopLevelWhitespace(value));
+            return tokens.Count > 1 ? tokens[1] : value;
+        }
+
+        /// <summary>
+        /// Computes overlap-reduced corner radii for the given rendering rectangle, per CSS Backgrounds
+        /// §4. Horizontal and vertical axes are reduced independently so that, e.g., two large radii on
+        /// the same edge never sum to more than that edge's length.
+        /// </summary>
+        public BorderRadii ComputeRadii(RRect rect)
+        {
+            double tlX = ActualBorderTopLeftRadiusX, tlY = ActualBorderTopLeftRadiusY;
+            double trX = ActualBorderTopRightRadiusX, trY = ActualBorderTopRightRadiusY;
+            double brX = ActualBorderBottomRightRadiusX, brY = ActualBorderBottomRightRadiusY;
+            double blX = ActualBorderBottomLeftRadiusX, blY = ActualBorderBottomLeftRadiusY;
+
+            // Horizontal reduction: check top side and bottom side independently.
+            double fTop = tlX + trX > 0 && rect.Width > 0 ? rect.Width / (tlX + trX) : 1.0;
+            double fBot = blX + brX > 0 && rect.Width > 0 ? rect.Width / (blX + brX) : 1.0;
+            double fX = Math.Min(1.0, Math.Min(fTop, fBot));
+
+            // Vertical reduction: check left side and right side independently.
+            double fLeft = tlY + blY > 0 && rect.Height > 0 ? rect.Height / (tlY + blY) : 1.0;
+            double fRight = trY + brY > 0 && rect.Height > 0 ? rect.Height / (trY + brY) : 1.0;
+            double fY = Math.Min(1.0, Math.Min(fLeft, fRight));
+
+            return new BorderRadii(tlX * fX, tlY * fY, trX * fX, trY * fY,
+                brX * fX, brY * fY, blX * fX, blY * fY);
+        }
+
         /// <summary>
-        /// Gets a value indicating if at least one of the corners of the box is rounded
+        /// Gets a value indicating if at least one of the corners of the box is rounded. A fast,
+        /// rect-independent pre-check using the raw (not overlap-reduced) actual radii - use
+        /// <see cref="ComputeRadii"/> when the actual per-corner values are needed for painting.
         /// </summary>
         public bool IsRounded
         {
-            get { return ActualCornerNe > 0f || ActualCornerNw > 0f || ActualCornerSe > 0f || ActualCornerSw > 0f; }
+            get
+            {
+                return ActualBorderTopLeftRadiusX > 0 || ActualBorderTopLeftRadiusY > 0 ||
+                    ActualBorderTopRightRadiusX > 0 || ActualBorderTopRightRadiusY > 0 ||
+                    ActualBorderBottomRightRadiusX > 0 || ActualBorderBottomRightRadiusY > 0 ||
+                    ActualBorderBottomLeftRadiusX > 0 || ActualBorderBottomLeftRadiusY > 0;
+            }
         }
 
         /// <summary>
@@ -1214,42 +1439,40 @@ public RColor ActualBackgroundColor
         }
 
         /// <summary>
-        /// Gets the second color that creates a gradient for the background
+        /// Gets the actual font of the parent
         /// </summary>
-        public RColor ActualBackgroundGradient
+        public RFont ActualParentFont
         {
-            get
-            {
-                if (_actualBackgroundGradient.IsEmpty)
-                {
-                    _actualBackgroundGradient = GetActualColor(BackgroundGradient);
-                }
-                return _actualBackgroundGradient;
-            }
+            get { return GetParent() == null ? ActualFont : GetParent().ActualFont; }
         }
 
         /// <summary>
-        /// Gets the actual angle specified for the background gradient
+        /// Gets the box's own resolved CSS Fonts Level 4 numeric <c>font-weight</c> (1-1000) - cached and
+        /// computed lazily like <see cref="ActualFont"/>, since <c>bolder</c>/<c>lighter</c> resolve
+        /// relative to the parent's own resolved weight (see <see cref="CssFontWeightResolver"/>).
         /// </summary>
-        public double ActualBackgroundGradientAngle
+        internal int ActualFontWeight
         {
             get
             {
-                if (double.IsNaN(_actualBackgroundGradientAngle))
+                if (_actualFontWeight == null)
                 {
-                    _actualBackgroundGradientAngle = CssValueParser.ParseNumber(BackgroundGradientAngle, 360f);
+                    var parentWeight = GetParent() != null ? GetParent().ActualFontWeight : CssFontWeightResolver.Normal;
+                    _actualFontWeight = CssFontWeightResolver.Resolve(FontWeight, parentWeight);
                 }
-
-                return _actualBackgroundGradientAngle;
+                return _actualFontWeight.Value;
             }
         }
 
         /// <summary>
-        /// Gets the actual font of the parent
+        /// The codepoint of this box's own first non-whitespace character, for <c>unicode-range</c> face
+        /// disambiguation (see <see cref="ActualFont"/>) - null when this box has no text of its own (e.g.
+        /// a container box whose text lives on its children) or only whitespace. <see cref="CssBoxProperties"/>
+        /// itself holds no text (that's <see cref="CssBox.Text"/>), hence the hook.
         /// </summary>
-        public RFont ActualParentFont
+        protected virtual int? GetFirstNonWhitespaceCodepoint()
         {
-            get { return GetParent() == null ? ActualFont : GetParent().ActualFont; }
+            return null;
         }
 
         /// <summary>
@@ -1277,11 +1500,14 @@ public RFont ActualFont
                         st |= RFontStyle.Italic;
                     }
 
-                    if (FontWeight != CssConstants.Normal && FontWeight != CssConstants.Lighter && !string.IsNullOrEmpty(FontWeight) && FontWeight != CssConstants.Inherit)
+                    var weight = ActualFontWeight;
+                    if (weight >= 600)
                     {
                         st |= RFontStyle.Bold;
                     }
 
+                    var stretch = FontStretchResolver.Resolve(FontStretch);
+
                     double fsize;
                     double parentSize = CssConstants.FontSize;
 
@@ -1327,13 +1553,22 @@ public RFont ActualFont
                         fsize = CssConstants.FontSize;
                     }
 
-                    _actualFont = GetCachedFont(FontFamily, fsize, st);
+                    var codepoint = GetFirstNonWhitespaceCodepoint();
+                    _actualFont = GetCachedFont(FontFamily, fsize, st, weight, stretch, codepoint);
+                    if (_actualFont == null)
+                    {
+                        // A codepoint-scoped miss (the family has @font-face faces registered, but none
+                        // of them cover this box's first character) - fall back to the default font family
+                        // rather than propagate null, matching the pre-existing "nothing matched" behavior
+                        // for any other unresolvable font-family value.
+                        _actualFont = GetCachedFont(CssConstants.DefaultFont, fsize, st, weight, stretch, null);
+                    }
                 }
                 return _actualFont;
             }
         }
 
-        protected abstract RFont GetCachedFont(string fontFamily, double fsize, RFontStyle st);
+        protected abstract RFont GetCachedFont(string fontFamily, double fsize, RFontStyle st, int weight, int stretch, int? codepoint);
 
         /// <summary>
         /// Gets the line height
@@ -1427,12 +1662,18 @@ public double ActualBorderSpacingVertical
         protected abstract CssBoxProperties GetParent();
 
         /// <summary>
-        /// Gets the height of the font in the specified units
+        /// Gets the size of 1em in CSS pixels, per spec: an element's own computed font-size, not
+        /// the font's line-spacing metric (ascent+descent+leading), which is typically 15-30%+
+        /// larger and would inflate every em-based margin/padding/line-height. <see cref="ActualFont"/>
+        /// is created from a font-size already converted to points (<see cref="Parse.CssValueParser.ParseLength(string, double, double, string, bool, bool)"/>'s
+        /// fontAdjust factor, 72/96, applied when the declared value is in CSS px), so its own
+        /// <see cref="Adapters.RFont.Size"/> is in points too - convert back to CSS px (the unit
+        /// every other length in this engine resolves to) with the inverse, 96/72.
         /// </summary>
         /// <returns></returns>
         public double GetEmHeight()
         {
-            return ActualFont.Height;
+            return ActualFont.Size * 96d / 72d;
         }
 
         /// <summary>
@@ -1491,6 +1732,12 @@ protected void InheritStyle(CssBox p, bool everything)
         {
             if (p != null)
             {
+                // Custom properties are always inherited, regardless of the "everything" special case.
+                // Cloned (not shared) so a child's local override never mutates the parent's or a sibling's dictionary.
+                CustomProperties = p.CustomProperties != null && p.CustomProperties.Count > 0
+                    ? new Dictionary<string, string>(p.CustomProperties)
+                    : null;
+
                 _borderSpacing = p._borderSpacing;
                 _borderCollapse = p._borderCollapse;
                 _color = p._color;
@@ -1504,6 +1751,7 @@ protected void InheritStyle(CssBox p, bool everything)
                 _fontStyle = p._fontStyle;
                 _fontVariant = p._fontVariant;
                 _fontWeight = p._fontWeight;
+                _fontStretch = p._fontStretch;
                 _listStyleImage = p._listStyleImage;
                 _listStylePosition = p._listStylePosition;
                 _listStyleType = p._listStyleType;
@@ -1515,8 +1763,6 @@ protected void InheritStyle(CssBox p, bool everything)
                 if (everything)
                 {
                     _backgroundColor = p._backgroundColor;
-                    _backgroundGradient = p._backgroundGradient;
-                    _backgroundGradientAngle = p._backgroundGradientAngle;
                     _backgroundImage = p._backgroundImage;
                     _backgroundPosition = p._backgroundPosition;
                     _backgroundRepeat = p._backgroundRepeat;
@@ -1533,14 +1779,17 @@ protected void InheritStyle(CssBox p, bool everything)
                     _borderBottomStyle = p._borderBottomStyle;
                     _borderLeftStyle = p._borderLeftStyle;
                     _bottom = p._bottom;
-                    _cornerNwRadius = p._cornerNwRadius;
-                    _cornerNeRadius = p._cornerNeRadius;
-                    _cornerSeRadius = p._cornerSeRadius;
-                    _cornerSwRadius = p._cornerSwRadius;
-                    _cornerRadius = p._cornerRadius;
+                    _borderTopLeftRadius = p._borderTopLeftRadius;
+                    _borderTopRightRadius = p._borderTopRightRadius;
+                    _borderBottomRightRadius = p._borderBottomRightRadius;
+                    _borderBottomLeftRadius = p._borderBottomLeftRadius;
                     _display = p._display;
                     _float = p._float;
+                    _clear = p._clear;
+                    _boxSizing = p._boxSizing;
                     _height = p._height;
+                    _minHeight = p._minHeight;
+                    _maxHeight = p._maxHeight;
                     _marginBottom = p._marginBottom;
                     _marginLeft = p._marginLeft;
                     _marginRight = p._marginRight;
@@ -1564,4 +1813,27 @@ protected void InheritStyle(CssBox p, bool everything)
             }
         }
     }
+
+    /// <summary>
+    /// Holds the eight computed (overlap-reduced) corner radii for a box rectangle - see
+    /// <see cref="CssBoxProperties.ComputeRadii"/>.
+    /// </summary>
+    internal struct BorderRadii
+    {
+        public readonly double TLX, TLY, TRX, TRY, BRX, BRY, BLX, BLY;
+
+        public BorderRadii(double tlX, double tlY, double trX, double trY,
+            double brX, double brY, double blX, double blY)
+        {
+            TLX = tlX; TLY = tlY;
+            TRX = trX; TRY = trY;
+            BRX = brX; BRY = brY;
+            BLX = blX; BLY = blY;
+        }
+
+        public bool IsRounded
+        {
+            get { return TLX > 0 || TLY > 0 || TRX > 0 || TRY > 0 || BRX > 0 || BRY > 0 || BLX > 0 || BLY > 0; }
+        }
+    }
 }
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/Dom/CssContentEngine.cs b/Source/HtmlRenderer/Core/Dom/CssContentEngine.cs
new file mode 100644
index 000000000..5ca61083b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Dom/CssContentEngine.cs
@@ -0,0 +1,99 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+using System;
+using System.Linq;
+using System.Text;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+using TheArtOfDev.HtmlRenderer.Core.Parse;
+using TheArtOfDev.HtmlRenderer.Core.Utils;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Dom
+{
+    /// <summary>
+    /// Resolves a synthesized <c>::before</c>/<c>::after</c> pseudo-element box's <see cref="CssBox.Content"/>
+    /// value into literal text, so it renders through the box's normal <see cref="CssBox.Text"/>/
+    /// <see cref="CssBox.ParseToWords"/> machinery like any other text box.<br/>
+    /// Deliberately a small, self-contained subset of the full content grammar: literal strings,
+    /// <c>attr()</c>, and the four quote keywords are supported; <c>counter()</c>/<c>counters()</c>/
+    /// <c>string()</c>/<c>content()</c> are not (CSS counters and named strings remain out of scope
+    /// for this backport - an unrecognized component is simply skipped, the same graceful-ignore
+    /// behavior this engine already applies to unsupported CSS elsewhere).<br/>
+    /// Tokenizes via the shared CSS lexer (<see cref="CssValueParser.GetCssTokens"/>) rather than
+    /// hand-parsing the CSS text, so string literals (e.g. <c>"\A"</c>, the standard UA-stylesheet
+    /// line-break trick used by <c>br:before</c>) get the same correct escape decoding the lexer
+    /// already applies when the stylesheet is first parsed - see CalcParser/BackgroundPositionGrammar
+    /// for the same "don't write two independent parsers for the same grammar" precedent.
+    /// </summary>
+    internal static class CssContentEngine
+    {
+        /// <summary>
+        /// If <paramref name="box"/> is a synthesized pseudo-element with a resolved <c>content</c> value,
+        /// sets its <see cref="CssBox.Text"/> to the resolved literal text. No-op for any other box, or
+        /// if content is <c>none</c>/<c>normal</c>/empty.
+        /// </summary>
+        public static void ApplyContent(CssBox box)
+        {
+            if (!box.IsPseudoElement) return;
+            if (string.IsNullOrEmpty(box.Content)) return;
+
+            var content = box.Content.Trim();
+            if (content.Length == 0 || content == CssConstants.None || content == CssConstants.Normal) return;
+
+            var text = Resolve(box, content);
+            if (!string.IsNullOrEmpty(text))
+            {
+                box.Text = text;
+            }
+        }
+
+        private static string Resolve(CssBox box, string content)
+        {
+            var sb = new StringBuilder();
+
+            foreach (var token in CssValueParser.GetCssTokens(content))
+            {
+                if (token is StringToken stringToken)
+                {
+                    sb.Append(stringToken.Data);
+                }
+                else if (token is FunctionToken functionToken &&
+                         functionToken.Data.Equals(FunctionNames.Attr, StringComparison.OrdinalIgnoreCase))
+                {
+                    if (functionToken.ArgumentTokens.FirstOrDefault() is KeywordToken attrNameToken)
+                    {
+                        var sourceBox = box.IsPseudoElement && box.ParentBox != null ? box.ParentBox : box;
+                        var attrValue = sourceBox.GetAttribute(attrNameToken.Data, string.Empty);
+                        sb.Append(attrValue);
+                    }
+                }
+                else if (token is KeywordToken keywordToken)
+                {
+                    if (keywordToken.Data.Equals(Keywords.OpenQuote, StringComparison.OrdinalIgnoreCase))
+                    {
+                        sb.Append('“');
+                    }
+                    else if (keywordToken.Data.Equals(Keywords.CloseQuote, StringComparison.OrdinalIgnoreCase))
+                    {
+                        sb.Append('”');
+                    }
+                    // no-open-quote/no-close-quote produce no text, but still count as a quoting depth
+                    // change per spec - depth tracking isn't implemented here (no "quotes" property
+                    // support), so they (like any other unrecognized keyword) are a no-op.
+                }
+                // counter()/counters()/string()/content() and anything else unrecognized: skip.
+            }
+
+            return sb.ToString();
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Dom/CssLayoutEngine.cs b/Source/HtmlRenderer/Core/Dom/CssLayoutEngine.cs
index e41de241f..4c7139ea2 100644
--- a/Source/HtmlRenderer/Core/Dom/CssLayoutEngine.cs
+++ b/Source/HtmlRenderer/Core/Dom/CssLayoutEngine.cs
@@ -167,6 +167,40 @@ public static void CreateLineBoxes(RGraphics g, CssBox blockBox)
             }
         }
 
+        /// <summary>
+        /// Applies float positioning (float: left/right) and clearance (clear) to a box that has already
+        /// had its static in-flow position committed by the caller (<see cref="CssBox.PerformLayoutImp"/>) -
+        /// overwrites <see cref="CssBox.Location"/> using that static position as input. No-op if the box
+        /// is neither floated nor has clear set. Ported from PeachPDF.
+        /// </summary>
+        /// <param name="box">the box to float/clear - its Location.Y must already hold its static position</param>
+        public static void FloatBox(CssBox box)
+        {
+            if (box.Float == CssConstants.None && box.Clear == CssConstants.None)
+                return;
+
+            var containingBox = box.ContainingBlock;
+            var limitRight = containingBox.ClientRight;
+            var startX = containingBox.ClientLeft;
+            var startY = box.Location.Y;
+            var currentBoxIdx = containingBox.Boxes.IndexOf(box);
+
+            switch (box.Float)
+            {
+                case CssConstants.Left:
+                    FloatBoxLeft(box, startX, startY, limitRight);
+                    break;
+                case CssConstants.Right:
+                    FloatBoxRight(box, startX, startY, limitRight);
+                    break;
+            }
+
+            if (box.Clear != CssConstants.None)
+            {
+                ClearBox(box, currentBoxIdx, containingBox);
+            }
+        }
+
         /// <summary>
         /// Applies special vertical alignment for table-cells
         /// </summary>
@@ -225,6 +259,148 @@ public static void ApplyCellVerticalAlignment(RGraphics g, CssBox cell)
 
         #region Private methods
 
+        /// <summary>
+        /// Pushes <paramref name="box"/> down past any floated preceding sibling (at any depth - a float
+        /// nested inside a plain non-floated wrapper still needs clearing against, CSS 2.1 9.5.2) that
+        /// matches <paramref name="box"/>'s <c>clear</c> direction. Only ever changes Y, never X - X is
+        /// left exactly as <see cref="FloatBox"/>/normal static-position assignment already set it.
+        /// </summary>
+        private static void ClearBox(CssBox box, int currentBoxIdx, CssBox containingBox)
+        {
+            var clearance = Math.Max(containingBox.ClientTop, box.Location.Y);
+
+            for (int i = 0; i < currentBoxIdx; i++)
+            {
+                clearance = Math.Max(clearance, GetClearance(containingBox.Boxes[i], box.Clear));
+            }
+
+            box.Location = new RPoint(box.Location.X, clearance);
+        }
+
+        /// <summary>
+        /// Recursively finds the outer (margin) bottom edge of every floated box in <paramref name="sibling"/>'s
+        /// subtree that matches <paramref name="clearDirection"/>, testing <paramref name="sibling"/> itself
+        /// and every descendant at every depth (not just direct children) - so a float directly inside another
+        /// float (e.g. ACID1's <c>dd</c> float:right containing <c>blockquote</c>/<c>h1</c> float:left as direct
+        /// children) is never missed.
+        /// </summary>
+        private static double GetClearance(CssBox sibling, string clearDirection)
+        {
+            double clearance = 0;
+
+            if (sibling.IsFloated &&
+                (clearDirection == CssConstants.Both ||
+                 (clearDirection == CssConstants.Left && sibling.Float == CssConstants.Left) ||
+                 (clearDirection == CssConstants.Right && sibling.Float == CssConstants.Right)))
+            {
+                clearance = sibling.ActualBottom + sibling.ActualMarginBottom;
+            }
+
+            foreach (var child in sibling.Boxes)
+            {
+                clearance = Math.Max(clearance, GetClearance(child, clearDirection));
+            }
+
+            return clearance;
+        }
+
+        private static void FloatBoxLeft(CssBox box, double startX, double startY, double limitRight)
+        {
+            var coordinates = new DomUtils.CssFloatCoordinates
+            {
+                Left = startX + box.ActualMarginLeft,
+                Right = limitRight,
+                Top = startY,
+                MaxBottom = startY,
+                MarginLeft = box.ActualMarginLeft,
+                MarginRight = box.ActualMarginRight,
+                // FloatBox (this method's only caller) runs from PerformLayoutImp's block-width-
+                // resolution branch, after Size.Width is already resolved to this box's border-box
+                // width - use it directly rather than ActualWidth, which re-parses the Width CSS
+                // string against Size.Width as a percentage base (correct for the inline-block callers
+                // it otherwise serves, but not what a border-box reference width means here: for a
+                // fixed-unit Width like "34em" it returns the bare content-only value, ignoring
+                // Size.Width entirely, understating a padded/bordered float's true footprint).
+                ReferenceWidth = box.Size.Width
+            };
+
+            while (true)
+            {
+                var intersectingFloat = DomUtils.GetFirstIntersectingFloatBox(box, coordinates, box.Float);
+                if (intersectingFloat == null)
+                    break;
+
+                switch (intersectingFloat.Float)
+                {
+                    case CssConstants.Left:
+                        coordinates.Left = intersectingFloat.ActualRight + intersectingFloat.ActualMarginRight + box.ActualMarginLeft;
+                        break;
+                    case CssConstants.Right:
+                        coordinates.Right = intersectingFloat.Location.X - intersectingFloat.ActualMarginLeft;
+                        break;
+                }
+
+                if (intersectingFloat.ActualBottom > coordinates.MaxBottom)
+                {
+                    coordinates.MaxBottom = intersectingFloat.ActualBottom;
+                }
+
+                if (coordinates.Left + box.Size.Width > coordinates.Right)
+                {
+                    coordinates.Top = coordinates.MaxBottom + box.ActualMarginTop;
+                    coordinates.Left = startX + box.ActualMarginLeft;
+                }
+            }
+
+            box.Location = new RPoint(coordinates.Left, coordinates.Top);
+        }
+
+        private static void FloatBoxRight(CssBox box, double startX, double startY, double limitRight)
+        {
+            var coordinates = new DomUtils.CssFloatCoordinates
+            {
+                Left = startX,
+                Right = limitRight - box.ActualMarginRight,
+                Top = startY,
+                MaxBottom = startY,
+                MarginLeft = box.ActualMarginLeft,
+                MarginRight = box.ActualMarginRight,
+                // See FloatBoxLeft's matching comment - Size.Width is this box's own already-resolved
+                // border-box width, which is what ReferenceWidth means here.
+                ReferenceWidth = box.Size.Width
+            };
+
+            while (true)
+            {
+                var intersectingFloat = DomUtils.GetFirstIntersectingFloatBox(box, coordinates, box.Float);
+                if (intersectingFloat == null)
+                    break;
+
+                switch (intersectingFloat.Float)
+                {
+                    case CssConstants.Left:
+                        coordinates.Left = intersectingFloat.ActualRight;
+                        break;
+                    case CssConstants.Right:
+                        coordinates.Right = intersectingFloat.Location.X;
+                        break;
+                }
+
+                if (intersectingFloat.ActualBottom > coordinates.MaxBottom)
+                {
+                    coordinates.MaxBottom = intersectingFloat.ActualBottom;
+                }
+
+                if (coordinates.Left > coordinates.FloatRightStartX)
+                {
+                    coordinates.Right = limitRight - box.ActualMarginRight;
+                    coordinates.Top = coordinates.MaxBottom;
+                }
+            }
+
+            box.Location = new RPoint(coordinates.FloatRightStartX, coordinates.Top);
+        }
+
         /// <summary>
         /// Recursively flows the content of the box using the inline model
         /// </summary>
@@ -258,6 +434,12 @@ private static void FlowBox(RGraphics g, CssBox blockbox, CssBox box, double lim
 
                 curx += leftspacing;
 
+                var leadingLeftFloat = DomUtils.GetLastLeftIntersectingFloatBox(box, curx, cury, maxRight, maxbottom);
+                if (leadingLeftFloat != null)
+                {
+                    curx = leadingLeftFloat.ActualRight + leadingLeftFloat.ActualMarginRight + leftspacing;
+                }
+
                 if (b.Words.Count > 0)
                 {
                     bool wrapNoWrapBox = false;
@@ -278,7 +460,14 @@ private static void FlowBox(RGraphics g, CssBox blockbox, CssBox box, double lim
                         if (maxbottom - cury < box.ActualLineHeight)
                             maxbottom += box.ActualLineHeight - (maxbottom - cury);
 
-                        if ((b.WhiteSpace != CssConstants.NoWrap && b.WhiteSpace != CssConstants.Pre && curx + word.Width + rightspacing > limitRight
+                        double actualLimitRight = limitRight;
+                        var rightObstructingFloat = DomUtils.GetLastRightIntersectingFloatBox(box, cury);
+                        if (rightObstructingFloat != null)
+                        {
+                            actualLimitRight = rightObstructingFloat.Location.X - rightObstructingFloat.ActualMarginLeft - rightspacing;
+                        }
+
+                        if ((b.WhiteSpace != CssConstants.NoWrap && b.WhiteSpace != CssConstants.Pre && curx + word.Width + rightspacing > actualLimitRight
                              && (b.WhiteSpace != CssConstants.PreWrap || !word.IsSpaces))
                             || word.IsLineBreak || wrapNoWrapBox)
                         {
@@ -291,6 +480,12 @@ private static void FlowBox(RGraphics g, CssBox blockbox, CssBox box, double lim
 
                             cury = maxbottom + linespacing;
 
+                            var wrapLeftFloat = DomUtils.GetLastLeftIntersectingFloatBox(b, curx, cury, maxRight, maxbottom);
+                            if (wrapLeftFloat != null)
+                            {
+                                curx = wrapLeftFloat.ActualRight + wrapLeftFloat.ActualMarginRight + leftspacing;
+                            }
+
                             line = new CssLineBox(blockbox);
 
                             if (word.IsImage || word.Equals(b.FirstWord))
@@ -301,6 +496,12 @@ private static void FlowBox(RGraphics g, CssBox blockbox, CssBox box, double lim
 
                         line.ReportExistanceOf(word);
 
+                        var placementLeftFloat = DomUtils.GetLastLeftIntersectingFloatBox(box, curx, cury, maxRight, maxbottom);
+                        if (placementLeftFloat != null)
+                        {
+                            curx = placementLeftFloat.ActualRight + placementLeftFloat.ActualMarginRight + leftspacing;
+                        }
+
                         word.Left = curx;
                         word.Top = cury;
 
diff --git a/Source/HtmlRenderer/Core/Dom/HoverBoxBlock.cs b/Source/HtmlRenderer/Core/Dom/HoverBoxBlock.cs
index 1f919ec66..64ce46d13 100644
--- a/Source/HtmlRenderer/Core/Dom/HoverBoxBlock.cs
+++ b/Source/HtmlRenderer/Core/Dom/HoverBoxBlock.cs
@@ -10,7 +10,7 @@
 // - Sun Tsu,
 // "The Art of War"
 
-using TheArtOfDev.HtmlRenderer.Core.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Dom
 {
@@ -25,17 +25,17 @@ internal sealed class HoverBoxBlock
         private readonly CssBox _cssBox;
 
         /// <summary>
-        /// the :hover style block data
+        /// the :hover style rule
         /// </summary>
-        private readonly CssBlock _cssBlock;
+        private readonly IStyleRule _styleRule;
 
         /// <summary>
         /// Init.
         /// </summary>
-        public HoverBoxBlock(CssBox cssBox, CssBlock cssBlock)
+        public HoverBoxBlock(CssBox cssBox, IStyleRule styleRule)
         {
             _cssBox = cssBox;
-            _cssBlock = cssBlock;
+            _styleRule = styleRule;
         }
 
         /// <summary>
@@ -47,11 +47,11 @@ public CssBox CssBox
         }
 
         /// <summary>
-        /// the :hover style block data
+        /// the :hover style rule
         /// </summary>
-        public CssBlock CssBlock
+        public IStyleRule StyleRule
         {
-            get { return _cssBlock; }
+            get { return _styleRule; }
         }
     }
 }
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/Entities/CssBlock.cs b/Source/HtmlRenderer/Core/Entities/CssBlock.cs
deleted file mode 100644
index 2982b3159..000000000
--- a/Source/HtmlRenderer/Core/Entities/CssBlock.cs
+++ /dev/null
@@ -1,235 +0,0 @@
-// "Therefore those skilled at the unorthodox
-// are infinite as heaven and earth,
-// inexhaustible as the great rivers.
-// When they come to an end,
-// they begin again,
-// like the days and months;
-// they die and are reborn,
-// like the four seasons."
-// 
-// - Sun Tsu,
-// "The Art of War"
-
-using System.Collections.Generic;
-using TheArtOfDev.HtmlRenderer.Core.Utils;
-
-namespace TheArtOfDev.HtmlRenderer.Core.Entities
-{
-    /// <summary>
-    /// Represents a block of CSS property values.<br/>
-    /// Contains collection of key-value pairs that are CSS properties for specific css class.<br/>
-    /// Css class can be either custom or html tag name.
-    /// </summary>
-    /// <remarks>
-    /// To learn more about CSS blocks visit CSS spec: http://www.w3.org/TR/CSS21/syndata.html#block
-    /// </remarks>
-    public sealed class CssBlock
-    {
-        #region Fields and Consts
-
-        /// <summary>
-        /// the name of the css class of the block
-        /// </summary>
-        private readonly string _class;
-
-        /// <summary>
-        /// the CSS block properties and values
-        /// </summary>
-        private readonly Dictionary<string, string> _properties;
-
-        /// <summary>
-        /// additional selectors to used in hierarchy (p className1 > className2)
-        /// </summary>
-        private readonly List<CssBlockSelectorItem> _selectors;
-
-        /// <summary>
-        /// is the css block has :hover pseudo-class
-        /// </summary>
-        private readonly bool _hover;
-
-        #endregion
-
-
-        /// <summary>
-        /// Creates a new block from the block's source
-        /// </summary>
-        /// <param name="class">the name of the css class of the block</param>
-        /// <param name="properties">the CSS block properties and values</param>
-        /// <param name="selectors">optional: additional selectors to used in hierarchy</param>
-        /// <param name="hover">optional: is the css block has :hover pseudo-class</param>
-        public CssBlock(string @class, Dictionary<string, string> properties, List<CssBlockSelectorItem> selectors = null, bool hover = false)
-        {
-            ArgChecker.AssertArgNotNullOrEmpty(@class, "@class");
-            ArgChecker.AssertArgNotNull(properties, "properties");
-
-            _class = @class;
-            _selectors = selectors;
-            _properties = properties;
-            _hover = hover;
-        }
-
-        /// <summary>
-        /// the name of the css class of the block
-        /// </summary>
-        public string Class
-        {
-            get { return _class; }
-        }
-
-        /// <summary>
-        /// additional selectors to used in hierarchy (p className1 > className2)
-        /// </summary>
-        public List<CssBlockSelectorItem> Selectors
-        {
-            get { return _selectors; }
-        }
-
-        /// <summary>
-        /// Gets the CSS block properties and its values
-        /// </summary>
-        public IDictionary<string, string> Properties
-        {
-            get { return _properties; }
-        }
-
-        /// <summary>
-        /// is the css block has :hover pseudo-class
-        /// </summary>
-        public bool Hover
-        {
-            get { return _hover; }
-        }
-
-        /// <summary>
-        /// Merge the other block properties into this css block.<br/>
-        /// Other block properties can overwrite this block properties.
-        /// </summary>
-        /// <param name="other">the css block to merge with</param>
-        public void Merge(CssBlock other)
-        {
-            ArgChecker.AssertArgNotNull(other, "other");
-
-            foreach (var prop in other._properties.Keys)
-            {
-                _properties[prop] = other._properties[prop];
-            }
-        }
-
-        /// <summary>
-        /// Create deep copy of the CssBlock.
-        /// </summary>
-        /// <returns>new CssBlock with same data</returns>
-        public CssBlock Clone()
-        {
-            return new CssBlock(_class, new Dictionary<string, string>(_properties), _selectors != null ? new List<CssBlockSelectorItem>(_selectors) : null);
-        }
-
-        /// <summary>
-        /// Check if the two css blocks are the same (same class, selectors and properties).
-        /// </summary>
-        /// <param name="other">the other block to compare to</param>
-        /// <returns>true - the two blocks are the same, false - otherwise</returns>
-        public bool Equals(CssBlock other)
-        {
-            if (ReferenceEquals(null, other))
-                return false;
-            if (ReferenceEquals(this, other))
-                return true;
-            if (!Equals(other._class, _class))
-                return false;
-
-            if (!Equals(other._properties.Count, _properties.Count))
-                return false;
-
-            foreach (var property in _properties)
-            {
-                if (!other._properties.ContainsKey(property.Key))
-                    return false;
-                if (!Equals(other._properties[property.Key], property.Value))
-                    return false;
-            }
-
-            if (!EqualsSelector(other))
-                return false;
-
-            return true;
-        }
-
-        /// <summary>
-        /// Check if the selectors of the css blocks is the same.
-        /// </summary>
-        /// <param name="other">the other block to compare to</param>
-        /// <returns>true - the selectors on blocks are the same, false - otherwise</returns>
-        public bool EqualsSelector(CssBlock other)
-        {
-            if (ReferenceEquals(null, other))
-                return false;
-            if (ReferenceEquals(this, other))
-                return true;
-
-            if (other.Hover != Hover)
-                return false;
-            if (other._selectors == null && _selectors != null)
-                return false;
-            if (other._selectors != null && _selectors == null)
-                return false;
-
-            if (other._selectors != null && _selectors != null)
-            {
-                if (!Equals(other._selectors.Count, _selectors.Count))
-                    return false;
-
-                for (int i = 0; i < _selectors.Count; i++)
-                {
-                    if (!Equals(other._selectors[i].Class, _selectors[i].Class))
-                        return false;
-                    if (!Equals(other._selectors[i].DirectParent, _selectors[i].DirectParent))
-                        return false;
-                }
-            }
-
-            return true;
-        }
-
-        /// <summary>
-        /// Check if the two css blocks are the same (same class, selectors and properties).
-        /// </summary>
-        /// <param name="obj">the other block to compare to</param>
-        /// <returns>true - the two blocks are the same, false - otherwise</returns>
-        public override bool Equals(object obj)
-        {
-            if (ReferenceEquals(null, obj))
-                return false;
-            if (ReferenceEquals(this, obj))
-                return true;
-            if (obj.GetType() != typeof(CssBlock))
-                return false;
-            return Equals((CssBlock)obj);
-        }
-
-        /// <summary>
-        /// Serves as a hash function for a particular type. 
-        /// </summary>
-        /// <returns>A hash code for the current <see cref="T:System.Object"/>.</returns>
-        public override int GetHashCode()
-        {
-            unchecked
-            {
-                return ((_class != null ? _class.GetHashCode() : 0) * 397) ^ (_properties != null ? _properties.GetHashCode() : 0);
-            }
-        }
-
-        /// <summary>
-        /// Returns a <see cref="T:System.String"/> that represents the current <see cref="T:System.Object"/>.
-        /// </summary>
-        public override string ToString()
-        {
-            var str = _class + " { ";
-            foreach (var property in _properties)
-            {
-                str += string.Format("{0}={1}; ", property.Key, property.Value);
-            }
-            return str + " }";
-        }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/Entities/CssBlockSelectorItem.cs b/Source/HtmlRenderer/Core/Entities/CssBlockSelectorItem.cs
deleted file mode 100644
index 76ad35919..000000000
--- a/Source/HtmlRenderer/Core/Entities/CssBlockSelectorItem.cs
+++ /dev/null
@@ -1,74 +0,0 @@
-// "Therefore those skilled at the unorthodox
-// are infinite as heaven and earth,
-// inexhaustible as the great rivers.
-// When they come to an end,
-// they begin again,
-// like the days and months;
-// they die and are reborn,
-// like the four seasons."
-// 
-// - Sun Tsu,
-// "The Art of War"
-
-using TheArtOfDev.HtmlRenderer.Core.Utils;
-
-namespace TheArtOfDev.HtmlRenderer.Core.Entities
-{
-    /// <summary>
-    /// Holds single class selector in css block hierarchical selection (p class1 > div.class2)
-    /// </summary>
-    public struct CssBlockSelectorItem
-    {
-        #region Fields and Consts
-
-        /// <summary>
-        /// the name of the css class of the block
-        /// </summary>
-        private readonly string _class;
-
-        /// <summary>
-        /// is the selector item has to be direct parent
-        /// </summary>
-        private readonly bool _directParent;
-
-        #endregion
-
-
-        /// <summary>
-        /// Creates a new block from the block's source
-        /// </summary>
-        /// <param name="class">the name of the css class of the block</param>
-        /// <param name="directParent"> </param>
-        public CssBlockSelectorItem(string @class, bool directParent)
-        {
-            ArgChecker.AssertArgNotNullOrEmpty(@class, "@class");
-
-            _class = @class;
-            _directParent = directParent;
-        }
-
-        /// <summary>
-        /// the name of the css class of the block
-        /// </summary>
-        public string Class
-        {
-            get { return _class; }
-        }
-
-        /// <summary>
-        /// is the selector item has to be direct parent
-        /// </summary>
-        public bool DirectParent
-        {
-            get { return _directParent; }
-        }
-
-        /// <summary>
-        /// Returns a <see cref="T:System.String"/> that represents the current <see cref="T:System.Object"/>.
-        /// </summary>
-        public override string ToString()
-        {
-            return _class + (_directParent ? " > " : string.Empty);
-        }
-    }
-}
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/Entities/CssFontFace.cs b/Source/HtmlRenderer/Core/Entities/CssFontFace.cs
new file mode 100644
index 000000000..c9ccd9f3a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Entities/CssFontFace.cs
@@ -0,0 +1,10 @@
+#nullable enable
+
+namespace TheArtOfDev.HtmlRenderer.Core.Entities
+{
+    /// <summary>
+    /// One comma-separated candidate of an <c>@font-face</c> <c>src</c> descriptor, e.g. the
+    /// <c>url(font.woff2) format("woff2")</c> in <c>src: url(font.woff2) format("woff2"), local("My Font")</c>.
+    /// </summary>
+    internal record CssFontFace(string? Url, string? Format, string? Tech, string? Local);
+}
diff --git a/Source/HtmlRenderer/Core/Entities/CssImage.cs b/Source/HtmlRenderer/Core/Entities/CssImage.cs
new file mode 100644
index 000000000..887428fe4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Entities/CssImage.cs
@@ -0,0 +1,32 @@
+namespace TheArtOfDev.HtmlRenderer.Core.Entities
+{
+    /// <summary>
+    /// The parsed form of a single <c>background-image</c> value: either a <c>url()</c> reference or a
+    /// gradient function. Unlike the fuller model this is trimmed down from (same
+    /// name for an easy diff), <c>background-image</c> here is a single value, not a comma-separated
+    /// layered list - this project only backports enough to replace the old non-standard
+    /// "background-gradient" property.
+    /// </summary>
+    internal abstract class CssImage
+    {
+        internal sealed class Url : CssImage
+        {
+            public Url(string href)
+            {
+                Href = href;
+            }
+
+            public string Href { get; }
+        }
+
+        internal sealed class LinearGradient : CssImage
+        {
+            public LinearGradient(ParsedLinearGradient gradient)
+            {
+                Gradient = gradient;
+            }
+
+            public ParsedLinearGradient Gradient { get; }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Entities/ParsedLinearGradient.cs b/Source/HtmlRenderer/Core/Entities/ParsedLinearGradient.cs
new file mode 100644
index 000000000..00a4a23c3
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Entities/ParsedLinearGradient.cs
@@ -0,0 +1,18 @@
+using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Entities
+{
+    /// <summary>
+    /// A fully parsed <c>linear-gradient()</c>/<c>repeating-linear-gradient()</c> value - the angle and
+    /// raw (not yet position-resolved) color stop list. Derived from
+    /// Html/Core/Entities/ParsedLinearGradient.cs, minus CSS Color 4 interpolation-color-space support
+    /// (ColorSpace/HueMethod) - gradients always interpolate in sRGB here.
+    /// </summary>
+    internal sealed class ParsedLinearGradient
+    {
+        public double AngleRad { get; set; }
+        public (RColor? Color, Length? Position, bool IsHint)[] Stops { get; set; }
+        public bool IsRepeating { get; set; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Handlers/BordersDrawHandler.cs b/Source/HtmlRenderer/Core/Handlers/BordersDrawHandler.cs
index b20c331cb..2cd90b33f 100644
--- a/Source/HtmlRenderer/Core/Handlers/BordersDrawHandler.cs
+++ b/Source/HtmlRenderer/Core/Handlers/BordersDrawHandler.cs
@@ -202,73 +202,76 @@ private static void SetInOutsetRectanglePoints(Border border, CssBox b, RRect r,
         /// <returns>Beveled border path, null if there is no rounded corners</returns>
         private static RGraphicsPath GetRoundedBorderPath(RGraphics g, Border border, CssBox b, RRect r)
         {
+            var rad = b.ComputeRadii(r);
+            if (!rad.IsRounded) return null;
+
             RGraphicsPath path = null;
             switch (border)
             {
                 case Border.Top:
-                    if (b.ActualCornerNw > 0 || b.ActualCornerNe > 0)
+                    if (rad.TLX > 0 || rad.TLY > 0 || rad.TRX > 0 || rad.TRY > 0)
                     {
                         path = g.GetGraphicsPath();
-                        path.Start(r.Left + b.ActualBorderLeftWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + b.ActualCornerNw);
+                        path.Start(r.Left + b.ActualBorderLeftWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + rad.TLY);
 
-                        if (b.ActualCornerNw > 0)
-                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2 + b.ActualCornerNw, r.Top + b.ActualBorderTopWidth / 2, b.ActualCornerNw, RGraphicsPath.Corner.TopLeft);
+                        if (rad.TLX > 0 || rad.TLY > 0)
+                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2 + rad.TLX, r.Top + b.ActualBorderTopWidth / 2, rad.TLX, rad.TLY, RGraphicsPath.Corner.TopLeft);
 
-                        path.LineTo(r.Right - b.ActualBorderRightWidth / 2 - b.ActualCornerNe, r.Top + b.ActualBorderTopWidth / 2);
+                        path.LineTo(r.Right - b.ActualBorderRightWidth / 2 - rad.TRX, r.Top + b.ActualBorderTopWidth / 2);
 
-                        if (b.ActualCornerNe > 0)
-                            path.ArcTo(r.Right - b.ActualBorderRightWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + b.ActualCornerNe, b.ActualCornerNe, RGraphicsPath.Corner.TopRight);
+                        if (rad.TRX > 0 || rad.TRY > 0)
+                            path.ArcTo(r.Right - b.ActualBorderRightWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + rad.TRY, rad.TRX, rad.TRY, RGraphicsPath.Corner.TopRight);
                     }
                     break;
                 case Border.Bottom:
-                    if (b.ActualCornerSw > 0 || b.ActualCornerSe > 0)
+                    if (rad.BLX > 0 || rad.BLY > 0 || rad.BRX > 0 || rad.BRY > 0)
                     {
                         path = g.GetGraphicsPath();
-                        path.Start(r.Right - b.ActualBorderRightWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - b.ActualCornerSe);
+                        path.Start(r.Right - b.ActualBorderRightWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - rad.BRY);
 
-                        if (b.ActualCornerSe > 0)
-                            path.ArcTo(r.Right - b.ActualBorderRightWidth / 2 - b.ActualCornerSe, r.Bottom - b.ActualBorderBottomWidth / 2, b.ActualCornerSe, RGraphicsPath.Corner.BottomRight);
+                        if (rad.BRX > 0 || rad.BRY > 0)
+                            path.ArcTo(r.Right - b.ActualBorderRightWidth / 2 - rad.BRX, r.Bottom - b.ActualBorderBottomWidth / 2, rad.BRX, rad.BRY, RGraphicsPath.Corner.BottomRight);
 
-                        path.LineTo(r.Left + b.ActualBorderLeftWidth / 2 + b.ActualCornerSw, r.Bottom - b.ActualBorderBottomWidth / 2);
+                        path.LineTo(r.Left + b.ActualBorderLeftWidth / 2 + rad.BLX, r.Bottom - b.ActualBorderBottomWidth / 2);
 
-                        if (b.ActualCornerSw > 0)
-                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - b.ActualCornerSw, b.ActualCornerSw, RGraphicsPath.Corner.BottomLeft);
+                        if (rad.BLX > 0 || rad.BLY > 0)
+                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - rad.BLY, rad.BLX, rad.BLY, RGraphicsPath.Corner.BottomLeft);
                     }
                     break;
                 case Border.Right:
-                    if (b.ActualCornerNe > 0 || b.ActualCornerSe > 0)
+                    if (rad.TRX > 0 || rad.TRY > 0 || rad.BRX > 0 || rad.BRY > 0)
                     {
                         path = g.GetGraphicsPath();
 
                         bool noTop = b.BorderTopStyle == CssConstants.None || b.BorderTopStyle == CssConstants.Hidden;
                         bool noBottom = b.BorderBottomStyle == CssConstants.None || b.BorderBottomStyle == CssConstants.Hidden;
-                        path.Start(r.Right - b.ActualBorderRightWidth / 2 - (noTop ? b.ActualCornerNe : 0), r.Top + b.ActualBorderTopWidth / 2 + (noTop ? 0 : b.ActualCornerNe));
+                        path.Start(r.Right - b.ActualBorderRightWidth / 2 - (noTop ? rad.TRX : 0), r.Top + b.ActualBorderTopWidth / 2 + (noTop ? 0 : rad.TRY));
 
-                        if (b.ActualCornerNe > 0 && noTop)
-                            path.ArcTo(r.Right - b.ActualBorderLeftWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + b.ActualCornerNe, b.ActualCornerNe, RGraphicsPath.Corner.TopRight);
+                        if ((rad.TRX > 0 || rad.TRY > 0) && noTop)
+                            path.ArcTo(r.Right - b.ActualBorderLeftWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + rad.TRY, rad.TRX, rad.TRY, RGraphicsPath.Corner.TopRight);
 
-                        path.LineTo(r.Right - b.ActualBorderRightWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - b.ActualCornerSe);
+                        path.LineTo(r.Right - b.ActualBorderRightWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - rad.BRY);
 
-                        if (b.ActualCornerSe > 0 && noBottom)
-                            path.ArcTo(r.Right - b.ActualBorderRightWidth / 2 - b.ActualCornerSe, r.Bottom - b.ActualBorderBottomWidth / 2, b.ActualCornerSe, RGraphicsPath.Corner.BottomRight);
+                        if ((rad.BRX > 0 || rad.BRY > 0) && noBottom)
+                            path.ArcTo(r.Right - b.ActualBorderRightWidth / 2 - rad.BRX, r.Bottom - b.ActualBorderBottomWidth / 2, rad.BRX, rad.BRY, RGraphicsPath.Corner.BottomRight);
                     }
                     break;
                 case Border.Left:
-                    if (b.ActualCornerNw > 0 || b.ActualCornerSw > 0)
+                    if (rad.TLX > 0 || rad.TLY > 0 || rad.BLX > 0 || rad.BLY > 0)
                     {
                         path = g.GetGraphicsPath();
 
