Refactored value model names

CHANGELOG.md

@@ -4,6 +4,7 @@ Released on tbd.
 
 - Updated to use AngleSharp 1.0 (#150)
 - Updated media parsing to media L4 spec (#133)
+- Updated naming of CSS values (e.g., `Color` to `CssColorValue`)
 - Fixed issue when updating shorthands with invalid values (#129)
 - Fixed issue with appended EOF character in `CssText` (#123)
 - Fixed missing semicolon in `@page` rule (#135)
@@ -15,6 +16,7 @@ Released on tbd.
 - Fixed `GetInnerText` multi-line / text node behavior (#155) @Seyden
 - Fixed computation of relative (`em`) values to absolute (`px`) for `Length` (#136)
 - Added further compactification of CSS tuples (#89, #93)
+- Added new value types `CssPercentageValue`, `CssNumberValue`, and `CssIntegerValue`
 - Added support for CSS nesting in style rules (#148)
 - Added resolution of CSS variable names (#62)
 - Added support for 8-digit hex color codes (#132)

CONTRIBUTORS.md

@@ -17,6 +17,7 @@ AngleSharp.Css contains code written by (in order of first pull request / commit
 * [Fraaankes](https://github.com/Fraaankes)
 * [Eric Mutta](https://github.com/ericmutta)
 * [Seyden](https://github.com/Seyden)
+* [Dave Dunkin](https://github.com/ddunkin)
 
 Without these awesome people AngleSharp.Css could not exist. Thanks to everyone for your contributions! :beers:
 

src/AngleSharp.Css.Tests/Values/Gradient.cs

@@ -41,10 +41,10 @@ namespace AngleSharp.Css.Tests.Values
             var gradient = value.Items[0] as CssLinearGradientValue;
             Assert.IsNotNull(gradient);
             Assert.IsFalse(gradient.IsRepeating);
-            Assert.AreEqual(Angle.TripleHalfQuarter, gradient.Angle);
+            Assert.AreEqual(CssAngleValue.TripleHalfQuarter, gradient.Angle);
             Assert.AreEqual(2, gradient.Stops.Length);
-            Assert.AreEqual(red, gradient.Stops.First().Color);
-            Assert.AreEqual(blue, gradient.Stops.Last().Color);
+            Assert.AreEqual(red, gradient.Stops.OfType<CssGradientStopValue>().First().Color);
+            Assert.AreEqual(blue, gradient.Stops.OfType<CssGradientStopValue>().Last().Color);
 
             Assert.AreEqual(source, property.CssText);
         }
@@ -61,16 +61,16 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(1, value.Items.Length);
             var gradient = value.Items[0] as CssLinearGradientValue;
             Assert.IsFalse(gradient.IsRepeating);
-            Assert.AreEqual(Angle.Quarter, gradient.Angle);
+            Assert.AreEqual(CssAngleValue.Quarter, gradient.Angle);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(7, stops.Length);
-            Assert.AreEqual(CssColors.GetColor("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColors.GetColor("orange").Value, stops[1].Color);
-            Assert.AreEqual(CssColors.GetColor("yellow").Value, stops[2].Color);
-            Assert.AreEqual(CssColors.GetColor("green").Value, stops[3].Color);
-            Assert.AreEqual(CssColors.GetColor("blue").Value, stops[4].Color);
-            Assert.AreEqual(CssColors.GetColor("indigo").Value, stops[5].Color);
-            Assert.AreEqual(CssColors.GetColor("violet").Value, stops[6].Color);
+            Assert.AreEqual(CssColors.GetColor("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColors.GetColor("orange").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColors.GetColor("yellow").Value, ((CssGradientStopValue)stops[2]).Color);
+            Assert.AreEqual(CssColors.GetColor("green").Value, ((CssGradientStopValue)stops[3]).Color);
+            Assert.AreEqual(CssColors.GetColor("blue").Value, ((CssGradientStopValue)stops[4]).Color);
+            Assert.AreEqual(CssColors.GetColor("indigo").Value, ((CssGradientStopValue)stops[5]).Color);
+            Assert.AreEqual(CssColors.GetColor("violet").Value, ((CssGradientStopValue)stops[6]).Color);
         }
 
         [Test]
@@ -85,10 +85,10 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(1, value.Items.Length);
             var gradient = value.Items[0] as CssLinearGradientValue;
             Assert.IsFalse(gradient.IsRepeating);
-            Assert.AreEqual(Angle.TripleHalfQuarter, gradient.Angle);
+            Assert.AreEqual(CssAngleValue.TripleHalfQuarter, gradient.Angle);
             Assert.AreEqual(2, gradient.Stops.Count());
-            Assert.AreEqual(CssColorValue.Red, gradient.Stops.First().Color);
-            Assert.AreEqual(CssColorValue.FromRgba(255, 0, 0, 0), gradient.Stops.Last().Color);
+            Assert.AreEqual(CssColorValue.Red, gradient.Stops.OfType<CssGradientStopValue>().First().Color);
+            Assert.AreEqual(CssColorValue.FromRgba(255, 0, 0, 0), gradient.Stops.OfType<CssGradientStopValue>().Last().Color);
         }
 
         [Test]
@@ -103,10 +103,10 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(1, value.Items.Length);
             var gradient = value.Items[0] as CssLinearGradientValue;
             Assert.IsFalse(gradient.IsRepeating);
-            Assert.AreEqual(Angle.Half, gradient.Angle);
+            Assert.AreEqual(CssAngleValue.Half, gradient.Angle);
             Assert.AreEqual(2, gradient.Stops.Count());
-            Assert.AreEqual(CssColorValue.FromHsl(0f, 0.8f, 0.7f), gradient.Stops.First().Color);
-            Assert.AreEqual(CssColorValue.FromHex("bada55"), gradient.Stops.Last().Color);
+            Assert.AreEqual(CssColorValue.FromHsl(0f, 0.8f, 0.7f), gradient.Stops.OfType<CssGradientStopValue>().First().Color);
+            Assert.AreEqual(CssColorValue.FromHex("bada55"), gradient.Stops.OfType<CssGradientStopValue>().Last().Color);
         }
 
         [Test]
@@ -121,11 +121,11 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(1, value.Items.Length);
             var gradient = value.Items[0] as CssLinearGradientValue;
             Assert.IsFalse(gradient.IsRepeating);
-            Assert.AreEqual(Angle.Half, gradient.Angle);
+            Assert.AreEqual(CssAngleValue.Half, gradient.Angle);
             Assert.AreEqual(3, gradient.Stops.Count());
-            Assert.AreEqual(CssColors.GetColor("yellow").Value, gradient.Stops.First().Color);
-            Assert.AreEqual(CssColors.GetColor("blue").Value, gradient.Stops.Skip(1).First().Color);
-            Assert.AreEqual(CssColorValue.FromRgb(0, 255, 0), gradient.Stops.Skip(2).First().Color);
+            Assert.AreEqual(CssColors.GetColor("yellow").Value, gradient.Stops.OfType<CssGradientStopValue>().First().Color);
+            Assert.AreEqual(CssColors.GetColor("blue").Value, gradient.Stops.OfType<CssGradientStopValue>().Skip(1).First().Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0, 255, 0), gradient.Stops.OfType<CssGradientStopValue>().Skip(2).First().Color);
         }
 