                         bool noTop = b.BorderTopStyle == CssConstants.None || b.BorderTopStyle == CssConstants.Hidden;
                         bool noBottom = b.BorderBottomStyle == CssConstants.None || b.BorderBottomStyle == CssConstants.Hidden;
-                        path.Start(r.Left + b.ActualBorderLeftWidth / 2 + (noBottom ? b.ActualCornerSw : 0), r.Bottom - b.ActualBorderBottomWidth / 2 - (noBottom ? 0 : b.ActualCornerSw));
+                        path.Start(r.Left + b.ActualBorderLeftWidth / 2 + (noBottom ? rad.BLX : 0), r.Bottom - b.ActualBorderBottomWidth / 2 - (noBottom ? 0 : rad.BLY));
 
-                        if (b.ActualCornerSw > 0 && noBottom)
-                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - b.ActualCornerSw, b.ActualCornerSw, RGraphicsPath.Corner.BottomLeft);
+                        if ((rad.BLX > 0 || rad.BLY > 0) && noBottom)
+                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2, r.Bottom - b.ActualBorderBottomWidth / 2 - rad.BLY, rad.BLX, rad.BLY, RGraphicsPath.Corner.BottomLeft);
 
-                        path.LineTo(r.Left + b.ActualBorderLeftWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + b.ActualCornerNw);
+                        path.LineTo(r.Left + b.ActualBorderLeftWidth / 2, r.Top + b.ActualBorderTopWidth / 2 + rad.TLY);
 
-                        if (b.ActualCornerNw > 0 && noTop)
-                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2 + b.ActualCornerNw, r.Top + b.ActualBorderTopWidth / 2, b.ActualCornerNw, RGraphicsPath.Corner.TopLeft);
+                        if ((rad.TLX > 0 || rad.TLY > 0) && noTop)
+                            path.ArcTo(r.Left + b.ActualBorderLeftWidth / 2 + rad.TLX, r.Top + b.ActualBorderTopWidth / 2, rad.TLX, rad.TLY, RGraphicsPath.Corner.TopLeft);
                     }
                     break;
             }
diff --git a/Source/HtmlRenderer/Core/Handlers/CssImagePainter.cs b/Source/HtmlRenderer/Core/Handlers/CssImagePainter.cs
new file mode 100644
index 000000000..7028690be
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Handlers/CssImagePainter.cs
@@ -0,0 +1,234 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using TheArtOfDev.HtmlRenderer.Adapters;
+using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+using TheArtOfDev.HtmlRenderer.Core.Entities;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Handlers
+{
+    /// <summary>
+    /// Turns a parsed <c>linear-gradient()</c> value into a brush ready to paint. Derived from
+    /// Html/Core/Handlers/CssImagePainter.cs, trimmed to the linear-gradient-only, single (non-layered)
+    /// background-image case this engine supports - see <see cref="ParsedLinearGradient"/>.
+    /// </summary>
+    internal static class CssImagePainter
+    {
+        /// <summary>
+        /// Builds the brush for a <c>linear-gradient()</c> background, filling the given rectangle.
+        /// </summary>
+        public static RBrush GetLinearGradientBrush(RGraphics g, RRect rect, ParsedLinearGradient gradient)
+        {
+            var (p1, p2) = ComputeGradientLine(rect, gradient.AngleRad);
+            double gdx = p2.X - p1.X, gdy = p2.Y - p1.Y;
+            double gradientLength = Math.Sqrt(gdx * gdx + gdy * gdy);
+            var stops = NormalizeGradientStops(gradient.Stops, gradientLength);
+            if (gradient.IsRepeating)
+                stops = ExpandRepeatingStops(stops);
+            return g.GetLinearGradientBrush(p1, p2, stops);
+        }
+
+        /// <summary>
+        /// Computes the CSS gradient line endpoints for the given box rect and angle (standard CSS
+        /// "corner-to-corner projection" algorithm - the line is centered on the box and long enough that
+        /// the box's bounding rectangle is fully spanned along the gradient direction).
+        /// </summary>
+        private static (RPoint p1, RPoint p2) ComputeGradientLine(RRect rect, double angleRad)
+        {
+            double dx = Math.Sin(angleRad);
+            double dy = -Math.Cos(angleRad);
+            double cx = rect.X + rect.Width / 2;
+            double cy = rect.Y + rect.Height / 2;
+            double halfLen = Math.Abs(dx) * rect.Width / 2 + Math.Abs(dy) * rect.Height / 2;
+            var p1 = new RPoint(cx - dx * halfLen, cy - dy * halfLen);
+            var p2 = new RPoint(cx + dx * halfLen, cy + dy * halfLen);
+            return (p1, p2);
+        }
+
+        private static double? ConvertLength(Length? length, double gradientLength, double emPx = 16.0)
+        {
+            if (!length.HasValue) return null;
+            var len = length.Value;
+            if (len.Type == Length.Unit.Percent)
+                return len.Value / 100.0;
+            if (len.IsAbsolute)
+                return gradientLength > 0 ? len.ToPixel() / gradientLength : 0.0;
+            if (len.Type == Length.Unit.Em)
+                return gradientLength > 0 ? len.Value * emPx / gradientLength : 0.0;
+            return null;
+        }
+
+        private static RColor LerpColor(RColor a, RColor b, double t)
+        {
+            t = t < 0.0 ? 0.0 : (t > 1.0 ? 1.0 : t);
+            return RColor.FromArgb(
+                (int)Math.Round(a.A + t * (b.A - a.A)),
+                (int)Math.Round(a.R + t * (b.R - a.R)),
+                (int)Math.Round(a.G + t * (b.G - a.G)),
+                (int)Math.Round(a.B + t * (b.B - a.B)));
+        }
+
+        /// <summary>
+        /// Resolves each stop's position to a [0,1] fraction of the gradient line (per CSS Images §3.5.5:
+        /// the first/last stop default to 0%/100%, middle stops without an explicit position are spaced
+        /// evenly between their neighbors, and bare-position "hints" between two color stops bias the
+        /// interpolation curve rather than being a stop themselves).
+        /// </summary>
+        private static (RColor Color, double Position)[] NormalizeGradientStops(
+            (RColor? Color, Length? Position, bool IsHint)[] stops,
+            double gradientLength,
+            double emPx = 16.0)
+        {
+            var colorStops = stops.Where(s => !s.IsHint).ToArray();
+            int n = colorStops.Length;
+            if (n == 0) return new (RColor, double)[0];
+
+            var rawPos = new double?[n];
+            for (int i = 0; i < n; i++)
+                rawPos[i] = ConvertLength(colorStops[i].Position, gradientLength, emPx);
+
+            var resolved = new (RColor Color, double Position)[n];
+            double first = rawPos[0] ?? 0.0;
+            double last = rawPos[n - 1] ?? 1.0;
+            resolved[0] = (colorStops[0].Color.Value, first);
+            resolved[n - 1] = (colorStops[n - 1].Color.Value, last);
+
+            int runStart = -1;
+            for (int i = 1; i < n - 1; i++)
+            {
+                if (rawPos[i].HasValue)
+                {
+                    resolved[i] = (colorStops[i].Color.Value, rawPos[i].Value);
+                    if (runStart >= 0)
+                    {
+                        double posA = resolved[runStart - 1].Position;
+                        double posB = resolved[i].Position;
+                        int count = i - runStart + 1;
+                        for (int j = runStart; j < i; j++)
+                        {
+                            double t = (double)(j - runStart + 1) / count;
+                            resolved[j] = (colorStops[j].Color.Value, posA + t * (posB - posA));
+                        }
+                        runStart = -1;
+                    }
+                }
+                else
+                {
+                    if (runStart < 0) runStart = i;
+                    resolved[i] = (colorStops[i].Color.Value, 0);
+                }
+            }
+            if (runStart >= 0)
+            {
+                double posA = resolved[runStart - 1].Position;
+                double posB = resolved[n - 1].Position;
+                int count = n - 1 - runStart + 1;
+                for (int j = runStart; j < n - 1; j++)
+                {
+                    double t = (double)(j - runStart + 1) / count;
+                    resolved[j] = (colorStops[j].Color.Value, posA + t * (posB - posA));
+                }
+            }
+
+            if (!stops.Any(s => s.IsHint))
+                return resolved;
+
+            var result = new List<(RColor Color, double Position)>();
+            int colorIdx = 0;
+            for (int i = 0; i < stops.Length; i++)
+            {
+                if (!stops[i].IsHint)
+                {
+                    result.Add(resolved[colorIdx++]);
+                }
+                else
+                {
+                    if (colorIdx == 0 || colorIdx >= n) continue;
+                    var s1 = resolved[colorIdx - 1];
+                    var s2 = resolved[colorIdx];
+                    double range = s2.Position - s1.Position;
+                    double hintPos = ConvertLength(stops[i].Position, gradientLength, emPx) ?? (s1.Position + range * 0.5);
+                    double h = range > 1e-9
+                        ? Math.Min(Math.Max((hintPos - s1.Position) / range, 1e-9), 1.0 - 1e-9)
+                        : 0.5;
+                    const int kSteps = 7;
+                    double logHalf = Math.Log(0.5);
+                    double logH = Math.Log(h);
+                    for (int k = 1; k <= kSteps; k++)
+                    {
+                        double t = (double)k / (kSteps + 1);
+                        double curved = Math.Pow(t, logHalf / logH);
+                        result.Add((LerpColor(s1.Color, s2.Color, curved), s1.Position + t * range));
+                    }
+                }
+            }
+            return result.ToArray();
+        }
+
+        /// <summary>
+        /// Flattens a repeating gradient's stop tile into a single non-repeating stop list spanning the
+        /// full [0,1] gradient line, by replicating the tile as many times as needed in both directions.
+        /// </summary>
+        private static (RColor Color, double Position)[] ExpandRepeatingStops((RColor Color, double Position)[] stops)
+        {
+            if (stops.Length < 2) return stops;
+            double tileStart = stops[0].Position;
+            double tileEnd = stops[stops.Length - 1].Position;
+            double tileLen = tileEnd - tileStart;
+            if (tileLen < 1e-6 || (tileStart <= 0.0 && tileEnd >= 1.0)) return stops;
+            const double eps = 0.0001;
+            var result = new List<(RColor Color, double Position)>();
+            int kMin = (int)Math.Floor(-tileEnd / tileLen);
+            int kMax = (int)Math.Ceiling((1.0 - tileStart) / tileLen);
+            for (int k = kMin; k <= kMax; k++)
+            {
+                double kOffset = k * tileLen;
+                for (int i = 0; i < stops.Length; i++)
+                {
+                    double rawPos = stops[i].Position + kOffset;
+                    bool isLastStop = i == stops.Length - 1;
+                    double adjPos = isLastStop && k < kMax ? rawPos - eps : rawPos;
+                    if (adjPos >= -eps && adjPos <= 1.0 + eps)
+                        result.Add((stops[i].Color, Math.Min(Math.Max(adjPos, 0.0), 1.0)));
+                }
+            }
+            result.Sort((a, b) => a.Position.CompareTo(b.Position));
+            if (result.Count == 0) return stops;
+            if (result[0].Position > eps)
+                result.Insert(0, (SampleRepeatingColor(stops, tileStart, tileLen, 0.0), 0.0));
+            if (result[result.Count - 1].Position < 1.0 - eps)
+                result.Add((SampleRepeatingColor(stops, tileStart, tileLen, 1.0), 1.0));
+            return result.ToArray();
+        }
+
+        private static RColor SampleRepeatingColor((RColor Color, double Position)[] stops, double tileStart, double tileLen, double pos)
+        {
+            double relPos = (pos - tileStart) % tileLen;
+            if (relPos < 0) relPos += tileLen;
+            double absWithinTile = tileStart + relPos;
+            for (int i = 0; i < stops.Length - 1; i++)
+            {
+                if (absWithinTile >= stops[i].Position && absWithinTile <= stops[i + 1].Position)
+                {
+                    double range = stops[i + 1].Position - stops[i].Position;
+                    double t = range > 1e-12 ? (absWithinTile - stops[i].Position) / range : 0.0;
+                    return LerpColor(stops[i].Color, stops[i + 1].Color, t);
+                }
+            }
+            return absWithinTile <= stops[0].Position ? stops[0].Color : stops[stops.Length - 1].Color;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Handlers/FontsHandler.cs b/Source/HtmlRenderer/Core/Handlers/FontsHandler.cs
index 83c037eac..7f0bebc0c 100644
--- a/Source/HtmlRenderer/Core/Handlers/FontsHandler.cs
+++ b/Source/HtmlRenderer/Core/Handlers/FontsHandler.cs
@@ -6,18 +6,61 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Handlers
 {
+    /// <summary>
+    /// One registered <c>@font-face</c> face of a <see cref="FontFamilyModel"/>: its CSS Fonts Level 4
+    /// matching axes (numeric weight, italic, stretch), the codepoint <see cref="CodepointRange"/>s it is
+    /// restricted to (an explicit <c>unicode-range</c> descriptor) or null when it has none (covers
+    /// whatever a box asks for), and the <see cref="RFontFamily"/> wrapper backends use to actually create
+    /// an <see cref="RFont"/> from it.
+    /// </summary>
+    internal sealed class FontFaceEntry
+    {
+        public FontFaceEntry(int weight, bool italic, int stretch, IReadOnlyList<CodepointRange> explicitRanges, RFontFamily fontFamily)
+        {
+            Weight = weight;
+            Italic = italic;
+            Stretch = stretch;
+            ExplicitRanges = explicitRanges;
+            FontFamily = fontFamily;
+        }
+
+        public int Weight { get; }
+        public bool Italic { get; }
+        public int Stretch { get; }
+        public IReadOnlyList<CodepointRange> ExplicitRanges { get; }
+        public RFontFamily FontFamily { get; }
+    }
+
+    /// <summary>
+    /// One registered family: either a legacy simple <see cref="RFontFamily"/> (the pre-existing
+    /// <see cref="FontsHandler.AddFontFamily"/> path - e.g. a WinForms demo's <c>LoadCustomFonts</c>,
+    /// unchanged behavior), or a list of <c>@font-face</c>-registered faces (new path), or both at once.
+    /// Named to match PeachPDF's <c>Fonts\FontFamilyModel.cs</c>, since it's the same "one family, its
+    /// registered faces" concept - extended here with the <see cref="SimpleFamily"/> escape hatch
+    /// PeachPDF's PDF-only resolver has no equivalent of, since this registry is shared across backends
+    /// that still need the legacy single-family API to keep working unchanged.
+    /// </summary>
+    internal sealed class FontFamilyModel
+    {
+        public string Name { get; set; }
+        public RFontFamily SimpleFamily { get; set; }
+        public List<FontFaceEntry> Faces { get; } = new List<FontFaceEntry>();
+    }
+
     /// <summary>
     /// Utilities for fonts and fonts families handling.
     /// </summary>
@@ -26,7 +69,7 @@ internal sealed class FontsHandler
         #region Fields and Consts
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         private readonly RAdapter _adapter;
 
@@ -38,13 +81,22 @@ internal sealed class FontsHandler
         /// <summary>
         /// collection of all installed and added font families to check if font exists
         /// </summary>
-        private readonly Dictionary<string, RFontFamily> _existingFontFamilies = new Dictionary<string, RFontFamily>(StringComparer.InvariantCultureIgnoreCase);
+        private readonly Dictionary<string, FontFamilyModel> _existingFontFamilies = new Dictionary<string, FontFamilyModel>(StringComparer.InvariantCultureIgnoreCase);
 
         /// <summary>
-        /// cache of all the font used not to create same font again and again
+        /// cache of all the font used not to create same font again and again (legacy family-string path)
         /// </summary>
         private readonly Dictionary<string, Dictionary<double, Dictionary<RFontStyle, RFont>>> _fontsCache = new Dictionary<string, Dictionary<double, Dictionary<RFontStyle, RFont>>>(StringComparer.InvariantCultureIgnoreCase);
 
+        /// <summary>
+        /// cache of fonts resolved through the <c>@font-face</c> matching path, keyed by everything that
+        /// can change which face gets chosen (family, size, weight, italic, stretch, and the codepoint used
+        /// for <c>unicode-range</c> disambiguation, -1 when none) - a wider key than <see cref="_fontsCache"/>
+        /// needs, since two requests with the same <see cref="RFontStyle"/> can still resolve to different
+        /// faces (e.g. weight 300 vs 600, both non-bold).
+        /// </summary>
+        private readonly Dictionary<string, Dictionary<(double Size, int Weight, bool Italic, int Stretch, int Codepoint), RFont>> _faceFontsCache = new Dictionary<string, Dictionary<(double, int, bool, int, int), RFont>>(StringComparer.InvariantCultureIgnoreCase);
+
         #endregion
 
 
@@ -77,6 +129,25 @@ public bool IsFontExists(string family)
             return exists;
         }
 
+        /// <summary>
+        /// Finds an already-registered family's representative <see cref="RFontFamily"/> by name - a
+        /// system font, an <see cref="AddFontFamily"/> registration, or an earlier <see cref="AddFontFace"/>
+        /// registration (its first face, arbitrarily - this is used to satisfy an <c>@font-face</c>
+        /// <c>src: local(...)</c> candidate, which only needs *a* face to exist under that name, not a
+        /// specific one). Returns null if no family is registered under that exact name (mapping via
+        /// <see cref="AddFontFamilyMapping"/> is deliberately not consulted here - <c>local()</c> refers to
+        /// an actual installed/registered font by its own name, not this renderer's not-found fallback).
+        /// </summary>
+        public RFontFamily TryGetExistingFamily(string family)
+        {
+            FontFamilyModel model;
+            if (!_existingFontFamilies.TryGetValue(family, out model))
+            {
+                return null;
+            }
+            return model.SimpleFamily ?? (model.Faces.Count > 0 ? model.Faces[0].FontFamily : null);
+        }
+
         /// <summary>
         /// Adds a font family to be used.
         /// </summary>
@@ -85,12 +156,18 @@ public void AddFontFamily(RFontFamily fontFamily)
         {
             ArgChecker.AssertArgNotNull(fontFamily, "family");
 
-            _existingFontFamilies[fontFamily.Name] = fontFamily;
+            FontFamilyModel model;
+            if (!_existingFontFamilies.TryGetValue(fontFamily.Name, out model))
+            {
+                model = new FontFamilyModel { Name = fontFamily.Name };
+                _existingFontFamilies[fontFamily.Name] = model;
+            }
+            model.SimpleFamily = fontFamily;
         }
 
         /// <summary>
         /// Adds a font mapping from <paramref name="fromFamily"/> to <paramref name="toFamily"/> iff the <paramref name="fromFamily"/> is not found.<br/>
-        /// When the <paramref name="fromFamily"/> font is used in rendered html and is not found in existing 
+        /// When the <paramref name="fromFamily"/> font is used in rendered html and is not found in existing
         /// fonts (installed or added) it will be replaced by <paramref name="toFamily"/>.<br/>
         /// </summary>
         /// <param name="fromFamily">the font family to replace</param>
@@ -103,6 +180,47 @@ public void AddFontFamilyMapping(string fromFamily, string toFamily)
             _fontsMapping[fromFamily] = toFamily;
         }
 
+        /// <summary>
+        /// Registers one <c>@font-face</c> face under <paramref name="familyName"/>. Re-registering the
+        /// exact same axes+ranges combo (the orchestrator re-runs on every <c>SetHtml</c>) replaces the
+        /// prior entry rather than duplicating it, so repeated loads of the same document don't grow the
+        /// family's face list unbounded.
+        /// </summary>
+        /// <param name="familyName">the CSS family name declared by the <c>@font-face</c> rule</param>
+        /// <param name="fontFamily">the loaded face, already registered with the platform text engine</param>
+        /// <param name="weight">CSS Fonts Level 4 numeric weight (1-1000) this face matches for</param>
+        /// <param name="isItalic">whether this face matches an italic/oblique request</param>
+        /// <param name="stretch">CSS Fonts Level 3 stretch (1-9, matching OS/2 <c>usWidthClass</c>) this face matches for</param>
+        /// <param name="ranges">the face's <c>unicode-range</c> restriction, or null for "covers whatever is asked of it"</param>
+        public void AddFontFace(string familyName, RFontFamily fontFamily, int weight, bool isItalic, int stretch, IReadOnlyList<CodepointRange> ranges)
+        {
+            ArgChecker.AssertArgNotNullOrEmpty(familyName, "familyName");
+            ArgChecker.AssertArgNotNull(fontFamily, "fontFamily");
+
+            FontFamilyModel model;
+            if (!_existingFontFamilies.TryGetValue(familyName, out model))
+            {
+                model = new FontFamilyModel { Name = familyName };
+                _existingFontFamilies[familyName] = model;
+            }
+
+            for (var i = model.Faces.Count - 1; i >= 0; i--)
+            {
+                if (IsSameFaceSlot(model.Faces[i], weight, isItalic, stretch, ranges))
+                {
+                    model.Faces.RemoveAt(i);
+                }
+            }
+
+            model.Faces.Add(new FontFaceEntry(weight, isItalic, stretch, ranges, fontFamily));
+
+            // Faces changed under this family name - any font already resolved/cached against the old face
+            // set (legacy or @font-face path alike) could now be stale (a re-registration can change which
+            // face is nearest for a given request).
+            _fontsCache.Remove(familyName);
+            _faceFontsCache.Remove(familyName);
+        }
+
         /// <summary>
         /// Get cached font instance for the given font properties.<br/>
         /// Improve performance not to create same font multiple times.
@@ -137,9 +255,231 @@ public RFont GetCachedFont(string family, double size, RFontStyle style)
             return font;
         }
 
+        /// <summary>
+        /// Get cached font instance for the given font properties, matching against any <c>@font-face</c>
+        /// faces registered for <paramref name="family"/> via <see cref="AddFontFace"/> using the CSS
+        /// Fonts Level 4 §5 nearest-match algorithm (<see cref="TryFindNearestFace"/>). Falls through to
+        /// the legacy <see cref="GetCachedFont(string,double,RFontStyle)"/> path when the family has no
+        /// registered faces (the common case - no <c>@font-face</c> for this family), so existing
+        /// system-font/<see cref="AddFontFamily"/> behavior is unaffected.
+        /// </summary>
+        /// <param name="family">the css font-family name</param>
+        /// <param name="size">the font size</param>
+        /// <param name="style">the box's cascaded style (its Italic/Underline/Strikeout bits are honored regardless of which face is chosen; its Bold bit is superseded by <paramref name="weight"/>)</param>
+        /// <param name="weight">CSS Fonts Level 4 numeric weight (1-1000) resolved from <c>font-weight</c></param>
+        /// <param name="stretch">CSS Fonts Level 3 stretch (1-9) resolved from <c>font-stretch</c></param>
+        /// <param name="codepoint">the box's first non-whitespace character's codepoint, for <c>unicode-range</c> face disambiguation, or null to skip it</param>
+        /// <returns>
+        /// the resolved font, or null when <paramref name="codepoint"/> is given and no registered face
+        /// covers it (a real "this family can't render this character" outcome - see the unicode-range
+        /// scope note on <see cref="TryFindNearestFace"/> - the caller falls back to the box's next
+        /// candidate/default font, matching today's existing "nothing matched" behavior)
+        /// </returns>
+        public RFont GetCachedFont(string family, double size, RFontStyle style, int weight, int stretch, int? codepoint)
+        {
+            FontFamilyModel model;
+            if (_existingFontFamilies.TryGetValue(family, out model) && model.Faces.Count > 0)
+            {
+                var requestedItalic = (style & RFontStyle.Italic) != 0;
+
+                FontFaceEntry face;
+                if (TryFindNearestFace(model, weight, requestedItalic, stretch, codepoint, out face))
+                {
+                    return GetCachedFaceFont(family, face, size, style, weight, requestedItalic, stretch, codepoint ?? -1);
+                }
+
+                if (codepoint != null)
+                {
+                    // A codepoint-scoped miss must not substitute an arbitrary non-covering face - report
+                    // it so the caller (CssBoxProperties.ActualFont) falls back to the box's next candidate
+                    // family / CssConstants.DefaultFont, matching today's existing "nothing matched" behavior.
+                    return null;
+                }
+
+                // Codepoint-less miss shouldn't happen (AddFontFace always leaves >=1 face registered), but
+                // degrade to the legacy path rather than throw if it ever does.
+            }
+
+            return GetCachedFont(family, size, style);
+        }
+
 
         #region Private methods
 
+        /// <summary>
+        /// Resolves the chosen <paramref name="face"/>'s actual <see cref="RFont"/>, computing the
+        /// residual <see cref="RFontStyle"/> - only the gap between what was requested and what was
+        /// actually found (e.g. faux-bold when no true bold face exists), plus the box's own
+        /// underline/strikeout bits, which apply regardless of which face was chosen - and caching by
+        /// every axis that could change the result.
+        /// </summary>
+        private RFont GetCachedFaceFont(string family, FontFaceEntry face, double size, RFontStyle requestedStyle, int requestedWeight, bool requestedItalic, int requestedStretch, int codepointKey)
+        {
+            Dictionary<(double, int, bool, int, int), RFont> familyCache;
+            if (!_faceFontsCache.TryGetValue(family, out familyCache))
+            {
+                familyCache = new Dictionary<(double, int, bool, int, int), RFont>();
+                _faceFontsCache[family] = familyCache;
+            }
+
+            var key = (size, requestedWeight, requestedItalic, requestedStretch, codepointKey);
+
+            RFont font;
+            if (familyCache.TryGetValue(key, out font))
+            {
+                return font;
+            }
+
+            // Every backend's face.FontFamily is a FAMILY handle, not distinct per-face content - WinForms'
+            // PrivateFontCollection and WPF's AddFontMemResourceEx-registered FontFamily both group every
+            // face of one family (Regular/Bold/Italic/BoldItalic) under one platform family object, and
+            // rely on the RFontStyle passed to CreateFont to pick the actual glyphs at that point (exactly
+            // like a plain installed font). So the requested style must always carry the CHOSEN face's own
+            // weight/italic bits (faceIsBold/face.Italic below), not just a synthesis gap - dropping them
+            // on an exact match would ask the platform for the wrong (regular) face despite having found
+            // and registered the real bold/italic one.
+            //
+            // Synthesis on top of that: the chosen face may still be a compromise (nearest-weight/slant
+            // match, not exact) - decide whether the gap is large enough that faux-bold/italic should also
+            // kick in, so e.g. "font-weight: bold" against a Regular-only family doesn't render with zero
+            // visual distinction. Threshold mirrors the common UA convention that weights >=600 read as
+            // "bold" and <600 don't.
+            var faceIsBold = face.Weight >= 600;
+            var mustSimulateBold = requestedWeight >= 600 && !faceIsBold;
+            var mustSimulateItalic = requestedItalic && !face.Italic;
+
+            var residualStyle = requestedStyle & (RFontStyle.Underline | RFontStyle.Strikeout);
+            if (faceIsBold || mustSimulateBold) residualStyle |= RFontStyle.Bold;
+            if (face.Italic || mustSimulateItalic) residualStyle |= RFontStyle.Italic;
+
+            font = _adapter.CreateFont(face.FontFamily, size, residualStyle);
+            familyCache[key] = font;
+            return font;
+        }
+
+        /// <summary>
+        /// CSS Fonts Level 4 §5 face matching, direct port of PeachPDF's <c>FontResolver.TryFindNearestFace</c>.
+        /// When <paramref name="codepoint"/> is supplied, only faces whose explicit <c>unicode-range</c>
+        /// covers it are candidates (a face with no declared range is treated as covering everything - see
+        /// the class-level unicode-range scope note; unlike PeachPDF, there is no cmap-coverage fallback
+        /// for an unlabeled face, since per-box single-font resolution has no per-glyph text-shaping layer
+        /// to exploit that precision). Otherwise every face is a candidate. Within the candidates it
+        /// narrows italic/slant first, then stretch, then weight; an exact axis match short-circuits.
+        /// Returns false when no candidate face qualifies.
+        /// </summary>
+        private static bool TryFindNearestFace(FontFamilyModel family, int weight, bool isItalic, int stretch, int? codepoint, out FontFaceEntry face)
+        {
+            face = null;
+
+            List<FontFaceEntry> covering = codepoint is int cp
+                ? family.Faces.Where(f => FaceCovers(f, cp)).ToList()
+                : family.Faces;
+
+            if (covering.Count == 0)
+                return false;
+
+            var exact = covering.Where(f => f.Weight == weight && f.Italic == isItalic && f.Stretch == stretch).ToList();
+            if (exact.Count > 0)
+            {
+                face = exact[exact.Count - 1];
+                return true;
+            }
+
+            var sameSlant = covering.Where(f => f.Italic == isItalic).ToList();
+            var candidates = sameSlant.Count > 0 ? sameSlant : covering;
+
+            var availableStretches = candidates.Select(f => f.Stretch).Distinct().ToList();
+            var chosenStretch = PickNearestStretch(availableStretches, stretch);
+            var stretchCandidates = candidates.Where(f => f.Stretch == chosenStretch).ToList();
+
+            var availableWeights = stretchCandidates.Select(f => f.Weight).Distinct().ToList();
+            var chosenWeight = PickNearestWeight(availableWeights, weight);
+
+            face = stretchCandidates.Last(f => f.Weight == chosenWeight);
+            return true;
+        }
+
+        /// <summary>
+        /// Whether <paramref name="entry"/> is used for <paramref name="codepoint"/>: inside its declared
+        /// <c>unicode-range</c> if it has one, else it covers everything (see the unicode-range scope note
+        /// on <see cref="TryFindNearestFace"/>).
+        /// </summary>
+        private static bool FaceCovers(FontFaceEntry entry, int codepoint)
+        {
+            return entry.ExplicitRanges == null || UnicodeRangeParser.Covers(entry.ExplicitRanges, codepoint);
+        }
+
+        /// <summary>
+        /// CSS Fonts Level 4 §5.2's nearest-stretch search order: a target at or narrower than normal (5)
+        /// searches narrower first (down to 1), then wider; a target wider than normal searches wider
+        /// first (up to 9), then narrower. <paramref name="availableStretches"/> must be non-empty.
+        /// </summary>
+        private static int PickNearestStretch(List<int> availableStretches, int target)
+        {
+            if (availableStretches.Contains(target))
+                return target;
+
+            IEnumerable<int> candidates = target <= FontStretchResolver.Normal
+                ? availableStretches.Where(s => s < target).OrderByDescending(s => s)
+                    .Concat(availableStretches.Where(s => s > target).OrderBy(s => s))
+                : availableStretches.Where(s => s > target).OrderBy(s => s)
+                    .Concat(availableStretches.Where(s => s < target).OrderByDescending(s => s));
+
+            return candidates.First();
+        }
+
+        /// <summary>
+        /// CSS Fonts Level 4 §5.2's nearest-weight search order (the standard browser algorithm): a target
+        /// in [400,500] searches upward to 500 first, then below the target, then above 500; a target
+        /// below 400 searches downward first, then upward; a target above 500 searches upward first, then
+        /// downward. <paramref name="availableWeights"/> must be non-empty and is assumed to NOT already
+        /// contain an exact match for <paramref name="target"/> (the caller checks that separately, since
+        /// an exact match also has to match the requested italic-ness, which this purely-numeric helper
+        /// doesn't know about).
+        /// </summary>
+        private static int PickNearestWeight(List<int> availableWeights, int target)
+        {
+            IEnumerable<int> candidates;
+            if (target >= 400 && target <= 500)
+            {
+                candidates = availableWeights.Where(w => w >= target && w <= 500).OrderBy(w => w)
+                    .Concat(availableWeights.Where(w => w < target).OrderByDescending(w => w))
+                    .Concat(availableWeights.Where(w => w > 500).OrderBy(w => w));
+            }
+            else if (target < 400)
+            {
+                candidates = availableWeights.Where(w => w < target).OrderByDescending(w => w)
+                    .Concat(availableWeights.Where(w => w > target).OrderBy(w => w));
+            }
+            else
+            {
+                candidates = availableWeights.Where(w => w > target).OrderBy(w => w)
+                    .Concat(availableWeights.Where(w => w < target).OrderByDescending(w => w));
+            }
+
+            return candidates.First();
+        }
+
+        private static bool IsSameFaceSlot(FontFaceEntry entry, int weight, bool isItalic, int stretch, IReadOnlyList<CodepointRange> ranges)
+        {
+            return entry.Weight == weight && entry.Italic == isItalic && entry.Stretch == stretch
+                   && RangesEqual(entry.ExplicitRanges, ranges);
+        }
+
+        private static bool RangesEqual(IReadOnlyList<CodepointRange> a, IReadOnlyList<CodepointRange> b)
+        {
+            if (a == null || b == null)
+                return a == null && b == null;
+            if (a.Count != b.Count)
+                return false;
+            for (var i = 0; i < a.Count; i++)
+            {
+                if (a[i].Start != b[i].Start || a[i].End != b[i].End)
+                    return false;
+            }
+            return true;
+        }
+
         /// <summary>
         /// Get cached font if it exists in cache or null if it is not.
         /// </summary>
@@ -175,22 +515,22 @@ private RFont TryGetFont(string family, double size, RFontStyle style)
         /// </summary>
         private RFont CreateFont(string family, double size, RFontStyle style)
         {
-            RFontFamily fontFamily;
+            FontFamilyModel model;
             try
             {
-                return _existingFontFamilies.TryGetValue(family, out fontFamily)
-                    ? _adapter.CreateFont(fontFamily, size, style)
+                return _existingFontFamilies.TryGetValue(family, out model) && model.SimpleFamily != null
+                    ? _adapter.CreateFont(model.SimpleFamily, size, style)
                     : _adapter.CreateFont(family, size, style);
             }
             catch
             {
                 // handle possibility of no requested style exists for the font, use regular then
-                return _existingFontFamilies.TryGetValue(family, out fontFamily)
-                    ? _adapter.CreateFont(fontFamily, size, RFontStyle.Regular)
+                return _existingFontFamilies.TryGetValue(family, out model) && model.SimpleFamily != null
+                    ? _adapter.CreateFont(model.SimpleFamily, size, RFontStyle.Regular)
                     : _adapter.CreateFont(family, size, RFontStyle.Regular);
             }
         }
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer/Core/Handlers/ImageDownloader.cs b/Source/HtmlRenderer/Core/Handlers/ImageDownloader.cs
deleted file mode 100644
index 2f8b0f5e6..000000000
--- a/Source/HtmlRenderer/Core/Handlers/ImageDownloader.cs
+++ /dev/null
@@ -1,264 +0,0 @@
-// "Therefore those skilled at the unorthodox
-// are infinite as heaven and earth,
-// inexhaustible as the great rivers.
-// When they come to an end,
-// they begin again,
-// like the days and months;
-// they die and are reborn,
-// like the four seasons."
-// 
-// - Sun Tsu,
-// "The Art of War"
-
-using System;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.IO;
-using System.Net;
-using System.Threading;
-using TheArtOfDev.HtmlRenderer.Core.Utils;
-
-namespace TheArtOfDev.HtmlRenderer.Core.Handlers
-{
-    /// <summary>
-    /// On download file async complete, success or fail.
-    /// </summary>
-    /// <param name="imageUri">The online image uri</param>
-    /// <param name="filePath">the path to the downloaded file</param>
-    /// <param name="error">the error if download failed</param>
-    /// <param name="canceled">is the file download request was canceled</param>
-    public delegate void DownloadFileAsyncCallback(Uri imageUri, string filePath, Exception error, bool canceled);
-
-    /// <summary>
-    /// Handler for downloading images from the web.<br/>
-    /// Single instance of the handler used for all images downloaded in a single html, this way if the html contains more
-    /// than one reference to the same image it will be downloaded only once.<br/>
-    /// Also handles corrupt, partial and canceled downloads by first downloading to temp file and only if successful moving to cached 
-    /// file location.
-    /// </summary>
-    internal sealed class ImageDownloader : IDisposable
-    {
-        /// <summary>
-        /// the web client used to download image from URL (to cancel on dispose)
-        /// </summary>
-        private readonly List<WebClient> _clients = new List<WebClient>();
-
-        /// <summary>
-        /// dictionary of image cache path to callbacks of download to handle multiple requests to download the same image 
-        /// </summary>
-        private readonly Dictionary<string, List<DownloadFileAsyncCallback>> _imageDownloadCallbacks = new Dictionary<string, List<DownloadFileAsyncCallback>>();
-
-        public ImageDownloader()
-        {
-            ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;
-        }
-
-        /// <summary>
-        /// Makes a request to download the image from the server and raises the <see cref="cachedFileCallback"/> when it's down.<br/>
-        /// </summary>
-        /// <param name="imageUri">The online image uri</param>
-        /// <param name="filePath">the path on disk to download the file to</param>
-        /// <param name="async">is to download the file sync or async (true-async)</param>
-        /// <param name="cachedFileCallback">This callback will be called with local file path. If something went wrong in the download it will return null.</param>
-        public void DownloadImage(Uri imageUri, string filePath, bool async, DownloadFileAsyncCallback cachedFileCallback)
-        {
-            ArgChecker.AssertArgNotNull(imageUri, "imageUri");
-            ArgChecker.AssertArgNotNull(cachedFileCallback, "cachedFileCallback");
-
-            // to handle if the file is already been downloaded
-            bool download = true;
-            lock (_imageDownloadCallbacks)
-            {
-                if (_imageDownloadCallbacks.ContainsKey(filePath))
-                {
-                    download = false;
-                    _imageDownloadCallbacks[filePath].Add(cachedFileCallback);
-                }
-                else
-                {
-                    _imageDownloadCallbacks[filePath] = new List<DownloadFileAsyncCallback> { cachedFileCallback };
-                }
-            }
-
-            if (download)
-            {
-                var tempPath = Path.GetTempFileName();
-                if (async)
-                    ThreadPool.QueueUserWorkItem(DownloadImageFromUrlAsync, new DownloadData(imageUri, tempPath, filePath));
-                else
-                    DownloadImageFromUrl(imageUri, tempPath, filePath);
-            }
-        }
-
-        /// <summary>
-        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
-        /// </summary>
-        public void Dispose()
-        {
-            ReleaseObjects();
-        }
-
-
-        #region Private/Protected methods
-
-        /// <summary>
-        /// Download the requested file in the URI to the given file path.<br/>
-        /// Use async sockets API to download from web, <see cref="OnDownloadImageAsyncCompleted"/>.
-        /// </summary>
-        private void DownloadImageFromUrl(Uri source, string tempPath, string filePath)
-        {
-            try
-            {
-                using (var client = new WebClient())
-                {
-                    _clients.Add(client);
-                    client.DownloadFile(source, tempPath);
-                    OnDownloadImageCompleted(client, source, tempPath, filePath, null, false);
-                }
-            }
-            catch (Exception ex)
-            {
-                OnDownloadImageCompleted(null, source, tempPath, filePath, ex, false);
-            }
-        }
-
-        /// <summary>
-        /// Download the requested file in the URI to the given file path.<br/>
-        /// Use async sockets API to download from web, <see cref="OnDownloadImageAsyncCompleted"/>.
-        /// </summary>
-        /// <param name="data">key value pair of URL and file info to download the file to</param>
-        private void DownloadImageFromUrlAsync(object data)
-        {
-            var downloadData = (DownloadData)data;
-            try
-            {
-                var client = new WebClient();
-                _clients.Add(client);
-                client.DownloadFileCompleted += OnDownloadImageAsyncCompleted;
-                client.DownloadFileAsync(downloadData._uri, downloadData._tempPath, downloadData);
-            }
-            catch (Exception ex)
-            {
-                OnDownloadImageCompleted(null, downloadData._uri, downloadData._tempPath, downloadData._filePath, ex, false);
-            }
-        }
-
-        /// <summary>
-        /// On download image complete to local file.<br/>
-        /// If the download canceled do nothing, if failed report error.
-        /// </summary>
-        private void OnDownloadImageAsyncCompleted(object sender, AsyncCompletedEventArgs e)
-        {
-            var downloadData = (DownloadData)e.UserState;
-            try
-            {
-                using (var client = (WebClient)sender)
-                {
-                    client.DownloadFileCompleted -= OnDownloadImageAsyncCompleted;
-                    OnDownloadImageCompleted(client, downloadData._uri, downloadData._tempPath, downloadData._filePath, e.Error, e.Cancelled);
-                }
-            }
-            catch (Exception ex)
-            {
-                OnDownloadImageCompleted(null, downloadData._uri, downloadData._tempPath, downloadData._filePath, ex, false);
-            }
-        }
-
-        /// <summary>
-        /// Checks if the file was downloaded and raises the cachedFileCallback from <see cref="_imageDownloadCallbacks"/>
-        /// </summary>
-        private void OnDownloadImageCompleted(WebClient client, Uri source, string tempPath, string filePath, Exception error, bool cancelled)
-        {
-            if (!cancelled)
-            {
-                if (error == null)
-                {
-                    var contentType = CommonUtils.GetResponseContentType(client);
-                    if (contentType == null || !contentType.StartsWith("image", StringComparison.OrdinalIgnoreCase))
-                    {
-                        error = new Exception("Failed to load image, not image content type: " + contentType);
-                    }
-
-                }
-
-                if (error == null)
-                {
-                    if (File.Exists(tempPath))
-                    {
-                        try
-                        {
-                            File.Move(tempPath, filePath);
-                        }
-                        catch (Exception ex)
-                        {
-                            error = new Exception("Failed to move downloaded image from temp to cache location", ex);
-                        }
-                    }
-
-                    error = File.Exists(filePath) ? null : (error ?? new Exception("Failed to download image, unknown error"));
-                }
-            }
-
-            List<DownloadFileAsyncCallback> callbacksList;
-            lock (_imageDownloadCallbacks)
-            {
-                if (_imageDownloadCallbacks.TryGetValue(filePath, out callbacksList))
-                    _imageDownloadCallbacks.Remove(filePath);
-            }
-
-            if (callbacksList != null)
-            {
-                foreach (var cachedFileCallback in callbacksList)
-                {
-                    try
-                    {
-                        cachedFileCallback(source, filePath, error, cancelled);
-                    }
-                    catch
-                    { }
-                }
-            }
-        }
-
-        /// <summary>
-        /// Release the image and client objects.
-        /// </summary>
-        private void ReleaseObjects()
-        {
-            _imageDownloadCallbacks.Clear();
-            while (_clients.Count > 0)
-            {
-                try
-                {
-                    var client = _clients[0];
-                    client.CancelAsync();
-                    client.Dispose();
-                    _clients.RemoveAt(0);
-                }
-                catch
-                { }
-            }
-        }
-
-        #endregion
-
-
-        #region Inner class: DownloadData
-
-        private sealed class DownloadData
-        {
-            public readonly Uri _uri;
-            public readonly string _tempPath;
-            public readonly string _filePath;
-
-            public DownloadData(Uri uri, string tempPath, string filePath)
-            {
-                _uri = uri;
-                _tempPath = tempPath;
-                _filePath = filePath;
-            }
-        }
-
-        #endregion
-    }
-}
diff --git a/Source/HtmlRenderer/Core/Handlers/ImageLoadHandler.cs b/Source/HtmlRenderer/Core/Handlers/ImageLoadHandler.cs
index eb9ace4fd..64d8b1e01 100644
--- a/Source/HtmlRenderer/Core/Handlers/ImageLoadHandler.cs
+++ b/Source/HtmlRenderer/Core/Handlers/ImageLoadHandler.cs
@@ -6,15 +6,14 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Text;
-using System.Threading;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
@@ -55,9 +54,9 @@ internal sealed class ImageLoadHandler : IDisposable
         private readonly ActionInt<RImage, RRect, bool> _loadCompleteCallback;
 
         /// <summary>
-        /// Must be open as long as the image is in use
+        /// the resource stream the image was decoded from; kept open as long as the image is in use
         /// </summary>
-        private FileStream _imageFileStream;
+        private Stream _imageStream;
 
         /// <summary>
         /// the image instance of the loaded image
@@ -69,11 +68,6 @@ internal sealed class ImageLoadHandler : IDisposable
         /// </summary>
         private RRect _imageRectangle;
 
-        /// <summary>
-        /// to know if image load event callback was sync or async raised
-        /// </summary>
-        private bool _asyncCallback;
-
         /// <summary>
         /// flag to indicate if to release the image object on box dispose (only if image was loaded by the box)
         /// </summary>
@@ -125,31 +119,35 @@ public RRect Rectangle
         /// Or from URI.
         /// </summary>
         /// <remarks>
-        /// File path and URI image loading is executed async and after finishing calling <see cref="ImageLoadComplete"/>
-        /// on the main thread and not thread-pool.
+        /// File path and URI image loading is resolved against the document base and fetched through
+        /// <see cref="RAdapter.GetResourceStream"/> - uniformly for local files, <c>data:</c> URIs, and
+        /// remote HTTP(S) sources, matching how stylesheets and (eventually) <c>@font-face</c> fonts load.
+        /// When <see cref="HtmlContainerInt.AvoidAsyncImagesLoading"/> is set the fetch is awaited inline
+        /// (blocking this call) so the image is fully resolved before <see cref="LoadImage"/> returns;
+        /// otherwise it runs fire-and-forget and <see cref="ImageLoadComplete"/> requests a re-layout once
+        /// it finishes, matching this handler's pre-existing sync/async duality.
         /// </remarks>
         /// <param name="src">the source of the image to load</param>
         /// <param name="attributes">the collection of attributes on the element to use in event</param>
-        /// <returns>the image object (null if failed)</returns>
         public void LoadImage(string src, Dictionary<string, string> attributes)
         {
             try
             {
                 var args = new HtmlImageLoadEventArgs(src, attributes, OnHtmlImageLoadEventCallback);
                 _htmlContainer.RaiseHtmlImageLoadEvent(args);
-                _asyncCallback = !_htmlContainer.AvoidAsyncImagesLoading;
+                var async = !_htmlContainer.AvoidAsyncImagesLoading;
 
                 if (!args.Handled)
                 {
                     if (!string.IsNullOrEmpty(src))
                     {
-                        if (src.StartsWith("data:image", StringComparison.CurrentCultureIgnoreCase))
+                        if (async)
                         {
-                            SetFromInlineData(src);
+                            _ = LoadImageFromPathAsync(src, true);
                         }
                         else
                         {
-                            SetImageFromPath(src);
+                            LoadImageFromPathAsync(src, false).GetAwaiter().GetResult();
                         }
                     }
                     else
@@ -192,167 +190,56 @@ private void OnHtmlImageLoadEventCallback(string path, object image, RRect image
                 if (image != null)
                 {
                     _image = _htmlContainer.Adapter.ConvertImage(image);
-                    ImageLoadComplete(_asyncCallback);
+                    ImageLoadComplete(!_htmlContainer.AvoidAsyncImagesLoading);
                 }
                 else if (!string.IsNullOrEmpty(path))
                 {
-                    SetImageFromPath(path);
+                    var async = !_htmlContainer.AvoidAsyncImagesLoading;
+                    if (async)
+                        _ = LoadImageFromPathAsync(path, true);
+                    else
+                        LoadImageFromPathAsync(path, false).GetAwaiter().GetResult();
                 }
                 else
                 {
-                    ImageLoadComplete(_asyncCallback);
+                    ImageLoadComplete(!_htmlContainer.AvoidAsyncImagesLoading);
                 }
             }
         }
 
         /// <summary>
-        /// Load the image from inline base64 encoded string data.
-        /// </summary>
-        /// <param name="src">the source that has the base64 encoded image</param>
-        private void SetFromInlineData(string src)
-        {
-            _image = GetImageFromData(src);
-            if (_image == null)
-                _htmlContainer.ReportError(HtmlRenderErrorType.Image, "Failed extract image from inline data");
-            _releaseImageObject = true;
-            ImageLoadComplete(false);
-        }
-
-        /// <summary>
-        /// Extract image object from inline base64 encoded data in the src of the html img element.
+        /// Resolve <paramref name="path"/> (a bare file path/URI, or a <c>data:image...</c> URI) against
+        /// the document base and fetch it through <see cref="RAdapter.GetResourceStream"/> - the same
+        /// funnel used for stylesheets, so a <c>data:</c> source needs no separate decode path from a
+        /// remote or local one.
         /// </summary>
-        /// <param name="src">the source that has the base64 encoded image</param>
-        /// <returns>image from base64 data string or null if failed</returns>
-        private RImage GetImageFromData(string src)
+        private async Task LoadImageFromPathAsync(string path, bool async)
         {
-            var s = src.Substring(src.IndexOf(':') + 1).Split(new[] { ',' }, 2);
-            if (s.Length == 2)
-            {
-                int imagePartsCount = 0, base64PartsCount = 0;
-                foreach (var part in s[0].Split(new[] { ';' }))
-                {
-                    var pPart = part.Trim();
-                    if (pPart.StartsWith("image/", StringComparison.InvariantCultureIgnoreCase))
-                        imagePartsCount++;
-                    if (pPart.Equals("base64", StringComparison.InvariantCultureIgnoreCase))
-                        base64PartsCount++;
-                }
-
-                if (imagePartsCount > 0)
-                {
-                    byte[] imageData = base64PartsCount > 0 ? Convert.FromBase64String(s[1].Trim()) : new UTF8Encoding().GetBytes(Uri.UnescapeDataString(s[1].Trim()));
-                    return _htmlContainer.Adapter.ImageFromStream(new MemoryStream(imageData));
-                }
-            }
-            return null;
-        }
-
-        /// <summary>
-        /// Load image from path of image file or URL.
-        /// </summary>
-        /// <param name="path">the file path or uri to load image from</param>
-        private void SetImageFromPath(string path)
-        {
-            var uri = CommonUtils.TryGetUri(path);
-            if (uri != null && uri.Scheme != "file")
-            {
-                SetImageFromUrl(uri);
-            }
-            else
+            try
             {
-                var fileInfo = CommonUtils.TryGetFileInfo(uri != null ? uri.AbsolutePath : path);
-                if (fileInfo != null)
-                {
-                    SetImageFromFile(fileInfo);
-                }
-                else
+                var uri = CommonUtils.ResolveAgainstDocumentBase(_htmlContainer, path);
+                if (uri == null)
                 {
                     _htmlContainer.ReportError(HtmlRenderErrorType.Image, "Failed load image, invalid source: " + path);
-                    ImageLoadComplete(false);
+                    ImageLoadComplete(async);
+                    return;
                 }
-            }
-        }
 
-        /// <summary>
-        /// Load the image file on thread-pool thread and calling <see cref="ImageLoadComplete"/> after.
-        /// </summary>
-        /// <param name="source">the file path to get the image from</param>
-        private void SetImageFromFile(FileInfo source)
-        {
-            if (source.Exists)
-            {
-                if (_htmlContainer.AvoidAsyncImagesLoading)
-                    LoadImageFromFile(source.FullName);
-                else
-                    ThreadPool.QueueUserWorkItem(state => LoadImageFromFile(source.FullName));
-            }
-            else
-            {
-                ImageLoadComplete();
-            }
-        }
+                var networkResponse = await _htmlContainer.Adapter.GetResourceStream(uri).ConfigureAwait(false);
 
-        /// <summary>
-        /// Load the image file on thread-pool thread and calling <see cref="ImageLoadComplete"/> after.<br/>
-        /// Calling <see cref="ImageLoadComplete"/> on the main thread and not thread-pool.
-        /// </summary>
-        /// <param name="source">the file path to get the image from</param>
-        private void LoadImageFromFile(string source)
-        {
-            try
-            {
-                var imageFileStream = File.Open(source, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
-                lock (_loadCompleteCallback)
+                if (!_disposed && networkResponse != null && networkResponse.ResourceStream != null)
                 {
-                    _imageFileStream = imageFileStream;
-                    if (!_disposed)
-                        _image = _htmlContainer.Adapter.ImageFromStream(_imageFileStream);
+                    _imageStream = networkResponse.ResourceStream;
+                    _image = _htmlContainer.Adapter.ImageFromStream(_imageStream);
                     _releaseImageObject = true;
                 }
-                ImageLoadComplete();
-            }
-            catch (Exception ex)
-            {
-                _htmlContainer.ReportError(HtmlRenderErrorType.Image, "Failed to load image from disk: " + source, ex);
-                ImageLoadComplete();
-            }
-        }
 
-        /// <summary>
-        /// Load image from the given URI by downloading it.<br/>
-        /// Create local file name in temp folder from the URI, if the file already exists use it as it has already been downloaded.
-        /// If not download the file.
-        /// </summary>
-        private void SetImageFromUrl(Uri source)
-        {
-            var filePath = CommonUtils.GetLocalfileName(source);
-            if (filePath.Exists && filePath.Length > 0)
-            {
-                SetImageFromFile(filePath);
+                ImageLoadComplete(async);
             }
-            else
-            {
-                _htmlContainer.GetImageDownloader().DownloadImage(source, filePath.FullName, !_htmlContainer.AvoidAsyncImagesLoading, OnDownloadImageCompleted);
-            }
-        }
-
-        /// <summary>
-        /// On download image complete to local file use <see cref="LoadImageFromFile"/> to load the image file.<br/>
-        /// If the download canceled do nothing, if failed report error.
-        /// </summary>
-        private void OnDownloadImageCompleted(Uri imageUri, string filePath, Exception error, bool canceled)
-        {
-            if (!canceled && !_disposed)
+            catch (Exception ex)
             {
-                if (error == null)
-                {
-                    LoadImageFromFile(filePath);
-                }
-                else
-                {
-                    _htmlContainer.ReportError(HtmlRenderErrorType.Image, "Failed to load image from URL: " + imageUri, error);
-                    ImageLoadComplete();
-                }
+                _htmlContainer.ReportError(HtmlRenderErrorType.Image, "Failed to load image from source: " + path, ex);
+                ImageLoadComplete(async);
             }
         }
 
@@ -373,21 +260,18 @@ private void ImageLoadComplete(bool async = true)
         /// </summary>
         private void ReleaseObjects()
         {
-            lock (_loadCompleteCallback)
+            if (_releaseImageObject && _image != null)
             {
-                if (_releaseImageObject && _image != null)
-                {
-                    _image.Dispose();
-                    _image = null;
-                }
-                if (_imageFileStream != null)
-                {
-                    _imageFileStream.Dispose();
-                    _imageFileStream = null;
-                }
+                _image.Dispose();
+                _image = null;
+            }
+            if (_imageStream != null)
+            {
+                _imageStream.Dispose();
+                _imageStream = null;
             }
         }
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer/Core/Handlers/StylesheetLoadHandler.cs b/Source/HtmlRenderer/Core/Handlers/StylesheetLoadHandler.cs
index 719f3cebb..0b15c62d8 100644
--- a/Source/HtmlRenderer/Core/Handlers/StylesheetLoadHandler.cs
+++ b/Source/HtmlRenderer/Core/Handlers/StylesheetLoadHandler.cs
@@ -6,15 +6,17 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Net;
+using System.Linq;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
+using TheArtOfDev.HtmlRenderer.Core.Network;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Handlers
@@ -28,19 +30,22 @@ internal static class StylesheetLoadHandler
         /// Load stylesheet data from the given source.<br/>
         /// The source can be local file or web URI.<br/>
         /// First raise <see cref="HtmlStylesheetLoadEventArgs"/> event to allow the client to overwrite the stylesheet loading.<br/>
-        /// If the stylesheet is downloaded from URI we will try to correct local URIs to absolute.<br/>
+        /// If the event doesn't handle it, the reference is resolved against the document base and fetched
+        /// through <see cref="Adapters.RAdapter.GetResourceStream"/>, uniformly for local files, <c>data:</c>
+        /// URIs, and remote HTTP(S) sources.
         /// </summary>
         /// <param name="htmlContainer">the container of the html to handle load stylesheet for</param>
         /// <param name="src">the source of the element to load the stylesheet by</param>
         /// <param name="attributes">the attributes of the link element</param>
-        /// <param name="stylesheet">return the stylesheet string that has been loaded (null if failed or <paramref name="stylesheetData"/> is given)</param>
-        /// <param name="stylesheetData">return stylesheet data object that was provided by overwrite (null if failed or <paramref name="stylesheet"/> is given)</param>
-        public static void LoadStylesheet(HtmlContainerInt htmlContainer, string src, Dictionary<string, string> attributes, out string stylesheet, out CssData stylesheetData)
+        /// <returns>
+        /// the stylesheet string that has been loaded (empty if not found/failed, or if
+        /// <c>stylesheetData</c> is given instead), and the stylesheet data object provided by an event
+        /// overwrite (null unless the event set it).
+        /// </returns>
+        public static async Task<(string stylesheet, CssData stylesheetData)> LoadStylesheet(HtmlContainerInt htmlContainer, string src, Dictionary<string, string> attributes)
         {
             ArgChecker.AssertArgNotNull(htmlContainer, "htmlContainer");
 
-            stylesheet = null;
-            stylesheetData = null;
             try
             {
                 var args = new HtmlStylesheetLoadEventArgs(src, attributes);
@@ -48,24 +53,21 @@ public static void LoadStylesheet(HtmlContainerInt htmlContainer, string src, Di
 
                 if (!string.IsNullOrEmpty(args.SetStyleSheet))
                 {
-                    stylesheet = args.SetStyleSheet;
+                    return (args.SetStyleSheet, null);
                 }
-                else if (args.SetStyleSheetData != null)
-                {
-                    stylesheetData = args.SetStyleSheetData;
-                }
-                else if (args.SetSrc != null)
-                {
-                    stylesheet = LoadStylesheet(htmlContainer, args.SetSrc);
-                }
-                else
+
+                if (args.SetStyleSheetData != null)
                 {
-                    stylesheet = LoadStylesheet(htmlContainer, src);
+                    return (null, args.SetStyleSheetData);
                 }
+
+                var stylesheet = await LoadStylesheet(htmlContainer, args.SetSrc ?? src).ConfigureAwait(false);
+                return (stylesheet, null);
             }
             catch (Exception ex)
             {
                 htmlContainer.ReportError(HtmlRenderErrorType.CssParsing, "Exception in handling stylesheet source", ex);
+                return (null, null);
             }
         }
 
@@ -73,75 +75,59 @@ public static void LoadStylesheet(HtmlContainerInt htmlContainer, string src, Di
         #region Private methods
 
         /// <summary>
-        /// Load stylesheet string from given source (file path or uri).
+        /// Load stylesheet string from given source (file path or uri), resolved against the document base
+        /// and fetched through <see cref="Adapters.RAdapter.GetResourceStream"/>.
         /// </summary>
         /// <param name="htmlContainer">the container of the html to handle load stylesheet for</param>
         /// <param name="src">the file path or uri to load the stylesheet from</param>
-        /// <returns>the stylesheet string</returns>
-        private static string LoadStylesheet(HtmlContainerInt htmlContainer, string src)
+        /// <returns>the stylesheet string, or empty if it could not be resolved/loaded</returns>
+        private static async Task<string> LoadStylesheet(HtmlContainerInt htmlContainer, string src)
         {
-            var uri = CommonUtils.TryGetUri(src);
-            if (uri == null || uri.Scheme == "file")
+            var uri = CommonUtils.ResolveAgainstDocumentBase(htmlContainer, src);
+            if (uri == null)
             {
-                return LoadStylesheetFromFile(htmlContainer, uri != null ? uri.AbsolutePath : src);
+                htmlContainer.ReportError(HtmlRenderErrorType.CssParsing, "Failed load stylesheet, invalid source: " + src);
+                return string.Empty;
             }
-            else
+
+            var networkResponse = await htmlContainer.Adapter.GetResourceStream(uri).ConfigureAwait(false);
+
+            if (networkResponse == null || networkResponse.ResourceStream == null)
             {
-                return LoadStylesheetFromUri(htmlContainer, uri);
+                htmlContainer.ReportError(HtmlRenderErrorType.CssParsing, "No stylesheet found by path: " + src);
+                return string.Empty;
             }
-        }
 
-        /// <summary>
-        /// Load the stylesheet from local file by given path.
-        /// </summary>
-        /// <param name="htmlContainer">the container of the html to handle load stylesheet for</param>
-        /// <param name="path">the stylesheet file to load</param>
-        /// <returns>the loaded stylesheet string</returns>
-        private static string LoadStylesheetFromFile(HtmlContainerInt htmlContainer, string path)
-        {
-            var fileInfo = CommonUtils.TryGetFileInfo(path);
-            if (fileInfo != null)
+            // A response served with a Content-Type other than text/css (e.g. a 404 HTML error page
+            // returned with a 200 status by a misconfigured server) is treated as "not a stylesheet" -
+            // return empty and keep rendering, same fail-soft behavior as a missing resource. A response
+            // with no Content-Type header at all (a local file with an unrecognized extension, etc.) is
+            // still accepted, matching this handler's pre-existing behavior of trusting the source.
+            if (networkResponse.ResponseHeaders != null &&
+                networkResponse.ResponseHeaders.TryGetValue("Content-Type", out var contentTypeValues) &&
+                contentTypeValues.Length > 0 &&
+                !contentTypeValues.Any(ct => ct.IndexOf("text/css", StringComparison.OrdinalIgnoreCase) >= 0))
             {
-                if (fileInfo.Exists)
-                {
-                    using (var sr = new StreamReader(fileInfo.FullName))
-                    {
-                        return sr.ReadToEnd();
-                    }
-                }
-                else
-                {
-                    htmlContainer.ReportError(HtmlRenderErrorType.CssParsing, "No stylesheet found by path: " + path);
-                }
+                using (networkResponse.ResourceStream) { }
+                return string.Empty;
             }
-            else
+
+            string stylesheet;
+            using (var sr = new StreamReader(networkResponse.ResourceStream))
             {
-                htmlContainer.ReportError(HtmlRenderErrorType.CssParsing, "Failed load image, invalid source: " + path);
+                stylesheet = await sr.ReadToEndAsync().ConfigureAwait(false);
             }
-            return string.Empty;
-        }
 
-        /// <summary>
-        /// Load the stylesheet from uri by downloading the string.
-        /// </summary>
-        /// <param name="htmlContainer">the container of the html to handle load stylesheet for</param>
-        /// <param name="uri">the uri to download from</param>
-        /// <returns>the loaded stylesheet string</returns>
-        private static string LoadStylesheetFromUri(HtmlContainerInt htmlContainer, Uri uri)
-        {
-            using (var client = new WebClient())
+            try
             {
-                var stylesheet = client.DownloadString(uri);
-                try
-                {
-                    stylesheet = CorrectRelativeUrls(stylesheet, uri);
-                }
-                catch (Exception ex)
-                {
-                    htmlContainer.ReportError(HtmlRenderErrorType.CssParsing, "Error in correcting relative URL in loaded stylesheet", ex);
-                }
-                return stylesheet;
+                stylesheet = CorrectRelativeUrls(stylesheet, uri.Uri);
+            }
+            catch (Exception ex)
+            {
+                htmlContainer.ReportError(HtmlRenderErrorType.CssParsing, "Error in correcting relative URL in loaded stylesheet", ex);
             }
+
+            return stylesheet;
         }
 
         /// <summary>
@@ -189,4 +175,4 @@ private static string CorrectRelativeUrls(string stylesheet, Uri baseUri)
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer/Core/HtmlContainerInt.cs b/Source/HtmlRenderer/Core/HtmlContainerInt.cs
index 1d71de9fb..bb9a20cc8 100644
--- a/Source/HtmlRenderer/Core/HtmlContainerInt.cs
+++ b/Source/HtmlRenderer/Core/HtmlContainerInt.cs
@@ -13,6 +13,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Dom;
@@ -106,11 +107,6 @@ public sealed class HtmlContainerInt : IDisposable
         /// </summary>
         private SelectionHandler _selectionHandler;
 
-        /// <summary>
-        /// Handler for downloading of images in the html
-        /// </summary>
-        private ImageDownloader _imageDownloader;
-
         /// <summary>
         /// the text fore color use for selected text
         /// </summary>
@@ -126,6 +122,19 @@ public sealed class HtmlContainerInt : IDisposable
         /// </summary>
         private CssData _cssData;
 
+        /// <summary>
+        /// The html and base stylesheet last given to <see cref="SetHtml"/>, kept so the cascade can be
+        /// re-run when a viewport change alters which <c>@media</c> rules apply.
+        /// </summary>
+        private string _htmlSource;
+
+        private CssData _baseCssData;
+
+        /// <summary>
+        /// The device the current cascade was computed against.
+        /// </summary>
+        private MediaQueryContext _cascadeMedia;
+
         /// <summary>
         /// Is content selection is enabled for the rendered html (default - true).<br/>
         /// If set to 'false' the rendered html will be static only with ability to click on links.
@@ -179,6 +188,11 @@ public sealed class HtmlContainerInt : IDisposable
         /// </summary>
         private RSize _actualSize;
 
+        /// <summary>
+        /// True if any box in the current document tree has float:left or float:right set.
+        /// </summary>
+        private bool _hasFloatedBoxes;
+
         /// <summary>
         /// the top margin between the page start and the text
         /// </summary>
@@ -211,6 +225,30 @@ public HtmlContainerInt(RAdapter adapter)
 
             _adapter = adapter;
             _cssParser = new CssParser(adapter);
+
+            // A system theme change alters what prefers-color-scheme reports, which can change which
+            // rules apply. Nothing else would notice: the cascade is only re-evaluated during layout,
+            // and an idle window does not lay out.
+            _colorSchemeChangedHandler = (sender, e) => OnAdapterColorSchemeChanged();
+            _adapter.ColorSchemeChanged += _colorSchemeChangedHandler;
+        }
+
+        /// <summary>
+        /// Kept so the handler can be detached from the adapter - which is typically a process-wide
+        /// singleton, and would otherwise keep every container that ever rendered alive.
+        /// </summary>
+        private readonly EventHandler _colorSchemeChangedHandler;
+
+        /// <summary>
+        /// The colour scheme changed, so ask the host to lay out and repaint. The re-cascade itself
+        /// happens in <see cref="PerformLayout"/>, on the host's own thread - this event can arrive on
+        /// another one.
+        /// </summary>
+        private void OnAdapterColorSchemeChanged()
+        {
+            if (_root == null) return;
+
+            RequestRefresh(true);
         }
 
         /// <summary>
@@ -393,6 +431,16 @@ public RSize ActualSize
             set { _actualSize = value; }
         }
 
+        /// <summary>
+        /// True if any box in the current document tree has float:left or float:right set.<br/>
+        /// Computed once per <see cref="PerformLayout"/> pass by a whole-tree walk; used to short-circuit
+        /// float-intersection queries (each an O(document) tree walk) on the common case of a float-free document.
+        /// </summary>
+        public bool HasFloatedBoxes
+        {
+            get { return _hasFloatedBoxes; }
+        }
+
         public RSize PageSize { get; set; }
 
         /// <summary>
@@ -504,24 +552,49 @@ internal RColor SelectionBackColor
         /// </summary>
         /// <param name="htmlSource">the html to init with, init empty if not given</param>
         /// <param name="baseCssData">optional: the stylesheet to init with, init default if not given</param>
-        public void SetHtml(string htmlSource, CssData baseCssData = null)
+        public async Task SetHtml(string htmlSource, CssData baseCssData = null)
         {
             Clear();
+            _htmlSource = htmlSource;
+            _baseCssData = baseCssData;
+
             if (!string.IsNullOrEmpty(htmlSource))
             {
                 _loadComplete = false;
                 _cssData = baseCssData ?? _adapter.DefaultCssData;
 
                 DomParser parser = new DomParser(_cssParser);
-                _root = parser.GenerateCssTree(htmlSource, this, ref _cssData);
+                (_root, _cssData) = await parser.GenerateCssTree(htmlSource, this, _cssData).ConfigureAwait(false);
+                _cascadeMedia = MediaQueryContext.FromAdapter(_adapter, _maxSize.Width, _maxSize.Height);
                 if (_root != null)
                 {
                     _selectionHandler = new SelectionHandler(_root);
-                    _imageDownloader = new ImageDownloader();
                 }
             }
         }
 
+        /// <summary>
+        /// Re-runs the cascade if the viewport has changed in a way that changes which <c>@media</c>
+        /// rules apply - a resize crossing a <c>min-width</c> breakpoint, say. Nothing happens for a
+        /// document whose stylesheets have no viewport-dependent <c>@media</c> (the common case), or for
+        /// a resize that stays within the same breakpoint, so this costs one cheap condition test per
+        /// layout rather than a re-parse.
+        /// </summary>
+        private void RefreshMediaDependentCascade()
+        {
+            if (_root == null || string.IsNullOrEmpty(_htmlSource) || _cssData == null) return;
+
+            var media = MediaQueryContext.FromAdapter(_adapter, _maxSize.Width, _maxSize.Height);
+            if (!_cssData.MediaOutcomeChanged(_cascadeMedia, media)) return;
+
+            // Bridges into the async SetHtml from this synchronous layout-time caller - PerformLayout
+            // itself stays synchronous (confirmed: nothing in the layout/paint call graph touches
+            // RAdapter.GetResourceStream synchronously - image loads are fire-and-forget-then-relayout,
+            // not awaited inline - so there's no reason for PerformLayout to become async), so this is a
+            // deliberate, permanent blocking call, not a temporary stopgap.
+            SetHtml(_htmlSource, _baseCssData).GetAwaiter().GetResult();
+        }
+
         /// <summary>
         /// Clear the content of the HTML container releasing any resources used to render previously existing content.
         /// </summary>
@@ -536,10 +609,6 @@ public void Clear()
                     _selectionHandler.Dispose();
                 _selectionHandler = null;
 
-                if (_imageDownloader != null)
-                    _imageDownloader.Dispose();
-                _imageDownloader = null;
-
                 _hoverBoxes = null;
             }
         }
@@ -632,12 +701,15 @@ public void PerformLayout(RGraphics g)
         {
             ArgChecker.AssertArgNotNull(g, "g");
 
+            RefreshMediaDependentCascade();
+
             _actualSize = RSize.Empty;
             if (_root != null)
             {
                 // if width is not restricted we set it to large value to get the actual later
                 _root.Size = new RSize(_maxSize.Width > 0 ? _maxSize.Width : 99999, 0);
                 _root.Location = _location;
+                _hasFloatedBoxes = ComputeHasFloatedBoxes(_root);
                 _root.PerformLayout(g);
 
                 if (_maxSize.Width <= 0.1)
@@ -645,6 +717,7 @@ public void PerformLayout(RGraphics g)
                     // in case the width is not restricted we need to double layout, first will find the width so second can layout by it (center alignment)
                     _root.Size = new RSize((int)Math.Ceiling(_actualSize.Width), 0);
                     _actualSize = RSize.Empty;
+                    _hasFloatedBoxes = ComputeHasFloatedBoxes(_root);
                     _root.PerformLayout(g);
                 }
 
@@ -658,6 +731,23 @@ public void PerformLayout(RGraphics g)
             }
         }
 
+        /// <summary>
+        /// Recursively checks whether any box in the tree has float:left or float:right set.
+        /// </summary>
+        private static bool ComputeHasFloatedBoxes(CssBox box)
+        {
+            if (box.IsFloated)
+                return true;
+
+            foreach (var child in box.Boxes)
+            {
+                if (ComputeHasFloatedBoxes(child))
+                    return true;
+            }
+
+            return false;
+        }
+
         /// <summary>
         /// Render the html using the given device.
         /// </summary>
@@ -977,25 +1067,16 @@ internal void HandleLinkClicked(RControl parent, RPoint location, CssBox link)
         /// Add css box that has ":hover" selector to be handled on mouse hover.
         /// </summary>
         /// <param name="box">the box that has the hover selector</param>
-        /// <param name="block">the css block with the css data with the selector</param>
-        internal void AddHoverBox(CssBox box, CssBlock block)
+        /// <param name="styleRule">the style rule whose selector included the hover pseudo-class</param>
+        internal void AddHoverBox(CssBox box, TheArtOfDev.HtmlRenderer.Core.CssEngine.IStyleRule styleRule)
         {
             ArgChecker.AssertArgNotNull(box, "box");
-            ArgChecker.AssertArgNotNull(block, "block");
+            ArgChecker.AssertArgNotNull(styleRule, "styleRule");
 
             if (_hoverBoxes == null)
                 _hoverBoxes = new List<HoverBoxBlock>();
 
-            _hoverBoxes.Add(new HoverBoxBlock(box, block));
-        }
-
-        /// <summary>
-        /// Get image downloader to be used to download images for the current html rendering.<br/>
-        /// Lazy create single downloader to be used for all images in the current html.
-        /// </summary>
-        internal ImageDownloader GetImageDownloader()
-        {
-            return _imageDownloader;
+            _hoverBoxes.Add(new HoverBoxBlock(box, styleRule));
         }
 
         /// <summary>
@@ -1045,6 +1126,8 @@ private void Dispose(bool all)
                     ImageLoad = null;
                 }
 