         [Test]
@@ -146,9 +146,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.FarthestCorner, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromRgb(0, 255, 255), stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromRgba(0, 0, 255, 0), stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 255), stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0, 255, 255), ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromRgba(0, 0, 255, 0), ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 255), ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -169,9 +169,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.FarthestCorner, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromRgb(0xFF, 0xFF, 0x80), stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromRgba(204, 153, 153, 0.4f), stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromRgb(0xE6, 0xE6, 0xFF), stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0xFF, 0xFF, 0x80), ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromRgba(204, 153, 153, 0.4f), ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0xE6, 0xE6, 0xFF), ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -192,8 +192,8 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.FarthestCorner, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(2, stops.Length);
-            Assert.AreEqual(CssColorValue.FromRgb(255, 0, 0), stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 255), stops[1].Color);
+            Assert.AreEqual(CssColorValue.FromRgb(255, 0, 0), ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 255), ((CssGradientStopValue)stops[1]).Color);
         }
 
         [Test]
@@ -216,10 +216,10 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssLengthValue.Full, gradient.MinorRadius);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(4, stops.Length);
-            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 0), stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 0), stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromRgba(0, 0, 0, 0.3), stops[2].Color);
-            Assert.AreEqual(CssColorValue.Transparent, stops[3].Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 0), ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromRgb(0, 0, 0), ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromRgba(0, 0, 0, 0.3), ((CssGradientStopValue)stops[2]).Color);
+            Assert.AreEqual(CssColorValue.Transparent, ((CssGradientStopValue)stops[3]).Color);
         }
 
         [Test]
@@ -240,8 +240,8 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.None, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(2, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[1].Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[1]).Color);
         }
 
         [Test]
@@ -262,8 +262,8 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.None, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(2, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[1].Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[1]).Color);
         }
 
         [Test]
@@ -284,8 +284,8 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.None, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(2, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[1].Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[1]).Color);
         }
 
         [Test]
@@ -306,8 +306,8 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.FarthestCorner, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(2, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[1].Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[1]).Color);
         }
 
         [Test]
@@ -328,9 +328,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.ClosestSide, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -353,9 +353,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(new CssLengthValue(30f, CssLengthValue.Unit.Px), gradient.MinorRadius);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -376,9 +376,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.ClosestSide, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -399,9 +399,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.FarthestSide, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -418,9 +418,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.IsTrue(gradient.IsRepeating);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("blue").Value, stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("blue").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -441,9 +441,9 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.None, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(3, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("blue").Value, stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[2].Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("blue").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[2]).Color);
         }
 
         [Test]
@@ -464,11 +464,11 @@ namespace AngleSharp.Css.Tests.Values
             Assert.AreEqual(CssRadialGradientValue.SizeMode.ClosestSide, gradient.Mode);
             var stops = gradient.Stops.ToArray();
             Assert.AreEqual(5, stops.Length);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[0].Color);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[1].Color);
-            Assert.AreEqual(CssColorValue.FromName("green").Value, stops[2].Color);
-            Assert.AreEqual(CssColorValue.FromName("yellow").Value, stops[3].Color);
-            Assert.AreEqual(CssColorValue.FromName("red").Value, stops[4].Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[0]).Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[1]).Color);
+            Assert.AreEqual(CssColorValue.FromName("green").Value, ((CssGradientStopValue)stops[2]).Color);
+            Assert.AreEqual(CssColorValue.FromName("yellow").Value, ((CssGradientStopValue)stops[3]).Color);
+            Assert.AreEqual(CssColorValue.FromName("red").Value, ((CssGradientStopValue)stops[4]).Color);
         }
     }
 }

src/AngleSharp.Css.Tests/Values/UnitConversion.cs

@@ -204,11 +204,11 @@ namespace AngleSharp.Css.Tests.Values
         public void AngleParseCorrectDegValue()
         {
             var s = "1.35e2deg";
-            var v = default(Angle);
-            var r = Angle.TryParse(s, out v);
+            var v = default(CssAngleValue);
+            var r = CssAngleValue.TryParse(s, out v);
             Assert.IsTrue(r);
             Assert.AreEqual(135f, v.Value);
-            Assert.AreEqual(Angle.Unit.Deg, v.Type);
+            Assert.AreEqual(CssAngleValue.Unit.Deg, v.Type);
         }
 
         [Test]
@@ -248,8 +248,8 @@ namespace AngleSharp.Css.Tests.Values
         public void AngleParseIncorrectValue()
         {
             var s = "123.deg";
-            var v = default(Angle);
-            var r = Angle.TryParse(s, out v);
+            var v = default(CssAngleValue);
+            var r = CssAngleValue.TryParse(s, out v);
             Assert.IsFalse(r);
         }
     }

src/AngleSharp.Css/Constants/Map.cs

@@ -26,16 +26,16 @@ namespace AngleSharp.Css
         /// <summary>
         /// Contains the string-Angle mapping for linear-gradients.s
         /// </summary>
-        public static readonly Dictionary<String, Angle> GradientAngles = new(StringComparer.OrdinalIgnoreCase)
+        public static readonly Dictionary<String, CssAngleValue> GradientAngles = new(StringComparer.OrdinalIgnoreCase)
         {
-            { CssKeywords.Left, new Angle(270.0, Angle.Unit.Deg) },
-            { CssKeywords.Top, new Angle(0.0, Angle.Unit.Deg) },
-            { CssKeywords.Right, new Angle(90.0, Angle.Unit.Deg) },
-            { CssKeywords.Bottom, new Angle(180.0, Angle.Unit.Deg) },
-            { CssKeywords.LeftTop, new Angle(315.0, Angle.Unit.Deg) },
-            { CssKeywords.LeftBottom, new Angle(225.0, Angle.Unit.Deg) },
-            { CssKeywords.RightTop, new Angle(45.0, Angle.Unit.Deg) },
-            { CssKeywords.RightBottom, new Angle(135.0, Angle.Unit.Deg) },
+            { CssKeywords.Left, new CssAngleValue(270.0, CssAngleValue.Unit.Deg) },
+            { CssKeywords.Top, new CssAngleValue(0.0, CssAngleValue.Unit.Deg) },
+            { CssKeywords.Right, new CssAngleValue(90.0, CssAngleValue.Unit.Deg) },
+            { CssKeywords.Bottom, new CssAngleValue(180.0, CssAngleValue.Unit.Deg) },
+            { CssKeywords.LeftTop, new CssAngleValue(315.0, CssAngleValue.Unit.Deg) },
+            { CssKeywords.LeftBottom, new CssAngleValue(225.0, CssAngleValue.Unit.Deg) },
+            { CssKeywords.RightTop, new CssAngleValue(45.0, CssAngleValue.Unit.Deg) },
+            { CssKeywords.RightBottom, new CssAngleValue(135.0, CssAngleValue.Unit.Deg) },
         };
 