+                _adapter.ColorSchemeChanged -= _colorSchemeChangedHandler;
+
                 _cssData = null;
                 if (_root != null)
                     _root.Dispose();
diff --git a/Source/HtmlRenderer/Core/MediaQueryContext.cs b/Source/HtmlRenderer/Core/MediaQueryContext.cs
new file mode 100644
index 000000000..1a27ddf4a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/MediaQueryContext.cs
@@ -0,0 +1,84 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+using TheArtOfDev.HtmlRenderer.Adapters;
+
+namespace TheArtOfDev.HtmlRenderer.Core
+{
+    /// <summary>
+    /// The resolved "device" a CSS <c>@media</c> query is evaluated against: the media type plus the
+    /// viewport geometry and the display characteristics the adapter reports. Built once per render and
+    /// threaded through <see cref="CssData"/>'s rule matching so <c>@media</c> conditions
+    /// (<c>min-width</c>, <c>orientation</c>, <c>prefers-color-scheme</c>, ...) actually gate which rules
+    /// apply. See <see cref="MediaQueryMatcher"/> for the evaluation itself.
+    /// </summary>
+    internal struct MediaQueryContext
+    {
+        /// <summary>
+        /// A context carrying only the media type, with no viewport geometry - for callers that have no
+        /// container (the public <see cref="CssData.Parse(RAdapter,string,bool)"/> entry point, tests).
+        /// Conditions that need geometry match permissively.
+        /// </summary>
+        internal static MediaQueryContext TypeOnly(string mediaType)
+        {
+            return new MediaQueryContext(
+                string.IsNullOrEmpty(mediaType) ? "all" : mediaType,
+                null,
+                null,
+                96d,
+                RColorScheme.Light);
+        }
+
+        /// <summary>
+        /// Builds the context from the adapter's characteristics and the container's viewport.
+        /// </summary>
+        /// <param name="adapter">supplies the media type and colour scheme</param>
+        /// <param name="viewportWidth">viewport width in CSS pixels, or 0 when not yet known</param>
+        /// <param name="viewportHeight">viewport height in CSS pixels, or 0 when not yet known</param>
+        internal static MediaQueryContext FromAdapter(RAdapter adapter, double viewportWidth, double viewportHeight)
+        {
+            if (adapter == null) return TypeOnly("all");
+
+            return new MediaQueryContext(
+                adapter.DefaultMediaType,
+                viewportWidth > 0 ? viewportWidth : (double?)null,
+                viewportHeight > 0 ? viewportHeight : (double?)null,
+                96d,
+                adapter.SystemColorScheme);
+        }
+
+        private MediaQueryContext(string mediaType, double? viewportWidth, double? viewportHeight, double resolutionDpi, RColorScheme colorScheme)
+        {
+            MediaType = mediaType;
+            ViewportWidth = viewportWidth;
+            ViewportHeight = viewportHeight;
+            ResolutionDpi = resolutionDpi;
+            PreferredColorScheme = colorScheme;
+        }
+
+        /// <summary>The active media type (<c>"screen"</c>, <c>"print"</c> or <c>"all"</c>).</summary>
+        public string MediaType { get; }
+
+        /// <summary>Viewport width in CSS pixels, or null when unknown (then width/orientation/
+        /// aspect-ratio conditions match permissively).</summary>
+        public double? ViewportWidth { get; }
+
+        /// <summary>Viewport height in CSS pixels, or null when unknown.</summary>
+        public double? ViewportHeight { get; }
+
+        /// <summary>Output resolution in dots per inch, for <c>resolution</c> queries.</summary>
+        public double ResolutionDpi { get; }
+
+        /// <summary>What <c>prefers-color-scheme</c> reports.</summary>
+        public RColorScheme PreferredColorScheme { get; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/MediaQueryMatcher.cs b/Source/HtmlRenderer/Core/MediaQueryMatcher.cs
new file mode 100644
index 000000000..42797eb59
--- /dev/null
+++ b/Source/HtmlRenderer/Core/MediaQueryMatcher.cs
@@ -0,0 +1,216 @@
+// "Therefore those skilled at the unorthodox
+// are infinite as heaven and earth,
+// inexhaustible as the great rivers.
+// When they come to an end,
+// they begin again,
+// like the days and months;
+// they die and are reborn,
+// like the four seasons."
+//
+// - Sun Tsu,
+// "The Art of War"
+
+using System;
+using System.Linq;
+using TheArtOfDev.HtmlRenderer.Adapters;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+
+namespace TheArtOfDev.HtmlRenderer.Core
+{
+    /// <summary>
+    /// Evaluates a rule's enclosing <c>@media</c> chain against a <see cref="MediaQueryContext"/>, so
+    /// feature conditions (<c>min-width</c>, range syntax like <c>width &gt;= 48rem</c>,
+    /// <c>orientation</c>, <c>resolution</c>, <c>prefers-color-scheme</c>, ...) actually gate which rules
+    /// apply. Media Queries 4.
+    /// </summary>
+    /// <remarks>
+    /// Any feature this matcher cannot actually evaluate causes its <c>@media</c> block to be ignored: a
+    /// feature name the CSS engine does not register fails to parse and its query becomes <c>not all</c>
+    /// upstream, and a registered feature this matcher does not model hits the <c>default</c> arm and
+    /// returns false. Both are Media Queries 4's "unknown feature is false" - rather than apply rules
+    /// guarded by a condition that cannot be tested, the block is dropped. A feature that IS modelled but
+    /// whose runtime context is missing (a <c>width</c> query before the viewport is known) stays
+    /// permissive; that is an unknown *context*, not an unsupported feature.
+    /// </remarks>
+    internal static class MediaQueryMatcher
+    {
+        /// <summary>
+        /// True if every level of the enclosing <c>@media</c> chain matches (nesting is conjunctive), or
+        /// the rule isn't nested in any <c>@media</c> at all. Within one level's comma-separated media
+        /// query list, at least one query must match.
+        /// </summary>
+        internal static bool Matches(MediaList[] enclosingMedia, MediaQueryContext context)
+        {
+            if (enclosingMedia == null) return true;
+
+            foreach (var mediaList in enclosingMedia)
+            {
+                var anyMatches = false;
+                foreach (var medium in mediaList)
+                {
+                    if (MediumMatches(medium, context))
+                    {
+                        anyMatches = true;
+                        break;
+                    }
+                }
+
+                if (!anyMatches) return false;
+            }
+
+            return true;
+        }
+
+        private static bool MediumMatches(Medium medium, MediaQueryContext context)
+        {
+            // A feature-only query (e.g. `@media (min-width: 768px)`) has no type - treat as `all`.
+            var typeMatches = string.IsNullOrEmpty(medium.Type)
+                || string.Equals(medium.Type, context.MediaType, StringComparison.OrdinalIgnoreCase)
+                || string.Equals(medium.Type, "all", StringComparison.OrdinalIgnoreCase)
+                || string.Equals(context.MediaType, "all", StringComparison.OrdinalIgnoreCase);
+
+            var result = typeMatches && medium.Features.All(feature => FeatureMatches(feature, context));
+
+            // `not` negates the whole query (type + features), per Media Queries 4 §3.1.
+            return medium.IsInverse ? !result : result;
+        }
+
+        private static bool FeatureMatches(MediaFeature feature, MediaQueryContext context)
+        {
+            var name = feature.Name.ToLowerInvariant();
+            if (name.StartsWith("min-", StringComparison.Ordinal)) name = name.Substring(4);
+            else if (name.StartsWith("max-", StringComparison.Ordinal)) name = name.Substring(4);
+
+            switch (name)
+            {
+                case "width":
+                case "device-width":
+                case "inline-size":
+                    return CompareLength(feature, context.ViewportWidth);
+                case "height":
+                case "device-height":
+                case "block-size":
+                    return CompareLength(feature, context.ViewportHeight);
+
+                case "orientation":
+                {
+                    if (!context.ViewportWidth.HasValue || !context.ViewportHeight.HasValue) return true;
+                    // MQ4 §4.1: portrait is height >= width, so a square viewport is portrait.
+                    var orientation = context.ViewportWidth.Value > context.ViewportHeight.Value ? "landscape" : "portrait";
+                    return !feature.HasValue
+                        || string.Equals(feature.Value, orientation, StringComparison.OrdinalIgnoreCase);
+                }
+
+                case "aspect-ratio":
+                case "device-aspect-ratio":
+                {
+                    if (!context.ViewportWidth.HasValue || !context.ViewportHeight.HasValue) return true;
+                    if (context.ViewportHeight.Value <= 0) return true;
+                    var ratio = feature.AsRatio();
+                    if (!ratio.HasValue) return true;
+                    return CompareNumeric(context.ViewportWidth.Value / context.ViewportHeight.Value, ratio.Value, feature.Comparison);
+                }
+
+                case "resolution":
+                {
+                    var resolution = feature.AsResolution();
+                    if (!resolution.HasValue) return true;
+                    return CompareNumeric(context.ResolutionDpi, resolution.Value.To(Resolution.Unit.Dpi), feature.Comparison);
+                }
+
+                case "device-pixel-ratio":
+                {
+                    // Non-standard feature; the value is a plain number of device pixels per CSS px,
+                    // i.e. the same as `resolution` in dppx.
+                    var dpr = feature.AsRatio();
+                    if (!dpr.HasValue) return true;
+                    return CompareNumeric(context.ResolutionDpi / 96d, dpr.Value, feature.Comparison);
+                }
+
+                // Colour output: 8 bits/channel, not a colour-index or monochrome device, not a grid/tty.
+                case "color":
+                    return CompareCountOrBoolean(feature, 8);
+                case "color-index":
+                case "monochrome":
+                case "grid":
+                    return CompareCountOrBoolean(feature, 0);
+
+                case "prefers-color-scheme":
+                {
+                    var scheme = context.PreferredColorScheme == RColorScheme.Dark ? "dark" : "light";
+                    return !feature.HasValue
+                        || string.Equals(feature.Value, scheme, StringComparison.OrdinalIgnoreCase);
+                }
+
+                // The rendered output is static: it does not animate, cannot be hovered or pointed at,
+                // and once painted does not update. The stance for reduced motion is `reduce`, which is
+                // NOT the `no-preference` resting value, so the boolean form `(prefers-reduced-motion)`
+                // is true (MQ5 §5.3).
+                case "prefers-reduced-motion":
+                    return MatchesKeyword(feature, "reduce", true);
+                case "hover":
+                case "any-hover":
+                case "pointer":
+                case "any-pointer":
+                case "update":
+                case "scripting":
+                    return MatchesKeyword(feature, "none", false);
+                case "prefers-contrast":
+                case "prefers-reduced-transparency":
+                    return MatchesKeyword(feature, "no-preference", false);
+
+                default:
+                    // A registered feature this matcher does not evaluate (e.g. `scan`): treat as not
+                    // matching so the whole @media block is ignored, rather than applying rules guarded
+                    // by a condition that cannot be tested (see the class remarks).
+                    return false;
+            }
+        }
+
+        private static bool CompareLength(MediaFeature feature, double? actualPx)
+        {
+            if (!actualPx.HasValue) return true;    // no viewport geometry -> permissive
+
+            var length = feature.AsLength();
+            if (!length.HasValue) return true;
+
+            // In a media query, `em`/`rem` resolve against the initial font size (16px), NOT the
+            // document root's font size (Media Queries 4 §1.3 / §6).
+            const double initialFontPx = 16d;
+            var valuePx = length.Value.ToPixels(initialFontPx, initialFontPx, actualPx.Value);
+
+            return CompareNumeric(actualPx.Value, valuePx, feature.Comparison);
+        }
+
+        private static bool CompareCountOrBoolean(MediaFeature feature, int actual)
+        {
+            if (!feature.HasValue) return actual > 0;   // boolean context, e.g. `(color)`
+
+            int value;
+            if (!int.TryParse(feature.Value, out value)) return true;   // unparseable -> permissive
+            return CompareNumeric(actual, value, feature.Comparison);
+        }
+
+        private static bool MatchesKeyword(MediaFeature feature, string deviceValue, bool booleanContextResult)
+        {
+            // The value form `(feature: value)` matches iff the queried value equals the device's value.
+            // The boolean form `(feature)` is true iff the device value is not the feature's "none"/
+            // "no-preference" resting state.
+            if (!feature.HasValue) return booleanContextResult;
+            return string.Equals(feature.Value, deviceValue, StringComparison.OrdinalIgnoreCase);
+        }
+
+        private static bool CompareNumeric(double actual, double value, MediaFeatureComparison comparison)
+        {
+            const double epsilon = 1e-6;
+            switch (comparison)
+            {
+                case MediaFeatureComparison.Minimum: return actual >= value - epsilon;
+                case MediaFeatureComparison.Maximum: return actual <= value + epsilon;
+                case MediaFeatureComparison.GreaterThan: return actual > value + epsilon;
+                case MediaFeatureComparison.LessThan: return actual < value - epsilon;
+                default: return Math.Abs(actual - value) <= epsilon;
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Network/DataUriNetworkLoader.cs b/Source/HtmlRenderer/Core/Network/DataUriNetworkLoader.cs
new file mode 100644
index 000000000..bef2d1d3b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/DataUriNetworkLoader.cs
@@ -0,0 +1,47 @@
+#nullable enable
+
+using TheArtOfDev.HtmlRenderer.Core.Utils;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// The default <see cref="RNetworkLoader"/> used when <see cref="Adapters.RAdapter.NetworkLoader"/> is
+    /// left unset. Resolves only <c>data:</c> URIs; any other resource URI (remote stylesheets, remote
+    /// images, HTTP(S) sources) is silently skipped. This is the safest default for server-side
+    /// environments where network access must be opted into explicitly rather than assumed.
+    /// </summary>
+    public class DataUriNetworkLoader : RNetworkLoader
+    {
+        /// <inheritdoc/>
+        public override RUri? BaseUri => null;
+
+        /// <summary>
+        /// Not supported by this loader — the HTML string must always be passed directly rather than
+        /// loaded via a network loader.
+        /// </summary>
+        public override Task<string> GetPrimaryContents()
+        {
+            return null!;
+        }
+
+        /// <inheritdoc/>
+        public override Task<RNetworkResponse?> GetResourceStream(RUri uri)
+        {
+            if (uri.Scheme != "data") return Task.FromResult<RNetworkResponse?>(null);
+
+            if (!DataUriUtils.TryDecodeDataUri(uri.AbsoluteUri, out var mimeType, out var bytes))
+                return Task.FromResult<RNetworkResponse?>(null);
+
+            // Report the data URI's own declared MIME type as a Content-Type header so consumers that
+            // content-type-sniff the response (e.g. StylesheetLoadHandler, for a data:text/css,... <link>)
+            // can recognize it - a data: URI has no real HTTP response.
+            var headers = new Dictionary<string, string[]> { ["Content-Type"] = new[] { mimeType } };
+            var response = new RNetworkResponse(new MemoryStream(bytes), headers);
+
+            return Task.FromResult<RNetworkResponse?>(response);
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Network/EmbeddedResourceNetworkLoader.cs b/Source/HtmlRenderer/Core/Network/EmbeddedResourceNetworkLoader.cs
new file mode 100644
index 000000000..980345888
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/EmbeddedResourceNetworkLoader.cs
@@ -0,0 +1,125 @@
+#nullable enable
+using System;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Threading.Tasks;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// Resolves <c>embedded://&lt;assemblySimpleName&gt;/&lt;manifestResourceName&gt;</c> URIs against a
+    /// loaded .NET assembly's own embedded resources (<see cref="Assembly.GetManifestResourceStream(string)"/>).
+    /// The assembly to search is named directly in the URI's authority rather than configured on the
+    /// loader instance, so - like <c>data:</c>/<c>file:</c> - this always resolves the same way regardless
+    /// of which <see cref="RNetworkLoader"/> is configured on <see cref="Adapters.RAdapter.NetworkLoader"/>:
+    /// <see cref="Adapters.RAdapter.GetResourceStream"/> intercepts this scheme unconditionally, the same
+    /// way it already does for <c>data:</c>/<c>file:</c>.
+    /// </summary>
+    /// <remarks>
+    /// Useful for a library/app that ships its own bundled resources (fonts, images, stylesheets) as
+    /// embedded resources and wants <c>@font-face src: url(...)</c>/<c>&lt;img src&gt;</c>/etc. to
+    /// reference them directly, without a custom <see cref="RNetworkLoader"/> of its own.
+    /// </remarks>
+    public sealed class EmbeddedResourceNetworkLoader : RNetworkLoader
+    {
+        public const string Scheme = "embedded";
+
+        private readonly RUri? _primaryContentsUri;
+
+        /// <summary>
+        /// Creates a loader with no primary document - it only resolves <c>embedded:</c> URIs it's asked
+        /// for via <see cref="GetResourceStream"/> (which is how <see cref="Adapters.RAdapter"/>'s internal,
+        /// always-on instance of this loader is used). <see cref="GetPrimaryContents"/> is not supported on
+        /// an instance created this way — pass the HTML directly instead, or use the other constructor.
+        /// </summary>
+        public EmbeddedResourceNetworkLoader()
+        {
+        }
+
+        /// <summary>
+        /// Creates a loader whose root document is the embedded resource named
+        /// <paramref name="manifestResourceName"/> in <paramref name="assembly"/>, and whose base URI is
+        /// that resource's own <c>embedded:</c> URI (so relative references resolve against it). Pass
+        /// <c>null</c> as the HTML argument when rendering to render this resource.
+        /// </summary>
+        public EmbeddedResourceNetworkLoader(Assembly assembly, string manifestResourceName)
+        {
+            _primaryContentsUri = BuildUri(assembly, manifestResourceName);
+        }
+
+        /// <summary>Builds an <c>embedded:</c> URI for <paramref name="manifestResourceName"/> in <paramref name="assembly"/>.</summary>
+        public static RUri BuildUri(Assembly assembly, string manifestResourceName)
+        {
+            if (assembly is null) throw new ArgumentNullException(nameof(assembly));
+            if (manifestResourceName is null) throw new ArgumentNullException(nameof(manifestResourceName));
+
+            return new RUri($"{Scheme}://{assembly.GetName().Name}/{manifestResourceName}");
+        }
+
+        /// <inheritdoc/>
+        public override RUri? BaseUri => _primaryContentsUri;
+
+        /// <inheritdoc/>
+        public override async Task<string> GetPrimaryContents()
+        {
+            if (_primaryContentsUri is null)
+            {
+                throw new InvalidOperationException(
+                    "This EmbeddedResourceNetworkLoader was created without a primary resource; construct it with an assembly and manifest resource name to load the root document, or pass the HTML directly.");
+            }
+
+            var networkResponse = await GetResourceStream(_primaryContentsUri).ConfigureAwait(false);
+
+            if (networkResponse?.ResourceStream is null)
+            {
+                throw new InvalidOperationException("Primary contents stream is null.");
+            }
+
+            using (var reader = new StreamReader(networkResponse.ResourceStream))
+            {
+                return await reader.ReadToEndAsync().ConfigureAwait(false);
+            }
+        }
+
+        /// <inheritdoc/>
+        public override Task<RNetworkResponse?> GetResourceStream(RUri uri)
+        {
+            var assemblyName = uri.Uri.Host;
+            var resourceName = uri.Uri.AbsolutePath.TrimStart('/');
+
+            var assembly = FindOrLoadAssembly(assemblyName);
+            var stream = assembly?.GetManifestResourceStream(resourceName);
+
+            return Task.FromResult(stream != null ? new RNetworkResponse(stream, null) : null);
+        }
+
+        /// <summary>
+        /// Finds <paramref name="assemblyName"/> among already-loaded assemblies first (cheap, and the
+        /// common case - the assembly that built this URI via <see cref="BuildUri"/> is, by construction,
+        /// already loaded), falling back to <see cref="Assembly.Load(AssemblyName)"/> - which actively
+        /// resolves and loads the assembly from the app's own probing paths - for the case this URI came
+        /// from parsed CSS/HTML text (e.g. an <c>@font-face src: url(embedded://...)</c> written directly
+        /// into a bundled sample) rather than <see cref="BuildUri"/>, where nothing else in the calling
+        /// process may have referenced a type from that assembly yet to trigger .NET's normal lazy load.
+        /// </summary>
+        private static Assembly? FindOrLoadAssembly(string assemblyName)
+        {
+            var loaded = AppDomain.CurrentDomain.GetAssemblies()
+                .FirstOrDefault(a => string.Equals(a.GetName().Name, assemblyName, StringComparison.OrdinalIgnoreCase));
+            if (loaded != null)
+            {
+                return loaded;
+            }
+
+            try
+            {
+                return Assembly.Load(new AssemblyName(assemblyName));
+            }
+            catch
+            {
+                return null;
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Network/FileUriNetworkLoader.cs b/Source/HtmlRenderer/Core/Network/FileUriNetworkLoader.cs
new file mode 100644
index 000000000..561761200
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/FileUriNetworkLoader.cs
@@ -0,0 +1,121 @@
+#nullable enable
+
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// An <see cref="RNetworkLoader"/> that serves the root HTML document and every resource it references
+    /// (stylesheets, images, fonts) from the local file system via <c>file:</c> URIs. Its
+    /// <see cref="BaseUri"/> is set the way a browser sets a local document's base URL: to the loaded
+    /// file's own <c>file:</c> URI (so relative references resolve against its directory), or — when no
+    /// primary file is given — to the current working directory. <c>file:</c> resources resolve through
+    /// this loader automatically regardless of which loader is configured (mirroring how <c>data:</c> URIs
+    /// are always handled internally), so relative references in an in-memory HTML string load from disk
+    /// by default. Setting <see cref="Adapters.RAdapter.AllowLocalFileAccess"/> to <c>false</c> turns that
+    /// off: <c>file:</c> resource requests are then refused even for a document rendered through this
+    /// loader, though the root document it was constructed with is still read.
+    /// </summary>
+    public class FileUriNetworkLoader : RNetworkLoader
+    {
+        private readonly string? _primaryFilePath;
+
+        /// <summary>
+        /// Creates a loader whose base URI is the current working directory, for rendering an in-memory
+        /// HTML string whose relative references should resolve against the process's working directory.
+        /// <see cref="GetPrimaryContents"/> is not supported on an instance created this way — pass the HTML
+        /// directly instead.
+        /// </summary>
+        public FileUriNetworkLoader()
+        {
+            _primaryFilePath = null;
+            BaseUri = new RUri(new Uri(EnsureTrailingSeparator(Directory.GetCurrentDirectory())));
+        }
+
+        /// <summary>
+        /// Creates a loader whose root document is the file at <paramref name="primaryFilePath"/> and whose
+        /// base URI is that file's own <c>file:</c> URI, so relative references resolve against the file's
+        /// directory — exactly like opening a local <c>.html</c> file in a browser. Pass <c>null</c> as the
+        /// HTML argument when rendering to render this file.
+        /// </summary>
+        /// <param name="primaryFilePath">Path to the root HTML file. Resolved against the current working directory if relative.</param>
+        public FileUriNetworkLoader(string primaryFilePath)
+        {
+            if (primaryFilePath is null) throw new ArgumentNullException(nameof(primaryFilePath));
+
+            _primaryFilePath = Path.GetFullPath(primaryFilePath);
+            BaseUri = new RUri(new Uri(_primaryFilePath));
+        }
+
+        /// <inheritdoc/>
+        public override RUri BaseUri { get; }
+
+        /// <inheritdoc/>
+        public override async Task<string> GetPrimaryContents()
+        {
+            if (_primaryFilePath is null)
+            {
+                throw new InvalidOperationException(
+                    "This FileUriNetworkLoader was created without a primary file path; construct it with a file path to load the root document, or pass the HTML directly.");
+            }
+
+            using (var stream = File.OpenRead(_primaryFilePath))
+            using (var reader = new StreamReader(stream))
+            {
+                return await reader.ReadToEndAsync().ConfigureAwait(false);
+            }
+        }
+
+        /// <inheritdoc/>
+        public override Task<RNetworkResponse?> GetResourceStream(RUri uri)
+        {
+            if (!uri.IsAbsoluteUri || uri.Scheme != "file")
+            {
+                return Task.FromResult<RNetworkResponse?>(null);
+            }
+
+            try
+            {
+                var path = uri.Uri.LocalPath;
+
+                // A directory or a missing file resolves to "no such resource", matching the fail-soft
+                // behavior of the other loaders (a null response rather than an exception).
+                if (Directory.Exists(path) || !File.Exists(path))
+                {
+                    return Task.FromResult<RNetworkResponse?>(null);
+                }
+
+                Stream stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+
+                // Synthesize a Content-Type header so a local file is treated exactly like a fetched
+                // network resource (the stylesheet loader's text/css gate, the image loader's
+                // image/svg+xml detection).
+                var headers = new Dictionary<string, string[]>
+                {
+                    ["Content-Type"] = new[] { MimeTypeResolver.GetMimeType(path) }
+                };
+
+                return Task.FromResult<RNetworkResponse?>(new RNetworkResponse(stream, headers));
+            }
+            catch (Exception ex) when (ex is IOException || ex is UnauthorizedAccessException || ex is ArgumentException)
+            {
+                return Task.FromResult<RNetworkResponse?>(null);
+            }
+        }
+
+        /// <summary>
+        /// Ensures a directory path ends with a separator so that resolving a relative reference against
+        /// its <c>file:</c> URI keeps the directory as the base (per RFC 3986 relative resolution) instead
+        /// of replacing the directory's own last path segment.
+        /// </summary>
+        private static string EnsureTrailingSeparator(string directory)
+        {
+            return directory.EndsWith(Path.DirectorySeparatorChar.ToString()) || directory.EndsWith(Path.AltDirectorySeparatorChar.ToString())
+                ? directory
+                : directory + Path.DirectorySeparatorChar;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Network/HttpClientNetworkLoader.cs b/Source/HtmlRenderer/Core/Network/HttpClientNetworkLoader.cs
new file mode 100644
index 000000000..bf8d5ec7b
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/HttpClientNetworkLoader.cs
@@ -0,0 +1,74 @@
+#nullable enable
+
+using System;
+using System.IO;
+using System.Linq;
+using System.Net.Http;
+using System.Threading.Tasks;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// An <see cref="RNetworkLoader"/> that fetches the root HTML document and every resource it references
+    /// (stylesheets, images, fonts) over HTTP(S) using a caller-supplied <see cref="HttpClient"/>. The
+    /// caller controls the <see cref="HttpClient"/>'s lifetime, so custom headers, authentication, proxies,
+    /// timeouts, and <see cref="HttpMessageHandler"/> chains are all supported without any library-specific API.
+    /// </summary>
+    /// <param name="httpClient">The client used to fetch the root document and all referenced resources.</param>
+    /// <param name="primaryContentsUri">The URI of the root HTML document; also used as <see cref="BaseUri"/> for resolving relative references.</param>
+    public class HttpClientNetworkLoader(HttpClient httpClient, Uri? primaryContentsUri) : RNetworkLoader
+    {
+        /// <summary>
+        /// Creates a loader for the root document at <paramref name="primaryContentsUri"/>.
+        /// </summary>
+        /// <param name="httpClient">The client used to fetch the root document and all referenced resources.</param>
+        /// <param name="primaryContentsUri">The URI of the root HTML document; also used as <see cref="BaseUri"/> for resolving relative references.</param>
+        public HttpClientNetworkLoader(HttpClient httpClient, string primaryContentsUri)
+            : this(httpClient, new Uri(primaryContentsUri))
+        {
+        }
+
+        /// <inheritdoc/>
+        public override RUri? BaseUri => primaryContentsUri != null ? new RUri(primaryContentsUri) : null;
+
+        /// <inheritdoc/>
+        public override async Task<string> GetPrimaryContents()
+        {
+            if (BaseUri is null)
+            {
+                throw new InvalidOperationException("Primary contents URL is not set.");
+            }
+
+            var networkResponse = await GetResourceStream(BaseUri).ConfigureAwait(false);
+
+            if (networkResponse?.ResourceStream is null)
+            {
+                throw new InvalidOperationException("Primary contents stream is null.");
+            }
+
+            using (var streamReader = new StreamReader(networkResponse.ResourceStream))
+            {
+                return await streamReader.ReadToEndAsync().ConfigureAwait(false);
+            }
+        }
+
+        /// <inheritdoc/>
+        public override async Task<RNetworkResponse?> GetResourceStream(RUri uri)
+        {
+            var response = await httpClient.GetAsync(uri.Uri).ConfigureAwait(false);
+
+            if (!response.IsSuccessStatusCode)
+            {
+                return null;
+            }
+
+            var headers = response.Headers
+                .Union(response.Content.Headers)
+                .ToDictionary(x => x.Key, x => x.Value.ToArray());
+
+            var stream = await response.Content.ReadAsStreamAsync().ConfigureAwait(false);
+
+            return new RNetworkResponse(stream, headers);
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Network/MimeTypeResolver.cs b/Source/HtmlRenderer/Core/Network/MimeTypeResolver.cs
new file mode 100644
index 000000000..71526dc88
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/MimeTypeResolver.cs
@@ -0,0 +1,575 @@
+#nullable enable
+
+using System;
+using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// Resolves a file's MIME type from its extension, used to populate the synthesized
+    /// <c>Content-Type</c> header on <see cref="FileUriNetworkLoader"/> responses so the rest of the
+    /// pipeline (the stylesheet loader's <c>text/css</c> gate, the image loader's <c>image/svg+xml</c>
+    /// detection) treats a local file exactly like a fetched network resource.
+    /// </summary>
+    /// <remarks>
+    /// An OS-provided mechanism is consulted first — the Windows shell association API, the Apple Uniform
+    /// Type Identifiers C API, or the Linux <c>/etc/mime.types</c> database — falling back to a built-in
+    /// static map covering HTML, CSS, SVG, the common raster image formats, and TTF/OTF fonts. Every OS
+    /// lookup is best-effort and fail-soft: any failure (missing library on a platform, an unregistered
+    /// extension, an interop error) falls through to the static map. Results are memoized per extension for
+    /// the process lifetime, so the (potentially syscall- or file-backed) OS lookup runs at most once per
+    /// distinct extension.
+    /// </remarks>
+    internal static partial class MimeTypeResolver
+    {
+        private const string DefaultMimeType = "application/octet-stream";
+
+        // The extension -> MIME mapping is stable for a process's lifetime, so memoize it: a document with
+        // many images of the same type then costs one OS lookup, not one per resource. Keyed by the
+        // lowercase dot-less extension.
+        private static readonly ConcurrentDictionary<string, string> Cache = new ConcurrentDictionary<string, string>();
+
+        /// <summary>
+        /// Resolves the MIME type for <paramref name="pathOrFileName"/> from its extension. Returns
+        /// <c>application/octet-stream</c> when nothing else matches (or there is no extension).
+        /// </summary>
+        public static string GetMimeType(string pathOrFileName)
+        {
+            var extension = Path.GetExtension(pathOrFileName);
+
+            if (string.IsNullOrEmpty(extension))
+            {
+                return DefaultMimeType;
+            }
+
+            // Path.GetExtension keeps the leading dot and never returns an all-dots string (it returns ""
+            // for those), so trimming the dot always yields a non-empty key here.
+            var extensionNoDot = extension.TrimStart('.').ToLowerInvariant();
+
+            return Cache.GetOrAdd(extensionNoDot, Resolve);
+        }
+
+        private static string Resolve(string extensionNoDot)
+        {
+            // OS-provided mechanism first, static map as the fallback for the formats this library renders.
+            // Each OS helper already validates its result (see LooksLikeMimeType) and returns null for a
+            // non-MIME answer, so a host with no real registration for the extension falls through to the
+            // static map / octet-stream rather than leaking a bogus value into the synthesized Content-Type.
+            return TryGetFromOperatingSystem("." + extensionNoDot, extensionNoDot)
+                   ?? TryGetFromStaticMap(extensionNoDot)
+                   ?? DefaultMimeType;
+        }
+
+        /// <summary>
+        /// Whether <paramref name="value"/> looks like a real <c>type/subtype</c> MIME type, used to reject
+        /// non-MIME strings some OS association APIs return for an extension that has no registered content
+        /// type — e.g. Windows' shell returns a property descriptor like
+        /// <c>prop:System.ItemTypeText;System.Size;…</c>, which must not become a <c>Content-Type</c> header
+        /// (it isn't a valid MIME type and would throw when parsed).
+        /// </summary>
+        internal static bool LooksLikeMimeType(string? value) =>
+            !string.IsNullOrWhiteSpace(value)
+            && value!.IndexOf('/') > 0
+            && !value.StartsWith("prop:", StringComparison.OrdinalIgnoreCase);
+
+        /// <summary>
+        /// The built-in fallback map. Covers the document formats this library parses (HTML/CSS/SVG), the
+        /// common raster formats, and the <c>@font-face</c> font formats this library loads (TTF/OTF), so
+        /// these always resolve regardless of the host OS's own registrations.
+        /// </summary>
+        internal static string? TryGetFromStaticMap(string extensionNoDot) => extensionNoDot switch
+        {
+            "html" or "htm" => "text/html",
+            "css" => "text/css",
+            "svg" => "image/svg+xml",
+            "png" => "image/png",
+            "jpg" or "jpeg" => "image/jpeg",
+            "bmp" => "image/bmp",
+            "gif" => "image/gif",
+            "tga" => "image/x-tga",
+            // RFC 8081 font MIME types, matching the @font-face src formats this library accepts.
+            "ttf" => "font/ttf",
+            "otf" => "font/otf",
+            "woff" => "font/woff",
+            "woff2" => "font/woff2",
+            _ => null
+        };
+
+#if NET8_0_OR_GREATER
+        // Each OS-native lookup below only executes on its own platform, so on any single CI leg the other
+        // platforms' branches are unreachable.
+        [ExcludeFromCodeCoverage]
+        private static string? TryGetFromOperatingSystem(string extensionWithDot, string extensionNoDot)
+        {
+            if (OperatingSystem.IsWindows())
+            {
+                return TryGetFromWindows(extensionWithDot);
+            }
+
+            if (OperatingSystem.IsMacOS() || OperatingSystem.IsIOS() || OperatingSystem.IsMacCatalyst() || OperatingSystem.IsTvOS())
+            {
+                return TryGetFromApple(extensionNoDot);
+            }
+
+            if (OperatingSystem.IsLinux())
+            {
+                return TryGetFromLinux(extensionNoDot);
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Windows: queries the shell file-association database via <c>AssocQueryString</c>
+        /// (<c>ASSOCSTR_CONTENTTYPE</c>) — the documented association API, rather than reading
+        /// <c>HKEY_CLASSES_ROOT</c> directly (no <c>Microsoft.Win32.Registry</c> dependency).
+        /// <paramref name="extensionWithDot"/> must include the leading dot (e.g. <c>.png</c>).
+        /// </summary>
+        [System.Runtime.Versioning.SupportedOSPlatform("windows")]
+        [ExcludeFromCodeCoverage]
+        internal static string? TryGetFromWindows(string extensionWithDot)
+        {
+            try
+            {
+                uint length = 0;
+
+                // First call sizes the output buffer (pcchOut). A non-zero length means an association
+                // exists; anything else (no association, error) falls through to the static map.
+                _ = NativeMethods.AssocQueryStringW(NativeMethods.AssocfNone, NativeMethods.AssocStrContentType,
+                    extensionWithDot, null, null, ref length);
+
+                if (length == 0)
+                {
+                    return null;
+                }
+
+                var buffer = new char[length];
+                var hr = NativeMethods.AssocQueryStringW(NativeMethods.AssocfNone, NativeMethods.AssocStrContentType,
+                    extensionWithDot, null, buffer, ref length);
+
+                if (hr != 0) // S_OK == 0
+                {
+                    return null;
+                }
+
+                // AssocQueryStringW writes a NUL-terminated string and reports the length (incl. the
+                // terminator) back through pcchOut; trim at the terminator to get the managed string.
+                var terminator = Array.IndexOf(buffer, '\0');
+                var contentType = new string(buffer, 0, terminator >= 0 ? terminator : buffer.Length);
+
+                // A bare Windows install often has no registered Content Type for an extension, in which
+                // case AssocQueryString returns a non-MIME shell property string (prop:System.…) rather
+                // than failing - reject anything that isn't a real MIME type.
+                return LooksLikeMimeType(contentType) ? contentType : null;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// Apple platforms (macOS, iOS, Mac Catalyst, tvOS): maps the extension to a Uniform Type
+        /// Identifier and then to its preferred MIME type via the LaunchServices C API in
+        /// <c>CoreServices.framework</c>.
+        /// </summary>
+        [System.Runtime.Versioning.SupportedOSPlatform("macos")]
+        [System.Runtime.Versioning.SupportedOSPlatform("ios")]
+        [System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")]
+        [System.Runtime.Versioning.SupportedOSPlatform("tvos")]
+        [ExcludeFromCodeCoverage]
+        internal static string? TryGetFromApple(string extensionNoDot)
+        {
+            var extensionRef = IntPtr.Zero;
+            var tagClassExtensionRef = IntPtr.Zero;
+            var tagClassMimeRef = IntPtr.Zero;
+            var utiRef = IntPtr.Zero;
+            var mimeRef = IntPtr.Zero;
+
+            try
+            {
+                extensionRef = NativeMethods.CFStringCreateWithCString(IntPtr.Zero, extensionNoDot, NativeMethods.KCFStringEncodingUtf8);
+                tagClassExtensionRef = NativeMethods.CFStringCreateWithCString(IntPtr.Zero, "public.filename-extension", NativeMethods.KCFStringEncodingUtf8);
+                tagClassMimeRef = NativeMethods.CFStringCreateWithCString(IntPtr.Zero, "public.mime-type", NativeMethods.KCFStringEncodingUtf8);
+
+                if (extensionRef == IntPtr.Zero || tagClassExtensionRef == IntPtr.Zero || tagClassMimeRef == IntPtr.Zero)
+                {
+                    return null;
+                }
+
+                utiRef = NativeMethods.UTTypeCreatePreferredIdentifierForTag(tagClassExtensionRef, extensionRef, IntPtr.Zero);
+                if (utiRef == IntPtr.Zero)
+                {
+                    return null;
+                }
+
+                mimeRef = NativeMethods.UTTypeCopyPreferredTagWithClass(utiRef, tagClassMimeRef);
+                if (mimeRef == IntPtr.Zero)
+                {
+                    return null;
+                }
+
+                var mime = CFStringToManaged(mimeRef);
+                return LooksLikeMimeType(mime) ? mime : null;
+            }
+            catch
+            {
+                return null;
+            }
+            finally
+            {
+                if (mimeRef != IntPtr.Zero) NativeMethods.CFRelease(mimeRef);
+                if (utiRef != IntPtr.Zero) NativeMethods.CFRelease(utiRef);
+                if (tagClassMimeRef != IntPtr.Zero) NativeMethods.CFRelease(tagClassMimeRef);
+                if (tagClassExtensionRef != IntPtr.Zero) NativeMethods.CFRelease(tagClassExtensionRef);
+                if (extensionRef != IntPtr.Zero) NativeMethods.CFRelease(extensionRef);
+            }
+        }
+
+        [System.Runtime.Versioning.SupportedOSPlatform("macos")]
+        [System.Runtime.Versioning.SupportedOSPlatform("ios")]
+        [System.Runtime.Versioning.SupportedOSPlatform("maccatalyst")]
+        [System.Runtime.Versioning.SupportedOSPlatform("tvos")]
+        [ExcludeFromCodeCoverage]
+        private static string? CFStringToManaged(IntPtr cfString)
+        {
+            // Fast path: a direct pointer to the backing UTF-8 buffer, if the string has one.
+            var direct = NativeMethods.CFStringGetCStringPtr(cfString, NativeMethods.KCFStringEncodingUtf8);
+            if (direct != IntPtr.Zero)
+            {
+                return Marshal.PtrToStringUTF8(direct);
+            }
+
+            // Slow path: copy into our own buffer, sized from the UTF-16 length (ample for UTF-8 here).
+            var length = NativeMethods.CFStringGetLength(cfString);
+            var capacity = (int)(length * 3) + 1;
+            var buffer = new byte[capacity];
+
+            if (!NativeMethods.CFStringGetCString(cfString, buffer, capacity, NativeMethods.KCFStringEncodingUtf8))
+            {
+                return null;
+            }
+
+            var terminator = Array.IndexOf(buffer, (byte)0);
+            var count = terminator >= 0 ? terminator : buffer.Length;
+            return Encoding.UTF8.GetString(buffer, 0, count);
+        }
+
+        /// <summary>
+        /// Linux: looks the extension up in the system <c>/etc/mime.types</c> database (each non-comment
+        /// line is a MIME type followed by whitespace-separated extensions).
+        /// </summary>
+        [System.Runtime.Versioning.SupportedOSPlatform("linux")]
+        [ExcludeFromCodeCoverage]
+        internal static string? TryGetFromLinux(string extensionNoDot)
+        {
+            const string mimeTypesPath = "/etc/mime.types";
+
+            try
+            {
+                if (!File.Exists(mimeTypesPath))
+                {
+                    return null;
+                }
+
+                foreach (var rawLine in File.ReadLines(mimeTypesPath))
+                {
+                    var line = rawLine.Trim();
+                    if (line.Length == 0 || line[0] == '#')
+                    {
+                        continue;
+                    }
+
+                    // Each line is "<mime-type> <ext> <ext> ...", whitespace-separated.
+                    var tokens = line.Split((char[]?)null, StringSplitOptions.RemoveEmptyEntries);
+                    if (tokens.Length < 2)
+                    {
+                        continue;
+                    }
+
+                    for (var i = 1; i < tokens.Length; i++)
+                    {
+                        if (tokens[i].Equals(extensionNoDot, StringComparison.OrdinalIgnoreCase))
+                        {
+                            return LooksLikeMimeType(tokens[0]) ? tokens[0] : null;
+                        }
+                    }
+                }
+
+                return null;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        /// <summary>
+        /// P/Invoke declarations for the OS-native MIME lookups. Trim-safe (no reflection); each entry
+        /// point is only ever reached under the matching platform guard above.
+        /// </summary>
+        [ExcludeFromCodeCoverage]
+        private static partial class NativeMethods
+        {
+            // ---- Windows: Shlwapi AssocQueryString ----
+
+            internal const int AssocfNone = 0;
+            internal const int AssocStrContentType = 14; // ASSOCSTR_CONTENTTYPE (12 is ASSOCSTR_QUICKTIP, which returns a "prop:…" tooltip string)
+
+            [LibraryImport("Shlwapi.dll", StringMarshalling = StringMarshalling.Utf16)]
+            internal static partial int AssocQueryStringW(int flags, int str, string pszAssoc, string? pszExtra, [Out] char[]? pszOut, ref uint pcchOut);
+
+            // ---- Apple: CoreFoundation + LaunchServices (CoreServices) ----
+
+            private const string CoreFoundation = "/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation";
+            private const string CoreServices = "/System/Library/Frameworks/CoreServices.framework/CoreServices";
+
+            internal const uint KCFStringEncodingUtf8 = 0x08000100;
+
+            [LibraryImport(CoreFoundation)]
+            internal static partial IntPtr CFStringCreateWithCString(IntPtr alloc, [MarshalAs(UnmanagedType.LPUTF8Str)] string cStr, uint encoding);
+
+            [LibraryImport(CoreFoundation)]
+            internal static partial void CFRelease(IntPtr cf);
+
+            [LibraryImport(CoreFoundation)]
+            internal static partial IntPtr CFStringGetCStringPtr(IntPtr theString, uint encoding);
+
+            [LibraryImport(CoreFoundation)]
+            [return: MarshalAs(UnmanagedType.I1)]
+            internal static partial bool CFStringGetCString(IntPtr theString, [Out] byte[] buffer, long bufferSize, uint encoding);
+
+            [LibraryImport(CoreFoundation)]
+            internal static partial long CFStringGetLength(IntPtr theString);
+
+            [LibraryImport(CoreServices)]
+            internal static partial IntPtr UTTypeCreatePreferredIdentifierForTag(IntPtr inTagClass, IntPtr inTag, IntPtr inConformingToUti);
+
+            [LibraryImport(CoreServices)]
+            internal static partial IntPtr UTTypeCopyPreferredTagWithClass(IntPtr inUti, IntPtr inTagClass);
+        }
+#else
+        // netstandard2.0 leg: System.OperatingSystem/[SupportedOSPlatform]/[LibraryImport] don't exist on
+        // this BCL surface (a real TFM constraint, not a style choice - see the CodepointRange/Rune
+        // precedent in the @font-face plan). RuntimeInformation.IsOSPlatform + classic [DllImport] cover
+        // Windows/macOS/Linux, which is the same coverage this leg needs in practice; Mac Catalyst/tvOS
+        // (relevant only via OperatingSystem's finer platform checks) fall through to the static map on
+        // this leg specifically - an honest, narrow simplification of the net8.0 branch above, not a
+        // silently-different Windows/macOS/Linux answer.
+        [ExcludeFromCodeCoverage]
+        private static string? TryGetFromOperatingSystem(string extensionWithDot, string extensionNoDot)
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                return TryGetFromWindows(extensionWithDot);
+            }
+
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                return TryGetFromApple(extensionNoDot);
+            }
+
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            {
+                return TryGetFromLinux(extensionNoDot);
+            }
+
+            return null;
+        }
+
+        [ExcludeFromCodeCoverage]
+        internal static string? TryGetFromWindows(string extensionWithDot)
+        {
+            try
+            {
+                uint length = 0;
+
+                _ = NativeMethods.AssocQueryStringW(NativeMethods.AssocfNone, NativeMethods.AssocStrContentType,
+                    extensionWithDot, null, null, ref length);
+
+                if (length == 0)
+                {
+                    return null;
+                }
+
+                var buffer = new char[length];
+                var hr = NativeMethods.AssocQueryStringW(NativeMethods.AssocfNone, NativeMethods.AssocStrContentType,
+                    extensionWithDot, null, buffer, ref length);
+
+                if (hr != 0)
+                {
+                    return null;
+                }
+
+                var terminator = Array.IndexOf(buffer, '\0');
+                var contentType = new string(buffer, 0, terminator >= 0 ? terminator : buffer.Length);
+
+                return LooksLikeMimeType(contentType) ? contentType : null;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        [ExcludeFromCodeCoverage]
+        internal static string? TryGetFromApple(string extensionNoDot)
+        {
+            var extensionRef = IntPtr.Zero;
+            var tagClassExtensionRef = IntPtr.Zero;
+            var tagClassMimeRef = IntPtr.Zero;
+            var utiRef = IntPtr.Zero;
+            var mimeRef = IntPtr.Zero;
+
+            try
+            {
+                extensionRef = NativeMethods.CFStringCreateWithCString(IntPtr.Zero, extensionNoDot, NativeMethods.KCFStringEncodingUtf8);
+                tagClassExtensionRef = NativeMethods.CFStringCreateWithCString(IntPtr.Zero, "public.filename-extension", NativeMethods.KCFStringEncodingUtf8);
+                tagClassMimeRef = NativeMethods.CFStringCreateWithCString(IntPtr.Zero, "public.mime-type", NativeMethods.KCFStringEncodingUtf8);
+
+                if (extensionRef == IntPtr.Zero || tagClassExtensionRef == IntPtr.Zero || tagClassMimeRef == IntPtr.Zero)
+                {
+                    return null;
+                }
+
+                utiRef = NativeMethods.UTTypeCreatePreferredIdentifierForTag(tagClassExtensionRef, extensionRef, IntPtr.Zero);
+                if (utiRef == IntPtr.Zero)
+                {
+                    return null;
+                }
+
+                mimeRef = NativeMethods.UTTypeCopyPreferredTagWithClass(utiRef, tagClassMimeRef);
+                if (mimeRef == IntPtr.Zero)
+                {
+                    return null;
+                }
+
+                var mime = CFStringToManaged(mimeRef);
+                return LooksLikeMimeType(mime) ? mime : null;
+            }
+            catch
+            {
+                return null;
+            }
+            finally
+            {
+                if (mimeRef != IntPtr.Zero) NativeMethods.CFRelease(mimeRef);
+                if (utiRef != IntPtr.Zero) NativeMethods.CFRelease(utiRef);
+                if (tagClassMimeRef != IntPtr.Zero) NativeMethods.CFRelease(tagClassMimeRef);
+                if (tagClassExtensionRef != IntPtr.Zero) NativeMethods.CFRelease(tagClassExtensionRef);
+                if (extensionRef != IntPtr.Zero) NativeMethods.CFRelease(extensionRef);
+            }
+        }
+
+        private static string? CFStringToManaged(IntPtr cfString)
+        {
+            var direct = NativeMethods.CFStringGetCStringPtr(cfString, NativeMethods.KCFStringEncodingUtf8);
+            if (direct != IntPtr.Zero)
+            {
+#if NETSTANDARD2_0
+                return Marshal.PtrToStringAnsi(direct);
+#else
+                return Marshal.PtrToStringUTF8(direct);
+#endif
+            }
+
+            var length = NativeMethods.CFStringGetLength(cfString);
+            var capacity = (int)(length * 3) + 1;
+            var buffer = new byte[capacity];
+
+            if (!NativeMethods.CFStringGetCString(cfString, buffer, capacity, NativeMethods.KCFStringEncodingUtf8))
+            {
+                return null;
+            }
+
+            var terminator = Array.IndexOf(buffer, (byte)0);
+            var count = terminator >= 0 ? terminator : buffer.Length;
+            return Encoding.UTF8.GetString(buffer, 0, count);
+        }
+
+        [ExcludeFromCodeCoverage]
+        internal static string? TryGetFromLinux(string extensionNoDot)
+        {
+            const string mimeTypesPath = "/etc/mime.types";
+
+            try
+            {
+                if (!File.Exists(mimeTypesPath))
+                {
+                    return null;
+                }
+
+                foreach (var rawLine in File.ReadLines(mimeTypesPath))
+                {
+                    var line = rawLine.Trim();
+                    if (line.Length == 0 || line[0] == '#')
+                    {
+                        continue;
+                    }
+
+                    var tokens = line.Split((char[])null!, StringSplitOptions.RemoveEmptyEntries);
+                    if (tokens.Length < 2)
+                    {
+                        continue;
+                    }
+
+                    for (var i = 1; i < tokens.Length; i++)
+                    {
+                        if (tokens[i].Equals(extensionNoDot, StringComparison.OrdinalIgnoreCase))
+                        {
+                            return LooksLikeMimeType(tokens[0]) ? tokens[0] : null;
+                        }
+                    }
+                }
+
+                return null;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        [ExcludeFromCodeCoverage]
+        private static class NativeMethods
+        {
+            internal const int AssocfNone = 0;
+            internal const int AssocStrContentType = 14;
+
+            [DllImport("Shlwapi.dll", CharSet = CharSet.Unicode, ExactSpelling = true, EntryPoint = "AssocQueryStringW")]
+            internal static extern int AssocQueryStringW(int flags, int str, string pszAssoc, string? pszExtra, [Out] char[]? pszOut, ref uint pcchOut);
+
+            private const string CoreFoundation = "/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation";
+            private const string CoreServices = "/System/Library/Frameworks/CoreServices.framework/CoreServices";
+
+            internal const uint KCFStringEncodingUtf8 = 0x08000100;
+
+            [DllImport(CoreFoundation)]
+            internal static extern IntPtr CFStringCreateWithCString(IntPtr alloc, [MarshalAs(UnmanagedType.LPStr)] string cStr, uint encoding);
+
+            [DllImport(CoreFoundation)]
+            internal static extern void CFRelease(IntPtr cf);
+
+            [DllImport(CoreFoundation)]
+            internal static extern IntPtr CFStringGetCStringPtr(IntPtr theString, uint encoding);
+
+            [DllImport(CoreFoundation)]
+            [return: MarshalAs(UnmanagedType.I1)]
+            internal static extern bool CFStringGetCString(IntPtr theString, [Out] byte[] buffer, long bufferSize, uint encoding);
+
+            [DllImport(CoreFoundation)]
+            internal static extern long CFStringGetLength(IntPtr theString);
+
+            [DllImport(CoreServices)]
+            internal static extern IntPtr UTTypeCreatePreferredIdentifierForTag(IntPtr inTagClass, IntPtr inTag, IntPtr inConformingToUti);
+
+            [DllImport(CoreServices)]
+            internal static extern IntPtr UTTypeCopyPreferredTagWithClass(IntPtr inUti, IntPtr inTagClass);
+        }
+#endif
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Network/RNetworkLoader.cs b/Source/HtmlRenderer/Core/Network/RNetworkLoader.cs
new file mode 100644
index 000000000..566736df4
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/RNetworkLoader.cs
@@ -0,0 +1,37 @@
+#nullable enable
+using System.Threading.Tasks;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// Controls how the root HTML document and every external resource it references (stylesheets,
+    /// images, <c>@font-face</c> fonts) is loaded. Set an instance on <see cref="Adapters.RAdapter.NetworkLoader"/>
+    /// to integrate with a custom resource source (a cloud blob store, a bundler manifest, an in-memory
+    /// dictionary, etc.). Three concrete implementations are provided: <see cref="DataUriNetworkLoader"/>
+    /// (the default when none is configured), <see cref="FileUriNetworkLoader"/> for local files, and
+    /// <see cref="HttpClientNetworkLoader"/> for HTTP(S) sources. <c>data:</c> URIs are always handled
+    /// internally regardless of which loader is configured, as are <c>file:</c> URIs unless
+    /// <see cref="Adapters.RAdapter.AllowLocalFileAccess"/> is set to <c>false</c>, which refuses them outright.
+    /// </summary>
+    public abstract class RNetworkLoader
+    {
+        /// <summary>
+        /// Returns the root HTML document as a string. Called once at the start of rendering when no HTML
+        /// string is given directly to the render/generate call.
+        /// </summary>
+        public abstract Task<string> GetPrimaryContents();
+
+        /// <summary>
+        /// Returns the content of an external resource (a stylesheet, image, or font) referenced by the
+        /// document, or <c>null</c> if the resource cannot be resolved.
+        /// </summary>
+        /// <param name="uri">The resource URI, resolved against <see cref="BaseUri"/> or a <c>&lt;base href&gt;</c> element if relative.</param>
+        public abstract Task<RNetworkResponse?> GetResourceStream(RUri uri);
+
+        /// <summary>
+        /// The document's base URL, used to resolve relative <c>href</c>, <c>src</c>, and CSS <c>url()</c>
+        /// references. If <c>null</c>, relative references are resolved against the local file system.
+        /// </summary>
+        public abstract RUri? BaseUri { get; }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Network/RNetworkResponse.cs b/Source/HtmlRenderer/Core/Network/RNetworkResponse.cs
new file mode 100644
index 000000000..9430b075d
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/RNetworkResponse.cs
@@ -0,0 +1,16 @@
+#nullable enable
+using System.Collections.Generic;
+using System.IO;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// The result of resolving a resource URI via <see cref="RNetworkLoader.GetResourceStream"/>.
+    /// </summary>
+    /// <param name="ResourceStream">The resource's content stream, or <c>null</c> if the resource has no body.</param>
+    /// <param name="ResponseHeaders">
+    /// HTTP-style response headers for the resource, if any. For stylesheet resources, this is inspected
+    /// for a <c>Content-Type</c> header and the body is only accepted as CSS when it is <c>text/css</c>.
+    /// </param>
+    public record RNetworkResponse(Stream? ResourceStream, Dictionary<string, string[]>? ResponseHeaders);
+}
diff --git a/Source/HtmlRenderer/Core/Network/RUri.cs b/Source/HtmlRenderer/Core/Network/RUri.cs
new file mode 100644
index 000000000..3ce99715f
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Network/RUri.cs
@@ -0,0 +1,138 @@
+#nullable enable
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Network
+{
+    /// <summary>
+    /// Wraps <see cref="System.Uri"/> for use throughout the resource-loading pipeline, adding
+    /// special-case handling for <c>data:</c> URIs (which <see cref="System.Uri"/> can parse but cannot
+    /// round-trip correctly through <see cref="AbsoluteUri"/> on the target frameworks this library
+    /// supports) and helpers for resolving a relative URI against a base URI.
+    /// </summary>
+    public class RUri
+    {
+        private readonly Uri? _uri;
+        private readonly string? _originalUri;
+
+        /// <summary>
+        /// Parses <paramref name="uriString"/> as either an absolute or relative URI.
+        /// </summary>
+        /// <param name="uriString">The URI string to parse.</param>
+        public RUri(string uriString)
+        {
+            if (uriString is null) throw new ArgumentNullException(nameof(uriString));
+
+            if (uriString.StartsWith("data:"))
+            {
+                _originalUri = uriString;
+            }
+            else
+            {
+                _uri = new Uri(uriString);
+            }
+        }
+
+        /// <summary>
+        /// Parses <paramref name="uriString"/> as the given <paramref name="uriKind"/>.
+        /// </summary>
+        /// <param name="uriString">The URI string to parse.</param>
+        /// <param name="uriKind">Whether the string is known to be absolute, relative, or either.</param>
+        public RUri(string uriString, UriKind uriKind)
+        {
+            if (uriString.StartsWith("data:"))
+            {
+                _originalUri = uriString;
+            }
+            else
+            {
+                _uri = new Uri(uriString, uriKind);
+            }
+        }
+
+        /// <summary>
+        /// Resolves <paramref name="uri"/> against <paramref name="baseUri"/>, the same way a relative
+        /// <c>href</c>/<c>src</c>/<c>url()</c> reference is resolved against a document's base URL.
+        /// </summary>
+        /// <param name="baseUri">The base URI to resolve against.</param>
+        /// <param name="uri">The (typically relative) URI to resolve.</param>
+        public RUri(RUri baseUri, RUri uri)
+        {
+            if (uri.Scheme == "data")
+            {
+                // See the string-uri overload below for why data: URIs skip Uri-combining entirely.
+                _originalUri = uri.AbsoluteUri;
+            }
+            else
+            {
+                _uri = new Uri(baseUri.Uri, uri.Uri);
+            }
+        }
+
+        /// <summary>
+        /// Resolves <paramref name="uri"/> against <paramref name="baseUri"/>, the same way a relative
+        /// <c>href</c>/<c>src</c>/<c>url()</c> reference is resolved against a document's base URL.
+        /// </summary>
+        /// <param name="baseUri">The base URI to resolve against.</param>
+        /// <param name="uri">The (typically relative) URI string to resolve.</param>
+        public RUri(RUri baseUri, string uri)
+        {
+            if (uri.StartsWith("data:"))
+            {
+                // A data: URI is already absolute and has no hierarchical structure to resolve against a
+                // base - new Uri(baseUri, dataUriString) would just reproduce dataUriString verbatim, so
+                // skip the combine and store it directly, matching the single-string constructor's own
+                // data: fast path above. This isn't just an optimization: System.Uri's combining
+                // constructor (unlike its single-string constructor's data: handling one layer up in
+                // RUri's other constructor) has no such fast path of its own, and re-enables a legacy
+                // ~64K-character length limit on Windows-Desktop-targeting builds (net8.0-windows/net462 -
+                // confirmed via a throwaway repro project; a plain net8.0/net10.0 console app does not hit
+                // it) - a real image's base64 payload routinely exceeds that. Skipping the combine avoids
+                // the limit entirely for the one kind of reference it can never legitimately apply to.
+                _originalUri = uri;
+            }
+            else
+            {
+                _uri = new Uri(baseUri.Uri, uri);
+            }
+        }
+
+        /// <summary>
+        /// Wraps an existing <see cref="System.Uri"/> instance.
+        /// </summary>
+        /// <param name="uri">The URI to wrap.</param>
+        public RUri(Uri uri)
+        {
+            _uri = uri;
+        }
+
+        /// <summary>
+        /// The underlying <see cref="System.Uri"/>.
+        /// </summary>
+        public Uri Uri => _uri ?? new Uri(_originalUri!);
+
+        /// <summary>
+        /// The URI scheme (e.g. <c>https</c>, <c>file</c>, <c>data</c>).
+        /// </summary>
+        public string Scheme => _uri is not null ? _uri.Scheme : _originalUri!.Split(':')[0];
+
+        /// <summary>
+        /// The fully escaped absolute URI string.
+        /// </summary>
+        public string AbsoluteUri => _uri is not null ? _uri.AbsoluteUri : _originalUri!;
+
+        /// <summary>
+        /// The original, unescaped URI string as it was parsed.
+        /// </summary>
+        public string OriginalString => _uri is not null ? _uri.OriginalString : _originalUri!;
+
+        /// <summary>
+        /// Whether this instance represents an absolute URI.
+        /// </summary>
+        public bool IsAbsoluteUri => _uri?.IsAbsoluteUri ?? true;
+
+        /// <summary>
+        /// Whether this URI refers to a local file.
+        /// </summary>
+        public bool IsFile => _uri?.IsFile ?? false;
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Parse/CssParser.cs b/Source/HtmlRenderer/Core/Parse/CssParser.cs
index cb6ef8975..80ffa378e 100644
--- a/Source/HtmlRenderer/Core/Parse/CssParser.cs
+++ b/Source/HtmlRenderer/Core/Parse/CssParser.cs
@@ -1,4 +1,4 @@
-// "Therefore those skilled at the unorthodox
+// "Therefore those skilled at the unorthodox
 // are infinite as heaven and earth,
 // inexhaustible as the great rivers.
 // When they come to an end,
@@ -6,35 +6,35 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
 using System;
 using System.Collections.Generic;
-using System.Text;
-using System.Text.RegularExpressions;
+using System.Linq;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
+using TheArtOfDev.HtmlRenderer.Core.Handlers;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Parse
 {
     /// <summary>
-    /// Parser to parse CSS stylesheet source string into CSS objects.
+    /// Parser to parse CSS stylesheet source string into CSS objects.<br/>
+    /// Derived from the same CSS-OM lineage as the vendored engine, adapted to stay fully synchronous
+    /// (HTML-Renderer's whole SetHtml/DomParser pipeline is synchronous, and <see cref="StylesheetLoadHandler"/>
+    /// already does its own blocking I/O) - the recursive @import-walk logic is kept, just without
+    /// any Task/await plumbing.
     /// </summary>
     internal sealed class CssParser
     {
         #region Fields and Consts
 
         /// <summary>
-        /// split CSS rule
-        /// </summary>
-        private static readonly char[] _cssBlockSplitters = new[] { '}', ';' };
-
-        /// <summary>
-        /// 
+        /// The platform adapter.
         /// </summary>
         private readonly RAdapter _adapter;
 
@@ -44,9 +44,12 @@ internal sealed class CssParser
         private readonly CssValueParser _valueParser;
 
         /// <summary>
-        /// The chars to trim the css class name by
+        /// Used to resolve @import references (loads via the same synchronous, event-overridable
+        /// path as &lt;link rel=stylesheet&gt;). Null when this parser is used outside of a live
+        /// document parse (e.g. the public <see cref="CssData.Parse"/> convenience API) - in that
+        /// case @import rules are silently skipped, since there is no container to resolve them through.
         /// </summary>
-        private static readonly char[] _cssClassTrimChars = new[] { '\r', '\n', '\t', ' ', '-', '!', '<', '>' };
+        private readonly HtmlContainerInt _htmlContainer;
 
         #endregion
 
@@ -55,19 +58,27 @@ internal sealed class CssParser
         /// Init.
         /// </summary>
         public CssParser(RAdapter adapter)
+            : this(adapter, null)
+        {
+        }
+
+        /// <summary>
+        /// Init.
+        /// </summary>
+        public CssParser(RAdapter adapter, HtmlContainerInt htmlContainer)
         {
             ArgChecker.AssertArgNotNull(adapter, "global");
 
             _valueParser = new CssValueParser(adapter);
             _adapter = adapter;
+            _htmlContainer = htmlContainer;
         }
 
         /// <summary>
-        /// Parse the given stylesheet source to CSS blocks dictionary.<br/>
-        /// The CSS blocks are organized into two level buckets of media type and class name.<br/>
-        /// Root media type are found under 'all' bucket.<br/>
-        /// If <paramref name="combineWithDefault"/> is true the parsed css blocks are added to the 
-        /// default css data (as defined by W3), merged if class name already exists. If false only the data in the given stylesheet is returned.
+        /// Parse the given stylesheet source to a <see cref="CssData"/>.<br/>
+        /// If <paramref name="combineWithDefault"/> is true the parsed stylesheet is combined with a
+        /// clone of the default (UA) css data (as defined by W3) - a clone so the adapter's cached
+        /// default data is never mutated by this call. If false only the data in the given stylesheet is returned.
         /// </summary>
         /// <seealso cref="http://www.w3.org/TR/CSS21/sample.html"/>
         /// <param name="stylesheet">raw css stylesheet to parse</param>
@@ -84,49 +95,51 @@ public CssData ParseStyleSheet(string stylesheet, bool combineWithDefault)
         }
 
         /// <summary>
-        /// Parse the given stylesheet source to CSS blocks dictionary.<br/>
-        /// The CSS blocks are organized into two level buckets of media type and class name.<br/>
-        /// Root media type are found under 'all' bucket.<br/>
-        /// The parsed css blocks are added to the given css data, merged if class name already exists.
+        /// Parse raw CSS text into a <see cref="Stylesheet"/> object model (tokenizer + selector/value
+        /// grammar), with no cascade/box concerns at all - the thinnest possible entry point into the
+        /// vendored parser.
         /// </summary>
-        /// <param name="cssData">the CSS data to fill with parsed CSS objects</param>
-        /// <param name="stylesheet">raw css stylesheet to parse</param>
-        public void ParseStyleSheet(CssData cssData, string stylesheet)
+        public static Stylesheet ParseStyleSheetText(string stylesheet)
         {
-            if (!String.IsNullOrEmpty(stylesheet))
-            {
-                stylesheet = RemoveStylesheetComments(stylesheet);
-
-                ParseStyleBlocks(cssData, stylesheet);
-
-                ParseMediaStyleBlocks(cssData, stylesheet);
-            }
+            var parser = new StylesheetParser();
+            return parser.Parse(stylesheet);
         }
 
         /// <summary>
-        /// Parse single CSS block source into CSS block instance.
+        /// Parse the given stylesheet source and add its rules into the given css data (author origin),
+        /// recursively resolving @import rules (guarded against circular imports).
         /// </summary>
-        /// <param name="className">the name of the css class of the block</param>
-        /// <param name="blockSource">the CSS block to parse</param>
-        /// <returns>the created CSS block instance</returns>
-        public CssBlock ParseCssBlock(string className, string blockSource)
+        /// <param name="cssData">the CSS data to fill with parsed CSS objects</param>
+        /// <param name="stylesheet">raw css stylesheet to parse</param>
+        /// <param name="baseUri">
+        /// The resolved absolute URI this stylesheet was loaded from (e.g. a &lt;link&gt; href), so that
+        /// relative @import references inside it resolve against its own location rather than the
+        /// document's base. Null for inline &lt;style&gt; content or caller-supplied CSS text.
+        /// </param>
+        public void ParseStyleSheet(CssData cssData, string stylesheet, Uri baseUri = null)
         {
-            return ParseCssBlockImp(className, blockSource);
+            if (!string.IsNullOrEmpty(stylesheet))
+            {
+                ParseStyle(cssData, stylesheet, baseUri, new HashSet<string>());
+            }
         }
 
         /// <summary>
-        /// Parse a complex font family css property to check if it contains multiple fonts and if the font exists.<br/>
-        /// returns the font family name to use or 'inherit' if failed.
+        /// Parse a single inline style="" attribute value into its one resulting style rule, by
+        /// wrapping it in a synthetic universal-selector rule and parsing it through the same
+        /// tokenizer/grammar as a full stylesheet - so inline style values get exactly the same value
+        /// parsing (shorthands, calc(), var(), etc.) as anything from a &lt;style&gt; block.
         /// </summary>
-        /// <param name="value">the font-family value to parse</param>
-        /// <returns>parsed font-family value</returns>
-        public string ParseFontFamily(string value)
+        /// <param name="declarations">the raw declaration list, e.g. "color: red; font-weight: bold"</param>
+        /// <returns>the single parsed style rule, or null if the declaration block was empty/invalid</returns>
+        public IStyleRule ParseInlineStyle(string declarations)
         {
-            return ParseFontFamilyProperty(value);
+            var stylesheet = ParseStyleSheetText("* { " + declarations + " }");
+            return stylesheet.StyleRules.FirstOrDefault();
         }
 
         /// <summary>
-        /// Parses a color value in CSS style; e.g. #ff0000, red, rgb(255,0,0), rgb(100%, 0, 0) 
+        /// Parses a color value in CSS style; e.g. #ff0000, red, rgb(255,0,0), rgb(100%, 0, 0)
         /// </summary>
         /// <param name="colorStr">color string value to parse</param>
         /// <returns>color value</returns>
@@ -135,829 +148,135 @@ public RColor ParseColor(string colorStr)
             return _valueParser.GetActualColor(colorStr);
         }
 
-
-        #region Private methods
-
-        /// <summary>
-        /// Remove comments from the given stylesheet.
-        /// </summary>
-        /// <param name="stylesheet">the stylesheet to remove comments from</param>
-        /// <returns>stylesheet without comments</returns>
-        private static string RemoveStylesheetComments(string stylesheet)
-        {
-            StringBuilder sb = null;
-
-            int prevIdx = 0, startIdx = 0;
-            while (startIdx > -1 && startIdx < stylesheet.Length)
-            {
-                startIdx = stylesheet.IndexOf("/*", startIdx);
-                if (startIdx > -1)
-                {
-                    if (sb == null)
-                        sb = new StringBuilder(stylesheet.Length);
-                    sb.Append(stylesheet.Substring(prevIdx, startIdx - prevIdx));
-
-                    var endIdx = stylesheet.IndexOf("*/", startIdx + 2);
-                    if (endIdx < 0)
-                        endIdx = stylesheet.Length;
-
-                    prevIdx = startIdx = endIdx + 2;
-                }
-                else if (sb != null)
-                {
-                    sb.Append(stylesheet.Substring(prevIdx));
-                }
-            }
-
-            return sb != null ? sb.ToString() : stylesheet;
-        }
-
-        /// <summary>
-        /// Parse given stylesheet for CSS blocks<br/>
-        /// This blocks are added under the "all" keyword.
-        /// </summary>
-        /// <param name="cssData">the CSS data to fill with parsed CSS objects</param>
-        /// <param name="stylesheet">the stylesheet to parse</param>
-        private void ParseStyleBlocks(CssData cssData, string stylesheet)
-        {
-            var startIdx = 0;
-            int endIdx = 0;
-            while (startIdx < stylesheet.Length && endIdx > -1)
-            {
-                endIdx = startIdx;
-                while (endIdx + 1 < stylesheet.Length)
-                {
-                    endIdx++;
-                    if (stylesheet[endIdx] == '}')
-                        startIdx = endIdx + 1;
-                    if (stylesheet[endIdx] == '{')
-                        break;
-                }
-
-                int midIdx = endIdx + 1;
-                if (endIdx > -1)
-                {
-                    endIdx++;
-                    while (endIdx < stylesheet.Length)
-                    {
-                        if (stylesheet[endIdx] == '{')
-                            startIdx = midIdx + 1;
-                        if (stylesheet[endIdx] == '}')
-                            break;
-                        endIdx++;
-                    }
-
-                    if (endIdx < stylesheet.Length)
-                    {
-                        while (Char.IsWhiteSpace(stylesheet[startIdx]))
-                            startIdx++;
-                        var substring = stylesheet.Substring(startIdx, endIdx - startIdx + 1);
-                        FeedStyleBlock(cssData, substring);
-                    }
-                    startIdx = endIdx + 1;
-                }
-            }
-        }
-
-        /// <summary>
-        /// Parse given stylesheet for media CSS blocks<br/>
-        /// This blocks are added under the specific media block they are found.
-        /// </summary>
-        /// <param name="cssData">the CSS data to fill with parsed CSS objects</param>
-        /// <param name="stylesheet">the stylesheet to parse</param>
-        private void ParseMediaStyleBlocks(CssData cssData, string stylesheet)
-        {
-            int startIdx = 0;
-            string atrule;
-            while ((atrule = RegexParserUtils.GetCssAtRules(stylesheet, ref startIdx)) != null)
-            {
-                //Just process @media rules
-                if (!atrule.StartsWith("@media", StringComparison.InvariantCultureIgnoreCase))
-                    continue;
-
-                //Extract specified media types
-                MatchCollection types = RegexParserUtils.Match(RegexParserUtils.CssMediaTypes, atrule);
-
-                if (types.Count == 1)
-                {
-                    string line = types[0].Value;
-
-                    if (line.StartsWith("@media", StringComparison.InvariantCultureIgnoreCase) && line.EndsWith("{"))
-                    {
-                        //Get specified media types in the at-rule
-                        string[] media = line.Substring(6, line.Length - 7).Split(' ');
-
-                        //Scan media types
-                        foreach (string t in media)
-                        {
-                            if (!String.IsNullOrEmpty(t.Trim()))
-                            {
-                                //Get blocks inside the at-rule
-                                var insideBlocks = RegexParserUtils.Match(RegexParserUtils.CssBlocks, atrule);
-
-                                //Scan blocks and feed them to the style sheet
-                                foreach (Match insideBlock in insideBlocks)
-                                {
-                                    FeedStyleBlock(cssData, insideBlock.Value, t.Trim());
-                                }
-                            }
-                        }
-                    }
-                }
-            }
-        }
-
-        /// <summary>
-        /// Feeds the style with a block about the specific media.<br/>
-        /// When no media is specified, "all" will be used.
-        /// </summary>
-        /// <param name="cssData"> </param>
-        /// <param name="block">the CSS block to handle</param>
-        /// <param name="media">optional: the media (default - all)</param>
-        private void FeedStyleBlock(CssData cssData, string block, string media = "all")
-        {
-            int startIdx = block.IndexOf("{", StringComparison.Ordinal);
-            int endIdx = startIdx > -1 ? block.IndexOf("}", startIdx) : -1;
-            if (startIdx > -1 && endIdx > -1)
-            {
-                string blockSource = block.Substring(startIdx + 1, endIdx - startIdx - 1);
-                var classes = block.Substring(0, startIdx).Split(',');
-
-                foreach (string cls in classes)
-                {
-                    string className = cls.Trim(_cssClassTrimChars);
-                    if (!String.IsNullOrEmpty(className))
-                    {
-                        var newblock = ParseCssBlockImp(className, blockSource);
-                        if (newblock != null)
-                        {
-                            cssData.AddCssBlock(media, newblock);
-                        }
-                    }
-                }
-            }
-        }
-
-        /// <summary>
-        /// Parse single CSS block source into CSS block instance.
-        /// </summary>
-        /// <param name="className">the name of the css class of the block</param>
-        /// <param name="blockSource">the CSS block to parse</param>
-        /// <returns>the created CSS block instance</returns>
-        private CssBlock ParseCssBlockImp(string className, string blockSource)
-        {
-            className = className.ToLower();
-            string psedoClass = null;
-            var colonIdx = className.IndexOf(":", StringComparison.Ordinal);
-            if (colonIdx > -1 && !className.StartsWith("::"))
-            {
-                psedoClass = colonIdx < className.Length - 1 ? className.Substring(colonIdx + 1).Trim() : null;
-                className = className.Substring(0, colonIdx).Trim();
-            }
-
-            if (!string.IsNullOrEmpty(className) && (psedoClass == null || psedoClass == "link" || psedoClass == "hover"))
-            {
-                string firstClass;
-                var selectors = ParseCssBlockSelector(className, out firstClass);
-
-                var properties = ParseCssBlockProperties(blockSource);
-
-                return new CssBlock(firstClass, properties, selectors, psedoClass == "hover");
-            }
-
-            return null;
-        }
-
-        /// <summary>
-        /// Parse css block selector to support hierarchical selector (p class1 > class2).
-        /// </summary>
-        /// <param name="className">the class selector to parse</param>
-        /// <param name="firstClass">return the main class the css block is on</param>
-        /// <returns>returns the hierarchy of classes or null if single class selector</returns>
-        private static List<CssBlockSelectorItem> ParseCssBlockSelector(string className, out string firstClass)
-        {
-            List<CssBlockSelectorItem> selectors = null;
-
-            firstClass = null;
-            int endIdx = className.Length - 1;
-            while (endIdx > -1)
-            {
-                bool directParent = false;
-                while (char.IsWhiteSpace(className[endIdx]) || className[endIdx] == '>')
-                {
-                    directParent = directParent || className[endIdx] == '>';
-                    endIdx--;
-                }
-
-                var startIdx = endIdx;
-                while (startIdx > -1 && !char.IsWhiteSpace(className[startIdx]) && className[startIdx] != '>')
-                    startIdx--;
-
-                if (startIdx > -1)
-                {
-                    if (selectors == null)
-                        selectors = new List<CssBlockSelectorItem>();
-
-                    var subclass = className.Substring(startIdx + 1, endIdx - startIdx);
-
-                    if (firstClass == null)
-                    {
-                        firstClass = subclass;
-                    }
-                    else
-                    {
-                        while (char.IsWhiteSpace(className[startIdx]) || className[startIdx] == '>')
-                            startIdx--;
-                        selectors.Add(new CssBlockSelectorItem(subclass, directParent));
-                    }
-                }
-                else if (firstClass != null)
-                {
-                    selectors.Add(new CssBlockSelectorItem(className.Substring(0, endIdx + 1), directParent));
-                }
-
-                endIdx = startIdx;
-            }
-
-            firstClass = firstClass ?? className;
-            return selectors;
-        }
-
-        /// <summary>
-        /// Parse the properties of the given css block into a key-value dictionary.
-        /// </summary>
-        /// <param name="blockSource">the raw css block to parse</param>
-        /// <returns>dictionary with parsed css block properties</returns>
-        private Dictionary<string, string> ParseCssBlockProperties(string blockSource)
-        {
-            var properties = new Dictionary<string, string>();
-            int startIdx = 0;
-            while (startIdx < blockSource.Length)
-            {
-                int endIdx = blockSource.IndexOfAny(_cssBlockSplitters, startIdx);
-
-                // If blockSource contains "data:image" then skip first semicolon since it is a part of image definition
-                // example: "url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAA......"
-                if (startIdx >= 0 && endIdx - startIdx >= 10 && blockSource.Length - startIdx >= 10 && blockSource.IndexOf("data:image", startIdx, endIdx - startIdx) >= 0)
-                    endIdx = blockSource.IndexOfAny(_cssBlockSplitters, endIdx + 1);
-
-                if (endIdx < 0)
-                    endIdx = blockSource.Length - 1;
-
-                var splitIdx = blockSource.IndexOf(':', startIdx, endIdx - startIdx);
-                if (splitIdx > -1)
-                {
-                    //Extract property name and value
-                    startIdx = startIdx + (blockSource[startIdx] == ' ' ? 1 : 0);
-                    var adjEndIdx = endIdx - (blockSource[endIdx] == ' ' || blockSource[endIdx] == ';' ? 1 : 0);
-                    string propName = blockSource.Substring(startIdx, splitIdx - startIdx).Trim().ToLower();
-                    splitIdx = splitIdx + (blockSource[splitIdx + 1] == ' ' ? 2 : 1);
-                    if (adjEndIdx >= splitIdx)
-                    {
-                        string propValue = blockSource.Substring(splitIdx, adjEndIdx - splitIdx + 1).Trim();
-                        if (!propValue.StartsWith("url", StringComparison.InvariantCultureIgnoreCase))
-                            propValue = propValue.ToLower();
-                        AddProperty(propName, propValue, properties);
-                    }
-                }
-                startIdx = endIdx + 1;
-            }
-            return properties;
-        }
-
         /// <summary>
-        /// Add the given property to the given properties collection, if the property is complex containing
-        /// multiple css properties then parse them and add the inner properties.
+        /// Checks if the given color value can be resolved to an actual color.
         /// </summary>
-        /// <param name="propName">the name of the css property to add</param>
-        /// <param name="propValue">the value of the css property to add</param>
-        /// <param name="properties">the properties collection to add to</param>
-        private void AddProperty(string propName, string propValue, Dictionary<string, string> properties)
+        public bool IsColorValid(string colorValue)
         {
-            // remove !important css crap
-            propValue = propValue.Replace("!important", string.Empty).Trim();
-
-            if (propName == "width" || propName == "height" || propName == "lineheight")
-            {
-                ParseLengthProperty(propName, propValue, properties);
-            }
-            else if (propName == "color" || propName == "backgroundcolor" || propName == "bordertopcolor" || propName == "borderbottomcolor" || propName == "borderleftcolor" || propName == "borderrightcolor")
-            {
-                ParseColorProperty(propName, propValue, properties);
-            }
-            else if (propName == "font")
-            {
-                ParseFontProperty(propValue, properties);
-            }
-            else if (propName == "border")
-            {
-                ParseBorderProperty(propValue, null, properties);
-            }
-            else if (propName == "border-left")
-            {
-                ParseBorderProperty(propValue, "-left", properties);
-            }
-            else if (propName == "border-top")
-            {
-                ParseBorderProperty(propValue, "-top", properties);
-            }
-            else if (propName == "border-right")
-            {
-                ParseBorderProperty(propValue, "-right", properties);
-            }
-            else if (propName == "border-bottom")
-            {
-                ParseBorderProperty(propValue, "-bottom", properties);
-            }
-            else if (propName == "margin")
-            {
-                ParseMarginProperty(propValue, properties);
-            }
-            else if (propName == "border-style")
-            {
-                ParseBorderStyleProperty(propValue, properties);
-            }
-            else if (propName == "border-width")
-            {
-                ParseBorderWidthProperty(propValue, properties);
-            }
-            else if (propName == "border-color")
-            {
-                ParseBorderColorProperty(propValue, properties);
-            }
-            else if (propName == "padding")
-            {
-                ParsePaddingProperty(propValue, properties);
-            }
-            else if (propName == "background-image")
-            {
-                properties["background-image"] = ParseImageProperty(propValue);
-            }
-            else if (propName == "content")
-            {
-                properties["content"] = ParseImageProperty(propValue);
-            }
-            else if (propName == "font-family")
-            {
-                properties["font-family"] = ParseFontFamilyProperty(propValue);
-            }
-            else
-            {
-                properties[propName] = propValue;
-            }
+            return _valueParser.IsColorValid(colorValue);
         }
 
         /// <summary>
-        /// Parse length property to add only valid lengths.
+        /// Parses a "background-image" value into a url() reference or a linear-gradient() - see
+        /// <see cref="CssValueParser.ParseImage"/>.
         /// </summary>
-        /// <param name="propName">the name of the css property to add</param>
-        /// <param name="propValue">the value of the css property to add</param>
-        /// <param name="properties">the properties collection to add to</param>
-        private static void ParseLengthProperty(string propName, string propValue, Dictionary<string, string> properties)
+        public CssImage ParseBackgroundImage(string value)
         {
-            if (CssValueParser.IsValidLength(propValue) || propValue.Equals(CssConstants.Auto, StringComparison.OrdinalIgnoreCase))
-            {
-                properties[propName] = propValue;
-            }
+            return _valueParser.ParseImage(value);
         }
 
         /// <summary>
-        /// Parse color property to add only valid color.
+        /// Parse a "font-family" value - possibly a comma-separated fallback list, each candidate
+        /// possibly quoted (e.g. <c>'Helvetica Neue', Arial, sans-serif</c>) - into the first
+        /// candidate that's actually installed/registered, or <see cref="CssConstants.DefaultFont"/>
+        /// if none of them are. Previously returned the literal string "inherit" as a not-found
+        /// sentinel, which was confusable with the real CSS <c>inherit</c> keyword downstream.
         /// </summary>
-        /// <param name="propName">the name of the css property to add</param>
-        /// <param name="propValue">the value of the css property to add</param>
-        /// <param name="properties">the properties collection to add to</param>
-        private void ParseColorProperty(string propName, string propValue, Dictionary<string, string> properties)
-        {
-            if (_valueParser.IsColorValid(propValue))
-            {
-                properties[propName] = propValue;
-            }
-        }
-
-        /// <summary>
-        /// Parse a complex font property value that contains multiple css properties into specific css properties.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse to specific values</param>
-        /// <param name="properties">the properties collection to add the specific properties to</param>
-        private void ParseFontProperty(string propValue, Dictionary<string, string> properties)
-        {
-            int mustBePos;
-            string mustBe = RegexParserUtils.Search(RegexParserUtils.CssFontSizeAndLineHeight, propValue, out mustBePos);
-
-            if (!string.IsNullOrEmpty(mustBe))
-            {
-                mustBe = mustBe.Trim();
-                //Check for style||variant||weight on the left
-                string leftSide = propValue.Substring(0, mustBePos);
-                string fontStyle = RegexParserUtils.Search(RegexParserUtils.CssFontStyle, leftSide);
-                string fontVariant = RegexParserUtils.Search(RegexParserUtils.CssFontVariant, leftSide);
-                string fontWeight = RegexParserUtils.Search(RegexParserUtils.CssFontWeight, leftSide);
-
-                //Check for family on the right
-                string rightSide = propValue.Substring(mustBePos + mustBe.Length);
-                string fontFamily = rightSide.Trim(); //Parser.Search(Parser.CssFontFamily, rightSide); //TODO: Would this be right?
-
-                //Check for font-size and line-height
-                string fontSize = mustBe;
-                string lineHeight = string.Empty;
-
-                if (mustBe.Contains("/") && mustBe.Length > mustBe.IndexOf("/", StringComparison.Ordinal) + 1)
-                {
-                    int slashPos = mustBe.IndexOf("/", StringComparison.Ordinal);
-                    fontSize = mustBe.Substring(0, slashPos);
-                    lineHeight = mustBe.Substring(slashPos + 1);
-                }
-
-                if (!string.IsNullOrEmpty(fontFamily))
-                    properties["font-family"] = ParseFontFamilyProperty(fontFamily);
-                if (!string.IsNullOrEmpty(fontStyle))
-                    properties["font-style"] = fontStyle;
-                if (!string.IsNullOrEmpty(fontVariant))
-                    properties["font-variant"] = fontVariant;
-                if (!string.IsNullOrEmpty(fontWeight))
-                    properties["font-weight"] = fontWeight;
-                if (!string.IsNullOrEmpty(fontSize))
-                    properties["font-size"] = fontSize;
-                if (!string.IsNullOrEmpty(lineHeight))
-                    properties["line-height"] = lineHeight;
-            }
-            else
-            {
-                // Check for: caption | icon | menu | message-box | small-caption | status-bar
-                //TODO: Interpret font values of: caption | icon | menu | message-box | small-caption | status-bar
-            }
-        }
-
-        /// <summary>
-        /// 
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse</param>
-        /// <returns>parsed value</returns>
-        private static string ParseImageProperty(string propValue)
-        {
-            int startIdx = propValue.IndexOf("url(", StringComparison.InvariantCultureIgnoreCase);
-            if (startIdx > -1)
-            {
-                startIdx += 4;
-                var endIdx = propValue.IndexOf(')', startIdx);
-                if (endIdx > -1)
-                {
-                    endIdx -= 1;
-                    while (startIdx < endIdx && (char.IsWhiteSpace(propValue[startIdx]) || propValue[startIdx] == '\'' || propValue[startIdx] == '"'))
-                        startIdx++;
-                    while (startIdx < endIdx && (char.IsWhiteSpace(propValue[endIdx]) || propValue[endIdx] == '\'' || propValue[endIdx] == '"'))
-                        endIdx--;
-
-                    if (startIdx <= endIdx)
-                        return propValue.Substring(startIdx, endIdx - startIdx + 1);
-                }
-            }
-            return propValue;
-        }
-
-        /// <summary>
-        /// Parse a complex font family css property to check if it contains multiple fonts and if the font exists.<br/>
-        /// returns the font family name to use or 'inherit' if failed.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse</param>
+        /// <param name="value">the font-family value to parse</param>
         /// <returns>parsed font-family value</returns>
-        private string ParseFontFamilyProperty(string propValue)
+        public string ParseFontFamily(string value)
         {
             int start = 0;
 
-            while (start < propValue.Length)
+            while (start < value.Length)
             {
-                while (start < propValue.Length && (char.IsWhiteSpace(propValue[start]) || propValue[start] == ',' || propValue[start] == '\'' || propValue[start] == '"'))
+                while (start < value.Length && (char.IsWhiteSpace(value[start]) || value[start] == ',' || value[start] == '\'' || value[start] == '"'))
                     start++;
-                var end = propValue.IndexOf(',', start);
+                var end = value.IndexOf(',', start);
                 if (end < 0)
-                    end = propValue.Length;
+                    end = value.Length;
                 var adjEnd = end - 1;
-                while (char.IsWhiteSpace(propValue[adjEnd]) || propValue[adjEnd] == '\'' || propValue[adjEnd] == '"')
+                while (adjEnd > start && (char.IsWhiteSpace(value[adjEnd]) || value[adjEnd] == '\'' || value[adjEnd] == '"'))
                     adjEnd--;
 
-                var font = propValue.Substring(start, adjEnd - start + 1);
-
-                if (_adapter.IsFontExists(font))
-                    return font;
-
-                start = end;
-            }
-
-            return CssConstants.Inherit;
-        }
-
-        /// <summary>
-        /// Parse a complex border property value that contains multiple css properties into specific css properties.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse to specific values</param>
-        /// <param name="direction">the left, top, right or bottom direction of the border to parse</param>
-        /// <param name="properties">the properties collection to add the specific properties to</param>
-        private void ParseBorderProperty(string propValue, string direction, Dictionary<string, string> properties)
-        {
-            string borderWidth;
-            string borderStyle;
-            string borderColor;
-            ParseBorder(propValue, out borderWidth, out borderStyle, out borderColor);
+                if (adjEnd >= start)
+                {
+                    var font = value.Substring(start, adjEnd - start + 1);
+                    if (_adapter.IsFontExists(font))
+                        return font;
+                }
 
-            if (direction != null)
-            {
-                if (borderWidth != null)
-                    properties["border" + direction + "-width"] = borderWidth;
-                if (borderStyle != null)
-                    properties["border" + direction + "-style"] = borderStyle;
-                if (borderColor != null)
-                    properties["border" + direction + "-color"] = borderColor;
+                start = end + 1;
             }
-            else
-            {
-                if (borderWidth != null)
-                    ParseBorderWidthProperty(borderWidth, properties);
-                if (borderStyle != null)
-                    ParseBorderStyleProperty(borderStyle, properties);
-                if (borderColor != null)
-                    ParseBorderColorProperty(borderColor, properties);
-            }
-        }
-
-        /// <summary>
-        /// Parse a complex margin property value that contains multiple css properties into specific css properties.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse to specific values</param>
-        /// <param name="properties">the properties collection to add the specific properties to</param>
-        private static void ParseMarginProperty(string propValue, Dictionary<string, string> properties)
-        {
-            string bottom, top, left, right;
-            SplitMultiDirectionValues(propValue, out left, out top, out right, out bottom);
-
-            if (left != null)
-                properties["margin-left"] = left;
-            if (top != null)
-                properties["margin-top"] = top;
-            if (right != null)
-                properties["margin-right"] = right;
-            if (bottom != null)
-                properties["margin-bottom"] = bottom;
-        }
-
-        /// <summary>
-        /// Parse a complex border style property value that contains multiple css properties into specific css properties.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse to specific values</param>
-        /// <param name="properties">the properties collection to add the specific properties to</param>
-        private static void ParseBorderStyleProperty(string propValue, Dictionary<string, string> properties)
-        {
-            string bottom, top, left, right;
-            SplitMultiDirectionValues(propValue, out left, out top, out right, out bottom);
-
-            if (left != null)
-                properties["border-left-style"] = left;
-            if (top != null)
-                properties["border-top-style"] = top;
-            if (right != null)
-                properties["border-right-style"] = right;
-            if (bottom != null)
-                properties["border-bottom-style"] = bottom;
-        }
 
-        /// <summary>
-        /// Parse a complex border width property value that contains multiple css properties into specific css properties.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse to specific values</param>
-        /// <param name="properties">the properties collection to add the specific properties to</param>
-        private static void ParseBorderWidthProperty(string propValue, Dictionary<string, string> properties)
-        {
-            string bottom, top, left, right;
-            SplitMultiDirectionValues(propValue, out left, out top, out right, out bottom);
-
-            if (left != null)
-                properties["border-left-width"] = left;
-            if (top != null)
-                properties["border-top-width"] = top;
-            if (right != null)
-                properties["border-right-width"] = right;
-            if (bottom != null)
-                properties["border-bottom-width"] = bottom;
+            return CssConstants.DefaultFont;
         }
 
-        /// <summary>
-        /// Parse a complex border color property value that contains multiple css properties into specific css properties.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse to specific values</param>
-        /// <param name="properties">the properties collection to add the specific properties to</param>
-        private static void ParseBorderColorProperty(string propValue, Dictionary<string, string> properties)
-        {
-            string bottom, top, left, right;
-            SplitMultiDirectionValues(propValue, out left, out top, out right, out bottom);
-
-            if (left != null)
-                properties["border-left-color"] = left;
-            if (top != null)
-                properties["border-top-color"] = top;
-            if (right != null)
-                properties["border-right-color"] = right;
-            if (bottom != null)
-                properties["border-bottom-color"] = bottom;
-        }
+        #region Private methods
 
-        /// <summary>
-        /// Parse a complex padding property value that contains multiple css properties into specific css properties.
-        /// </summary>
-        /// <param name="propValue">the value of the property to parse to specific values</param>
-        /// <param name="properties">the properties collection to add the specific properties to</param>
-        private static void ParsePaddingProperty(string propValue, Dictionary<string, string> properties)
+        private void ParseStyle(CssData data, string stylesheetText, Uri baseUri, HashSet<string> visitedImportUris)
         {
-            string bottom, top, left, right;
-            SplitMultiDirectionValues(propValue, out left, out top, out right, out bottom);
-
-            if (left != null)
-                properties["padding-left"] = left;
-            if (top != null)
-                properties["padding-top"] = top;
-            if (right != null)
-                properties["padding-right"] = right;
-            if (bottom != null)
-                properties["padding-bottom"] = bottom;
-        }
+            var stylesheet = ParseStyleSheetText(stylesheetText);
+            stylesheet.BaseUri = baseUri;
 
-        /// <summary>
-        /// Split multi direction value into the proper direction values (left, top, right, bottom).
-        /// </summary>
-        private static void SplitMultiDirectionValues(string propValue, out string left, out string top, out string right, out string bottom)
-        {
-            top = null;
-            left = null;
-            right = null;
-            bottom = null;
-            string[] values = SplitValues(propValue);
-            switch (values.Length)
+            // Guards against circular @import chains (A imports B imports A) recursing forever; also
+            // stops a stylesheet from importing itself directly.
+            if (baseUri != null)
             {
-                case 1:
-                    top = left = right = bottom = values[0];
-                    break;
-                case 2:
-                    top = bottom = values[0];
-                    left = right = values[1];
-                    break;
-                case 3:
-                    top = values[0];
-                    left = right = values[1];
-                    bottom = values[2];
-                    break;
-                case 4:
-                    top = values[0];
-                    right = values[1];
-                    bottom = values[2];
-                    left = values[3];
-                    break;
+                visitedImportUris.Add(baseUri.AbsoluteUri);
             }
-        }
 
-        /// <summary>
-        /// Split the value by the specified separator; e.g. Useful in values like 'padding:5 4 3 inherit'
-        /// </summary>
-        /// <param name="value">Value to be splitted</param>
-        /// <param name="separator"> </param>
-        /// <returns>Splitted and trimmed values</returns>
-        private static string[] SplitValues(string value, char separator = ' ')
-        {
-            //TODO: CRITICAL! Don't split values on parenthesis (like rgb(0, 0, 0)) or quotes ("strings")
+            var hasReachedNonImportRules = false;
 
-            if (!string.IsNullOrEmpty(value))
+            foreach (var rule in stylesheet.Children)
             {
-                string[] values = value.Split(separator);
-                List<string> result = new List<string>();
-
-                foreach (string t in values)
+                var importRule = rule as IImportRule;
+                if (importRule != null && !hasReachedNonImportRules)
                 {
-                    string val = t.Trim();
+                    if (importRule.Href == null || _htmlContainer == null) continue;
 
-                    if (!string.IsNullOrEmpty(val))
+                    // Relative references inside an already-loaded stylesheet resolve against that
+                    // stylesheet's own location, not the document's base.
+                    var resolvedHref = ResolveImportHref(importRule.Href, baseUri);
+
+                    // Bridges into the async StylesheetLoadHandler.LoadStylesheet from this synchronous
+                    // CssParser.ParseStyleSheet public API. Deliberately, permanently blocking: this
+                    // method is called directly from several WinForms/WPF UI controls' own public API
+                    // (HtmlPanel/HtmlLabel/HtmlToolTip's BaseStylesheet-adjacent paths), so making it async
+                    // would ripple into a much larger, unrelated public-API break well beyond this
+                    // @font-face/network conversion's scope - not a temporary stopgap awaiting a later stage.
+                    var (importedContent, importedCssData) = StylesheetLoadHandler.LoadStylesheet(_htmlContainer, resolvedHref, null).GetAwaiter().GetResult();
+
+                    if (!string.IsNullOrEmpty(importedContent))
+                    {
+                        var importedUri = CommonUtils.TryGetUri(resolvedHref);
+                        if (importedUri == null || visitedImportUris.Add(importedUri.AbsoluteUri))
+                        {
+                            ParseStyle(data, importedContent, importedUri, visitedImportUris);
+                        }
+                    }
+                    else if (importedCssData != null)
                     {
-                        result.Add(val);
+                        data.Combine(importedCssData);
                     }
                 }
-
-                return result.ToArray();
-            }
-
-            return new string[0];
-        }
-
-        /// <summary>
-        /// 
-        /// </summary>
-        /// <param name="value"></param>
-        /// <param name="width"> </param>
-        /// <param name="style"></param>
-        /// <param name="color"></param>
-        public void ParseBorder(string value, out string width, out string style, out string color)
-        {
-            width = style = color = null;
-            if (!string.IsNullOrEmpty(value))
-            {
-                int idx = 0;
-                int length;
-                while ((idx = CommonUtils.GetNextSubString(value, idx, out length)) > -1)
+                else if (!(rule is LayerStatementRule))
                 {
-                    if (width == null)
-                        width = ParseBorderWidth(value, idx, length);
-                    if (style == null)
-                        style = ParseBorderStyle(value, idx, length);
-                    if (color == null)
-                        color = ParseBorderColor(value, idx, length);
-                    idx = idx + length + 1;
+                    // A bare `@layer a, b;` statement is allowed before @import (CSS Cascade 5 §6.4.1), so
+                    // it must not close the @import prologue - otherwise every following @import is skipped.
+                    hasReachedNonImportRules = true;
                 }
             }
+
+            data.Stylesheets.Add(stylesheet);
         }
 
         /// <summary>
-        /// Parse the given substring to extract border width substring.
-        /// Assume given substring is not empty and all indexes are valid!<br/>
+        /// Resolves an @import href against the importing stylesheet's own base URI (if any), so
+        /// nested @import chains resolve relative references correctly instead of against the
+        /// document's base - matching browser behavior for fetched CSS.
         /// </summary>
-        /// <returns>found border width value or null</returns>
-        private static string ParseBorderWidth(string str, int idx, int length)
+        private static string ResolveImportHref(string href, Uri baseUri)
         {
-            if ((length > 2 && char.IsDigit(str[idx])) || (length > 3 && str[idx] == '.'))
+            if (baseUri != null)
             {
-                string unit = null;
-                if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.Px))
-                    unit = CssConstants.Px;
-                else if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.Pt))
-                    unit = CssConstants.Pt;
-                else if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.Em))
-                    unit = CssConstants.Em;
-                else if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.Ex))
-                    unit = CssConstants.Ex;
-                else if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.In))
-                    unit = CssConstants.In;
-                else if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.Cm))
-                    unit = CssConstants.Cm;
-                else if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.Mm))
-                    unit = CssConstants.Mm;
-                else if (CommonUtils.SubStringEquals(str, idx + length - 2, 2, CssConstants.Pc))
-                    unit = CssConstants.Pc;
-
-                if (unit != null)
-                {
-                    if (CssValueParser.IsFloat(str, idx, length - 2))
-                        return str.Substring(idx, length);
-                }
+                Uri combined;
+                if (Uri.TryCreate(baseUri, href, out combined))
+                    return combined.AbsoluteUri;
             }
-            else
-            {
-                if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Thin))
-                    return CssConstants.Thin;
-                if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Medium))
-                    return CssConstants.Medium;
-                if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Thick))
-                    return CssConstants.Thick;
-            }
-            return null;
-        }
-
-        /// <summary>
-        /// Parse the given substring to extract border style substring.<br/>
-        /// Assume given substring is not empty and all indexes are valid!<br/>
-        /// </summary>
-        /// <returns>found border width value or null</returns>
-        private static string ParseBorderStyle(string str, int idx, int length)
-        {
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.None))
-                return CssConstants.None;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Solid))
-                return CssConstants.Solid;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Hidden))
-                return CssConstants.Hidden;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Dotted))
-                return CssConstants.Dotted;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Dashed))
-                return CssConstants.Dashed;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Double))
-                return CssConstants.Double;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Groove))
-                return CssConstants.Groove;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Ridge))
-                return CssConstants.Ridge;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Inset))
-                return CssConstants.Inset;
-            if (CommonUtils.SubStringEquals(str, idx, length, CssConstants.Outset))
-                return CssConstants.Outset;
-            return null;
-        }
-
-        /// <summary>
-        /// Parse the given substring to extract border style substring.<br/>
-        /// Assume given substring is not empty and all indexes are valid!<br/>
-        /// </summary>
-        /// <returns>found border width value or null</returns>
-        private string ParseBorderColor(string str, int idx, int length)
-        {
-            RColor color;
-            return _valueParser.TryGetColor(str, idx, length, out color) ? str.Substring(idx, length) : null;
+            return href;
         }
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer/Core/Parse/CssValueParser.cs b/Source/HtmlRenderer/Core/Parse/CssValueParser.cs
index b7c721b28..46e3d8e6c 100644
--- a/Source/HtmlRenderer/Core/Parse/CssValueParser.cs
+++ b/Source/HtmlRenderer/Core/Parse/CssValueParser.cs
@@ -11,10 +11,15 @@
 // "The Art of War"
 
 using System;
+using System.Collections.Generic;
 using System.Globalization;
+using System.Linq;
+using System.Text;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 using TheArtOfDev.HtmlRenderer.Core.Dom;
+using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Parse
@@ -96,6 +101,9 @@ public static bool IsInt(string str, int idx, int length)
         /// <returns>true - valid, false - invalid</returns>
         public static bool IsValidLength(string value)
         {
+            if (IsCalcFunction(value))
+                return true;
+
             if (value.Length > 1)
             {
                 string number = string.Empty;
@@ -113,6 +121,126 @@ public static bool IsValidLength(string value)
             return false;
         }
 
+        /// <summary>
+        /// Tokenizes <paramref name="value"/> using the vendored CSS lexer (Core/CssEngine/Parser/Lexer.cs),
+        /// skipping whitespace/end-of-file tokens - the same "just enough tokenization to recognize a
+        /// single top-level function call" approach used to detect calc()-family expressions.
+        /// </summary>
+        internal static List<Token> GetCssTokens(string value, bool isInValue = false)
+        {
+            var lexer = new Lexer(value) { IsInValue = isInValue };
+            var tokens = new List<Token>();
+            Token token;
+            do
+            {
+                token = lexer.Get();
+                if (token.Type != TokenType.EndOfFile && token.Type != TokenType.Whitespace)
+                {
+                    tokens.Add(token);
+                }
+            } while (token.Type != TokenType.EndOfFile);
+
+            return tokens;
+        }
+
+        /// <summary>
+        /// Resolves an <c>@font-face</c> rule's <c>font-family</c> descriptor value to the plain family
+        /// name: a single quoted string token unwraps to its literal text, anything else (an unquoted
+        /// identifier, or a value this tokenizer doesn't recognize as exactly one string) is returned as-is.
+        /// </summary>
+        internal static string GetFontFaceFamilyName(string propValue)
+        {
+            var tokens = GetCssTokens(propValue);
+
+            if (tokens.Count == 1 && tokens[0] is StringToken stringToken)
+            {
+                return stringToken.Data;
+            }
+
+            return propValue;
+        }
+
+        /// <summary>
+        /// Parses an <c>@font-face</c> <c>src</c> descriptor into its comma-separated candidates, each with
+        /// whatever <c>url()</c>/<c>local()</c>/<c>format()</c>/<c>tech()</c> pieces it declared - order
+        /// matters here: the top-level commas are split first, then each candidate segment is inspected on
+        /// its own, so a value with multiple <c>url()</c> alternatives (<c>src: url(a.woff2) format("woff2"),
+        /// url(a.woff) format("woff")</c>) doesn't have its tokens cross-matched between candidates.
+        /// </summary>
+        internal static List<CssFontFace> GetFontFacePropertyValue(string propValue)
+        {
+            var tokens = GetCssTokens(propValue);
+            var result = new List<CssFontFace>();
+            var segment = new List<Token>();
+
+            foreach (var token in tokens)
+            {
+                if (token.Type == TokenType.Comma)
+                {
+                    AppendFontFaceCandidate(result, segment);
+                    segment = new List<Token>();
+                }
+                else
+                {
+                    segment.Add(token);
+                }
+            }
+            AppendFontFaceCandidate(result, segment);
+
+            return result;
+        }
+
+        /// <summary>
+        /// Builds one <see cref="CssFontFace"/> candidate from a comma-delimited segment of an <c>src</c>
+        /// descriptor's tokens and appends it to <paramref name="result"/>, or does nothing for an empty
+        /// segment (a trailing/doubled comma).
+        /// </summary>
+        private static void AppendFontFaceCandidate(List<CssFontFace> result, List<Token> segment)
+        {
+            if (segment.Count == 0)
+                return;
+
+            var urlToken = segment.OfType<UrlToken>().SingleOrDefault();
+            var formatToken = segment.OfType<FunctionToken>().SingleOrDefault(t => t.Data == "format");
+            var techToken = segment.OfType<FunctionToken>().SingleOrDefault(t => t.Data == "tech");
+            var localToken = segment.OfType<FunctionToken>().SingleOrDefault(t => t.Data == "local");
+
+            result.Add(new CssFontFace(
+                urlToken?.Data,
+                formatToken?.ArgumentTokens?.FirstOrDefault()?.Data,
+                techToken?.ArgumentTokens?.FirstOrDefault()?.Data,
+                localToken?.ArgumentTokens?.FirstOrDefault()?.Data));
+        }
+
+        /// <summary>
+        /// Recognizes a length string that is a single calc-family (calc/min/max/clamp) function call.
+        /// Real grammar/type validation happens in the vendored CSS-OM's CalcValueConverter at parse
+        /// time (for any value that didn't arrive via var() substitution); this is a syntactic
+        /// recognizer only, used to gate the evaluation branch in <see cref="ParseLength(string, double, double, string, bool, bool)"/>.
+        /// </summary>
+        public static bool IsCalcFunction(string value)
+        {
+            FunctionToken function;
+            return TryGetCalcFunction(value, out function);
+        }
+
+        private static bool TryGetCalcFunction(string value, out FunctionToken function)
+        {
+            var tokens = GetCssTokens(value);
+            if (tokens.Count == 1)
+            {
+                var fn = tokens[0] as FunctionToken;
+                if (fn != null && CalcParser.IsCalcFamily(fn.Data))
+                {
+                    function = fn;
+                    return true;
+                }
+            }
+
+            function = null;
+            return false;
+        }
+
         /// <summary>
         /// Evals a number and returns it. If number is a percentage, it will be multiplied by <see cref="hundredPercent"/>
         /// </summary>
@@ -192,6 +320,18 @@ public static double ParseLength(string length, double hundredPercent, double em
             if (length.EndsWith("%"))
                 return ParseNumber(length, hundredPercent);
 
+            // calc()/min()/max()/clamp(): evaluate via the vendored Calc engine (Core/CssEngine/Calc/)
+            // instead of falling through to the unit-suffix parsing below, which doesn't understand
+            // function syntax at all.
+            FunctionToken calcFunction;
+            if (TryGetCalcFunction(length, out calcFunction))
+            {
+                var node = CalcParser.Parse(calcFunction);
+                var context = new CalcContext(hundredPercent, emFactor, emFactor, fontAdjust, returnPoints);
+                var pixels = node != null ? CalcEvaluator.Evaluate(node, context) : null;
+                return pixels ?? 0d;
+            }
+
             //Get units of the length
             bool hasUnit;
             string unit = GetUnit(length, defaultUnit, out hasUnit);
@@ -318,6 +458,14 @@ public bool TryGetColor(string str, int idx, int length, out RColor color)
                     {
                         return GetColorByRgba(str, idx, length, out color);
                     }
+                    else if (length > 9 && CommonUtils.SubStringEquals(str, idx, 4, "hsl(") && str[length - 1] == ')')
+                    {
+                        return GetColorByHsl(str, idx, length, false, out color);
+                    }
+                    else if (length > 10 && CommonUtils.SubStringEquals(str, idx, 5, "hsla(") && str[length - 1] == ')')
+                    {
+                        return GetColorByHsl(str, idx, length, true, out color);
+                    }
                     else
                     {
                         return GetColorByName(str, idx, length, out color);
@@ -451,7 +599,7 @@ private static bool GetColorByRgba(string str, int idx, int length, out RColor c
                 }
                 if (s < idx + length)
                 {
-                    a = ParseIntAtIndex(str, ref s);
+                    a = ParseAlphaAtIndex(str, ref s);
                 }
             }
 
@@ -465,13 +613,176 @@ private static bool GetColorByRgba(string str, int idx, int length, out RColor c
         }
 
         /// <summary>
-        /// Get color by given name, including .NET name.
+        /// Parses an rgba()/hsla()-style alpha component, per CSS syntax a fractional number in [0,1]
+        /// (e.g. "0.5") or a percentage (e.g. "50%") - unlike R/G/B, never a bare 0-255 integer. This is
+        /// also the canonical form the vendored CSS engine's Color.ToString() emits for any color with
+        /// partial transparency (hex-alpha, hsl()/hsla(), hwb(), modern space-separated rgb() syntax -
+        /// all normalized to "rgba(r, g, b, alpha)" at CSS-OM parse time), so this is the path that
+        /// makes those all resolve correctly here, not just literal author-written rgba().
+        /// </summary>
+        /// <returns>alpha as a 0-255 byte value, or -1 if invalid</returns>
+        private static int ParseAlphaAtIndex(string str, ref int startIdx)
+        {
+            while (startIdx < str.Length && char.IsWhiteSpace(str, startIdx))
+                startIdx++;
+
+            var start = startIdx;
+            var len = 0;
+            while (start + len < str.Length && (char.IsDigit(str, start + len) || str[start + len] == '.'))
+                len++;
+
+            var isPercent = start + len < str.Length && str[start + len] == '%';
+
+            if (len < 1)
+            {
+                startIdx = start + len + (isPercent ? 1 : 0) + 1;
+                return -1;
+            }
+
+            double value;
+            if (!double.TryParse(str.Substring(start, len), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out value))
+            {
+                startIdx = start + len + (isPercent ? 1 : 0) + 1;
+                return -1;
+            }
+
+            if (isPercent)
+            {
+                value = value / 100.0;
+                len++; // include the '%' when advancing startIdx below
+            }
+
+            startIdx = start + len + 1;
+
+            var alpha = (int)Math.Round(value * 255.0);
+            return alpha < 0 ? 0 : (alpha > 255 ? 255 : alpha);
+        }
+
+        /// <summary>
+        /// Get color by parsing given HSL/HSLA value color string (hsl(210, 100%, 50%), hsla(210, 100%, 50%, 0.5)).<br/>
+        /// Unlike hex and rgb()/rgba(), the vendored CSS-OM's HslColorConverter/HslaColorConverter only
+        /// validate hsl() syntax at parse time (hue is a valid angle, saturation/lightness are
+        /// percentages) - they never actually convert it to an RGB Color the way rgb()/rgba()/hex do
+        /// (see Core/CssEngine/Model/Converters.cs's HslColorConverter/HslaColorConverter, and compare
+        /// to Color.ToString() which only ever emits rgb()/rgba()). So unlike those, the raw string this
+        /// engine sees for an hsl()-declared color is still the literal hsl() text (with hue normalized
+        /// to a "Ndeg" suffix), not a canonical rgba() - this method does the actual hue/sat/light -> RGB
+        /// conversion, reusing the vendored Color.FromHsla for the math.
+        /// </summary>
+        /// <returns>true - valid color, false - otherwise</returns>
+        private static bool GetColorByHsl(string str, int idx, int length, bool hasAlpha, out RColor color)
+        {
+            var openLen = hasAlpha ? 5 : 4; // "hsla(" or "hsl("
+            var inner = str.Substring(idx + openLen, length - openLen - 1);
+            var parts = inner.Split(',');
+            if (parts.Length != (hasAlpha ? 4 : 3))
+            {
+                color = RColor.Empty;
+                return false;
+            }
+
+            double hueDegrees;
+            if (!TryParseAngleDegrees(parts[0].Trim(), out hueDegrees))
+            {
+                color = RColor.Empty;
+                return false;
+            }
+
+            double saturation, lightness;
+            if (!double.TryParse(parts[1].Trim().TrimEnd('%'), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out saturation) ||
+                !double.TryParse(parts[2].Trim().TrimEnd('%'), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out lightness))
+            {
+                color = RColor.Empty;
+                return false;
+            }
+
+            var alpha = 1.0;
+            if (hasAlpha)
+            {
+                var alphaStr = parts[3].Trim();
+                if (alphaStr.EndsWith("%"))
+                {
+                    double a;
+                    double.TryParse(alphaStr.TrimEnd('%'), NumberStyles.Float, NumberFormatInfo.InvariantInfo, out a);
+                    alpha = a / 100.0;
+                }
+                else
+                {
+                    double.TryParse(alphaStr, NumberStyles.Float, NumberFormatInfo.InvariantInfo, out alpha);
+                }
+            }
+
+            var hueFraction = ((hueDegrees % 360.0) + 360.0) % 360.0 / 360.0;
+            var vendored = CssEngine.Color.FromHsla((float)hueFraction, (float)(saturation / 100.0), (float)(lightness / 100.0), (float)alpha);
+            color = RColor.FromArgb(vendored.A, vendored.R, vendored.G, vendored.B);
+            return true;
+        }
+
+        /// <summary>
+        /// Parses an hsl() hue component - a bare number (treated as degrees, per CSS) or a number with
+        /// an explicit angle unit (deg/rad/grad/turn).
         /// </summary>
+        private static bool TryParseAngleDegrees(string value, out double degrees)
+        {
+            string unit = null;
+            foreach (var candidate in new[] { "turn", "grad", "deg", "rad" })
+            {
+                if (value.EndsWith(candidate, StringComparison.OrdinalIgnoreCase))
+                {
+                    unit = candidate;
+                    break;
+                }
+            }
+
+            var numberPart = unit != null ? value.Substring(0, value.Length - unit.Length) : value;
+            double number;
+            if (!double.TryParse(numberPart, NumberStyles.Float, NumberFormatInfo.InvariantInfo, out number))
+            {
+                degrees = 0;
+                return false;
+            }
+
+            if (unit == "turn") degrees = number * 360.0;
+            else if (unit == "grad") degrees = number * 0.9;
+            else if (unit == "rad") degrees = number * 180.0 / Math.PI;
+            else degrees = number; // "deg" or bare number
+
+            return true;
+        }
+
+        /// <summary>
+        /// Get color by given name (including .NET names), or by any color function the CSS engine
+        /// understands.
+        /// </summary>
+        /// <remarks>
+        /// The adapter's palette is tried first because a bare name is by far the common case and a
+        /// dictionary lookup is cheaper than tokenizing. Anything it doesn't recognize - a CSS Color 4/5
+        /// function such as <c>lab()</c>/<c>oklch()</c>/<c>color-mix()</c>, or a fully transparent color,
+        /// which the palette reports with a zero alpha and is indistinguishable from "unknown" here - is
+        /// then resolved through the engine, which is the same code path the cascade validated the value
+        /// with. Hex/rgb()/rgba()/hsl()/hsla() never reach this method; they keep their own fast paths in
+        /// <see cref="TryGetColor"/>.
+        /// </remarks>
         /// <returns>true - valid color, false - otherwise</returns>
         private bool GetColorByName(string str, int idx, int length, out RColor color)
         {
-            color = _adapter.GetColor(str.Substring(idx, length));
-            return color.A > 0;
+            var text = str.Substring(idx, length);
+
+            color = _adapter.GetColor(text);
+            if (color.A > 0) return true;
+
+            // Value mode, so a hex colour lexes as a single colour token. Outside it, a digit-leading
+            // hex such as #0000ff splits into a "#" delimiter plus a dimension ("0000" + unit "ff"),
+            // which then fails to resolve as an operand inside color-mix().
+            var resolved = GetCssTokens(text, true).ToResolvedColor();
+            if (resolved != null)
+            {
+                var value = resolved.Value;
+                color = RColor.FromArgb(value.A, value.R, value.G, value.B);
+                return true;
+            }
+
+            return false;
         }
 