         /// <summary>

src/AngleSharp.Css/Declarations/ContentDeclaration.cs

@@ -108,9 +108,9 @@ namespace AngleSharp.Css.Declarations
                 return null;
             }
 
-            private sealed class ContentValue : ICssValue
+            private sealed class ContentValue : ICssValue, IEquatable<ContentValue>
             {
-                private ICssValue[] _modes;
+                private readonly ICssValue[] _modes;
 
                 public ContentValue(ICssValue[] modes)
                 {
@@ -124,6 +124,30 @@ namespace AngleSharp.Css.Declarations
                     var modes = _modes.Select(mode => mode.Compute(context)).ToArray();
                     return new ContentValue(modes);
                 }
+                public Boolean Equals(ContentValue other)
+                {
+                    var l = _modes.Length;
+
+                    if (l == other._modes.Length)
+                    {
+                        for (var i = 0; i < l; i++)
+                        {
+                            var a = _modes[i];
+                            var b = other._modes[i];
+
+                            if (!a.Equals(b))
+                            {
+                                return false;
+                            }
+                        }
+
+                        return true;
+                    }
+
+                    return false;
+                }
+
+                Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is ContentValue value && Equals(value);
             }
 
             private abstract class ContentMode : ICssValue
@@ -134,10 +158,9 @@ namespace AngleSharp.Css.Declarations
 
                 public abstract String GetCssText();
 
-                ICssValue ICssValue.Compute(ICssComputeContext context)
-                {
-                    return this;
-                }
+                ICssValue ICssValue.Compute(ICssComputeContext context) => this;
+
+                public virtual Boolean Equals(ICssValue other) => Object.ReferenceEquals(this, other);
             }
 
             /// <summary>
@@ -209,6 +232,16 @@ namespace AngleSharp.Css.Declarations
                 public override String GetCssText() => _text.CssString();
 
                 public override String Stringify(IElement element) => _text;
+
+                public override Boolean Equals(ICssValue other)
+                {
+                    if (other is TextContentMode o)
+                    {
+                        return _text.Equals(o._text);
+                    }
+
+                    return false;
+                }
             }
 
             /// <summary>
@@ -228,6 +261,16 @@ namespace AngleSharp.Css.Declarations
                 public override String GetCssText() => _counter.CssText;
 
                 public override String Stringify(IElement element) => String.Empty;
+
+                public override Boolean Equals(ICssValue other)
+                {
+                    if (other is CounterContentMode o)
+                    {
+                        return _counter.Equals(o._counter);
+                    }
+
+                    return false;
+                }
             }
 
             /// <summary>
@@ -246,6 +289,16 @@ namespace AngleSharp.Css.Declarations
                 public override String GetCssText() => FunctionNames.Attr.CssFunction(_attribute);
 
                 public override String Stringify(IElement element) => element.GetAttribute(_attribute) ?? String.Empty;
+
+                public override Boolean Equals(ICssValue other)
+                {
+                    if (other is AttributeContentMode o)
+                    {
+                        return _attribute.Equals(o._attribute);
+                    }
+
+                    return false;
+                }
             }
 
             /// <summary>
@@ -265,6 +318,16 @@ namespace AngleSharp.Css.Declarations
                 public override String GetCssText() => _url.CssText;
 
                 public override String Stringify(IElement element) => String.Empty;
+
+                public override Boolean Equals(ICssValue other)
+                {
+                    if (other is UrlContentMode o)
+                    {
+                        return _url.Equals(o._url);
+                    }
+
+                    return false;
+                }
             }
         }
     }

src/AngleSharp.Css/Declarations/CursorDeclaration.cs

@@ -21,20 +21,19 @@ namespace AngleSharp.Css.Declarations
         {
             public ICssValue Convert(StringSource source)
             {
-                var cursor = default(ICssValue);
                 var definitions = new List<ICssValue>();
 
                 while (!source.IsDone)
                 {
                     var imageSource = source.ParseImageSource();
-                    var c = source.SkipSpacesAndComments();
+                    source.SkipSpacesAndComments();
 
                     if (imageSource != null)
                     {
                         var x = source.ParseNumber();
-                        c = source.SkipSpacesAndComments();
+                        source.SkipSpacesAndComments();
                         var y = source.ParseNumber();
-                        c = source.SkipSpacesAndComments();
+                        var c = source.SkipSpacesAndComments();
 
                         if (x.HasValue != y.HasValue || c != Symbols.Comma)
                             break;
@@ -44,16 +43,14 @@ namespace AngleSharp.Css.Declarations
 
                         if (x.HasValue)
                         {
-                            var xp = new CssLengthValue(x.Value, CssLengthValue.Unit.None);
-                            var yp = new CssLengthValue(y.Value, CssLengthValue.Unit.None);
-                            position = new CssPoint2D(xp, yp);
+                            position = new CssPoint2D(x, y);
                         }
 
                         definitions.Add(new CssCustomCursorValue(imageSource, position));
                     }
                     else
                     {
-                        cursor = source.ParseConstant(Map.SystemCursors);
+                        var cursor = source.ParseConstant(Map.SystemCursors);
 
                         if (cursor != null)
                         {

src/AngleSharp.Css/Dom/ICssValue.cs

@@ -1,12 +1,12 @@
 namespace AngleSharp.Css.Dom
 {
-    using System;
     using AngleSharp.Css.Values;
+    using System;
 
     /// <summary>
     /// Represents a value of a CSS property.
     /// </summary>
-    public interface ICssValue
+    public interface ICssValue : IEquatable<ICssValue>
     {
         /// <summary>
         /// The text representation of the value.

src/AngleSharp.Css/Extensions/CssValueExtensions.cs

@@ -16,17 +16,41 @@ namespace AngleSharp.Css.Dom
         /// <returns>The resulting number.</returns>
         public static Double AsDouble(this ICssValue value)
         {
-            if (value is CssLengthValue length && length.Type == CssLengthValue.Unit.None)
+            if (value is null)
             {
-                return length.Value;
+                return 0.0;
+            }
+            else if (value is CssLengthValue l && l.Type == CssLengthValue.Unit.None)
+            {
+                return l.Value;
+            }
+            else if (value is CssTimeValue t && t.Type == CssTimeValue.Unit.None)
+            {
+                return t.Value;
+            }
+            else if (value is CssFrequencyValue f && f.Type == CssFrequencyValue.Unit.None)
+            {
+                return f.Value;
+            }
+            else if (value is CssNumberValue n)
+            {
+                return n.Value;
+            }
+            else if (value is CssIntegerValue i)
+            {
+                return i.Value;
+            }
+            else if (value is CssPercentageValue p)
+            {
+                return p.Value;
             }
             else if (value is CssFractionValue fr)
             {
                 return fr.Value;
             }
-            else if (value is CssRatioValue ratio)
+            else if (value is CssRatioValue r)
             {
-                return ratio.Value;
+                return r.Top.AsDouble() / r.Bottom.AsDouble();
             }
             else if (value is ICssMultipleValue multiple && multiple.Count == 1)
             {
@@ -49,7 +73,11 @@ namespace AngleSharp.Css.Dom
         /// <returns>The resulting number.</returns>
         public static Double AsPx(this ICssValue value, IRenderDimensions renderDimensions, RenderMode mode)
         {
-            if (value is CssLengthValue length && length.Type != CssLengthValue.Unit.None)
+            if (value is null)
+            {
+                return 0.0;
+            }
+            else if (value is CssLengthValue length && length.Type != CssLengthValue.Unit.None)
             {
                 return length.ToPixel(renderDimensions, mode);
             }
@@ -72,7 +100,11 @@ namespace AngleSharp.Css.Dom
         /// <returns>The resulting number.</returns>
         public static Double AsMs(this ICssValue value)
         {
-            if (value is CssTimeValue time && time.Type != CssTimeValue.Unit.None)
+            if (value is null)
+            {
+                return 0.0;
+            }
+            else if (value is CssTimeValue time && time.Type != CssTimeValue.Unit.None)
             {
                 return time.ToMilliseconds();
             }
@@ -95,7 +127,11 @@ namespace AngleSharp.Css.Dom
         /// <returns>The resulting number.</returns>
         public static Double AsHz(this ICssValue value)
         {
-            if (value is CssFrequencyValue freq && freq.Type != CssFrequencyValue.Unit.None)
+            if (value is null)
+            {
+                return 0.0;
+            }
+            else if (value is CssFrequencyValue freq && freq.Type != CssFrequencyValue.Unit.None)
             {
                 return freq.ToHertz();
             }
@@ -118,9 +154,13 @@ namespace AngleSharp.Css.Dom
         /// <returns>The resulting number.</returns>
         public static Double AsDeg(this ICssValue value)
         {
-            if (value is Angle angle && angle.Type != Angle.Unit.None)
+            if (value is null)
             {
-                return angle.Value;
+                return 0.0;
+            }
+            else if (value is CssAngleValue angle && angle.Type != CssAngleValue.Unit.None)
+            {
+                return angle.ToDegree();
             }
             else if (value is ICssMultipleValue multiple && multiple.Count == 1)
             {
@@ -134,6 +174,33 @@ namespace AngleSharp.Css.Dom
             return 0.0;
         }
 
+        /// <summary>
+        /// Tries to convert the value to a number of degrees.
+        /// </summary>
+        /// <param name="value">The value to convert.</param>
+        /// <returns>The resulting number.</returns>
+        public static Double AsRad(this ICssValue value)
+        {
+            if (value is null)
+            {
+                return 0.0;
+            }
+            else if (value is CssAngleValue angle && angle.Type != CssAngleValue.Unit.None)
+            {
+                return angle.ToRadian();
+            }
+            else if (value is ICssMultipleValue multiple && multiple.Count == 1)
+            {
+                return multiple[0].AsRad();
+            }
+            else if (value is ICssSpecialValue special && special.Value != null)
+            {
+                return special.Value.AsRad();
+            }
+
+            return 0.0;
+        }
+
         /// <summary>
         /// Tries to convert the value to a number of dots per inch.
         /// </summary>
@@ -141,7 +208,11 @@ namespace AngleSharp.Css.Dom
         /// <returns>The resulting number.</returns>
         public static Double AsDpi(this ICssValue value)
         {
-            if (value is CssResolutionValue res && res.Type != CssResolutionValue.Unit.None)
+            if (value is null)
+            {
+                return 0.0;
+            }
+            else if (value is CssResolutionValue res && res.Type != CssResolutionValue.Unit.None)
             {
                 return res.ToDotsPerPixel();
             }

src/AngleSharp.Css/Parser/Micro/CalcParser.cs

@@ -166,10 +166,10 @@ namespace AngleSharp.Css.Parser
                     source.SkipSpacesAndComments();
                     return new CssTimeValue(result, CssTimeValue.GetUnit(unit.Dimension));
                 }
-                else if (Angle.GetUnit(unit.Dimension) != Angle.Unit.None)
+                else if (CssAngleValue.GetUnit(unit.Dimension) != CssAngleValue.Unit.None)
                 {
                     source.SkipSpacesAndComments();
-                    return new Angle(result, Angle.GetUnit(unit.Dimension));
+                    return new CssAngleValue(result, CssAngleValue.GetUnit(unit.Dimension));
                 }
                 else if (CssFrequencyValue.GetUnit(unit.Dimension) != CssFrequencyValue.Unit.None)
                 {

src/AngleSharp.Css/Parser/Micro/ColorParser.cs

@@ -478,11 +478,11 @@ namespace AngleSharp.Css.Parser
             if (unit != null &&
                 Double.TryParse(unit.Value, NumberStyles.Float, CultureInfo.InvariantCulture, out var value))
             {
-                var dim = Angle.Unit.Deg;
+                var dim = CssAngleValue.Unit.Deg;
 
-                if (unit.Dimension == String.Empty || (dim = Angle.GetUnit(unit.Dimension)) != Angle.Unit.None)
+                if (unit.Dimension == String.Empty || (dim = CssAngleValue.GetUnit(unit.Dimension)) != CssAngleValue.Unit.None)
                 {
-                    var angle = new Angle(value, dim);
+                    var angle = new CssAngleValue(value, dim);
                     return angle.ToTurns();
                 }
             }

src/AngleSharp.Css/Parser/Micro/NumberParser.cs

@@ -14,7 +14,7 @@ namespace AngleSharp.Css.Parser
         /// <summary>
         /// Parses the number (double) value.
         /// </summary>
-        public static Double? ParseNumber(this StringSource source)
+        public static CssNumberValue? ParseNumber(this StringSource source)
         {
             var unit = source.ParseUnit();
 
@@ -22,7 +22,7 @@ namespace AngleSharp.Css.Parser
                 unit.Dimension == String.Empty &&
                 Double.TryParse(unit.Value, NumberStyles.Float, CultureInfo.InvariantCulture, out var result))
             {
-                return result;
+                return new CssNumberValue(result);
             }
 
             return null;
@@ -50,12 +50,12 @@ namespace AngleSharp.Css.Parser
         /// <summary>
         /// Parses the integer (double) value.
         /// </summary>
-        public static Double? ParseNaturalNumber(this StringSource source)
+        public static CssNumberValue? ParseNaturalNumber(this StringSource source)
         {
             var pos = source.Index;
             var element = source.ParseNumber();
 