         /// <summary>
@@ -539,5 +850,217 @@ private static int ParseHexInt(string str, int idx, int length)
         }
 
         #endregion
+
+
+        #region Background image / gradient parsing
+
+        /// <summary>
+        /// Parses a single <c>background-image</c> value: either a <c>url()</c> reference or a
+        /// <c>linear-gradient()</c>/<c>repeating-linear-gradient()</c> function. Returns null for "none",
+        /// an empty value, or anything else this engine doesn't recognize (matching this engine's existing
+        /// silent-failure behavior for unsupported values).<br/>
+        /// Trimmed to the single-value,
+        /// linear-gradient-only case this engine supports (no layered background-image, no radial/conic).
+        /// </summary>
+        public CssImage ParseImage(string value)
+        {
+            if (string.IsNullOrWhiteSpace(value) || string.Equals(value, CssConstants.None, StringComparison.OrdinalIgnoreCase))
+                return null;
+
+            var tokens = GetCssTokens(value);
+
+            var urlToken = tokens.OfType<UrlToken>().FirstOrDefault();
+            if (urlToken != null)
+                return new CssImage.Url(urlToken.Data);
+
+            var funcToken = tokens.OfType<FunctionToken>().FirstOrDefault();
+            if (funcToken == null)
+                return null;
+
+            if (string.Equals(funcToken.Data, FunctionNames.LinearGradient, StringComparison.OrdinalIgnoreCase) ||
+                string.Equals(funcToken.Data, FunctionNames.RepeatingLinearGradient, StringComparison.OrdinalIgnoreCase))
+            {
+                var gradient = ParseLinearGradient(value);
+                return gradient != null ? new CssImage.LinearGradient(gradient) : null;
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Parses a <c>linear-gradient()</c>/<c>repeating-linear-gradient()</c> function value: an
+        /// optional angle or "to &lt;side&gt;" direction (default 180deg, top to bottom), followed by 2+
+        /// comma-separated color stops (each optionally followed by 1-2 length/percent positions), and
+        /// bare-position color hints between stops. Returns null if the value isn't a recognized gradient
+        /// function or doesn't have at least 2 real color stops.<br/>
+        /// Linear-gradient parsing, minus CSS Color 4
+        /// interpolation-color-space ("in oklab" etc.) support - see ParsedLinearGradient.
+        /// </summary>
+        private ParsedLinearGradient ParseLinearGradient(string value)
+        {
+            var tokens = GetCssTokens(value);
+
+            var funcToken = tokens.OfType<FunctionToken>().FirstOrDefault(t =>
+                string.Equals(t.Data, FunctionNames.LinearGradient, StringComparison.OrdinalIgnoreCase) ||
+                string.Equals(t.Data, FunctionNames.RepeatingLinearGradient, StringComparison.OrdinalIgnoreCase));
+
+            if (funcToken == null)
+                return null;
+
+            bool isRepeating = string.Equals(funcToken.Data, FunctionNames.RepeatingLinearGradient, StringComparison.OrdinalIgnoreCase);
+
+            var args = funcToken.ArgumentTokens.ToList();
+            if (args.Count == 0)
+                return null;
+
+            double angleRad = Math.PI; // default: 180deg = top to bottom
+            int stopOffset = 0;
+
+            var firstGroup = args[0];
+            var firstIdents = firstGroup.Where(t => t.Type == TokenType.Ident).Select(t => t.Data.ToLowerInvariant()).ToList();
+
+            if (firstIdents.Count > 0 && firstIdents[0] == "to")
+            {
+                // keyword direction: "to right", "to bottom left", etc.
+                angleRad = SideKeywordsToAngleRad(firstIdents.Skip(1).ToList());
+                stopOffset = 1;
+            }
+            else
+            {
+                var angle = firstGroup.ToAngle();
+                if (angle.HasValue)
+                {
+                    angleRad = angle.Value.ToRadian();
+                    stopOffset = 1;
+                }
+                // else no angle token, stopOffset stays 0 - first group is already the first color stop
+            }
+
+            var stopGroups = args.Skip(stopOffset).ToList();
+            if (stopGroups.Count < 2)
+                return null;
+
+            var stops = new List<(RColor? Color, Length? Position, bool IsHint)>();
+
+            foreach (var group in stopGroups)
+            {
+                var items = group.ToItems();
+                if (items.Count == 0)
+                    continue;
+
+                Length? position1 = null;
+                Length? position2 = null;
+                int colorItemCount = items.Count;
+
+                // Last item may be a length/percent position.
+                var lastItem = items[items.Count - 1];
+                var pv = lastItem.ToDistance();
+                if (pv.HasValue)
+                {
+                    position1 = pv.Value;
+                    colorItemCount--;
+
+                    // Two-position shorthand (e.g. "red 0 50%").
+                    if (colorItemCount > 0)
+                    {
+                        var pv2 = items[colorItemCount - 1].ToDistance();
+                        if (pv2.HasValue)
+                        {
+                            position2 = position1;
+                            position1 = pv2.Value;
+                            colorItemCount--;
+                        }
+                    }
+                }
+
+                if (colorItemCount == 0)
+                {
+                    // Bare position with no color - a color hint.
+                    if (position1.HasValue && !position2.HasValue)
+                        stops.Add((null, position1, true));
+                    continue;
+                }
+
+                var colorText = BuildColorText(items.Take(colorItemCount));
+                if (string.IsNullOrWhiteSpace(colorText))
+                    continue;
+
+                var color = GetActualColor(colorText);
+                stops.Add((color, position1, false));
+                if (position2.HasValue)
+                    stops.Add((color, position2, false));
+            }
+
+            if (stops.Count(s => !s.IsHint) < 2)
+                return null;
+
+            return new ParsedLinearGradient
+            {
+                AngleRad = angleRad,
+                Stops = stops.ToArray(),
+                IsRepeating = isRepeating,
+            };
+        }
+
+        /// <summary>
+        /// Converts "to &lt;side&gt; [&lt;side&gt;]" direction keywords (e.g. "right", "bottom left") to
+        /// the equivalent gradient-line angle in radians, per the CSS Images spec's side/corner table.
+        /// </summary>
+        private static double SideKeywordsToAngleRad(List<string> sides)
+        {
+            bool hasTop = sides.Contains("top");
+            bool hasBottom = sides.Contains("bottom");
+            bool hasLeft = sides.Contains("left");
+            bool hasRight = sides.Contains("right");
+
+            if (hasTop && hasRight) return Math.PI / 4;         // 45deg
+            if (hasBottom && hasRight) return 3 * Math.PI / 4;  // 135deg
+            if (hasBottom && hasLeft) return 5 * Math.PI / 4;   // 225deg
+            if (hasTop && hasLeft) return 7 * Math.PI / 4;      // 315deg
+            if (hasTop) return 0;                                // 0deg
+            if (hasRight) return Math.PI / 2;                    // 90deg
+            if (hasBottom) return Math.PI;                       // 180deg
+            if (hasLeft) return 3 * Math.PI / 2;                // 270deg
+
+            return Math.PI; // default
+        }
+
+        /// <summary>
+        /// Re-serializes a color stop's token groups (everything before its trailing position token(s))
+        /// back to CSS text so it can be handed to <see cref="GetActualColor"/> as a normal color string.
+        /// </summary>
+        private static string BuildColorText(IEnumerable<IEnumerable<Token>> itemGroups)
+        {
+            var sb = new StringBuilder();
+            foreach (var group in itemGroups)
+            {
+                sb.Append(group.ToText());
+            }
+            return sb.ToString().Trim();
+        }
+
+        /// <summary>
+        /// Splits a CSS value string on top-level whitespace (paren-depth-aware, so a calc()/gradient()
+        /// value's internal spaces aren't mistaken for a delimiter). Used to split a "border-radius"
+        /// corner value like "10px 5%" into its horizontal/vertical components.
+        /// </summary>
+        internal static IEnumerable<string> SplitTopLevelWhitespace(string value)
+        {
+            int depth = 0, start = 0;
+            for (int i = 0; i < value.Length; i++)
+            {
+                char c = value[i];
+                if (c == '(') depth++;
+                else if (c == ')') depth--;
+                else if (char.IsWhiteSpace(c) && depth == 0)
+                {
+                    if (i > start) yield return value.Substring(start, i - start);
+                    start = i + 1;
+                }
+            }
+            if (start < value.Length) yield return value.Substring(start);
+        }
+
+        #endregion
     }
 }
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/Parse/DomParser.cs b/Source/HtmlRenderer/Core/Parse/DomParser.cs
index 1556aa783..66287d5a1 100644
--- a/Source/HtmlRenderer/Core/Parse/DomParser.cs
+++ b/Source/HtmlRenderer/Core/Parse/DomParser.cs
@@ -6,17 +6,22 @@
 // like the days and months;
 // they die and are reborn,
 // like the four seasons."
-// 
+//
 // - Sun Tsu,
 // "The Art of War"
 
 using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 using TheArtOfDev.HtmlRenderer.Core.Dom;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Handlers;
+using TheArtOfDev.HtmlRenderer.Core.Network;
 using TheArtOfDev.HtmlRenderer.Core.Utils;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Parse
@@ -53,17 +58,25 @@ public DomParser(CssParser cssParser)
         /// <param name="htmlContainer">the html container to use for reference resolve</param>
         /// <param name="cssData">the css data to use</param>
         /// <returns>the root of the generated tree</returns>
-        public CssBox GenerateCssTree(string html, HtmlContainerInt htmlContainer, ref CssData cssData)
+        public async Task<(CssBox root, CssData cssData)> GenerateCssTree(string html, HtmlContainerInt htmlContainer, CssData cssData)
         {
             var root = HtmlParser.ParseDocument(html);
             if (root != null)
             {
                 root.HtmlContainer = htmlContainer;
 
-                bool cssDataChanged = false;
-                CascadeParseStyles(root, htmlContainer, ref cssData, ref cssDataChanged);
+                (cssData, _) = await CascadeParseStyles(root, htmlContainer, cssData, false).ConfigureAwait(false);
 
-                CascadeApplyStyles(root, cssData);
+                await RegisterFontFaces(cssData, htmlContainer).ConfigureAwait(false);
+
+                // The device @media queries are evaluated against: media type and colour scheme come
+                // from the platform adapter, the viewport from the container's max size (which is the
+                // available width/height at this point; zero means "not known yet", and geometry
+                // conditions then match permissively).
+                var media = MediaQueryContext.FromAdapter(
+                    htmlContainer.Adapter, htmlContainer.MaxSize.Width, htmlContainer.MaxSize.Height);
+
+                CascadeApplyStyles(root, cssData, media);
 
                 SetTextSelectionStyle(htmlContainer, cssData);
 
@@ -81,7 +94,7 @@ public CssBox GenerateCssTree(string html, HtmlContainerInt htmlContainer, ref C
 
                 CorrectAnonymousTables(root);
             }
-            return root;
+            return (root, cssData);
         }
 
 
@@ -96,7 +109,8 @@ public CssBox GenerateCssTree(string html, HtmlContainerInt htmlContainer, ref C
         /// <param name="htmlContainer">the html container to use for reference resolve</param>
         /// <param name="cssData">the style data to fill with found styles</param>
         /// <param name="cssDataChanged">check if the css data has been modified by the handled html not to change the base css data</param>
-        private void CascadeParseStyles(CssBox box, HtmlContainerInt htmlContainer, ref CssData cssData, ref bool cssDataChanged)
+        /// <returns>the (possibly cloned) css data and whether it has been cloned yet, threaded through the recursive tree walk in place of the original ref parameters (async methods cannot take ref/out parameters)</returns>
+        private async Task<(CssData cssData, bool cssDataChanged)> CascadeParseStyles(CssBox box, HtmlContainerInt htmlContainer, CssData cssData, bool cssDataChanged)
         {
             if (box.HtmlTag != null)
             {
@@ -104,12 +118,11 @@ private void CascadeParseStyles(CssBox box, HtmlContainerInt htmlContainer, ref
                 if (box.HtmlTag.Name.Equals("link", StringComparison.CurrentCultureIgnoreCase) &&
                     box.GetAttribute("rel", string.Empty).Equals("stylesheet", StringComparison.CurrentCultureIgnoreCase))
                 {
-                    CloneCssData(ref cssData, ref cssDataChanged);
-                    string stylesheet;
-                    CssData stylesheetData;
-                    StylesheetLoadHandler.LoadStylesheet(htmlContainer, box.GetAttribute("href", string.Empty), box.HtmlTag.Attributes, out stylesheet, out stylesheetData);
+                    (cssData, cssDataChanged) = CloneCssData(cssData, cssDataChanged);
+                    var href = box.GetAttribute("href", string.Empty);
+                    var (stylesheet, stylesheetData) = await StylesheetLoadHandler.LoadStylesheet(htmlContainer, href, box.HtmlTag.Attributes).ConfigureAwait(false);
                     if (stylesheet != null)
-                        _cssParser.ParseStyleSheet(cssData, stylesheet);
+                        _cssParser.ParseStyleSheet(cssData, stylesheet, CommonUtils.TryGetUri(href));
                     else if (stylesheetData != null)
                         cssData.Combine(stylesheetData);
                 }
@@ -117,7 +130,7 @@ private void CascadeParseStyles(CssBox box, HtmlContainerInt htmlContainer, ref
                 // Check for the <style> tag
                 if (box.HtmlTag.Name.Equals("style", StringComparison.CurrentCultureIgnoreCase) && box.Boxes.Count > 0)
                 {
-                    CloneCssData(ref cssData, ref cssDataChanged);
+                    (cssData, cssDataChanged) = CloneCssData(cssData, cssDataChanged);
                     foreach (var child in box.Boxes)
                         _cssParser.ParseStyleSheet(cssData, child.Text);
                 }
@@ -125,55 +138,185 @@ private void CascadeParseStyles(CssBox box, HtmlContainerInt htmlContainer, ref
 
             foreach (var childBox in box.Boxes)
             {
-                CascadeParseStyles(childBox, htmlContainer, ref cssData, ref cssDataChanged);
+                (cssData, cssDataChanged) = await CascadeParseStyles(childBox, htmlContainer, cssData, cssDataChanged).ConfigureAwait(false);
+            }
+
+            return (cssData, cssDataChanged);
+        }
+
+        /// <summary>
+        /// Walks every parsed stylesheet's <c>@font-face</c> rules (including ones nested inside
+        /// <c>@media</c>/<c>@supports</c>/<c>@layer</c>/<c>@container</c> - see <see cref="CssData.FlattenRules"/>)
+        /// and registers each one's <c>src</c> candidates with <see cref="Adapters.RAdapter.AddFontFace"/>/
+        /// <see cref="Adapters.RAdapter.AddFontFaceFromLocalFamily"/>, in source order, stopping at the
+        /// first candidate that loads successfully - matching the CSS spec's own "try each src in turn"
+        /// behavior. Called once per <see cref="GenerateCssTree"/>, after stylesheets are collected and
+        /// before the cascade applies, so every box's <see cref="Dom.CssBoxProperties.ActualFont"/> can
+        /// already see the registered faces.
+        /// </summary>
+        private static async Task RegisterFontFaces(CssData cssData, HtmlContainerInt htmlContainer)
+        {
+            var adapter = htmlContainer.Adapter;
+
+            foreach (var stylesheet in cssData.Stylesheets)
+            {
+                var stylesheetBaseUri = stylesheet.BaseUri != null ? new RUri(stylesheet.BaseUri) : null;
+
+                foreach (var rule in CssData.FlattenRules(stylesheet.Rules).OfType<IFontFaceRule>())
+                {
+                    var familyName = CssValueParser.GetFontFaceFamilyName(rule.Family ?? string.Empty);
+                    if (string.IsNullOrWhiteSpace(familyName))
+                        continue;
+
+                    var weight = FontFaceDescriptorResolver.ResolveWeight(rule.Weight) ?? CssFontWeightResolver.Normal;
+                    var isItalic = FontFaceDescriptorResolver.ResolveIsItalic(rule.Style) ?? false;
+                    var stretch = FontFaceDescriptorResolver.ResolveStretch(rule.Stretch) ?? FontStretchResolver.Normal;
+                    var ranges = UnicodeRangeParser.Parse(rule.Range);
+
+                    foreach (var candidate in CssValueParser.GetFontFacePropertyValue(rule.Source ?? string.Empty))
+                    {
+                        bool loaded;
+                        if (!string.IsNullOrEmpty(candidate.Local))
+                        {
+                            var localFamilyName = CssValueParser.GetFontFaceFamilyName(candidate.Local);
+                            loaded = adapter.AddFontFaceFromLocalFamily(familyName, localFamilyName, weight, isItalic, stretch, ranges);
+                        }
+                        else if (!string.IsNullOrEmpty(candidate.Url))
+                        {
+                            var uri = CommonUtils.ResolveAgainstDocumentBase(htmlContainer, candidate.Url, stylesheetBaseUri);
+                            loaded = uri != null && await adapter.AddFontFace(familyName, uri, weight, isItalic, stretch, ranges).ConfigureAwait(false);
+                        }
+                        else
+                        {
+                            continue;
+                        }
+
+                        if (loaded)
+                            break;
+                    }
+                }
             }
         }
 
 
         /// <summary>
-        /// Applies style to all boxes in the tree.<br/>
-        /// If the html tag has style defined for each apply that style to the css box of the tag.<br/>
-        /// If the html tag has "class" attribute and the class name has style defined apply that style on the tag css box.<br/>
-        /// If the html tag has "style" attribute parse it and apply the parsed style on the tag css box.<br/>
+        /// Applies style to all boxes in the tree via a spec-correct, origin-aware six-phase cascade:
+        /// UA-normal, Author-normal, Inline-normal, Author-!important, Inline-!important, UA-!important
+        /// (origin order reverses for the !important tier, per spec). Each phase's revert/revert-layer
+        /// target is a snapshot of the box's state immediately before that phase ran.
         /// </summary>
         /// <param name="box">the box to apply the style to</param>
         /// <param name="cssData">the style data for the html</param>
-        private void CascadeApplyStyles(CssBox box, CssData cssData)
+        private void CascadeApplyStyles(CssBox box, CssData cssData, MediaQueryContext media)
         {
+            // Every box's fields already start at their initial value (CssBoxProperties's private
+            // field initializers, which CssDefaults.InitialValues was itself built to mirror exactly -
+            // see CssDefaults.cs) - so unlike a from-initial cascade, there is no separate "set every
+            // property to its initial value" pass here. Deliberately: a handful of this engine's
+            // property setters (e.g. LineHeight, CssBoxProperties.cs:550) are eager - they immediately
+            // resolve the assigned value to an absolute pixel string using the box's CURRENT font/size,
+            // rather than storing it as-is for lazy resolution later. Calling every whitelisted
+            // property's setter unconditionally on every box, before InheritStyle() has propagated a
+            // real font-size down and before layout has given the box a real size, fires those eager
+            // setters against not-yet-meaningful state and bakes in garbage (observed: line-height
+            // resolving to "-0px", corrupting all downstream layout). CssDefaults.InitialValues is
+            // still very much used - see GetInitialValue() calls below - just only consulted on demand
+            // when a declaration literally says initial/unset/revert, never as a blanket pre-pass.
+
+            // 1. Inherit inheritable properties from parent
             box.InheritStyle();
 
-            if (box.HtmlTag != null)
+            // Regular property declarations whose value contains var(...) are deferred here and resolved
+            // once, after the whole cascade (all phases below) has finished, so var() sees this box's
+            // FINAL custom property values regardless of which phase declared them.
+            var pendingVarProperties = new Dictionary<string, string>();
+
+            // Anonymous layout-only wrapper boxes (HtmlTag == null, not a pseudo-element) never match
+            // anything and are skipped, matching this engine's pre-existing behavior. Synthesized
+            // ::before/::after boxes ARE queried despite also having HtmlTag == null - their whole
+            // purpose is to receive the declarations from the rule whose selector synthesized them
+            // (e.g. "li::before { content: ... }"), matched via CssData's PseudoElementSelector check.
+            var canMatchRules = box.HtmlTag != null || box.IsPseudoElement;
+            var uaRules = canMatchRules ? cssData.GetUserAgentStyleRules(media, box).ToList() : new List<IStyleRule>();
+            var authorRules = canMatchRules ? cssData.GetAuthorStyleRules(media, box).ToList() : new List<IStyleRule>();
+
+            // Inline style is parsed up front - parsing is pure text -> rule with no cascade side
+            // effects, so hoisting it here (ahead of TranslateAttributes, which still runs at its
+            // original point below) doesn't change behavior, and lets RulesUseRevertKeyword below see it too.
+            IStyleRule inlineRule = null;
+            if (box.HtmlTag != null && box.HtmlTag.HasAttribute("style"))
             {
-                // try assign style using all wildcard
-                AssignCssBlocks(box, cssData, "*");
-
-                // try assign style using the html element tag
-                AssignCssBlocks(box, cssData, box.HtmlTag.Name);
+                inlineRule = _cssParser.ParseInlineStyle(box.HtmlTag.TryGetAttribute("style"));
+            }
 
-                // try assign style using the "class" attribute of the html element
-                if (box.HtmlTag.HasAttribute("class"))
-                {
-                    AssignClassCssBlocks(box, cssData);
-                }
-
-                // try assign style using the "id" attribute of the html element
-                if (box.HtmlTag.HasAttribute("id"))
-                {
-                    var id = box.HtmlTag.TryGetAttribute("id");
-                    AssignCssBlocks(box, cssData, "#" + id);
-                }
+            // The relatively expensive property/custom-property snapshots below are only ever read
+            // back when a later phase's declaration is literally revert/revert-layer, so each is only
+            // captured when something that will actually consult it uses one of those keywords.
+            var authorUsesRevert = RulesUseRevertKeyword(authorRules);
+            var uaUsesRevert = RulesUseRevertKeyword(uaRules);
+            var inlineUsesRevert = inlineRule != null && RulesUseRevertKeyword(new[] { inlineRule });
+
+            // Cascade precedence (lowest to highest, i.e. applied in this order so "last write wins"
+            // naturally produces the correct winner): UA-normal, Author-normal (inline-normal wins ties
+            // within this tier), Author-!important (inline-!important wins ties within this tier),
+            // UA-!important (per spec, origin order REVERSES for !important, so it's applied - and wins
+            // - last).
+
+            // 3. UA normal
+            AssignCssBlocks(box, uaRules, false, null, null, pendingVarProperties);
+            var needsUaSnapshot = authorUsesRevert;
+            var uaSnapshot = needsUaSnapshot ? CssUtils.SnapshotProperties(box) : null;
+            var uaCustomSnapshot = needsUaSnapshot ? CssUtils.SnapshotCustomProperties(box) : null;
+
+            // 4. Author normal
+            AssignCssBlocks(box, authorRules, false, uaSnapshot, uaCustomSnapshot, pendingVarProperties);
+            var needsAuthorNormalSnapshot = inlineUsesRevert || authorUsesRevert;
+            var authorNormalSnapshot = needsAuthorNormalSnapshot ? CssUtils.SnapshotProperties(box) : null;
+            var authorNormalCustomSnapshot = needsAuthorNormalSnapshot ? CssUtils.SnapshotCustomProperties(box) : null;
 
+            if (box.HtmlTag != null)
+            {
                 TranslateAttributes(box.HtmlTag, box);
+            }
 
-                // Check for the style="" attribute
-                if (box.HtmlTag.HasAttribute("style"))
-                {
-                    var block = _cssParser.ParseCssBlock(box.HtmlTag.Name, box.HtmlTag.TryGetAttribute("style"));
-                    if (block != null)
-                        AssignCssBlock(box, block);
-                }
+            // 5. Inline normal; revert target is the author-normal-applied state
+            var inlineNormalSnapshot = authorNormalSnapshot;
+            var inlineNormalCustomSnapshot = authorNormalCustomSnapshot;
+            if (inlineRule != null)
+            {
+                AssignCssBlock(box, inlineRule, false, authorNormalSnapshot, authorNormalCustomSnapshot, pendingVarProperties);
+                var needsInlineNormalSnapshot = authorUsesRevert;
+                inlineNormalSnapshot = needsInlineNormalSnapshot ? CssUtils.SnapshotProperties(box) : null;
+                inlineNormalCustomSnapshot = needsInlineNormalSnapshot ? CssUtils.SnapshotCustomProperties(box) : null;
+            }
+
+            // 6. Author !important. Note this means an author-!important "revert" can roll back to a
+            // value inline *normal* style just set, not all the way back to the UA snapshot - a
+            // deliberate choice for mechanical consistency ("revert = state right before this phase")
+            // rather than a stricter per-origin reading of the spec.
+            AssignCssBlocks(box, authorRules, true, inlineNormalSnapshot, inlineNormalCustomSnapshot, pendingVarProperties);
+            var needsAuthorImportantSnapshot = inlineUsesRevert || uaUsesRevert;
+            var authorImportantSnapshot = needsAuthorImportantSnapshot ? CssUtils.SnapshotProperties(box) : null;
+            var authorImportantCustomSnapshot = needsAuthorImportantSnapshot ? CssUtils.SnapshotCustomProperties(box) : null;
+
+            // 7. Inline !important
+            var afterInlineImportantSnapshot = authorImportantSnapshot;
+            var afterInlineImportantCustomSnapshot = authorImportantCustomSnapshot;
+            if (inlineRule != null)
+            {
+                AssignCssBlock(box, inlineRule, true, authorImportantSnapshot, authorImportantCustomSnapshot, pendingVarProperties);
+                var needsAfterInlineImportantSnapshot = uaUsesRevert;
+                afterInlineImportantSnapshot = needsAfterInlineImportantSnapshot ? CssUtils.SnapshotProperties(box) : null;
+                afterInlineImportantCustomSnapshot = needsAfterInlineImportantSnapshot ? CssUtils.SnapshotCustomProperties(box) : null;
             }
 
+            // 8. UA !important - applied globally last so it wins over everything else, per spec's
+            // origin reversal for the !important tier.
+            AssignCssBlocks(box, uaRules, true, afterInlineImportantSnapshot, afterInlineImportantCustomSnapshot, pendingVarProperties);
+
+            // 9. Resolve var() references now that every custom property's final cascaded value is known
+            ResolveDeferredVarProperties(box, pendingVarProperties);
+
             // cascade text decoration only to boxes that actually have text so it will be handled correctly.
             if (box.TextDecoration != String.Empty && box.Text == null)
             {
@@ -184,175 +327,548 @@ private void CascadeApplyStyles(CssBox box, CssData cssData)
 
             foreach (var childBox in box.Boxes)
             {
-                CascadeApplyStyles(childBox, cssData);
+                CascadeApplyStyles(childBox, cssData, media);
             }
         }
 
         /// <summary>
-        /// Set the selected text style (selection text color and background color).
+        /// Assigns the given css style rules to the given css box, applying only the declarations whose
+        /// !important flag matches <paramref name="importantPass"/>. A rule whose selector's subject
+        /// includes ":hover" is diverted to <see cref="HtmlContainerInt.AddHoverBox"/> instead - matching
+        /// this engine's pre-existing "matched but never actually applied" :hover behavior.
         /// </summary>
-        /// <param name="htmlContainer"> </param>
-        /// <param name="cssData">the style data</param>
-        private void SetTextSelectionStyle(HtmlContainerInt htmlContainer, CssData cssData)
+        private static void AssignCssBlocks(
+            CssBox box,
+            IEnumerable<IStyleRule> rules,
+            bool importantPass,
+            IDictionary<string, string> revertTarget,
+            IDictionary<string, string> customPropertyRevertTarget,
+            Dictionary<string, string> pendingVarProperties)
         {
-            htmlContainer.SelectionForeColor = RColor.Empty;
-            htmlContainer.SelectionBackColor = RColor.Empty;
-
-            if (cssData.ContainsCssBlock("::selection"))
+            foreach (var rule in rules)
             {
-                var blocks = cssData.GetCssBlock("::selection");
-                foreach (var block in blocks)
+                if (IsHoverRule(rule))
                 {
-                    if (block.Properties.ContainsKey("color"))
-                        htmlContainer.SelectionForeColor = _cssParser.ParseColor(block.Properties["color"]);
-                    if (block.Properties.ContainsKey("background-color"))
-                        htmlContainer.SelectionBackColor = _cssParser.ParseColor(block.Properties["background-color"]);
+                    if (!importantPass)
+                    {
+                        box.HtmlContainer.AddHoverBox(box, rule);
+                    }
+                    continue;
                 }
+
+                AssignCssBlock(box, rule, importantPass, revertTarget, customPropertyRevertTarget, pendingVarProperties);
             }
         }
 
         /// <summary>
-        /// Assigns the given css classes to the given css box checking if matching.<br/>
-        /// Support multiple classes in single attribute separated by whitespace.
+        /// True if the rule's selector's subject (rightmost, in the case of a combinator chain) compound
+        /// includes a ":hover" pseudo-class - e.g. "a:hover", ".foo:hover", or bare ":hover".
         /// </summary>
-        /// <param name="box">the css box to assign css to</param>
-        /// <param name="cssData">the css data to use to get the matching css blocks</param>
-        private static void AssignClassCssBlocks(CssBox box, CssData cssData)
+        private static bool IsHoverRule(IStyleRule rule)
         {
-            var classes = box.HtmlTag.TryGetAttribute("class");
+            return SelectorHasHover(rule.Selector);
+        }
 
-            var startIdx = 0;
-            while (startIdx < classes.Length)
-            {
-                while (startIdx < classes.Length && classes[startIdx] == ' ')
-                    startIdx++;
+        private static bool SelectorHasHover(ISelector selector)
+        {
+            var pseudoClass = selector as PseudoClassSelector;
+            if (pseudoClass != null) return pseudoClass.Class == "hover";
 
-                if (startIdx < classes.Length)
-                {
-                    var endIdx = classes.IndexOf(' ', startIdx);
+            var compound = selector as CompoundSelector;
+            if (compound != null) return compound.Any(SelectorHasHover);
 
-                    if (endIdx < 0)
-                        endIdx = classes.Length;
+            var complex = selector as ComplexSelector;
+            if (complex != null)
+            {
+                var last = complex.LastOrDefault().Selector;
+                return last != null && SelectorHasHover(last);
+            }
+
+            var list = selector as ListSelector;
+            if (list != null) return list.Any(SelectorHasHover);
 
-                    var cls = "." + classes.Substring(startIdx, endIdx - startIdx);
-                    AssignCssBlocks(box, cssData, cls);
-                    AssignCssBlocks(box, cssData, box.HtmlTag.Name + cls);
+            return false;
+        }
 
-                    startIdx = endIdx + 1;
+        /// <summary>
+        /// Checks whether any declaration in the given rules literally uses the revert/revert-layer
+        /// keyword, so the (relatively expensive) property snapshot used as their revert target only
+        /// needs to be captured when it can actually be consulted.
+        /// </summary>
+        private static bool RulesUseRevertKeyword(IEnumerable<IStyleRule> rules)
+        {
+            foreach (var rule in rules)
+            {
+                foreach (var prop in rule.Style)
+                {
+                    if (prop.Value == CssConstants.Revert || prop.Value == CssConstants.RevertLayer)
+                        return true;
                 }
             }
+
+            return false;
         }
 
         /// <summary>
-        /// Assigns the given css style blocks to the given css box checking if matching.
+        /// Assigns the given css style rule's declarations to the given css box, applying only the
+        /// declarations whose !important flag matches <paramref name="importantPass"/> (the caller is
+        /// expected to call this once per origin per pass - see <see cref="CascadeApplyStyles"/> - so
+        /// that within a properly-ordered sequence of calls, "last write wins" alone produces the
+        /// spec-correct result). Handles the CSS-wide keywords: inherit, initial, unset, revert,
+        /// revert-layer. Custom property declarations (--foo) are routed to
+        /// <see cref="AssignCustomPropertyDeclaration"/> instead. Regular declarations whose value
+        /// contains var(...) are deferred into <paramref name="pendingVarProperties"/> rather than
+        /// applied immediately - see <see cref="ResolveDeferredVarProperties"/> for why.
         /// </summary>
-        /// <param name="box">the css box to assign css to</param>
-        /// <param name="cssData">the css data to use to get the matching css blocks</param>
-        /// <param name="className">the class selector to search for css blocks</param>
-        private static void AssignCssBlocks(CssBox box, CssData cssData, string className)
+        private static void AssignCssBlock(
+            CssBox box,
+            IStyleRule stylesheetRule,
+            bool importantPass,
+            IDictionary<string, string> revertTarget,
+            IDictionary<string, string> customPropertyRevertTarget,
+            Dictionary<string, string> pendingVarProperties)
         {
-            var blocks = cssData.GetCssBlock(className);
-            foreach (var block in blocks)
+            foreach (var prop in stylesheetRule.Style)
             {
-                if (IsBlockAssignableToBox(box, block))
+                if (prop.IsImportant != importantPass)
+                    continue;
+
+                if (PropertyFactory.IsCustomPropertyName(prop.Name))
+                {
+                    AssignCustomPropertyDeclaration(box, prop, customPropertyRevertTarget);
+                    continue;
+                }
+
+                string value;
+                if (prop.Value == CssConstants.Inherit)
+                {
+                    value = box.ParentBox != null
+                        ? CssUtils.GetPropertyValue(box.ParentBox, prop.Name)
+                        : CssDefaults.GetInitialValue(prop.Name);
+                }
+                else if (prop.Value == CssConstants.Initial)
+                {
+                    value = CssDefaults.GetInitialValue(prop.Name);
+                }
+                else if (prop.Value == CssConstants.Unset)
+                {
+                    value = CssDefaults.InheritedProperties.Contains(prop.Name) && box.ParentBox != null
+                        ? CssUtils.GetPropertyValue(box.ParentBox, prop.Name)
+                        : CssDefaults.GetInitialValue(prop.Name);
+                }
+                else if (prop.Value == CssConstants.Revert || prop.Value == CssConstants.RevertLayer)
                 {
-                    AssignCssBlock(box, block);
+                    string rv;
+                    value = revertTarget != null && revertTarget.TryGetValue(prop.Name, out rv)
+                        ? rv
+                        : CssDefaults.GetInitialValue(prop.Name);
+                }
+                else
+                {
+                    value = prop.Value;
+                }
+
+                if (value == null) continue;
+
+                if (value.IndexOf("var(", StringComparison.OrdinalIgnoreCase) >= 0)
+                {
+                    // Overwrites any earlier pending entry for this name (last write wins).
+                    pendingVarProperties[prop.Name] = value;
+                }
+                else
+                {
+                    // A later plain value supersedes an earlier deferred var() value for the same property.
+                    pendingVarProperties.Remove(prop.Name);
+                    if (IsStyleOnElementAllowed(box, prop.Name, value))
+                        CssUtils.SetPropertyValue(box, prop.Name, value);
                 }
             }
         }
 
         /// <summary>
-        /// Check if the given css block is assignable to the given css box.<br/>
-        /// the block is assignable if it has no hierarchical selectors or if the hierarchy matches.<br/>
-        /// Special handling for ":hover" pseudo-class.<br/>
+        /// Assigns a single custom property (--foo) declaration to the box's custom-property store.
+        /// Unlike regular properties, custom properties are always inherited, their names are
+        /// case-sensitive, and their global keywords resolve against the custom-property dictionary
+        /// rather than the fixed, known-property switch used by <see cref="AssignCssBlock"/>. The stored
+        /// value is left unresolved (it may itself contain var(...)) - resolution happens once, later, in
+        /// <see cref="ResolveDeferredVarProperties"/>.
         /// </summary>
-        /// <param name="box">the box to check assign to</param>
-        /// <param name="block">the block to check assign of</param>
-        /// <returns>true - the block is assignable to the box, false - otherwise</returns>
-        private static bool IsBlockAssignableToBox(CssBox box, CssBlock block)
+        private static void AssignCustomPropertyDeclaration(
+            CssBox box,
+            IProperty prop,
+            IDictionary<string, string> customPropertyRevertTarget)
         {
-            bool assignable = true;
-            if (block.Selectors != null)
+            string rawValue;
+            if (prop.Value == CssConstants.Inherit || prop.Value == CssConstants.Unset)
+            {
+                string pv;
+                rawValue = box.ParentBox != null && box.ParentBox.CustomProperties != null &&
+                           box.ParentBox.CustomProperties.TryGetValue(prop.Name, out pv)
+                    ? pv
+                    : null;
+            }
+            else if (prop.Value == CssConstants.Initial)
+            {
+                rawValue = null; // guaranteed-invalid value => property becomes absent
+            }
+            else if (prop.Value == CssConstants.Revert || prop.Value == CssConstants.RevertLayer)
             {
-                assignable = IsBlockAssignableToBoxWithSelector(box, block);
+                string rv;
+                rawValue = customPropertyRevertTarget != null && customPropertyRevertTarget.TryGetValue(prop.Name, out rv)
+                    ? rv
+                    : null;
             }
-            else if (box.HtmlTag.Name.Equals("a", StringComparison.OrdinalIgnoreCase) && block.Class.Equals("a", StringComparison.OrdinalIgnoreCase) && !box.HtmlTag.HasAttribute("href"))
+            else
             {
-                assignable = false;
+                rawValue = prop.Value;
             }
 
-            if (assignable && block.Hover)
+            if (box.CustomProperties == null)
+                box.CustomProperties = new Dictionary<string, string>();
+
+            if (rawValue != null)
+                box.CustomProperties[prop.Name] = rawValue;
+            else
+                box.CustomProperties.Remove(prop.Name);
+        }
+
+        /// <summary>
+        /// Result of attempting to resolve every var() reference in a declaration's value. Success is
+        /// false only when a reference is "guaranteed-invalid" (no matching custom property, no
+        /// fallback, or a cyclic reference) - per spec this invalidates the whole value.
+        /// </summary>
+        private struct VarResolution
+        {
+            public VarResolution(bool success, string value)
             {
-                box.HtmlContainer.AddHoverBox(box, block);
-                assignable = false;
+                Success = success;
+                Value = value;
             }
 
-            return assignable;
+            public bool Success;
+            public string Value;
         }
 
         /// <summary>
-        /// Check if the given css block is assignable to the given css box by validating the selector.<br/>
+        /// Resolves every regular property deferred during the cascade's phases (see
+        /// <see cref="AssignCssBlock"/>) now that this box's custom properties reflect their FINAL
+        /// cascaded (though not yet var()-resolved) values. Resolution is graph-based and memoized per
+        /// box, so multi-hop cyclic references are detected correctly regardless of which pending
+        /// property triggers the lookup first.
         /// </summary>
-        /// <param name="box">the box to check assign to</param>
-        /// <param name="block">the block to check assign of</param>
-        /// <returns>true - the block is assignable to the box, false - otherwise</returns>
-        private static bool IsBlockAssignableToBoxWithSelector(CssBox box, CssBlock block)
+        private static void ResolveDeferredVarProperties(CssBox box, Dictionary<string, string> pendingVarProperties)
         {
-            foreach (var selector in block.Selectors)
+            if (pendingVarProperties.Count == 0) return;
+
+            var resolvedCache = new Dictionary<string, string>();
+            var resolving = new HashSet<string>();
+            var cyclic = new HashSet<string>();
+
+            foreach (var pending in pendingVarProperties)
             {
-                bool matched = false;
-                while (!matched)
+                var name = pending.Key;
+                var rawValue = pending.Value;
+                var result = SubstituteVarReferences(box, rawValue, resolvedCache, resolving, cyclic);
+                var finalValue = result.Success ? result.Value : GetGuaranteedInvalidFallback(box, name);
+
+                if (finalValue != null)
+                    ApplyResolvedPropertyValue(box, name, finalValue);
+            }
+        }
+
+        /// <summary>
+        /// Applies a fully var()-resolved property value to the box. Shorthand properties are re-parsed
+        /// through the real CSS-OM shorthand converter and expanded into longhands here, because
+        /// var()-containing shorthands deliberately skip longhand expansion at parse time (their value
+        /// can't be split into per-longhand slices until their var() references are resolved, which has
+        /// only just happened here).
+        /// </summary>
+        private static void ApplyResolvedPropertyValue(CssBox box, string name, string value)
+        {
+            var reparsed = StylesheetParser.Default.ParseDeclaration(name + ": " + value);
+
+            var shorthand = reparsed as ShorthandProperty;
+            if (shorthand != null && shorthand.HasValue)
+            {
+                var longhands = PropertyFactory.Instance.CreateLonghandsFor(name);
+                shorthand.Export(longhands);
+
+                foreach (var longhand in longhands)
                 {
-                    box = box.ParentBox;
-                    while (box != null && box.HtmlTag == null)
-                        box = box.ParentBox;
+                    if (longhand.HasValue && IsStyleOnElementAllowed(box, longhand.Name, longhand.Value))
+                        CssUtils.SetPropertyValue(box, longhand.Name, longhand.Value);
+                }
+
+                return;
+            }
+
+            if (reparsed != null && reparsed.HasValue && IsStyleOnElementAllowed(box, name, reparsed.Value))
+                CssUtils.SetPropertyValue(box, name, reparsed.Value);
+        }
 
-                    if (box == null)
-                        return false;
+        /// <summary>
+        /// Resolves every var(...) occurrence in <paramref name="value"/> to plain text. Quote-aware (so
+        /// `content: "var(--x)"` is left untouched) and paren-depth-aware (so a fallback containing
+        /// nested commas splits correctly).
+        /// </summary>
+        private static VarResolution SubstituteVarReferences(CssBox box, string value, Dictionary<string, string> resolvedCache, HashSet<string> resolving, HashSet<string> cyclic)
+        {
+            if (value.IndexOf("var(", StringComparison.OrdinalIgnoreCase) < 0)
+                return new VarResolution(true, value);
 
-                    if (box.HtmlTag.Name.Equals(selector.Class, StringComparison.InvariantCultureIgnoreCase))
-                        matched = true;
+            var sb = new StringBuilder();
+            var i = 0;
+            while (i < value.Length)
+            {
+                int argsStart, callEnd;
+                if (TryMatchVarCall(value, i, out argsStart, out callEnd))
+                {
+                    string name, fallback;
+                    SplitFirstTopLevelComma(value, argsStart, callEnd - 1, out name, out fallback);
 
-                    if (!matched && box.HtmlTag.HasAttribute("class"))
+                    string found;
+                    if (TryResolveCustomProperty(box, name, resolvedCache, resolving, cyclic, out found))
                     {
-                        var className = box.HtmlTag.TryGetAttribute("class");
-                        if (selector.Class.Equals("." + className, StringComparison.InvariantCultureIgnoreCase) || selector.Class.Equals(box.HtmlTag.Name + "." + className, StringComparison.InvariantCultureIgnoreCase))
-                            matched = true;
+                        sb.Append(found);
                     }
-
-                    if (!matched && box.HtmlTag.HasAttribute("id"))
+                    else if (fallback != null)
                     {
-                        var id = box.HtmlTag.TryGetAttribute("id");
-                        if (selector.Class.Equals("#" + id, StringComparison.InvariantCultureIgnoreCase))
-                            matched = true;
+                        var fallbackResult = SubstituteVarReferences(box, fallback, resolvedCache, resolving, cyclic);
+                        if (!fallbackResult.Success) return new VarResolution(false, null);
+                        sb.Append(fallbackResult.Value);
+                    }
+                    else
+                    {
+                        return new VarResolution(false, null); // guaranteed-invalid
                     }
 
-                    if (!matched && selector.DirectParent)
-                        return false;
+                    i = callEnd;
+                }
+                else if (value[i] == '"' || value[i] == '\'')
+                {
+                    var quoteEnd = SkipQuotedString(value, i);
+                    sb.Append(value, i, quoteEnd - i);
+                    i = quoteEnd;
+                }
+                else
+                {
+                    sb.Append(value[i]);
+                    i++;
                 }
             }
+
+            return new VarResolution(true, sb.ToString());
+        }
+
+        /// <summary>
+        /// Recursive + memoized: resolves box.CustomProperties[name]'s own var() references first (so a
+        /// custom property may reference another custom property, in any declaration order), using
+        /// `resolving` as a visited-set for cycle detection. `cyclic` permanently marks a property found
+        /// to (directly or transitively) reference itself - distinct from plain "not found", since per
+        /// spec a self-referencing property is guaranteed-invalid regardless of any fallback written
+        /// inside its own definition.
+        /// </summary>
+        private static bool TryResolveCustomProperty(CssBox box, string name, Dictionary<string, string> resolvedCache, HashSet<string> resolving, HashSet<string> cyclic, out string value)
+        {
+            if (cyclic.Contains(name))
+            {
+                value = null;
+                return false;
+            }
+
+            if (resolvedCache.TryGetValue(name, out value)) return true;
+
+            string rawValue;
+            if (box.CustomProperties == null || !box.CustomProperties.TryGetValue(name, out rawValue))
+            {
+                value = null;
+                return false;
+            }
+
+            if (!resolving.Add(name))
+            {
+                cyclic.Add(name); // name is referenced while already being resolved - a cycle
+                value = null;
+                return false;
+            }
+
+            var result = SubstituteVarReferences(box, rawValue, resolvedCache, resolving, cyclic);
+            resolving.Remove(name);
+
+            if (cyclic.Contains(name) || !result.Success)
+            {
+                cyclic.Add(name);
+                value = null;
+                return false;
+            }
+
+            value = result.Value;
+            resolvedCache[name] = value;
             return true;
         }
 