-            if (element.HasValue && element.Value >= 0f)
+            if (element.HasValue && element.Value.Value >= 0f)
             {
                 return element;
             }
@@ -67,12 +67,12 @@ namespace AngleSharp.Css.Parser
         /// <summary>
         /// Parses the natural number (double) value.
         /// </summary>
-        public static Double? ParseGreaterOrEqualOneNumber(this StringSource source)
+        public static CssNumberValue? ParseGreaterOrEqualOneNumber(this StringSource source)
         {
             var pos = source.Index;
             var element = source.ParseNumber();
 
-            if (element.HasValue && element.Value >= 1f)
+            if (element.HasValue && element.Value.Value >= 1f)
             {
                 return element;
             }

src/AngleSharp.Css/Parser/Micro/TransformParser.cs

@@ -69,7 +69,7 @@ namespace AngleSharp.Css.Parser
         private static CssSkewValue ParseSkew2d(StringSource source)
         {
             ICssValue x = source.ParseAngleOrCalc();
-            ICssValue y = Angle.Zero;
+            ICssValue y = CssAngleValue.Zero;
             var c = source.SkipGetSkip();
 
             if (x == null)
@@ -148,7 +148,7 @@ namespace AngleSharp.Css.Parser
         /// </summary>
         private static CssMatrixValue ParseMatrix(StringSource source, Int32 count)
         {
-            var numbers = new Double[count];
+            var numbers = new ICssValue[count];
             var num = source.ParseNumber();
 
             if (num.HasValue)
@@ -184,7 +184,7 @@ namespace AngleSharp.Css.Parser
         /// </summary>
         private static CssRotateValue ParseRotate2d(StringSource source)
         {
-            return ParseRotate(source, Double.NaN, Double.NaN, Double.NaN);
+            return ParseRotate(source, null, null, null);
         }
 
         /// <summary>
@@ -214,7 +214,7 @@ namespace AngleSharp.Css.Parser
         /// </summary>
         private static CssRotateValue ParseRotateX(StringSource source)
         {
-            return ParseRotate(source, 1f, 0f, 0f);
+            return ParseRotate(source, CssNumberValue.One, null, null);
         }
 
         /// <summary>
@@ -223,7 +223,7 @@ namespace AngleSharp.Css.Parser
         /// </summary>
         private static CssRotateValue ParseRotateY(StringSource source)
         {
-            return ParseRotate(source, 0f, 1f, 0f);
+            return ParseRotate(source, null, CssNumberValue.One, null);
         }
 
         /// <summary>
@@ -232,21 +232,21 @@ namespace AngleSharp.Css.Parser
         /// </summary>
         private static CssRotateValue ParseRotateZ(StringSource source)
         {
-            return ParseRotate(source, 0f, 0f, 1f);
+            return ParseRotate(source, null, null, CssNumberValue.One);
         }
 
         /// <summary>
         /// A broad variety of rotate transforms.
         /// http://www.w3.org/TR/css3-transforms/#funcdef-rotate3d
         /// </summary>
-        private static CssRotateValue ParseRotate(StringSource source, Double x, Double y, Double z)
+        private static CssRotateValue ParseRotate(StringSource source, ICssValue x, ICssValue y, ICssValue z)
         {
             var angle = source.ParseAngleOrCalc();
             var f = source.SkipGetSkip();
 
             if (angle != null && f == Symbols.RoundBracketClose)
             {
-                return new CssRotateValue(x, z, y, angle);
+                return new CssRotateValue(x, y, z, angle);
             }
 
             return null;
@@ -263,7 +263,7 @@ namespace AngleSharp.Css.Parser
 
             if (x.HasValue)
             {
-                var y = default(Double?);
+                var y = default(ICssValue);
 
                 if (f == Symbols.Comma)
                 {
@@ -273,7 +273,7 @@ namespace AngleSharp.Css.Parser
 
                 if (f == Symbols.RoundBracketClose)
                 {
-                    return new CssScaleValue(x.Value, y ?? x.Value, 1.0);
+                    return new CssScaleValue(x.Value, y ?? x.Value, null);
                 }
             }
 
@@ -291,15 +291,15 @@ namespace AngleSharp.Css.Parser
 
             if (x.HasValue)
             {
-                var y = default(Double?);
-                var z = default(Double?);
+                var y = default(ICssValue);
+                var z = default(ICssValue);
 
                 if (f == Symbols.Comma)
                 {
                     y = source.ParseNumber();
                     f = source.SkipGetSkip();
 
-                    if (!y.HasValue)
+                    if (y is null)
                     {
                         return null;
                     }
@@ -331,7 +331,7 @@ namespace AngleSharp.Css.Parser
 
             if (x.HasValue && f == Symbols.RoundBracketClose)
             {
-                return new CssScaleValue(x.Value, 1.0, 1.0);
+                return new CssScaleValue(x.Value, null, null);
             }
 
             return null;
@@ -348,7 +348,7 @@ namespace AngleSharp.Css.Parser
 
             if (y.HasValue && f == Symbols.RoundBracketClose)
             {
-                return new CssScaleValue(1.0, y.Value, 1.0);
+                return new CssScaleValue(null, y.Value, null);
             }
 
             return null;
@@ -365,7 +365,7 @@ namespace AngleSharp.Css.Parser
 
             if (z.HasValue && f == Symbols.RoundBracketClose)
             {
-                return new CssScaleValue(1.0, 1.0, z.Value);
+                return new CssScaleValue(null, null, z.Value);
             }
 
             return null;

src/AngleSharp.Css/Parser/Micro/UnitParser.cs

@@ -119,19 +119,19 @@ namespace AngleSharp.Css.Parser
         /// <summary>
         /// Parses an angle value.
         /// </summary>
-        public static Angle? ParseAngle(this StringSource source)
+        public static CssAngleValue? ParseAngle(this StringSource source)
         {
             var pos = source.Index;
             var test = source.ParseUnit();
 
             if (test != null)
             {
-                var unit = Angle.GetUnit(test.Dimension);
+                var unit = CssAngleValue.GetUnit(test.Dimension);
 
-                if (unit != Angle.Unit.None &&
+                if (unit != CssAngleValue.Unit.None &&
                     Double.TryParse(test.Value, NumberStyles.Float, CultureInfo.InvariantCulture, out var value))
                 {
-                    return new Angle(value, unit);
+                    return new CssAngleValue(value, unit);
                 }
 
                 source.BackTo(pos);

src/AngleSharp.Css/ValueConverters.cs

@@ -167,7 +167,7 @@ namespace AngleSharp.Css
         /// Represents a number object.
         /// https://developer.mozilla.org/en-US/docs/Web/CSS/number
         /// </summary>
-        public static readonly IValueConverter OnlyNumberConverter = new StructValueConverter<CssLengthValue>(FromNumber(NumberParser.ParseNumber));
+        public static readonly IValueConverter OnlyNumberConverter = new StructValueConverter<CssNumberValue>(NumberParser.ParseNumber);
 
         /// <summary>
         /// Represents a (calculated) number object.
@@ -202,7 +202,7 @@ namespace AngleSharp.Css
         /// <summary>
         /// Represents an number object that is zero or greater.
         /// </summary>
-        public static readonly IValueConverter NaturalNumberConverter = new StructValueConverter<CssLengthValue>(FromNumber(NumberParser.ParseNaturalNumber));
+        public static readonly IValueConverter NaturalNumberConverter = new StructValueConverter<CssNumberValue>(NumberParser.ParseNaturalNumber);
 
         /// <summary>
         /// Represents an color object (usually hex or name).
@@ -753,7 +753,7 @@ namespace AngleSharp.Css
 		/// <summary>
 		/// Represents a converter for the StrokeMiterlimit enumeration.
 		/// </summary>
-		public static readonly IValueConverter StrokeMiterlimitConverter = new StructValueConverter<CssLengthValue>(FromNumber(NumberParser.ParseGreaterOrEqualOneNumber));
+		public static readonly IValueConverter StrokeMiterlimitConverter = new StructValueConverter<CssNumberValue>(NumberParser.ParseGreaterOrEqualOneNumber);
 
 		/// <summary>
 		/// Represents a ratio object.

src/AngleSharp.Css/Values/Composites/CssBackgroundLayerValue.cs

@@ -4,7 +4,7 @@ namespace AngleSharp.Css.Values
     using AngleSharp.Text;
     using System;
 
-    sealed class CssBackgroundLayerValue : ICssCompositeValue
+    sealed class CssBackgroundLayerValue : ICssCompositeValue, IEquatable<CssBackgroundLayerValue>
     {
         #region Fields
 
@@ -132,6 +132,22 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssBackgroundLayerValue other)
+        {
+            return _clip.Equals(other._clip) &&
+                _repeat.Equals(other._repeat) &&
+                _attachment.Equals(other._attachment) &&
+                _origin.Equals(other._origin) &&
+                _size.Equals(other._size);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssBackgroundLayerValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var image = _image.Compute(context);

src/AngleSharp.Css/Values/Composites/CssBackgroundSizeValue.cs

@@ -89,6 +89,15 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Compares to another background size.
+        /// </summary>
+        /// <param name="other">The other background size.</param>
+        /// <returns>True if both are equivalent, otherwise false.</returns>
+        public Boolean Equals(CssBackgroundSizeValue other) => _mode == other._mode && _height.Equals(other._height) && _width.Equals(other._width);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssBackgroundSizeValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             if (_mode == ValueMode.Explicit)
@@ -101,13 +110,6 @@ namespace AngleSharp.Css.Values
             return this;
         }
 
-        /// <summary>
-        /// Compares to another background size.
-        /// </summary>
-        /// <param name="other">The other background size.</param>
-        /// <returns>True if both are equivalent, otherwise false.</returns>
-        public Boolean Equals(CssBackgroundSizeValue other) => _mode == other._mode && _height == other._height && _width == other._width;
-
         #endregion
 
         #region Value Mode

src/AngleSharp.Css/Values/Composites/CssBackgroundValue.cs

@@ -6,7 +6,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS background definition.
     /// </summary>
-    sealed class CssBackgroundValue : ICssCompositeValue
+    sealed class CssBackgroundValue : ICssCompositeValue, IEquatable<CssBackgroundValue>
     {
         #region Fields
 
@@ -71,6 +71,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssBackgroundValue other)
+        {
+            return _color.Equals(other._color) && _layers.Equals(other._layers);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssBackgroundValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var layers = _layers.Compute(context);

src/AngleSharp.Css/Values/Composites/CssBorderImageSliceValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents the CSS border image slice definition.
     /// </summary>
-    public sealed class CssBorderImageSliceValue : ICssCompositeValue
+    public sealed class CssBorderImageSliceValue : ICssCompositeValue, IEquatable<CssBorderImageSliceValue>
     {
         #region Fields
 
@@ -117,6 +117,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssBorderImageSliceValue other)
+        {
+            return _filled == other._filled && _bottom.Equals(other._bottom) && _left.Equals(other._left) && _right.Equals(other._right) && _top.Equals(other._top);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssBorderImageSliceValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var bottom = (CssLengthValue)((ICssValue)_bottom).Compute(context);

src/AngleSharp.Css/Values/Composites/CssBorderImageValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS border image definition.
     /// </summary>
-    sealed class CssBorderImageValue : ICssCompositeValue
+    sealed class CssBorderImageValue : ICssCompositeValue, IEquatable<CssBorderImageValue>
     {
         #region Fields
 
@@ -113,6 +113,22 @@ namespace AngleSharp.Css.Values
 
         #region
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssBorderImageValue other)
+        {
+            return _image.Equals(other._image) &&
+                _slice.Equals(other._slice) &&
+                _widths.Equals(other._widths) &&
+                _outsets.Equals(other._outsets) &&
+                _repeat.Equals(other._repeat);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssBorderImageValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var image = _image.Compute(context);

src/AngleSharp.Css/Values/Composites/CssBorderRadiusValue.cs

@@ -6,7 +6,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a border radius value.
     /// </summary>
-    sealed class CssBorderRadiusValue : ICssCompositeValue
+    sealed class CssBorderRadiusValue : ICssCompositeValue, IEquatable<CssBorderRadiusValue>
     {
         #region Fields
 
@@ -67,6 +67,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssBorderRadiusValue other)
+        {
+            return _horizontal.Equals(other._horizontal) && _vertical.Equals(other._vertical);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssBorderRadiusValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var h = ((ICssValue)_horizontal).Compute(context);

src/AngleSharp.Css/Values/Composites/CssCursorValue.cs

@@ -8,7 +8,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS cursor definition.
     /// </summary>
-    sealed class CssCursorValue : ICssCompositeValue
+    sealed class CssCursorValue : ICssCompositeValue, IEquatable<CssCursorValue>
     {
         #region Fields
 
@@ -67,6 +67,36 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssCursorValue other)
+        {
+            var l = _definitions.Length;
+
+            if (_cursor.Equals(other._cursor) && l == other._definitions.Length)
+            {
+                for (var i = 0; i < l; i++)
+                {
+                    var a = _definitions[i];
+                    var b = other._definitions[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssCursorValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var cursor = _cursor.Compute(context);

src/AngleSharp.Css/Values/Composites/CssCustomCursorValue.cs

@@ -4,12 +4,12 @@ namespace AngleSharp.Css.Values
     using AngleSharp.Text;
     using System;
 