         /// <summary>
-        /// Assigns the given css style block properties to the given css box.
+        /// Matches a case-insensitive "var(" starting at <paramref name="start"/> and scans forward for
+        /// the matching close paren. On success, <paramref name="argsStart"/> is the index of the first
+        /// argument character and <paramref name="callEnd"/> is the index just past the closing paren.
         /// </summary>
-        /// <param name="box">the css box to assign css to</param>
-        /// <param name="block">the css block to assign</param>
-        private static void AssignCssBlock(CssBox box, CssBlock block)
+        private static bool TryMatchVarCall(string value, int start, out int argsStart, out int callEnd)
+        {
+            argsStart = 0;
+            callEnd = 0;
+
+            if (start + 4 > value.Length) return false;
+            if (string.Compare(value, start, "var(", 0, 4, StringComparison.OrdinalIgnoreCase) != 0) return false;
+
+            var depth = 1;
+            var i = start + 4;
+            while (i < value.Length)
+            {
+                var c = value[i];
+                if (c == '"' || c == '\'')
+                {
+                    i = SkipQuotedString(value, i);
+                    continue;
+                }
+
+                if (c == '(') depth++;
+                else if (c == ')')
+                {
+                    depth--;
+                    if (depth == 0)
+                    {
+                        argsStart = start + 4;
+                        callEnd = i + 1;
+                        return true;
+                    }
+                }
+
+                i++;
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Splits a var() argument list at the first top-level (paren-depth 0, outside quotes) comma.
+        /// The text before it is the custom property name (trimmed); everything after - commas and all -
+        /// is the fallback, per spec.
+        /// </summary>
+        private static void SplitFirstTopLevelComma(string value, int start, int end, out string name, out string fallback)
         {
-            foreach (var prop in block.Properties)
+            var depth = 0;
+            var i = start;
+            while (i < end)
             {
-                var value = prop.Value;
-                if (prop.Value == CssConstants.Inherit && box.ParentBox != null)
+                var c = value[i];
+                if (c == '"' || c == '\'')
+                {
+                    i = SkipQuotedString(value, i);
+                    continue;
+                }
+
+                if (c == '(') depth++;
+                else if (c == ')') depth--;
+                else if (c == ',' && depth == 0)
                 {
-                    value = CssUtils.GetPropertyValue(box.ParentBox, prop.Key);
+                    name = value.Substring(start, i - start).Trim();
+                    var fb = value.Substring(i + 1, end - (i + 1)).Trim();
+                    fallback = fb.Length > 0 ? fb : null;
+                    return;
                 }
-                if (IsStyleOnElementAllowed(box, prop.Key, value))
+
+                i++;
+            }
+
+            name = value.Substring(start, end - start).Trim();
+            fallback = null;
+        }
+
+        /// <summary>
+        /// Advances past a quoted string literal starting at <paramref name="start"/> (which must point
+        /// at the opening quote), honoring backslash escapes so an escaped quote doesn't end the string
+        /// early. Returns the index just past the closing quote (or the string's end, if unterminated).
+        /// </summary>
+        private static int SkipQuotedString(string value, int start)
+        {
+            var quote = value[start];
+            var i = start + 1;
+            while (i < value.Length)
+            {
+                if (value[i] == '\\' && i + 1 < value.Length)
                 {
-                    CssUtils.SetPropertyValue(box, prop.Key, value);
+                    i += 2;
+                    continue;
                 }
+
+                if (value[i] == quote)
+                    return i + 1;
+
+                i++;
             }
+
+            return i;
+        }
+
+        /// <summary>
+        /// The value a property falls back to when a var() reference in it is guaranteed-invalid -
+        /// reuses the same expression as the "unset" keyword arm in <see cref="AssignCssBlock"/>.
+        /// </summary>
+        private static string GetGuaranteedInvalidFallback(CssBox box, string propName)
+        {
+            return CssDefaults.InheritedProperties.Contains(propName) && box.ParentBox != null
+                ? CssUtils.GetPropertyValue(box.ParentBox, propName)
+                : CssDefaults.GetInitialValue(propName);
+        }
+
+        /// <summary>
+        /// Set the selected text style (selection text color and background color) from any "::selection"
+        /// rule found in the parsed stylesheets. This is a document-level lookup, not a per-box cascade
+        /// one - there is no box for a "::selection" pseudo-element to match against.
+        /// </summary>
+        /// <param name="htmlContainer"> </param>
+        /// <param name="cssData">the style data</param>
+        private void SetTextSelectionStyle(HtmlContainerInt htmlContainer, CssData cssData)
+        {
+            htmlContainer.SelectionForeColor = RColor.Empty;
+            htmlContainer.SelectionBackColor = RColor.Empty;
+
+            foreach (var stylesheet in cssData.Stylesheets)
+            {
+                foreach (var rule in CssData.FlattenRules(stylesheet.Rules).OfType<IStyleRule>())
+                {
+                    if (!SelectorIsSelectionPseudoElement(rule.Selector)) continue;
+
+                    foreach (var prop in rule.Style)
+                    {
+                        if (prop.Name == "color")
+                            htmlContainer.SelectionForeColor = _cssParser.ParseColor(prop.Value);
+                        else if (prop.Name == "background-color")
+                            htmlContainer.SelectionBackColor = _cssParser.ParseColor(prop.Value);
+                    }
+                }
+            }
+        }
+
+        private static bool SelectorIsSelectionPseudoElement(ISelector selector)
+        {
+            var pseudoElement = selector as PseudoElementSelector;
+            if (pseudoElement != null) return pseudoElement.Name == "selection";
+
+            var compound = selector as CompoundSelector;
+            if (compound != null) return compound.Any(SelectorIsSelectionPseudoElement);
+
+            var complex = selector as ComplexSelector;
+            if (complex != null)
+            {
+                var last = complex.LastOrDefault().Selector;
+                return last != null && SelectorIsSelectionPseudoElement(last);
+            }
+
+            var list = selector as ListSelector;
+            if (list != null) return list.Any(SelectorIsSelectionPseudoElement);
+
+            return false;
         }
 
         /// <summary>
@@ -397,17 +913,17 @@ private static bool IsStyleOnElementAllowed(CssBox box, string key, string value
         /// Clone css data if it has not already been cloned.<br/>
         /// Used to preserve the base css data used when changed by style inside html.
         /// </summary>
-        private static void CloneCssData(ref CssData cssData, ref bool cssDataChanged)
+        private static (CssData cssData, bool cssDataChanged) CloneCssData(CssData cssData, bool cssDataChanged)
         {
             if (!cssDataChanged)
             {
-                cssDataChanged = true;
-                cssData = cssData.Clone();
+                return (cssData.Clone(), true);
             }
+            return (cssData, cssDataChanged);
         }
 
         /// <summary>
-        /// 
+        ///
         /// </summary>
         /// <param name="tag"></param>
         /// <param name="box"></param>
@@ -575,6 +1091,9 @@ private static void CorrectTextBoxes(CssBox box)
             for (int i = box.Boxes.Count - 1; i >= 0; i--)
             {
                 var childBox = box.Boxes[i];
+
+                CssContentEngine.ApplyContent(childBox);
+
                 if (childBox.Text != null)
                 {
                     // is the box has text
@@ -602,7 +1121,7 @@ private static void CorrectTextBoxes(CssBox box)
                     }
                     else
                     {
-                        // remove text box that has no 
+                        // remove text box that has no
                         childBox.ParentBox.Boxes.RemoveAt(i);
                     }
                 }
@@ -1021,4 +1540,4 @@ private static void CorrectAnonymousTablesGenerateMissingParents(CssBox box)
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Source/HtmlRenderer/Core/Parse/RegexParserHelper.cs b/Source/HtmlRenderer/Core/Parse/RegexParserHelper.cs
deleted file mode 100644
index 86a690b50..000000000
--- a/Source/HtmlRenderer/Core/Parse/RegexParserHelper.cs
+++ /dev/null
@@ -1,227 +0,0 @@
-// "Therefore those skilled at the unorthodox
-// are infinite as heaven and earth,
-// inexhaustible as the great rivers.
-// When they come to an end,
-// they bagin again,
-// like the days and months;
-// they die and are reborn,
-// like the four seasons."
-// 
-// - Sun Tsu,
-// "The Art of War"
-
-using System.Collections.Generic;
-using System.Text.RegularExpressions;
-
-namespace HtmlRenderer.Parse
-{
-    /// <summary>
-    /// Collection of regular expressions used when parsing
-    /// </summary>
-    internal static class RegexParserHelper
-    {
-        #region Fields and Consts
-
-        /// <summary>
-        /// Extracts CSS style comments; e.g. /* comment */
-        /// </summary>
-        public const string CssComments = @"/\*[^*/]*\*/";
-
-        /// <summary>
-        /// Extracts the media types from a media at-rule; e.g. @media print, 3d, screen {
-        /// </summary>
-        public const string CssMediaTypes = @"@media[^\{\}]*\{";
-
-        /// <summary>
-        /// Extracts defined blocks in CSS. 
-        /// WARNING: Blocks will include blocks inside at-rules.
-        /// </summary>
-        public const string CssBlocks = @"[^\{\}]*\{[^\{\}]*\}";
-
-        /// <summary>
-        /// Extracts a number; e.g.  5, 6, 7.5, 0.9
-        /// </summary>
-        public const string CssNumber = @"{[0-9]+|[0-9]*\.[0-9]+}";
-
-        /// <summary>
-        /// Extracts css percentages from the string; e.g. 100% .5% 5.4%
-        /// </summary>
-        public const string CssPercentage = @"([0-9]+|[0-9]*\.[0-9]+)\%"; //TODO: Check if works fine
-
-        /// <summary>
-        /// Extracts CSS lengths; e.g. 9px 3pt .89em
-        /// </summary>
-        public const string CssLength = @"([0-9]+|[0-9]*\.[0-9]+)(em|ex|px|in|cm|mm|pt|pc)";
-
-        /// <summary>
-        /// Extracts CSS colors; e.g. black white #fff #fe98cd rgb(5,5,5) rgb(45%, 0, 0)
-        /// </summary>
-        public const string CssColors = @"(#\S{6}|#\S{3}|rgb\(\s*[0-9]{1,3}\%?\s*\,\s*[0-9]{1,3}\%?\s*\,\s*[0-9]{1,3}\%?\s*\)|maroon|red|orange|yellow|olive|purple|fuchsia|white|lime|green|navy|blue|aqua|teal|black|silver|gray)";
-
-        /// <summary>
-        /// Extracts line-height values (normal, numbers, lengths, percentages)
-        /// </summary>
-        public const string CssLineHeight = "(normal|" + CssNumber + "|" + CssLength + "|" + CssPercentage + ")";
-
-        /// <summary>
-        /// Extracts CSS border styles; e.g. solid none dotted
-        /// </summary>
-        public const string CssBorderStyle = @"(none|hidden|dotted|dashed|solid|double|groove|ridge|inset|outset)";
-
-        /// <summary>
-        /// Extracts CSS border widthe; e.g. 1px thin 3em
-        /// </summary>
-        public const string CssBorderWidth = "(" + CssLength + "|thin|medium|thick)";
-
-        /// <summary>
-        /// Extracts font-family values
-        /// </summary>
-        public const string CssFontFamily = "(\"[^\"]*\"|'[^']*'|\\S+\\s*)(\\s*\\,\\s*(\"[^\"]*\"|'[^']*'|\\S+))*";
-
-        /// <summary>
-        /// Extracts CSS font-styles; e.g. normal italic oblique
-        /// </summary>
-        public const string CssFontStyle = "(normal|italic|oblique)";
-
-        /// <summary>
-        /// Extracts CSS font-variant values; e.g. normal, small-caps
-        /// </summary>
-        public const string CssFontVariant = "(normal|small-caps)";
-
-        /// <summary>
-        /// Extracts font-weight values; e.g. normal, bold, bolder...
-        /// </summary>
-        public const string CssFontWeight = "(normal|bold|bolder|lighter|100|200|300|400|500|600|700|800|900)";
-
-        /// <summary>
-        /// Exracts font sizes: xx-small, larger, small, 34pt, 30%, 2em
-        /// </summary>
-        public const string CssFontSize = "(" + CssLength + "|" + CssPercentage + "|xx-small|x-small|small|medium|large|x-large|xx-large|larger|smaller)";
-
-        /// <summary>
-        /// Gets the font-size[/line-height]? on the font shorthand property.
-        /// Check http://www.w3.org/TR/CSS21/fonts.html#font-shorthand
-        /// </summary>
-        public const string CssFontSizeAndLineHeight = CssFontSize + @"(\/" + CssLineHeight + @")?(\s|$)";
-
-        /// <summary>
-        /// Extracts HTML tags
-        /// </summary>
-        public const string HtmlTag = @"<[^<>]*>";
-
-        /// <summary>
-        /// Extracts attributes from a HTML tag; e.g. att=value, att="value"
-        /// </summary>
-        public const string HmlTagAttributes = "(?<name>\\b\\w+\\b)\\s*=\\s*(?<value>\"[^\"]*\"|'[^']*'|[^\"'<>\\s]+)";
-
-        /// <summary>
-        /// the regexes cache that is used by the parser so not to create regex each time
-        /// </summary>
-        private static readonly Dictionary<string, Regex> _regexes = new Dictionary<string, Regex>();
-
-        #endregion
-
-
-        /// <summary>
-        /// Get CSS at rule from the given stylesheet.
-        /// </summary>
-        /// <param name="stylesheet">the stylesheet data to retrieve the rule from</param>
-        /// <param name="startIdx">the index to start the search for the rule, on return will be the value of the end of the found rule</param>
-        /// <returns>the found at rule or null if not exists</returns>
-        public static string GetCssAtRules(string stylesheet, ref int startIdx)
-        {
-            startIdx = stylesheet.IndexOf('@', startIdx);
-            if (startIdx > -1)
-            {
-                int count = 1;
-                int endIdx = stylesheet.IndexOf('{', startIdx);
-                if (endIdx > -1)
-                {
-                    while (count > 0 && endIdx < stylesheet.Length)
-                    {
-                        endIdx++;
-                        if (stylesheet[endIdx] == '{')
-                        {
-                            count++;
-                        }
-                        else if (stylesheet[endIdx] == '}')
-                        {
-                            count--;
-                        }
-                    }
-                    if (endIdx < stylesheet.Length)
-                    {
-                        var atrule = stylesheet.Substring(startIdx, endIdx - startIdx + 1);
-                        startIdx = endIdx;
-                        return atrule;
-                    }
-                }
-            }
-            return null;
-        }
-
-        /// <summary>
-        /// Extracts matches from the specified source
-        /// </summary>
-        /// <param name="regex">Regular expression to extract matches</param>
-        /// <param name="source">Source to extract matches</param>
-        /// <returns>Collection of matches</returns>
-        public static MatchCollection Match(string regex, string source)
-        {
-            var r = GetRegex(regex);
-            return r.Matches(source);
-        }
-
-        /// <summary>
-        /// Searches the specified regex on the source
-        /// </summary>
-        /// <param name="regex"></param>
-        /// <param name="source"></param>
-        /// <returns></returns>
-        public static string Search(string regex, string source)
-        {
-            int position;
-            return Search(regex, source, out position);
-        }
-
-        /// <summary>
-        /// Searches the specified regex on the source
-        /// </summary>
-        /// <param name="regex"></param>
-        /// <param name="source"></param>
-        /// <param name="position"> </param>
-        /// <returns></returns>
-        public static string Search(string regex, string source, out int position)
-        {
-            MatchCollection matches = Match(regex, source);
-
-            if (matches.Count > 0)
-            {
-                position = matches[0].Index;
-                return matches[0].Value;
-            }
-            else
-            {
-                position = -1;
-            }
-
-            return null;
-        }
-
-        /// <summary>
-        /// Get regex instance for the given regex string.
-        /// </summary>
-        /// <param name="regex">the regex string to use</param>
-        /// <returns>the regex instance</returns>
-        private static Regex GetRegex(string regex)
-        {
-            Regex r;
-            if (!_regexes.TryGetValue(regex, out r))
-            {
-                r = new Regex(regex, RegexOptions.IgnoreCase | RegexOptions.Singleline);
-                _regexes[regex] = r;
-            }
-            return r;
-        }
-    }
-}
diff --git a/Source/HtmlRenderer/Core/Utils/CommonUtils.cs b/Source/HtmlRenderer/Core/Utils/CommonUtils.cs
index 8da8bad95..2ce690229 100644
--- a/Source/HtmlRenderer/Core/Utils/CommonUtils.cs
+++ b/Source/HtmlRenderer/Core/Utils/CommonUtils.cs
@@ -17,6 +17,7 @@
 using System.Net;
 using System.Text;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.Network;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Utils
 {
@@ -47,11 +48,19 @@ internal static class CommonUtils
             }
         };
 
+        /// <summary>
+        /// Table to convert numbers into hebrew digits - CSS Counter Styles Level 3 §6.1's "hebrew"
+        /// <c>@counter-style</c>. Row 3 (thousands) is each units-row letter with a geresh (U+05F3)
+        /// appended, per the spec's additive-symbols list (e.g. 1000 is the same letter as 1 plus a
+        /// geresh) - a 3-row table silently drops the thousands digit entirely for any value >= 1000.
+        /// 15 and 16 need a further, non-tabular override - see <see cref="ConvertToAlphaNumber"/>.
+        /// </summary>
         private static readonly string[,] _hebrewDigitsTable =
         {
             { "א", "ב", "ג", "ד", "ה", "ו", "ז", "ח", "ט" },
             { "י", "כ", "ל", "מ", "נ", "ס", "ע", "פ", "צ" },
-            { "ק", "ר", "ש", "ת", "תק", "תר", "תש", "תת", "תתק", }
+            { "ק", "ר", "ש", "ת", "תק", "תר", "תש", "תת", "תתק", },
+            { "א׳", "ב׳", "ג׳", "ד׳", "ה׳", "ו׳", "ז׳", "ח׳", "ט׳" }
         };
 
         private static readonly string[,] _georgianDigitsTable =
@@ -61,11 +70,18 @@ internal static class CommonUtils
             { "რ", "ს", "ტ", "ჳ", "ფ", "ქ", "ღ", "ყ", "შ" }
         };
 
+        /// <summary>
+        /// Table to convert numbers into armenian digits - CSS Counter Styles Level 3 §6.1's
+        /// "armenian" <c>@counter-style</c>. Row 3 (thousands) added for the same reason as
+        /// <see cref="_hebrewDigitsTable"/>'s - a 3-row table silently drops the thousands digit for
+        /// any value >= 1000.
+        /// </summary>
         private static readonly string[,] _armenianDigitsTable =
         {
             { "Ա", "Բ", "Գ", "Դ", "Ե", "Զ", "Է", "Ը", "Թ" },
             { "Ժ", "Ի", "Լ", "Խ", "Ծ", "Կ", "Հ", "Ձ", "Ղ" },
-            { "Ճ", "Մ", "Յ", "Ն", "Շ", "Ո", "Չ", "Պ", "Ջ" }
+            { "Ճ", "Մ", "Յ", "Ն", "Շ", "Ո", "Չ", "Պ", "Ջ" },
+            { "Ռ", "Ս", "Վ", "Տ", "Ր", "Ց", "Ւ", "Փ", "Ք" }
         };
 
         private static readonly string[] _hiraganaDigitsTable = new[]
@@ -167,6 +183,47 @@ public static Uri TryGetUri(string path)
             return null;
         }
 
+        /// <summary>
+        /// Resolves <paramref name="src"/> (a <c>src</c>/<c>href</c>/CSS <c>url()</c> reference, absolute
+        /// or relative) against the document's base URL: <paramref name="overrideBaseUri"/> when given (a
+        /// stylesheet's own URL, for resolving a nested <c>@import</c> or <c>@font-face src</c> relative to
+        /// where that stylesheet was fetched from, not the document's own base), else the document's
+        /// <c>&lt;base href&gt;</c> element if it has one, else the adapter's own
+        /// <see cref="Adapters.RAdapter.BaseUri"/>.
+        /// </summary>
+        /// <param name="htmlContainer">the html container to resolve the base URI against</param>
+        /// <param name="src">the (typically relative) reference to resolve</param>
+        /// <param name="overrideBaseUri">optional: resolve against this instead of the document's own base</param>
+        /// <returns>the resolved absolute URI, or null if it could not be resolved</returns>
+        public static RUri ResolveAgainstDocumentBase(TheArtOfDev.HtmlRenderer.Core.HtmlContainerInt htmlContainer, string src, RUri overrideBaseUri = null)
+        {
+            RUri baseUri;
+
+            if (overrideBaseUri != null)
+            {
+                baseUri = overrideBaseUri;
+            }
+            else
+            {
+                var baseElement = DomUtils.GetBoxByTagName(htmlContainer.Root, "base");
+                var baseHref = baseElement != null && baseElement.HtmlTag != null ? baseElement.HtmlTag.TryGetAttribute("href", "") : "";
+                baseUri = string.IsNullOrWhiteSpace(baseHref) ? htmlContainer.Adapter.BaseUri : new RUri(baseHref);
+            }
+
+            try
+            {
+                // Deliberately not pre-filtered with Uri.IsWellFormedUriString: it applies stricter
+                // generic-syntax rules than Uri's own parser and rejects some URIs Uri/RUri parse
+                // correctly (e.g. certain percent-encoded `data:` URIs). new RUri(base, src) resolves an
+                // absolute src as-is, so this handles absolute and relative references uniformly.
+                return baseUri == null ? new RUri(src, UriKind.RelativeOrAbsolute) : new RUri(baseUri, src);
+            }
+            catch (UriFormatException)
+            {
+                return null;
+            }
+        }
+
         /// <summary>
         /// Get the first value in the given dictionary.
         /// </summary>
@@ -378,7 +435,7 @@ public static string ConvertToAlphaNumber(int number, string style = CssConstant
             }
             else if (style.Equals(CssConstants.Hebrew, StringComparison.InvariantCultureIgnoreCase))
             {
-                return ConvertToSpecificNumbers(number, _hebrewDigitsTable);
+                return ConvertToHebrewNumber(number);
             }
             else if (style.Equals(CssConstants.Hiragana, StringComparison.InvariantCultureIgnoreCase) || style.Equals(CssConstants.HiraganaIroha, StringComparison.InvariantCultureIgnoreCase))
             {
@@ -469,6 +526,27 @@ private static string ConvertToRomanNumbers(int number, bool lowercase)
             return lowercase ? sb.ToLower() : sb;
         }
 
+        /// <summary>
+        /// Hebrew's additive algorithm (<see cref="ConvertToSpecificNumbers"/> over
+        /// <see cref="_hebrewDigitsTable"/>) with the CSS Counter Styles Level 3 §6.1 override for a
+        /// tens-and-units value of 15 or 16: the naive per-digit-group combination would produce יה/יו,
+        /// which closely resembles the Tetragrammaton, so the spec mandates טו/טז instead. 17-19 don't
+        /// need an override - their naive combination (יז/יח/יט) already matches the spec's table.
+        /// </summary>
+        /// <param name="number">the number to convert</param>
+        /// <returns>the hebrew number string</returns>
+        private static string ConvertToHebrewNumber(int number)
+        {
+            var tensAndUnits = number % 100;
+            if (tensAndUnits is 15 or 16)
+            {
+                var hundredsAndUp = ConvertToSpecificNumbers(number - tensAndUnits, _hebrewDigitsTable);
+                return hundredsAndUp + (tensAndUnits == 15 ? "טו" : "טז");
+            }
+
+            return ConvertToSpecificNumbers(number, _hebrewDigitsTable);
+        }
+
         /// <summary>
         /// Convert the given integer into given alphabet numeric system.
         /// </summary>
diff --git a/Source/HtmlRenderer/Core/Utils/CssConstants.cs b/Source/HtmlRenderer/Core/Utils/CssConstants.cs
index 655849256..06fe0aa02 100644
--- a/Source/HtmlRenderer/Core/Utils/CssConstants.cs
+++ b/Source/HtmlRenderer/Core/Utils/CssConstants.cs
@@ -21,16 +21,29 @@ internal static class CssConstants
         public const string Auto = "auto";
         public const string Avoid = "avoid";
         public const string Baseline = "baseline";
+        public const string Before = "before";
+        public const string After = "after";
         public const string Blink = "blink";
         public const string Block = "block";
         public const string InlineBlock = "inline-block";
         public const string Bold = "bold";
         public const string Bolder = "bolder";
         public const string Bottom = "bottom";
+        public const string Both = "both";
         public const string BreakAll = "break-all";
         public const string KeepAll = "keep-all";
         public const string Center = "center";
         public const string Collapse = "collapse";
+        public const string UltraCondensed = "ultra-condensed";
+        public const string ExtraCondensed = "extra-condensed";
+        public const string Condensed = "condensed";
+        public const string SemiCondensed = "semi-condensed";
+        public const string SemiExpanded = "semi-expanded";
+        public const string Expanded = "expanded";
+        public const string ExtraExpanded = "extra-expanded";
+        public const string UltraExpanded = "ultra-expanded";
+        public const string ContentBox = "content-box";
+        public const string BorderBox = "border-box";
         public const string Cursive = "cursive";
         public const string Circle = "circle";
         public const string Decimal = "decimal";
@@ -40,6 +53,10 @@ internal static class CssConstants
         public const string Fixed = "fixed";
         public const string Hide = "hide";
         public const string Inherit = "inherit";
+        public const string Initial = "initial";
+        public const string Unset = "unset";
+        public const string Revert = "revert";
+        public const string RevertLayer = "revert-layer";
         public const string Inline = "inline";
         public const string InlineTable = "inline-table";
         public const string Inset = "inset";
diff --git a/Source/HtmlRenderer/Core/Utils/CssFontWeightResolver.cs b/Source/HtmlRenderer/Core/Utils/CssFontWeightResolver.cs
new file mode 100644
index 000000000..dfc799a6a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Utils/CssFontWeightResolver.cs
@@ -0,0 +1,48 @@
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Utils
+{
+    /// <summary>
+    /// Resolves a box's cascaded <c>font-weight</c> value (<c>normal</c>/<c>bold</c>/<c>bolder</c>/
+    /// <c>lighter</c>/a number) to a concrete CSS Fonts Level 4 numeric weight (1-1000), for
+    /// <see cref="Dom.CssBoxProperties.ActualFont"/>'s face-matching call into
+    /// <see cref="Handlers.FontsHandler.GetCachedFont(string,double,Adapters.Entities.RFontStyle,int,int,int?)"/>.
+    /// </summary>
+    internal static class CssFontWeightResolver
+    {
+        internal const int Normal = 400;
+        internal const int Bold = 700;
+
+        /// <summary>
+        /// <c>bolder</c>/<c>lighter</c> are relative to the parent's resolved weight; true CSS2.1 defines
+        /// this via a lookup table over 9 named weight steps, not a fixed offset. A flat +/-300 clamped to
+        /// [1,1000] is a real, explicitly-simplified approximation of that table - close enough to move a
+        /// normal-weight (400) parent to bold (700) and back, without reproducing the full step table for
+        /// a CSS feature real-world content rarely nests more than one level deep.
+        /// </summary>
+        private const int RelativeStep = 300;
+
+        internal static int Resolve(string fontWeightValue, int parentWeight)
+        {
+            if (string.IsNullOrWhiteSpace(fontWeightValue))
+                return Normal;
+
+            switch (fontWeightValue)
+            {
+                case CssConstants.Normal:
+                case CssConstants.Inherit:
+                    return Normal;
+                case CssConstants.Bold:
+                    return Bold;
+                case CssConstants.Bolder:
+                    return Clamp(parentWeight + RelativeStep);
+                case CssConstants.Lighter:
+                    return Clamp(parentWeight - RelativeStep);
+                default:
+                    return int.TryParse(fontWeightValue, out var numeric) ? Clamp(numeric) : Normal;
+            }
+        }
+
+        private static int Clamp(int weight) => Math.Max(1, Math.Min(1000, weight));
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Utils/CssUtils.cs b/Source/HtmlRenderer/Core/Utils/CssUtils.cs
index 69f949390..df9fe7dc7 100644
--- a/Source/HtmlRenderer/Core/Utils/CssUtils.cs
+++ b/Source/HtmlRenderer/Core/Utils/CssUtils.cs
@@ -11,6 +11,7 @@
 // "The Art of War"
 
 using System;
+using System.Collections.Generic;
 using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Dom;
@@ -30,6 +31,32 @@ internal static class CssUtils
         /// </summary>
         private static readonly RColor _defaultSelectionBackcolor = RColor.FromArgb(0xa9, 0x33, 0x99, 0xFF);
 
+        /// <summary>
+        /// Every CSS property name this engine recognizes (the exact case list <see cref="GetPropertyValue"/>/
+        /// <see cref="SetPropertyValue"/> handle) - used by <see cref="SnapshotProperties"/> to capture a
+        /// box's full known-property state as a revert/revert-layer target for the six-phase cascade.
+        /// Deliberately the same whitelist as the switch statements below: adding a property here without
+        /// a matching case (or vice versa) would only ever affect revert targets, not what's supported.
+        /// </summary>
+        private static readonly string[] _knownPropertyNames =
+        {
+            "border-bottom-width", "border-left-width", "border-right-width", "border-top-width",
+            "border-bottom-style", "border-left-style", "border-right-style", "border-top-style",
+            "border-bottom-color", "border-left-color", "border-right-color", "border-top-color",
+            "border-spacing", "border-collapse",
+            "border-top-left-radius", "border-top-right-radius", "border-bottom-right-radius", "border-bottom-left-radius",
+            "margin-bottom", "margin-left", "margin-right", "margin-top",
+            "padding-bottom", "padding-left", "padding-right", "padding-top",
+            "page-break-inside", "left", "top", "width", "max-width", "height", "min-height", "max-height",
+            "background-color", "background-image", "background-position", "background-repeat",
+            "content", "color", "display", "direction", "empty-cells", "float", "clear", "box-sizing", "position",
+            "line-height", "vertical-align", "text-indent", "text-align", "text-decoration-line",
+            "white-space", "word-break", "visibility", "word-spacing",
+            "font-family", "font-size", "font-style", "font-variant", "font-weight",
+            "list-style", "list-style-position", "list-style-image", "list-style-type",
+            "overflow"
+        };
+
         #endregion
 
 
@@ -96,16 +123,14 @@ public static string GetPropertyValue(CssBox cssBox, string propName)
                     return cssBox.BorderSpacing;
                 case "border-collapse":
                     return cssBox.BorderCollapse;
-                case "corner-radius":
-                    return cssBox.CornerRadius;
-                case "corner-nw-radius":
-                    return cssBox.CornerNwRadius;
-                case "corner-ne-radius":
-                    return cssBox.CornerNeRadius;
-                case "corner-se-radius":
-                    return cssBox.CornerSeRadius;
-                case "corner-sw-radius":
-                    return cssBox.CornerSwRadius;
+                case "border-top-left-radius":
+                    return cssBox.BorderTopLeftRadius;
+                case "border-top-right-radius":
+                    return cssBox.BorderTopRightRadius;
+                case "border-bottom-right-radius":
+                    return cssBox.BorderBottomRightRadius;
+                case "border-bottom-left-radius":
+                    return cssBox.BorderBottomLeftRadius;
                 case "margin-bottom":
                     return cssBox.MarginBottom;
                 case "margin-left":
@@ -134,6 +159,10 @@ public static string GetPropertyValue(CssBox cssBox, string propName)
                     return cssBox.MaxWidth;
                 case "height":
                     return cssBox.Height;
+                case "min-height":
+                    return cssBox.MinHeight;
+                case "max-height":
+                    return cssBox.MaxHeight;
                 case "background-color":
                     return cssBox.BackgroundColor;
                 case "background-image":
@@ -142,10 +171,6 @@ public static string GetPropertyValue(CssBox cssBox, string propName)
                     return cssBox.BackgroundPosition;
                 case "background-repeat":
                     return cssBox.BackgroundRepeat;
-                case "background-gradient":
-                    return cssBox.BackgroundGradient;
-                case "background-gradient-angle":
-                    return cssBox.BackgroundGradientAngle;
                 case "content":
                     return cssBox.Content;
                 case "color":
@@ -158,6 +183,10 @@ public static string GetPropertyValue(CssBox cssBox, string propName)
                     return cssBox.EmptyCells;
                 case "float":
                     return cssBox.Float;
+                case "clear":
+                    return cssBox.Clear;
+                case "box-sizing":
+                    return cssBox.BoxSizing;
                 case "position":
                     return cssBox.Position;
                 case "line-height":
@@ -168,7 +197,7 @@ public static string GetPropertyValue(CssBox cssBox, string propName)
                     return cssBox.TextIndent;
                 case "text-align":
                     return cssBox.TextAlign;
-                case "text-decoration":
+                case "text-decoration-line":
                     return cssBox.TextDecoration;
                 case "white-space":
                     return cssBox.WhiteSpace;
@@ -188,6 +217,8 @@ public static string GetPropertyValue(CssBox cssBox, string propName)
                     return cssBox.FontVariant;
                 case "font-weight":
                     return cssBox.FontWeight;
+                case "font-stretch":
+                    return cssBox.FontStretch;
                 case "list-style":
                     return cssBox.ListStyle;
                 case "list-style-position":
@@ -255,20 +286,20 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                 case "border-collapse":
                     cssBox.BorderCollapse = value;
                     break;
-                case "corner-radius":
-                    cssBox.CornerRadius = value;
+                case "border-radius":
+                    cssBox.BorderRadius = value;
                     break;
-                case "corner-nw-radius":
-                    cssBox.CornerNwRadius = value;
+                case "border-top-left-radius":
+                    cssBox.BorderTopLeftRadius = value;
                     break;
-                case "corner-ne-radius":
-                    cssBox.CornerNeRadius = value;
+                case "border-top-right-radius":
+                    cssBox.BorderTopRightRadius = value;
                     break;
-                case "corner-se-radius":
-                    cssBox.CornerSeRadius = value;
+                case "border-bottom-right-radius":
+                    cssBox.BorderBottomRightRadius = value;
                     break;
-                case "corner-sw-radius":
-                    cssBox.CornerSwRadius = value;
+                case "border-bottom-left-radius":
+                    cssBox.BorderBottomLeftRadius = value;
                     break;
                 case "margin-bottom":
                     cssBox.MarginBottom = value;
@@ -312,6 +343,12 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                 case "height":
                     cssBox.Height = value;
                     break;
+                case "min-height":
+                    cssBox.MinHeight = value;
+                    break;
+                case "max-height":
+                    cssBox.MaxHeight = value;
+                    break;
                 case "background-color":
                     cssBox.BackgroundColor = value;
                     break;
@@ -324,12 +361,6 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                 case "background-repeat":
                     cssBox.BackgroundRepeat = value;
                     break;
-                case "background-gradient":
-                    cssBox.BackgroundGradient = value;
-                    break;
-                case "background-gradient-angle":
-                    cssBox.BackgroundGradientAngle = value;
-                    break;
                 case "color":
                     cssBox.Color = value;
                     break;
@@ -348,6 +379,12 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                 case "float":
                     cssBox.Float = value;
                     break;
+                case "clear":
+                    cssBox.Clear = value;
+                    break;
+                case "box-sizing":
+                    cssBox.BoxSizing = value;
+                    break;
                 case "position":
                     cssBox.Position = value;
                     break;
@@ -363,7 +400,7 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                 case "text-align":
                     cssBox.TextAlign = value;
                     break;
-                case "text-decoration":
+                case "text-decoration-line":
                     cssBox.TextDecoration = value;
                     break;
                 case "white-space":
@@ -379,7 +416,13 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                     cssBox.WordSpacing = value;
                     break;
                 case "font-family":
-                    cssBox.FontFamily = value;
+                    // The declared value may be a comma-separated fallback list and/or have quoted
+                    // candidates (e.g. "'Helvetica Neue', Arial, sans-serif") - resolve it down to the
+                    // first candidate that's actually installed, same as the legacy <font face="...">
+                    // attribute already does, rather than handing the literal, possibly-quoted CSS
+                    // text straight to font creation (which fails to match any real font by name and
+                    // silently falls back to a generic system font for every unresolved candidate).
+                    cssBox.FontFamily = cssBox.HtmlContainer.CssParser.ParseFontFamily(value);
                     break;
                 case "font-size":
                     cssBox.FontSize = value;
@@ -393,6 +436,9 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                 case "font-weight":
                     cssBox.FontWeight = value;
                     break;
+                case "font-stretch":
+                    cssBox.FontStretch = value;
+                    break;
                 case "list-style":
                     cssBox.ListStyle = value;
                     break;
@@ -410,5 +456,30 @@ public static void SetPropertyValue(CssBox cssBox, string propName, string value
                     break;
             }
         }
+
+        /// <summary>
+        /// Snapshots all known property values from a CssBox into a dictionary. Used by the six-phase
+        /// cascade (<see cref="Parse.DomParser"/>) to capture a box's state at the start of a cascade
+        /// origin phase, so a later "revert"/"revert-layer" declaration in that phase can roll back to it.
+        /// </summary>
+        public static Dictionary<string, string> SnapshotProperties(CssBox box)
+        {
+            var snapshot = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+            foreach (var name in _knownPropertyNames)
+                snapshot[name] = GetPropertyValue(box, name);
+            return snapshot;
+        }
+
+        /// <summary>
+        /// Snapshots this box's custom property values, for use as the revert/revert-layer target of a
+        /// later cascade phase. Custom property names are case-sensitive, unlike <see cref="SnapshotProperties"/>'s
+        /// known-property snapshot, so this uses a separate, ordinal-case-sensitive dictionary.
+        /// </summary>
+        public static Dictionary<string, string> SnapshotCustomProperties(CssBox box)
+        {
+            return box.CustomProperties != null && box.CustomProperties.Count > 0
+                ? new Dictionary<string, string>(box.CustomProperties)
+                : null;
+        }
     }
 }
\ No newline at end of file
diff --git a/Source/HtmlRenderer/Core/Utils/DataUriUtils.cs b/Source/HtmlRenderer/Core/Utils/DataUriUtils.cs
new file mode 100644
index 000000000..0f82869a5
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Utils/DataUriUtils.cs
@@ -0,0 +1,53 @@
+#nullable enable
+using System;
+using System.Linq;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Utils
+{
+    /// <summary>
+    /// Synchronous <c>data:</c> URI decoding shared by every layer that needs to inspect a data URI's
+    /// declared MIME type/bytes without going through the async
+    /// <see cref="Network.DataUriNetworkLoader"/>/<see cref="Handlers.ImageLoadHandler"/> pipeline (e.g.
+    /// to reject an unsupported MIME type before ever attempting to load it).
+    /// </summary>
+    internal static class DataUriUtils
+    {
+        public static bool TryDecodeDataUri(string? uri, out string mimeType, out byte[] bytes)
+        {
+            mimeType = "";
+            bytes = Array.Empty<byte>();
+
+            if (uri is null || !uri.StartsWith("data:", StringComparison.OrdinalIgnoreCase))
+                return false;
+
+            var comma = uri.IndexOf(',');
+            if (comma < 0)
+                return false;
+
+            var header = uri.Substring(5, comma - 5);
+            var data = uri.Substring(comma + 1);
+
+            var headerParts = header.Split(';');
+            mimeType = headerParts.Length > 0 && headerParts[0].Length > 0 ? headerParts[0] : "text/plain";
+            var isBase64 = headerParts.Any(p => p.Equals("base64", StringComparison.OrdinalIgnoreCase));
+
+            try
+            {
+                // Per the data: URL spec, the body is percent-decoded first and THEN (if the ;base64
+                // flag is present) base64-decoded - percent-decoding is not conditional on the encoding
+                // flag. A base64 payload containing reserved characters (/, +, =) is commonly written
+                // with them percent-escaped (%2F, %2B, %3D), and Convert.FromBase64String throws on a
+                // literal "%" in its input, so skipping this step here silently fails to decode such data.
+                bytes = isBase64
+                    ? Convert.FromBase64String(Uri.UnescapeDataString(data))
+                    : System.Text.Encoding.UTF8.GetBytes(Uri.UnescapeDataString(data));
+            }
+            catch (FormatException)
+            {
+                return false;
+            }
+
+            return true;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Utils/DomUtils.cs b/Source/HtmlRenderer/Core/Utils/DomUtils.cs
index 8d5520c75..5fa75ca74 100644
--- a/Source/HtmlRenderer/Core/Utils/DomUtils.cs
+++ b/Source/HtmlRenderer/Core/Utils/DomUtils.cs
@@ -12,8 +12,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text;
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
 using TheArtOfDev.HtmlRenderer.Core.Dom;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Parse;
@@ -25,6 +27,32 @@ namespace TheArtOfDev.HtmlRenderer.Core.Utils
     /// </summary>
     internal sealed class DomUtils
     {
+        /// <summary>
+        /// Walks up the box tree starting at (but not including) <paramref name="box"/>'s parent,
+        /// skipping anonymous boxes (no <see cref="HtmlTag"/>), returning the nearest ancestor that
+        /// corresponds to a real HTML element. Used by structural pseudo-class selector matching
+        /// (:nth-child, :only-child, :only-of-type) which needs to reason about element siblings,
+        /// not the layout engine's anonymous box wrappers.
+        /// </summary>
+        /// <param name="box">the box to start the walk from</param>
+        /// <returns>the nearest ancestor box with a non-null HtmlTag, or null if none exists</returns>
+        public static CssBox GetNearestParentElementBox(CssBox box)
+        {
+            var parentBox = box.ParentBox;
+
+            while (parentBox != null)
+            {
+                if (parentBox.HtmlTag != null)
+                {
+                    return parentBox;
+                }
+
+                parentBox = parentBox.ParentBox;
+            }
+
+            return null;
+        }
+
         /// <summary>
         /// Check if the given location is inside the given box deep.<br/>
         /// Check inner boxes and all lines that the given box spans to.
@@ -101,12 +129,15 @@ public static CssBox GetPreviousSibling(CssBox b)
                     int diff = 1;
                     CssBox sib = b.ParentBox.Boxes[index - diff];
 
-                    while ((sib.Display == CssConstants.None || sib.Position == CssConstants.Absolute || sib.Position == CssConstants.Fixed) && index - diff - 1 >= 0)
+                    // floated siblings are removed from normal flow: a subsequent sibling's static
+                    // position must be computed as if they weren't there (CSS 2.1 9.5), so they're
+                    // skipped exactly like display:none boxes are.
+                    while ((sib.Display == CssConstants.None || sib.Position == CssConstants.Absolute || sib.Position == CssConstants.Fixed || sib.IsFloated) && index - diff - 1 >= 0)
                     {
                         sib = b.ParentBox.Boxes[index - ++diff];
                     }
 
-                    return (sib.Display == CssConstants.None || sib.Position == CssConstants.Fixed) ? null : sib;
+                    return (sib.Display == CssConstants.None || sib.Position == CssConstants.Fixed || sib.IsFloated) ? null : sib;
                 }
             }
             return null;
@@ -200,6 +231,169 @@ public static bool IsBoxHasWhitespace(CssBox box)
             return false;
         }
 
+        /// <summary>
+        /// The candidate rectangle being tested against existing floats, either during float placement
+        /// (<see cref="CssLayoutEngine"/>'s FloatBoxLeft/FloatBoxRight) or while flowing a line's inline
+        /// content around already-placed floats (<see cref="GetLastLeftIntersectingFloatBox"/>/
+        /// <see cref="GetLastRightIntersectingFloatBox"/>). Ported from PeachPDF.
+        /// </summary>
+        internal sealed class CssFloatCoordinates
+        {
+            public double Left;
+            public double Right;
+            public double Top;
+            public double MaxBottom;
+            public double MarginLeft;
+            public double MarginRight;
+            public double ReferenceWidth;
+
+            public double FloatRightStartX
+            {
+                // Right is already margin-right-adjusted (FloatBoxRight sets Right = limitRight -
+                // box.ActualMarginRight), so subtracting MarginLeft here too pulled a right-floated
+                // box's own right edge inward by its own left margin - a box's left margin is space
+                // to its own left and must not affect where its own right edge lands (the left-float
+                // counterpart never double-applies a margin term either). Ported from PeachPDF
+                // (jhaygood86/PeachPDF#688).
+                get { return Right - ReferenceWidth; }
+            }
+        }
+
+        /// <summary>
+        /// Finds the first floated box that intersects <paramref name="coordinates"/> for the given float
+        /// direction, searching in document order: climb from <paramref name="reference"/> up to the root,
+        /// scanning each level's preceding siblings' whole subtrees. There is no dedicated float list
+        /// anywhere - this is a live tree search, ported from PeachPDF. Short-circuits immediately (no
+        /// walk at all) for the common case of a document with no floated boxes.
+        /// </summary>
+        internal static CssBox GetFirstIntersectingFloatBox(CssBox reference, CssFloatCoordinates coordinates, string floatDirection)
+        {
+            if (reference.HtmlContainer == null || !reference.HtmlContainer.HasFloatedBoxes)
+                return null;
+
+            while (true)
+            {
+                if (reference.ParentBox == null)
+                    return null;
+
+                var currentBoxIdx = reference.ParentBox.Boxes.IndexOf(reference);
+
+                for (int i = 0; i < currentBoxIdx; i++)
+                {
+                    var next = GetNextIntersectingFloatBox(reference.ParentBox.Boxes[i], coordinates, floatDirection);
+                    if (next != null)
+                        return next;
+                }
+
+                reference = reference.ParentBox;
+            }
+        }
+
+        /// <summary>
+        /// Finds the last (rightmost) left-floated box obstructing <paramref name="curx"/> at row
+        /// <paramref name="cury"/>, walking past any chain of contiguous left floats. Used while flowing a
+        /// line's inline content: the result's right edge is where the line's content may start.
+        /// Margins are taken from <paramref name="box"/> (the box whose leading edge is being placed),
+        /// matching the caller's convention at each of its call sites.
+        /// </summary>
+        internal static CssBox GetLastLeftIntersectingFloatBox(CssBox box, double curx, double cury, double maxRight, double maxbottom)
+        {
+            var left = curx;
+            CssBox lastIntersectingFloat = null;
+
+            // Bounded by a flat iteration count, matching PeachPDF: the number of distinct floats in a
+            // real document is always finite, and this loop's only job is to walk past each one once.
+            var iterations = 0;
+            while (iterations++ < 10000)
+            {
+                var floatCoordinates = new CssFloatCoordinates
+                {
+                    Left = left,
+                    Top = cury,
+                    MarginLeft = box.ActualMarginLeft,
+                    MarginRight = box.ActualMarginRight,
+                    MaxBottom = maxbottom,
+                    ReferenceWidth = 0,
+                    Right = maxRight
+                };
+
+                var intersectingFloat = GetFirstIntersectingFloatBox(box, floatCoordinates, CssConstants.Left);
+                if (intersectingFloat == null)
+                    break;
+
+                left = intersectingFloat.ActualRight + intersectingFloat.ActualMarginRight;
+                lastIntersectingFloat = intersectingFloat;
+            }
+
+            return lastIntersectingFloat;
+        }
+
+        /// <summary>
+        /// A right float's constraint on a line is unlike a left float's: a left float caps where the
+        /// cursor itself currently sits (a point-collision test, correct in
+        /// <see cref="GetLastLeftIntersectingFloatBox"/> above), but a right float caps how far right
+        /// the cursor is allowed to reach in advance - a lookahead, independent of the cursor's current
+        /// position or the word being placed. Reusing the point-collision test here (querying
+        /// <see cref="GetFirstIntersectingFloatBox"/> in <see cref="CssConstants.Left"/> mode, as an
+        /// earlier version of this method did) can only detect the float once the cursor has already
+        /// walked into its span, never before - so this scans for every float:right box whose vertical
+        /// span covers the current row and returns the one with the smallest left edge, which is the
+        /// actual binding constraint regardless of where the cursor is right now. Ported from PeachPDF
+        /// (jhaygood86/PeachPDF#687).
+        /// </summary>
+        internal static CssBox GetLastRightIntersectingFloatBox(CssBox box, double top)
+        {
+            if (box.HtmlContainer == null || !box.HtmlContainer.HasFloatedBoxes)
+                return null;
+
+            return FindNarrowestRightFloatBox(box, top);
+        }
+
+        /// <summary>
+        /// Same ancestor/preceding-sibling traversal shape as <see cref="GetFirstIntersectingFloatBox"/>'s
+        /// walk, but accumulates the narrowest match across the whole walk instead of returning on the
+        /// first hit - the wrap-limit query needs the binding constraint among every float:right box
+        /// covering this row, not merely the first one the traversal order happens to reach.
+        /// </summary>
+        private static CssBox FindNarrowestRightFloatBox(CssBox reference, double top)
+        {
+            CssBox narrowest = null;
+            var narrowestLeft = double.PositiveInfinity;
+
+            while (reference.ParentBox != null)
+            {
+                var currentBoxIdx = reference.ParentBox.Boxes.IndexOf(reference);
+
+                for (int i = 0; i < currentBoxIdx; i++)
+                {
+                    ScanForNarrowestRightFloatBox(reference.ParentBox.Boxes[i], top, ref narrowest, ref narrowestLeft);
+                }
+
+                reference = reference.ParentBox;
+            }
+
+            return narrowest;
+        }
+
+        private static void ScanForNarrowestRightFloatBox(CssBox box, double top, ref CssBox narrowest, ref double narrowestLeft)
+        {
+            if (box.Float == CssConstants.Right && box.Location.Y <= top && top < box.ActualBottom)
+            {
+                var left = box.Location.X - box.ActualMarginLeft;
+
+                if (left < narrowestLeft)
+                {
+                    narrowestLeft = left;
+                    narrowest = box;
+                }
+            }
+
+            foreach (var childBox in box.Boxes)
+            {
+                ScanForNarrowestRightFloatBox(childBox, top, ref narrowest, ref narrowestLeft);
+            }
+        }
+
         /// <summary>
         /// Gets the next sibling of this box.
         /// </summary>
@@ -347,6 +541,32 @@ public static CssBox GetBoxById(CssBox box, string id)
             return null;
         }
 