-    sealed class CssCustomCursorValue : ICssCompositeValue
+    sealed class CssCustomCursorValue : ICssCompositeValue, IEquatable<CssCustomCursorValue>
     {
         #region Fields
 
         private readonly ICssImageValue _source;
-        private readonly CssPoint2D? _position;
+        private readonly ICssValue _position;
 
         #endregion
 
@@ -20,7 +20,7 @@ namespace AngleSharp.Css.Values
         /// </summary>
         /// <param name="source">The image source to display.</param>
         /// <param name="position">The position offset, if any.</param>
-        public CssCustomCursorValue(ICssImageValue source, CssPoint2D? position)
+        public CssCustomCursorValue(ICssImageValue source, ICssValue position)
         {
             _source = source;
             _position = position;
@@ -38,7 +38,7 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets the positional offset, if any.
         /// </summary>
-        public CssPoint2D? Position => _position;
+        public ICssValue Position => _position;
 
         /// <summary>
         /// Gets the CSS text representation.
@@ -51,10 +51,10 @@ namespace AngleSharp.Css.Values
 
                 sb.Append(_source.CssText);
 
-                if (_position.HasValue)
+                if (_position is not null)
                 {
                     sb.Append(Symbols.Space);
-                    sb.Append(_position.Value.CssText);
+                    sb.Append(_position.CssText);
                 }
 
                 return sb.ToPool();
@@ -65,10 +65,22 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssCustomCursorValue other)
+        {
+            return _position.Equals(other._position) && _source.Equals(other._source);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssCustomCursorValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var source = (ICssImageValue)_source.Compute(context);
-            var position = _position.HasValue ? (CssPoint2D?)((ICssValue)_position.Value).Compute(context) : null;
+            var position = _position?.Compute(context);
             return new CssCustomCursorValue(source, position);
         }
 

src/AngleSharp.Css/Values/Composites/CssFontValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS font definition.
     /// </summary>
-    sealed class CssFontValue : ICssCompositeValue
+    sealed class CssFontValue : ICssCompositeValue, IEquatable<CssFontValue>
     {
         #region Fields
 
@@ -138,6 +138,24 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssFontValue other)
+        {
+            return _lineHeight.Equals(other._lineHeight) &&
+                _size.Equals(other._size) &&
+                _weight.Equals(other._weight) &&
+                _stretch.Equals(other._stretch) &&
+                _variant.Equals(other._variant) &&
+                _style.Equals(other._style) &&
+                _fontFamilies.Equals(other._fontFamilies);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssFontValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var fontFamilies = _fontFamilies.Compute(context);

src/AngleSharp.Css/Values/Composites/CssGradientStopValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// More information can be found at the W3C:
     /// http://dev.w3.org/csswg/css-images-3/#color-stop-syntax
     /// </summary>
-    public sealed class CssGradientStopValue : ICssCompositeValue
+    public sealed class CssGradientStopValue : ICssCompositeValue, IEquatable<CssGradientStopValue>
     {
         #region Fields
 
@@ -62,6 +62,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssGradientStopValue other)
+        {
+            return _color.Equals(other._color) && _location.Equals(other._location);
+        }
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var color = ((ICssValue)_color).Compute(context);
@@ -69,6 +79,8 @@ namespace AngleSharp.Css.Values
             return new CssGradientStopValue((CssColorValue)color, location);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssGradientStopValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Composites/CssGridTemplateValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS grid template definition.
     /// </summary>
-    sealed class CssGridTemplateValue : ICssCompositeValue
+    sealed class CssGridTemplateValue : ICssCompositeValue, IEquatable<CssGridTemplateValue>
     {
         #region Fields
 
@@ -107,6 +107,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssGridTemplateValue other)
+        {
+            return _areas.Equals(other._areas) && _columns.Equals(other._columns) && _rows.Equals(other._rows);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssGridTemplateValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var rows = _rows.Compute(context);

src/AngleSharp.Css/Values/Composites/CssGridValue.cs

@@ -9,7 +9,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS grid definition.
     /// </summary>
-    sealed class CssGridValue : ICssCompositeValue
+    sealed class CssGridValue : ICssCompositeValue, IEquatable<CssGridValue>
     {
         #region Fields
 
@@ -92,6 +92,37 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssGridValue other)
+        {
+            if (_rows.Equals(other._rows) && _columns.Equals(other._columns) && _dense == other._dense)
+            {
+                var l = _sizes.Length;
+
+                if (l == other._sizes.Length)
+                {
+                    for (var i = 0; i < l; i++)
+                    {
+                        var a = _sizes[i];
+                        var b = other._sizes[i];
+
+                        if (!a.Equals(b))
+                        {
+                            return false;
+                        }
+                    }
+
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var rows = _rows.Compute(context);
@@ -100,6 +131,8 @@ namespace AngleSharp.Css.Values
             return new CssGridValue(rows, columns, sizes, _dense);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssGridValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Composites/CssImageRepeatsValue.cs

@@ -7,11 +7,17 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS image repeat definition.
     /// </summary>
-    public sealed class CssImageRepeatsValue : ICssCompositeValue
+    public sealed class CssImageRepeatsValue : ICssCompositeValue, IEquatable<CssImageRepeatsValue>
     {
+        #region Fields
+
         private readonly ICssValue _horizontal;
         private readonly ICssValue _vertical;
 
+        #endregion
+
+        #region ctor
+
         /// <summary>
         /// Creates a new CSS image repeat definition.
         /// </summary>
@@ -23,6 +29,10 @@ namespace AngleSharp.Css.Values
             _vertical = vertical;
         }
 
+        #endregion
+
+        #region Properties
+
         /// <summary>
         /// Gets the value of the horizontal repeat component.
         /// </summary>
@@ -60,11 +70,29 @@ namespace AngleSharp.Css.Values
             }
         }
 
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssImageRepeatsValue other)
+        {
+            return _horizontal.Equals(other._horizontal) && _vertical.Equals(other._vertical);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssImageRepeatsValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var h = _horizontal.Compute(context);
             var v = _vertical.Compute(context);
             return new CssImageRepeatsValue(h, v);
         }
+
+        #endregion
     }
 }

src/AngleSharp.Css/Values/Composites/CssOriginValue.cs

@@ -6,7 +6,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS origin definition.
     /// </summary>
-    public sealed class CssOriginValue : ICssCompositeValue
+    public sealed class CssOriginValue : ICssCompositeValue, IEquatable<CssOriginValue>
     {
         #region Fields
 