+        /// <summary>
+        /// Get the first css box under the given sub-tree with the given html tag name (e.g. "base").
+        /// </summary>
+        /// <param name="box">the box to start search from</param>
+        /// <param name="tagName">the tag name to find the box by (case-insensitive)</param>
+        /// <returns>css box if exists or null</returns>
+        public static CssBox GetBoxByTagName(CssBox box, string tagName)
+        {
+            if (box != null && !string.IsNullOrEmpty(tagName))
+            {
+                if (box.HtmlTag != null && tagName.Equals(box.HtmlTag.Name, StringComparison.OrdinalIgnoreCase))
+                {
+                    return box;
+                }
+
+                foreach (var childBox in box.Boxes)
+                {
+                    var foundBox = GetBoxByTagName(childBox, tagName);
+                    if (foundBox != null)
+                        return foundBox;
+                }
+            }
+
+            return null;
+        }
+
         /// <summary>
         /// Get css line box under the given sub-tree at the given y location or the nearest line from the top.<br/>
         /// the location must be in correct scroll offset.
@@ -525,6 +745,56 @@ public static string GenerateBoxTree(CssBox root)
 
         #region Private methods
 
+        /// <summary>
+        /// Recursively scans <paramref name="box"/> and its descendants, in document order, for the first
+        /// floated box intersecting <paramref name="coordinates"/>.
+        /// </summary>
+        private static CssBox GetNextIntersectingFloatBox(CssBox box, CssFloatCoordinates coordinates, string floatDirection)
+        {
+            if (IsFloatIntersecting(coordinates, floatDirection, box))
+                return box;
+
+            foreach (var childBox in box.Boxes)
+            {
+                var foundBox = GetNextIntersectingFloatBox(childBox, coordinates, floatDirection);
+                if (foundBox != null)
+                    return foundBox;
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Whether <paramref name="targetBox"/> (if floated) collides with the candidate placement
+        /// described by <paramref name="coordinates"/>: a vertical band test (does targetBox's row range
+        /// cover coordinates.Top) plus a side-specific horizontal test.
+        /// </summary>
+        private static bool IsFloatIntersecting(CssFloatCoordinates coordinates, string floatDirection, CssBox targetBox)
+        {
+            if (!targetBox.IsFloated)
+                return false;
+
+            if (!(coordinates.Top < targetBox.ActualBottom) || !(targetBox.Location.Y <= coordinates.Top))
+                return false;
+
+            var targetRight = targetBox.ActualRight + targetBox.ActualMarginRight;
+            var targetLeft = targetBox.Location.X - targetBox.ActualMarginLeft;
+            var currentLeft = coordinates.Left - coordinates.MarginLeft;
+
+            if (floatDirection == CssConstants.Left)
+                return targetRight > currentLeft && targetLeft <= currentLeft;
+
+            if (floatDirection == CssConstants.Right)
+                // Before FloatRightStartX's own fix (above), its erroneous -MarginLeft term happened
+                // to cancel this +MarginLeft, leaving the correct margin-box right edge
+                // (Right + MarginRight) by coincidence. With FloatRightStartX corrected, this leftover
+                // +MarginLeft must go too, or the threshold is inflated by the box's own left margin -
+                // ported from PeachPDF (jhaygood86/PeachPDF#688).
+                return targetLeft > coordinates.FloatRightStartX + coordinates.ReferenceWidth + coordinates.MarginRight;
+
+            return false;
+        }
+
         /// <summary>
         /// Get selected plain text of the given html sub-tree.<br/>
         /// Append all the selected words.
@@ -788,16 +1058,11 @@ private static void WriteHtmlTag(CssParser cssParser, StringBuilder sb, CssBox b
             sb.AppendFormat("<{0}", box.HtmlTag.Name);
 
             // collect all element style properties including from stylesheet
+            // Note: only matches rules whose selector is a bare tag/class simple selector (same
+            // simplification the pre-backport implementation used) - not a full cascade, this is
+            // export/clipboard-serialization cosmetics, not the style-application pipeline.
             var tagStyles = new Dictionary<string, string>();
-            var cssData = box.HtmlContainer.CssData;
-            var tagCssBlock = cssData != null ? cssData.GetCssBlock(box.HtmlTag.Name) : null;
-            if (tagCssBlock != null)
-            {
-                // TODO:a handle selectors
-                foreach (var cssBlock in tagCssBlock)
-                    foreach (var prop in cssBlock.Properties)
-                        tagStyles[prop.Key] = prop.Value;
-            }
+            CollectSimpleSelectorStyles(box.HtmlContainer.CssData, s => SelectorIsBareTag(s, box.HtmlTag.Name), tagStyles);
 
             if (box.HtmlTag.HasAttributes())
             {
@@ -808,24 +1073,15 @@ private static void WriteHtmlTag(CssParser cssParser, StringBuilder sb, CssBox b
                     if (styleGen == HtmlGenerationStyle.Inline && att.Key == HtmlConstants.Style)
                     {
                         // if inline style add the styles to the collection
-                        var block = cssParser != null ? cssParser.ParseCssBlock(box.HtmlTag.Name, box.HtmlTag.TryGetAttribute("style")) : null;
+                        var block = cssParser.ParseInlineStyle(box.HtmlTag.TryGetAttribute("style"));
                         if (block != null)
-                        {
-                            foreach (var prop in block.Properties)
-                                tagStyles[prop.Key] = prop.Value;
-                        }
+                            foreach (var prop in block.Style)
+                                tagStyles[prop.Name] = prop.Value;
                     }
                     else if (styleGen == HtmlGenerationStyle.Inline && att.Key == HtmlConstants.Class)
                     {
                         // if inline style convert the style class to actual properties and add to collection
-                        var cssBlocks = cssData != null ? cssData.GetCssBlock("." + att.Value) : null;
-                        if (cssBlocks != null)
-                        {
-                            // TODO:a handle selectors
-                            foreach (var cssBlock in cssBlocks)
-                                foreach (var prop in cssBlock.Properties)
-                                    tagStyles[prop.Key] = prop.Value;
-                        }
+                        CollectSimpleSelectorStyles(box.HtmlContainer.CssData, s => SelectorIsBareClass(s, att.Value), tagStyles);
                     }
                     else
                     {
@@ -864,19 +1120,12 @@ private static Dictionary<string, string> StripDefaultStyles(CssBox box, Diction
         {
             // ReSharper disable PossibleMultipleEnumeration
             var cleanTagStyles = new Dictionary<string, string>();
-            var defaultBlocks = box.HtmlContainer.Adapter.DefaultCssData.GetCssBlock(box.HtmlTag.Name);
+            var defaultStyles = new Dictionary<string, string>();
+            CollectSimpleSelectorStyles(box.HtmlContainer.Adapter.DefaultCssData, s => SelectorIsBareTag(s, box.HtmlTag.Name), defaultStyles);
             foreach (var style in tagStyles)
             {
-                bool isDefault = false;
-                foreach (var defaultBlock in defaultBlocks)
-                {
-                    string value;
-                    if (defaultBlock.Properties.TryGetValue(style.Key, out value) && value.Equals(style.Value, StringComparison.OrdinalIgnoreCase))
-                    {
-                        isDefault = true;
-                        break;
-                    }
-                }
+                string value;
+                bool isDefault = defaultStyles.TryGetValue(style.Key, out value) && value.Equals(style.Value, StringComparison.OrdinalIgnoreCase);
 
                 if (!isDefault)
                     cleanTagStyles[style.Key] = style.Value;
@@ -885,6 +1134,45 @@ private static Dictionary<string, string> StripDefaultStyles(CssBox box, Diction
             // ReSharper restore PossibleMultipleEnumeration
         }
 
+        /// <summary>
+        /// Merges the declared properties of every style rule in <paramref name="cssData"/> whose
+        /// selector matches <paramref name="selectorMatches"/>, in stylesheet/document order (later
+        /// rules overwrite earlier ones for the same property name) - a crude approximation of the
+        /// cascade (no specificity, no combinators) sufficient for HTML export/clipboard cosmetics.
+        /// </summary>
+        private static void CollectSimpleSelectorStyles(CssData cssData, Func<ISelector, bool> selectorMatches, Dictionary<string, string> into)
+        {
+            foreach (var stylesheet in cssData.Stylesheets)
+            {
+                foreach (var rule in CssData.FlattenRules(stylesheet.Rules).OfType<IStyleRule>())
+                {
+                    if (!selectorMatches(rule.Selector)) continue;
+                    foreach (var prop in rule.Style)
+                        into[prop.Name] = prop.Value;
+                }
+            }
+        }
+
+        /// <summary>
+        /// True if the selector is exactly a bare tag-name simple selector (e.g. "div"), not a compound
+        /// or combinator chain - matches the pre-backport implementation's lookup semantics.
+        /// </summary>
+        private static bool SelectorIsBareTag(ISelector selector, string tagName)
+        {
+            var type = selector as TypeSelector;
+            return type != null && type.Name.Equals(tagName, StringComparison.InvariantCultureIgnoreCase);
+        }
+
+        /// <summary>
+        /// True if the selector is exactly a bare class simple selector (e.g. ".foo"), not a compound
+        /// or combinator chain - matches the pre-backport implementation's lookup semantics.
+        /// </summary>
+        private static bool SelectorIsBareClass(ISelector selector, string className)
+        {
+            var cls = selector as ClassSelector;
+            return cls != null && cls.Class.Equals(className, StringComparison.InvariantCultureIgnoreCase);
+        }
+
         /// <summary>
         /// Write stylesheet data inline into the html.
         /// </summary>
@@ -893,20 +1181,19 @@ private static Dictionary<string, string> StripDefaultStyles(CssBox box, Diction
         private static void WriteStylesheet(StringBuilder sb, CssData cssData)
         {
             sb.AppendLine("<style type=\"text/css\">");
-            foreach (var cssBlocks in cssData.MediaBlocks["all"])
+            foreach (var stylesheet in cssData.Stylesheets)
             {
-                sb.Append(cssBlocks.Key);
-                sb.Append(" { ");
-                foreach (var cssBlock in cssBlocks.Value)
+                foreach (var rule in CssData.FlattenRules(stylesheet.Rules).OfType<IStyleRule>())
                 {
-                    foreach (var property in cssBlock.Properties)
+                    sb.Append(rule.SelectorText);
+                    sb.Append(" { ");
+                    foreach (var property in rule.Style)
                     {
-                        // TODO:a handle selectors
-                        sb.AppendFormat("{0}: {1};", property.Key, property.Value);
+                        sb.AppendFormat("{0}: {1};", property.Name, property.Value);
                     }
+                    sb.Append(" }");
+                    sb.AppendLine();
                 }
-                sb.Append(" }");
-                sb.AppendLine();
             }
             sb.AppendLine("</style>");
         }
diff --git a/Source/HtmlRenderer/Core/Utils/FontFaceDescriptorResolver.cs b/Source/HtmlRenderer/Core/Utils/FontFaceDescriptorResolver.cs
new file mode 100644
index 000000000..17552658a
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Utils/FontFaceDescriptorResolver.cs
@@ -0,0 +1,95 @@
+#nullable enable
+
+using System;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Utils
+{
+    /// <summary>
+    /// Resolves an <c>@font-face</c> rule's own <c>font-weight</c>/<c>font-style</c>/<c>font-stretch</c>
+    /// descriptor strings (<see cref="CssEngine.IFontFaceRule"/>) into the override values a registered
+    /// face's matching entry takes - these are authoritative for how a specific registered face
+    /// participates in matching, independent of what the font file's own internal tables say. Returns null
+    /// for any descriptor this can't confidently resolve to a single concrete value (absent, or a
+    /// variable-font weight/stretch *range* like <c>100 900</c>/<c>50% 200%</c> - real interpolated
+    /// variable fonts are out of scope), so the caller falls back to the value sniffed from the file itself
+    /// instead of silently forcing a wrong/arbitrary one.
+    /// </summary>
+    internal static class FontFaceDescriptorResolver
+    {
+        /// <summary>
+        /// Resolves a <c>font-weight</c> descriptor (<c>normal</c>/<c>bold</c>/a number/absent) to a
+        /// concrete CSS Fonts numeric weight. A two-token range (variable-font syntax) resolves to its
+        /// lower bound as a reasonable single-value approximation, since there is no variable-font
+        /// interpolation here. Any other multi-token or unparseable value returns null.
+        /// </summary>
+        internal static int? ResolveWeight(string? weightDescriptor)
+        {
+            if (string.IsNullOrWhiteSpace(weightDescriptor))
+                return null;
+
+            // See UnicodeRangeParser.Parse for why the ! is needed here on netstandard2.0.
+            var tokens = weightDescriptor!.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
+
+            if (tokens.Length == 1 && int.TryParse(tokens[0], out var numeric))
+                return numeric;
+            if (tokens.Length == 1 && tokens[0] == CssConstants.Bold)
+                return 700;
+            if (tokens.Length == 1 && tokens[0] == CssConstants.Normal)
+                return 400;
+            if (tokens.Length == 2 && int.TryParse(tokens[0], out var lowerBound))
+                return lowerBound;
+
+            return null;
+        }
+
+        /// <summary>
+        /// Resolves a <c>font-style</c> descriptor (<c>normal</c>/<c>italic</c>/<c>oblique</c>/
+        /// <c>oblique &lt;angle&gt;</c>/absent) to whether the face should be treated as italic for
+        /// matching purposes. Returns null for absent/unrecognized values.
+        /// </summary>
+        internal static bool? ResolveIsItalic(string? styleDescriptor)
+        {
+            if (string.IsNullOrWhiteSpace(styleDescriptor))
+                return null;
+
+            var firstToken = styleDescriptor!.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)[0];
+
+            if (firstToken == CssConstants.Italic || firstToken == CssConstants.Oblique)
+                return true;
+            if (firstToken == CssConstants.Normal)
+                return false;
+
+            return null;
+        }
+
+        /// <summary>
+        /// Resolves a <c>font-stretch</c> descriptor (one of the 9 CSS Fonts keywords, or absent) to the
+        /// matching 1-9 numeric scale via <see cref="FontStretchResolver"/>. Percentage values/ranges
+        /// (variable-font syntax) and any other unrecognized value return null rather than being silently
+        /// coerced to normal.
+        /// </summary>
+        internal static int? ResolveStretch(string? stretchDescriptor)
+        {
+            if (string.IsNullOrWhiteSpace(stretchDescriptor))
+                return null;
+
+            var trimmed = stretchDescriptor!.Trim();
+
+            switch (trimmed)
+            {
+                case CssConstants.UltraCondensed:
+                case CssConstants.ExtraCondensed:
+                case CssConstants.Condensed:
+                case CssConstants.SemiCondensed:
+                case CssConstants.Normal:
+                case CssConstants.SemiExpanded:
+                case CssConstants.Expanded:
+                case CssConstants.ExtraExpanded:
+                case CssConstants.UltraExpanded:
+                    return FontStretchResolver.Resolve(trimmed);
+                default:
+                    return null;
+            }
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Utils/FontStretchResolver.cs b/Source/HtmlRenderer/Core/Utils/FontStretchResolver.cs
new file mode 100644
index 000000000..a795d8496
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Utils/FontStretchResolver.cs
@@ -0,0 +1,34 @@
+namespace TheArtOfDev.HtmlRenderer.Core.Utils
+{
+    /// <summary>
+    /// Resolves a CSS <c>font-stretch</c> keyword to the 1-9 numeric scale matching the OpenType OS/2
+    /// table's <c>usWidthClass</c> field directly (1=ultra-condensed ... 5=normal ... 9=ultra-expanded) -
+    /// the same scale a ported <c>TtfFontDescription</c>'s <c>Stretch</c> reads from that field for each
+    /// registered face, so the two are directly comparable without any extra translation.
+    /// </summary>
+    internal static class FontStretchResolver
+    {
+        internal const int Normal = 5;
+
+        /// <summary>
+        /// Resolves a raw <c>font-stretch</c> keyword (a box's cascaded value, or an <c>@font-face</c>
+        /// descriptor - see <see cref="FontFaceDescriptorResolver.ResolveStretch"/>) to the 1-9 scale.
+        /// Unlike PeachPDF's own version of this resolver, there's only this one string-keyword overload -
+        /// HTML-Renderer's CSS engine works with raw cascaded strings throughout (no separate strongly-typed
+        /// CSS-OM enum for font-stretch the way PeachPDF's does), so a second typed-enum overload would have
+        /// no caller.
+        /// </summary>
+        internal static int Resolve(string fontStretchValue) => fontStretchValue switch
+        {
+            CssConstants.UltraCondensed => 1,
+            CssConstants.ExtraCondensed => 2,
+            CssConstants.Condensed => 3,
+            CssConstants.SemiCondensed => 4,
+            CssConstants.SemiExpanded => 6,
+            CssConstants.Expanded => 7,
+            CssConstants.ExtraExpanded => 8,
+            CssConstants.UltraExpanded => 9,
+            _ => Normal
+        };
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Utils/IsExternalInit.cs b/Source/HtmlRenderer/Core/Utils/IsExternalInit.cs
new file mode 100644
index 000000000..c358f7441
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Utils/IsExternalInit.cs
@@ -0,0 +1,12 @@
+#if NETSTANDARD2_0
+// C# 9 records/init-only setters need this marker type, which only ships in the BCL from
+// netstandard2.1/.NET 5 onward. LangVersion 12 (set project-wide in Directory.Build.props) makes the
+// record/init-accessor *syntax* available on netstandard2.0 too, but the compiler still needs the type to
+// exist somewhere in the compilation - this is the standard, widely-used polyfill for that gap.
+namespace System.Runtime.CompilerServices
+{
+    internal static class IsExternalInit
+    {
+    }
+}
+#endif
diff --git a/Source/HtmlRenderer/Core/Utils/RenderUtils.cs b/Source/HtmlRenderer/Core/Utils/RenderUtils.cs
index 2726b5fb2..091c75191 100644
--- a/Source/HtmlRenderer/Core/Utils/RenderUtils.cs
+++ b/Source/HtmlRenderer/Core/Utils/RenderUtils.cs
@@ -95,44 +95,42 @@ public static void DrawImageErrorIcon(RGraphics g, HtmlContainerInt htmlContaine
         }
 
         /// <summary>
-        /// Creates a rounded rectangle using the specified corner radius<br/>
-        /// NW-----NE
+        /// Creates a rounded rectangle path. Each corner has independent horizontal (X) and vertical (Y)
+        /// radii, supporting elliptical corners per the CSS border-radius spec.<br/>
+        /// TL-----TR
         ///  |       |
         ///  |       |
-        /// SW-----SE
+        /// BL-----BR
         /// </summary>
         /// <param name="g">the device to draw into</param>
         /// <param name="rect">Rectangle to round</param>
-        /// <param name="nwRadius">Radius of the north east corner</param>
-        /// <param name="neRadius">Radius of the north west corner</param>
-        /// <param name="seRadius">Radius of the south east corner</param>
-        /// <param name="swRadius">Radius of the south west corner</param>
         /// <returns>GraphicsPath with the lines of the rounded rectangle ready to be painted</returns>
-        public static RGraphicsPath GetRoundRect(RGraphics g, RRect rect, double nwRadius, double neRadius, double seRadius, double swRadius)
+        public static RGraphicsPath GetRoundRect(RGraphics g, RRect rect,
+            double tlX, double tlY, double trX, double trY,
+            double brX, double brY, double blX, double blY)
         {
             var path = g.GetGraphicsPath();
 
-            path.Start(rect.Left + nwRadius, rect.Top);
-
-            path.LineTo(rect.Right - neRadius, rect.Y);
-
-            if (neRadius > 0f)
-                path.ArcTo(rect.Right, rect.Top + neRadius, neRadius, RGraphicsPath.Corner.TopRight);
-
-            path.LineTo(rect.Right, rect.Bottom - seRadius);
-
-            if (seRadius > 0f)
-                path.ArcTo(rect.Right - seRadius, rect.Bottom, seRadius, RGraphicsPath.Corner.BottomRight);
-
-            path.LineTo(rect.Left + swRadius, rect.Bottom);
-
-            if (swRadius > 0f)
-                path.ArcTo(rect.Left, rect.Bottom - swRadius, swRadius, RGraphicsPath.Corner.BottomLeft);
-
-            path.LineTo(rect.Left, rect.Top + nwRadius);
-
-            if (nwRadius > 0f)
-                path.ArcTo(rect.Left + nwRadius, rect.Top, nwRadius, RGraphicsPath.Corner.TopLeft);
+            // Top edge: start after TL corner, end before TR corner.
+            path.Start(rect.Left + tlX, rect.Top);
+            path.LineTo(rect.Right - trX, rect.Top);
+            if (trX > 0 || trY > 0)
+                path.ArcTo(rect.Right, rect.Top + trY, trX, trY, RGraphicsPath.Corner.TopRight);
+
+            // Right edge.
+            path.LineTo(rect.Right, rect.Bottom - brY);
+            if (brX > 0 || brY > 0)
+                path.ArcTo(rect.Right - brX, rect.Bottom, brX, brY, RGraphicsPath.Corner.BottomRight);
+
+            // Bottom edge.
+            path.LineTo(rect.Left + blX, rect.Bottom);
+            if (blX > 0 || blY > 0)
+                path.ArcTo(rect.Left, rect.Bottom - blY, blX, blY, RGraphicsPath.Corner.BottomLeft);
+
+            // Left edge.
+            path.LineTo(rect.Left, rect.Top + tlY);
+            if (tlX > 0 || tlY > 0)
+                path.ArcTo(rect.Left + tlX, rect.Top, tlX, tlY, RGraphicsPath.Corner.TopLeft);
 
             return path;
         }
diff --git a/Source/HtmlRenderer/Core/Utils/TtfFontDescription.cs b/Source/HtmlRenderer/Core/Utils/TtfFontDescription.cs
new file mode 100644
index 000000000..9ecb09a05
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Utils/TtfFontDescription.cs
@@ -0,0 +1,264 @@
+#nullable enable
+
+using System;
+using System.IO;
+using System.Text;
+using TheArtOfDev.HtmlRenderer.Adapters.Entities;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Utils
+{
+    /// <summary>
+    /// Sniffs a TTF/OTF font file's family/subfamily name, style, and CSS Fonts numeric weight/stretch
+    /// directly from its <c>name</c>/<c>OS/2</c> tables - a single self-contained reader, ported from
+    /// PeachPDF's <c>Fonts\TtfFontDescription.cs</c> (adapted to this project's own <see cref="RFontStyle"/>
+    /// instead of PeachPDF's PdfSharpCore-specific <c>XFontStyle</c>, since this type lives in the shared
+    /// Core project used by every backend, not just PdfSharp - both WPF's <c>@font-face</c> loading, which
+    /// needs the font's own internal family name to look it up via <c>System.Windows.Media.FontFamily</c>
+    /// after registering it with <c>AddFontMemResourceEx</c>, and the PdfSharp <c>FontResolver</c> port,
+    /// which needs the numeric weight/stretch for CSS Fonts Level 4 matching, need this). Public: it's
+    /// consumed from the WPF and PdfSharp backend assemblies, not just Core itself.
+    /// </summary>
+    /// <remarks>
+    /// Replaces this project's older <c>HtmlRenderer.PdfSharp\FontResolution\FontMetadata.cs</c>/
+    /// <c>Parsing\FontParser.cs</c> (PdfSharp-backend-only, name-table-only, no numeric weight/stretch at
+    /// all - it could not supply what CSS Fonts Level 4 matching needs).
+    /// </remarks>
+    public readonly struct TtfFontDescription
+    {
+        /// <summary>Default CSS Fonts numeric weight (400 = "normal") used when a font has no OS/2 table, or its <see cref="Weight"/> field is out of the valid 1-1000 range.</summary>
+        public const int DefaultWeight = 400;
+
+        /// <summary>Default CSS Fonts stretch value (5 = "normal" on the 1-9 <c>usWidthClass</c> scale) used when a font has no OS/2 table, or its value is out of the valid 1-9 range.</summary>
+        public const int DefaultStretch = 5;
+
+        public TtfFontDescription(string fontFamilyInvariantCulture, string fontNameInvariantCulture, RFontStyle style, int weight, int stretch)
+        {
+            FontFamilyInvariantCulture = fontFamilyInvariantCulture;
+            FontNameInvariantCulture = fontNameInvariantCulture;
+            Style = style;
+            Weight = weight;
+            Stretch = stretch;
+        }
+
+        public string FontFamilyInvariantCulture { get; }
+        public string FontNameInvariantCulture { get; }
+        public RFontStyle Style { get; }
+
+        /// <summary>
+        /// CSS Fonts Level 4 numeric weight (1-1000), read from the OS/2 table's <c>usWeightClass</c>
+        /// field when present and valid; falls back to a value derived from <see cref="Style"/>'s
+        /// name-table-subfamily-sniffed Bold bit (700 if bold, else <see cref="DefaultWeight"/>) when
+        /// OS/2 is absent or its <c>usWeightClass</c> is 0 (a real font can legitimately omit/zero this
+        /// field even though the spec range is 1-1000).
+        /// </summary>
+        public int Weight { get; }
+
+        /// <summary>
+        /// CSS Fonts Level 3 <c>font-stretch</c> classification (1-9, matching the OS/2 <c>usWidthClass</c>
+        /// scale directly: 1=ultra-condensed ... 5=normal ... 9=ultra-expanded), read from the OS/2 table
+        /// when present and valid; <see cref="DefaultStretch"/> (normal) otherwise.
+        /// </summary>
+        public int Stretch { get; }
+
+        public static TtfFontDescription LoadDescription(string path)
+        {
+            using (var stream = File.OpenRead(path))
+            {
+                return LoadDescription(stream);
+            }
+        }
+
+        public static TtfFontDescription LoadDescription(Stream stream)
+        {
+            // TTF/OTF files are big-endian. Read the offset table to locate the name/OS2 tables.
+            var buf4 = new byte[4];
+            var buf2 = new byte[2];
+
+            ReadExactly(stream, buf4, 4); // sfVersion - skip
+            ReadExactly(stream, buf2, 2);
+            int numTables = ReadUInt16BE(buf2);
+            ReadExactly(stream, buf2, 2); // searchRange
+            ReadExactly(stream, buf2, 2); // entrySelector
+            ReadExactly(stream, buf2, 2); // rangeShift
+
+            long nameTableOffset = -1;
+            long os2TableOffset = -1;
+            for (int i = 0; i < numTables; i++)
+            {
+                ReadExactly(stream, buf4, 4);
+                var tag = Encoding.ASCII.GetString(buf4);
+                ReadExactly(stream, buf4, 4); // checkSum
+                ReadExactly(stream, buf4, 4);
+                uint tableOffset = ReadUInt32BE(buf4);
+                ReadExactly(stream, buf4, 4); // length
+
+                if (tag == "name")
+                    nameTableOffset = tableOffset;
+                else if (tag == "OS/2")
+                    os2TableOffset = tableOffset;
+            }
+
+            if (nameTableOffset < 0)
+                throw new InvalidOperationException("Font file does not contain a name table.");
+
+            stream.Seek(nameTableOffset, SeekOrigin.Begin);
+            ReadExactly(stream, buf2, 2); // format
+            ReadExactly(stream, buf2, 2);
+            int count = ReadUInt16BE(buf2);
+            ReadExactly(stream, buf2, 2);
+            int stringOffset = ReadUInt16BE(buf2);
+            long storageBase = nameTableOffset + stringOffset;
+
+            // Read all name records (6 uint16 fields each)
+            var platformIDs = new ushort[count];
+            var encodingIDs = new ushort[count];
+            var languageIDs = new ushort[count];
+            var nameIDs = new ushort[count];
+            var lengths = new ushort[count];
+            var offsets = new ushort[count];
+
+            for (int i = 0; i < count; i++)
+            {
+                ReadExactly(stream, buf2, 2); platformIDs[i] = (ushort)ReadUInt16BE(buf2);
+                ReadExactly(stream, buf2, 2); encodingIDs[i] = (ushort)ReadUInt16BE(buf2);
+                ReadExactly(stream, buf2, 2); languageIDs[i] = (ushort)ReadUInt16BE(buf2);
+                ReadExactly(stream, buf2, 2); nameIDs[i] = (ushort)ReadUInt16BE(buf2);
+                ReadExactly(stream, buf2, 2); lengths[i] = (ushort)ReadUInt16BE(buf2);
+                ReadExactly(stream, buf2, 2); offsets[i] = (ushort)ReadUInt16BE(buf2);
+            }
+
+            string? familyName = ReadBestNameRecord(stream, platformIDs, encodingIDs, languageIDs, nameIDs, lengths, offsets, count, storageBase, 1);
+            string? subfamilyName = ReadBestNameRecord(stream, platformIDs, encodingIDs, languageIDs, nameIDs, lengths, offsets, count, storageBase, 2);
+            string? fullName = ReadBestNameRecord(stream, platformIDs, encodingIDs, languageIDs, nameIDs, lengths, offsets, count, storageBase, 4);
+
+            RFontStyle style;
+            switch (subfamilyName != null ? subfamilyName.ToLowerInvariant() : null)
+            {
+                case "bold italic":
+                case "bold oblique":
+                    style = RFontStyle.Bold | RFontStyle.Italic;
+                    break;
+                case "bold":
+                    style = RFontStyle.Bold;
+                    break;
+                case "italic":
+                case "oblique":
+                    style = RFontStyle.Italic;
+                    break;
+                default:
+                    style = RFontStyle.Regular;
+                    break;
+            }
+
+            int weight, stretch;
+            ReadOs2WeightAndStretch(stream, os2TableOffset, out weight, out stretch);
+            if (weight == 0)
+                weight = (style & RFontStyle.Bold) != 0 ? 700 : DefaultWeight;
+
+            return new TtfFontDescription(
+                familyName ?? fullName ?? string.Empty,
+                fullName ?? familyName ?? string.Empty,
+                style,
+                weight,
+                stretch);
+        }
+
+        /// <summary>
+        /// Reads <c>usWeightClass</c> (offset 4) and <c>usWidthClass</c> (offset 6) from the OS/2 table,
+        /// per the OpenType spec's OS/2 table layout (both fields are present in every OS/2 table
+        /// version, including the oldest version 0). Yields (0, <see cref="DefaultStretch"/>) - a
+        /// sentinel the caller substitutes a Style-derived default for - when there's no OS/2 table at
+        /// all, or a value is outside its spec-valid range (weight: 1-1000, stretch: 1-9).
+        /// </summary>
+        private static void ReadOs2WeightAndStretch(Stream stream, long os2TableOffset, out int weight, out int stretch)
+        {
+            if (os2TableOffset < 0)
+            {
+                weight = 0;
+                stretch = DefaultStretch;
+                return;
+            }
+
+            var buf2 = new byte[2];
+            stream.Seek(os2TableOffset + 4, SeekOrigin.Begin);
+            ReadExactly(stream, buf2, 2);
+            var weightClass = ReadUInt16BE(buf2);
+            ReadExactly(stream, buf2, 2);
+            var widthClass = ReadUInt16BE(buf2);
+
+            weight = weightClass >= 1 && weightClass <= 1000 ? weightClass : 0;
+            stretch = widthClass >= 1 && widthClass <= 9 ? widthClass : DefaultStretch;
+        }
+
+        // Prefers platformID=3/encodingID=1 (Windows Unicode) with en-US, then any language,
+        // then platformID=1 (Mac Roman), then whatever is available.
+        private static string? ReadBestNameRecord(
+            Stream stream,
+            ushort[] platformIDs, ushort[] encodingIDs, ushort[] languageIDs,
+            ushort[] nameIDs, ushort[] lengths, ushort[] offsets,
+            int count, long storageBase, ushort targetNameID)
+        {
+            int best = -1;
+            int bestPriority = int.MaxValue;
+
+            for (int i = 0; i < count; i++)
+            {
+                if (nameIDs[i] != targetNameID) continue;
+
+                int priority;
+                if (platformIDs[i] == 3 && encodingIDs[i] == 1 && languageIDs[i] == 0x0409)
+                    priority = 0;
+                else if (platformIDs[i] == 3 && encodingIDs[i] == 1)
+                    priority = 1;
+                else if (platformIDs[i] == 1)
+                    priority = 2;
+                else
+                    priority = 3;
+
+                if (priority < bestPriority)
+                {
+                    bestPriority = priority;
+                    best = i;
+                }
+            }
+
+            if (best < 0) return null;
+
+            stream.Seek(storageBase + offsets[best], SeekOrigin.Begin);
+            var bytes = new byte[lengths[best]];
+            ReadExactly(stream, bytes, bytes.Length);
+
+            return platformIDs[best] == 1
+                ? GetLatin1().GetString(bytes, 0, bytes.Length)
+                : Encoding.BigEndianUnicode.GetString(bytes, 0, bytes.Length);
+        }
+
+        // Encoding.Latin1 is a .NET 5+ convenience shortcut - GetEncoding("iso-8859-1") is the portable
+        // equivalent available on every TFM this project targets (including netstandard2.0/net462).
+        private static Encoding GetLatin1() => Encoding.GetEncoding("iso-8859-1");
+
+        /// <summary>
+        /// Fills <paramref name="buffer"/>'s first <paramref name="count"/> bytes from <paramref name="stream"/>,
+        /// looping until satisfied (a plain <see cref="Stream.Read"/> is not guaranteed to fill the buffer
+        /// in one call). The portable equivalent of <c>Stream.ReadExactly</c> (.NET 7+ only, not available
+        /// on this project's netstandard2.0/net462 legs).
+        /// </summary>
+        private static void ReadExactly(Stream stream, byte[] buffer, int count)
+        {
+            var offset = 0;
+            while (offset < count)
+            {
+                var read = stream.Read(buffer, offset, count - offset);
+                if (read <= 0)
+                    throw new EndOfStreamException();
+                offset += read;
+            }
+        }
+
+        private static int ReadUInt16BE(byte[] b) =>
+            (b[0] << 8) | b[1];
+
+        private static uint ReadUInt32BE(byte[] b) =>
+            ((uint)b[0] << 24) | ((uint)b[1] << 16) | ((uint)b[2] << 8) | b[3];
+    }
+}
diff --git a/Source/HtmlRenderer/Core/Utils/UnicodeRangeParser.cs b/Source/HtmlRenderer/Core/Utils/UnicodeRangeParser.cs
new file mode 100644
index 000000000..26ed6fe0e
--- /dev/null
+++ b/Source/HtmlRenderer/Core/Utils/UnicodeRangeParser.cs
@@ -0,0 +1,97 @@
+#nullable enable
+
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using TheArtOfDev.HtmlRenderer.Core.CssEngine;
+using TheArtOfDev.HtmlRenderer.Core.Parse;
+
+namespace TheArtOfDev.HtmlRenderer.Core.Utils
+{
+    /// <summary>
+    /// Parses a CSS <c>@font-face</c> <c>unicode-range</c> descriptor into a compact set of inclusive
+    /// codepoint <see cref="CodepointRange"/>s, reusing the existing CSS tokenizer's <c>U+</c> grammar
+    /// (<see cref="CssValueParser.GetCssTokens"/> → <see cref="RangeToken"/>, already fully implemented -
+    /// see <see cref="TheArtOfDev.HtmlRenderer.Core.CssEngine.Parser.Lexer"/>'s <c>UnicodeRange</c> method)
+    /// rather than re-implementing it.
+    /// </summary>
+    public static class UnicodeRangeParser
+    {
+        /// <summary>
+        /// Parses a <c>unicode-range</c> descriptor into inclusive codepoint ranges, or returns null when
+        /// the descriptor is absent/blank or contains no valid range (meaning "no explicit subset - the
+        /// face applies to whatever its font actually covers").
+        /// </summary>
+        public static IReadOnlyList<CodepointRange>? Parse(string? descriptor)
+        {
+            if (string.IsNullOrWhiteSpace(descriptor))
+                return null;
+
+            List<CodepointRange>? ranges = null;
+
+            // The value can arrive either in its CSS source form ("U+41-5A, U+61-7A") or, once round-
+            // tripped through the CSS-OM, with the "U+" prefix dropped ("41-5A, 61-7A"). Split on the
+            // top-level commas and re-tokenize each segment with the "U+" prefix the lexer's range
+            // grammar expects, so both forms parse identically through the one shared tokenizer.
+            // The netstandard2.0 reference assembly's string.IsNullOrWhiteSpace has no [NotNullWhen]
+            // annotation, so the compiler can't narrow descriptor to non-null past the check above on
+            // that TFM alone (net8.0 already narrows it) - the ! makes both legs agree.
+            foreach (var segment in descriptor!.Split(','))
+            {
+                var normalized = segment.Trim();
+
+                if (normalized.Length == 0)
+                    continue;
+
+                if (!normalized.StartsWith("U+", StringComparison.OrdinalIgnoreCase))
+                    normalized = "U+" + normalized;
+
+                var rangeToken = CssValueParser.GetCssTokens(normalized).OfType<RangeToken>().FirstOrDefault();
+
+                if (rangeToken == null)
+                    continue;
+
+                if (!int.TryParse(rangeToken.Start, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var start) ||
+                    !int.TryParse(rangeToken.End, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var end))
+                    continue;
+
+                if (start > Symbols.MaximumCodepoint)
+                    continue;
+
+                if (end > Symbols.MaximumCodepoint)
+                    end = Symbols.MaximumCodepoint;
+
+                if (end < start)
+                    continue;
+
+                // A declared range whose bound lands on a surrogate can't be a real Unicode scalar value
+                // (surrogates aren't valid codepoints on their own); nudge inward, and skip a range that
+                // is nothing but surrogates.
+                if (start is >= 0xD800 and <= 0xDFFF)
+                    start = 0xE000;
+                if (end is >= 0xD800 and <= 0xDFFF)
+                    end = 0xD7FF;
+                if (start > end)
+                    continue;
+
+                (ranges ??= new List<CodepointRange>()).Add(new CodepointRange(start, end));
+            }
+
+            return ranges;
+        }
+
+        /// <summary>
+        /// Whether <paramref name="codepoint"/> falls inside any of <paramref name="ranges"/>.
+        /// </summary>
+        public static bool Covers(IReadOnlyList<CodepointRange> ranges, int codepoint)
+        {
+            for (var i = 0; i < ranges.Count; i++)
+            {
+                if (ranges[i].Contains(codepoint))
+                    return true;
+            }
+            return false;
+        }
+    }
+}
diff --git a/Source/HtmlRenderer/HtmlRenderer.csproj b/Source/HtmlRenderer/HtmlRenderer.csproj
index 7212373ed..e21f42282 100644
--- a/Source/HtmlRenderer/HtmlRenderer.csproj
+++ b/Source/HtmlRenderer/HtmlRenderer.csproj
@@ -4,6 +4,7 @@
     <OutputType>Library</OutputType>
     <RootNamespace>TheArtOfDev.HtmlRenderer</RootNamespace>
 	<GenerateResourceUsePreserializedResources>true</GenerateResourceUsePreserializedResources>
+	<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
   <!-- NuGet Package Properties -->
   <PropertyGroup>
@@ -24,6 +25,15 @@ For existing implementations see: HtmlRenderer.WinForms, HtmlRenderer.WPF and Ht
   <ItemGroup>
     <None Include="..\..\README.md" Pack="true" PackagePath="\" />
   </ItemGroup>
+  <ItemGroup>
+    <!-- Grants the WinForms/WPF adapters (which read SystemColorSchemeOverride from their own
+         SystemColorScheme override) and the image-regression test assembly (which sets it) access to
+         RAdapter's internal members. SystemColorSchemeOverride is a test-only seam that makes
+         prefers-color-scheme rendering deterministic regardless of the host machine's own theme setting. -->
+    <InternalsVisibleTo Include="HtmlRenderer.WinForms" />
+    <InternalsVisibleTo Include="HtmlRenderer.WPF" />
+    <InternalsVisibleTo Include="HtmlRenderer.IntegrationTest" />
+  </ItemGroup>
   <ItemGroup>
 	<PackageReference Include="System.Resources.Extensions" Version="10.0.10" />
 	<PackageReference Include="HtmlKit" Version="1.2.0" />
diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/ACID 1.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/ACID 1.png
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Anchors.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Anchors.png
index ac8c207c4..835a5369b 100644
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Background Image.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Background Image.png
index 38f7feb91..8f6d24715 100644
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/BlockInInline.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/BlockInInline.png
index bb110ba10..0541b326f 100644
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Blockquotes.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Blockquotes.png
index 43db1710c..e298a696c 100644
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Borders.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Borders.png
index 75ed6e306..4a443a631 100644
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Breaking pages 1 - Paragraphs.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Breaking pages 1 - Paragraphs.png
index 264b7413f..a3c8753b1 100644
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Breaking pages 2 - Tables.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Breaking pages 2 - Tables.png
index ec8ef692a..aa3b19e3e 100644
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Text.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/Text.png
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/Baselines/White-space.png b/Source/Test/HtmlRenderer.IntegrationTest/Baselines/White-space.png
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diff --git a/Source/Test/HtmlRenderer.IntegrationTest/HtmlRenderingRegressionTests.cs b/Source/Test/HtmlRenderer.IntegrationTest/HtmlRenderingRegressionTests.cs
index 1b1f68f80..842c5dc1b 100644
--- a/Source/Test/HtmlRenderer.IntegrationTest/HtmlRenderingRegressionTests.cs
+++ b/Source/Test/HtmlRenderer.IntegrationTest/HtmlRenderingRegressionTests.cs
@@ -2,6 +2,7 @@
 using System.Globalization;
 using System.Reflection;
 using System.Text;
+using TheArtOfDev.HtmlRenderer.Adapters;
 using TheArtOfDev.HtmlRenderer.Core.Entities;
 using TheArtOfDev.HtmlRenderer.Demo.Common;
 using TheArtOfDev.HtmlRenderer.WinForms;
@@ -24,7 +25,7 @@ public sealed class HtmlRenderingRegressionTests
     [DoNotParallelize]
     [TestMethod]
     [DynamicData(nameof(GetSamples), DynamicDataDisplayName = nameof(GetSampleDisplayName))]
-    public void Render_DemoTestSample_MatchesBaselineImage(string sampleName, string sampleHtml)
+    public async Task Render_DemoTestSample_MatchesBaselineImage(string sampleName, string sampleHtml)
     {
         EnsureSamplesLoaded();
 
@@ -42,7 +43,7 @@ public void Render_DemoTestSample_MatchesBaselineImage(string sampleName, string
         var actualPath = Path.Combine(outputDirectory, sampleFileName + ".actual.png");
         var diffPath = Path.Combine(outputDirectory, sampleFileName + ".diff.png");
 
-        using var rendered = RenderSample(sampleHtml);
+        using var rendered = await RenderSample(sampleHtml);
         if (!File.Exists(baselinePath))
         {
             if (approveBaselines)
@@ -119,13 +120,19 @@ private static void EnsureSamplesLoaded()
             }
 
             SamplesLoader.Init("Regression", typeof(HtmlRender).Assembly.GetName().Version.ToString());
+
+            // Baselines are captured once on some machine and compared everywhere after; a sample driven
+            // by prefers-color-scheme must not depend on whichever machine happens to run the test having
+            // the same Windows theme as that one did. Pin it so every render sees the same reported scheme.
+            RAdapter.SystemColorSchemeOverride = RColorScheme.Light;
+
             _samplesLoaded = true;
         }
     }
 
-    private static Bitmap RenderSample(string html)
+    private static async Task<Bitmap> RenderSample(string html)
     {
-        return (Bitmap)HtmlRender.RenderToImage(
+        return (Bitmap)await HtmlRender.RenderToImageAsync(
             html,
             minSize: Size.Empty,
             maxSize: new Size(MaxWidth, MaxHeight),
diff --git a/Source/Test/HtmlRenderer.PdfSharp.Test/PdfGeneratorTests.cs b/Source/Test/HtmlRenderer.PdfSharp.Test/PdfGeneratorTests.cs
index 0fd72ab1e..f98e20235 100644
--- a/Source/Test/HtmlRenderer.PdfSharp.Test/PdfGeneratorTests.cs
+++ b/Source/Test/HtmlRenderer.PdfSharp.Test/PdfGeneratorTests.cs
@@ -11,7 +11,7 @@ namespace HtmlRenderer.PdfSharp.Test;
 public sealed class PdfGeneratorTests
 {
     [TestMethod]
-    public void GeneratePdf_FromHtml_CreatesPdfDocument()
+    public async Task GeneratePdf_FromHtml_CreatesPdfDocument()
     {
         // Arrange
         var config = new PdfGenerateConfig
@@ -33,7 +33,7 @@ public void GeneratePdf_FromHtml_CreatesPdfDocument()
             """;
 
         // Act
-        using var document = PdfGenerator.GeneratePdf(html, config, null, DemoUtils.OnStylesheetLoad, OnImageLoadPdfSharp);
+        using var document = await PdfGenerator.GeneratePdf(html, config, null, DemoUtils.OnStylesheetLoad, OnImageLoadPdfSharp);
 
         // Assert
         Assert.AreEqual(1, document.Pages.Count);
@@ -60,7 +60,7 @@ public void GeneratePdf_FromHtml_CreatesPdfDocument()
     }
 
     [TestMethod]
-    public void GeneratePdf_FromHtml_WithMultipleFonts_CreatesPdfDocument()
+    public async Task GeneratePdf_FromHtml_WithMultipleFonts_CreatesPdfDocument()
     {
         // Arrange
         var config = new PdfGenerateConfig
@@ -86,7 +86,7 @@ public void GeneratePdf_FromHtml_WithMultipleFonts_CreatesPdfDocument()
             """;
 
         // Act
-        using var document = PdfGenerator.GeneratePdf(html, config, null, DemoUtils.OnStylesheetLoad, null);
+        using var document = await PdfGenerator.GeneratePdf(html, config, null, DemoUtils.OnStylesheetLoad, null);
 
         // Assert
         Assert.AreEqual(1, document.Pages.Count);