@@ -66,6 +66,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssOriginValue other)
+        {
+            return _x.Equals(other._x) && _y.Equals(other._y) && _z.Equals(other._z);
+        }
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var x = _x.Compute(context);
@@ -80,6 +90,8 @@ namespace AngleSharp.Css.Values
             return this;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssOriginValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Composites/CssPoint2D.cs

@@ -6,7 +6,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a point value consisting of two distances.
     /// </summary>
-    public readonly struct CssPoint2D : IEquatable<CssPoint2D>, ICssPrimitiveValue
+    public readonly struct CssPoint2D : ICssCompositeValue, IEquatable<CssPoint2D>
     {
         #region Basic values
 
@@ -147,6 +147,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssPoint2D other)
+        {
+            return _x.Equals(other._x) && _y.Equals(other._y);
+        }
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var x = _x.Compute(context);
@@ -160,59 +170,7 @@ namespace AngleSharp.Css.Values
             return this;
         }
 
-        #endregion
-
-        #region Equality
-
-        /// <summary>
-        /// Checks the equality of the two given points.
-        /// </summary>
-        /// <param name="a">The left point.</param>
-        /// <param name="b">The right point.</param>
-        /// <returns>True if both points are equal, otherwise false.</returns>
-        public static Boolean operator ==(CssPoint2D a, CssPoint2D b) => a.Equals(b);
-
-        /// <summary>
-        /// Checks the inequality of the two given points.
-        /// </summary>
-        /// <param name="a">The left point.</param>
-        /// <param name="b">The right point.</param>
-        /// <returns>True if both points are not equal, otherwise false.</returns>
-        public static Boolean operator !=(CssPoint2D a, CssPoint2D b) => !a.Equals(b);
-
-        /// <summary>
-        /// Checks if both points are actually equal.
-        /// </summary>
-        /// <param name="other">The other point to compare to.</param>
-        /// <returns>True if both points are equal, otherwise false.</returns>
-        public Boolean Equals(CssPoint2D other) => _x.Equals(other._x) && _y.Equals(other._y);
-
-        /// <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 Boolean Equals(Object obj)
-        {
-            var other = obj as CssPoint2D?;
-
-            if (other != null)
-            {
-                return Equals(other.Value);
-            }
-
-            return false;
-        }
-
-        /// <summary>
-        /// Returns a hash code that defines the current point.
-        /// </summary>
-        /// <returns>The integer value of the hashcode.</returns>
-        public override Int32 GetHashCode()
-        {
-            var hash = 17 * 37 + _x.GetHashCode();
-            return hash * 37 + _y.GetHashCode();
-        }
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssPoint2D value && Equals(value);
 
         #endregion
     }

src/AngleSharp.Css/Values/Composites/CssRatioValue.cs

@@ -0,0 +1,81 @@
+namespace AngleSharp.Css.Values
+{
+    using AngleSharp.Css.Dom;
+    using System;
+
+    /// <summary>
+    /// Represents a ratio (top to bottom) value.
+    /// </summary>
+    public readonly struct CssRatioValue : ICssCompositeValue, IEquatable<CssRatioValue>
+    {
+        #region Fields
+
+        private readonly ICssValue _top;
+        private readonly ICssValue _bottom;
+
+        #endregion
+
+        #region ctor
+
+        /// <summary>
+        /// Creates a new ratio value.
+        /// </summary>
+        /// <param name="top">The first number.</param>
+        /// <param name="bottom">The second number.</param>
+        public CssRatioValue(ICssValue top, ICssValue bottom)
+        {
+            _top = top;
+            _bottom = bottom;
+        }
+
+        #endregion
+
+        #region Properties
+
+        /// <summary>
+        /// Gets the CSS text representation.
+        /// </summary>
+        public String CssText => String.Concat(_top.CssText, "/", _bottom.CssText);
+
+        /// <summary>
+        /// Gets the first number of the ratio.
+        /// </summary>
+        public ICssValue Top => _top;
+
+        /// <summary>
+        /// Gets the second number of the ratio.
+        /// </summary>
+        public ICssValue Bottom => _bottom;
+
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssRatioValue other)
+        {
+            return _top.Equals(other._top) && _bottom.Equals(other._bottom);
+        }
+
+        ICssValue ICssValue.Compute(ICssComputeContext context)
+        {
+            var top = _top.Compute(context);
+            var bottom = _bottom.Compute(context);
+
+            if (top != _top || bottom != _bottom)
+            {
+                return new CssRatioValue(top, bottom);
+            }
+
+            return this;
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssRatioValue value && Equals(value);
+
+        #endregion
+    }
+}

src/AngleSharp.Css/Values/Composites/CssShadowValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// The shadow class for holding information about a box or text-shadow.
     /// </summary>
-    public sealed class CssShadowValue : ICssCompositeValue
+    public sealed class CssShadowValue : ICssCompositeValue, IEquatable<CssShadowValue>
     {
         #region Fields
 
@@ -115,6 +115,23 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssShadowValue other)
+        {
+            return _blurRadius.Equals(other._blurRadius) &&
+                _spreadRadius.Equals(other._spreadRadius) &&
+                _color.Equals(other._color) &&
+                _inset == other._inset &&
+                _offsetX.Equals(other._offsetX) &&
+                _offsetY.Equals(other._offsetY);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssShadowValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var offsetX = _offsetX.Compute(context);

src/AngleSharp.Css/Values/CssChildValue.cs

@@ -6,7 +6,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS value that was born from a shorthand.
     /// </summary>
-    class CssChildValue : ICssValue
+    sealed class CssChildValue : ICssValue, IEquatable<CssChildValue>
     {
         #region Fields
 
@@ -51,6 +51,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssChildValue other)
+        {
+            return _parent.Equals(other._parent) && _value.Equals(other._value);
+        }
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var parent = _parent.Compute(context);
@@ -58,6 +68,8 @@ namespace AngleSharp.Css.Values
             return new CssChildValue(parent, value);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssChildValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Expressions/CssCalcAddExpression.cs

@@ -8,9 +8,15 @@ namespace AngleSharp.Css.Values
     /// </summary>
     sealed class CssCalcAddExpression : ICssCompositeValue
     {
+        #region Fields
+
         private readonly ICssValue _left;
         private readonly ICssValue _right;
 
+        #endregion
+
+        #region ctor
+
         /// <summary>
         /// Creates a new calc add expression.
         /// </summary>
@@ -22,6 +28,10 @@ namespace AngleSharp.Css.Values
             _right = right;
         }
 
+        #endregion
+
+        #region Properties
+
         /// <summary>
         /// Gets the left operand.
         /// </summary>
@@ -37,6 +47,10 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public String CssText => String.Concat(_left.CssText, " + ", _right.CssText);
 
+        #endregion
+
+        #region Methods
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var left = _left.Compute(context);
@@ -48,8 +62,11 @@ namespace AngleSharp.Css.Values
                 return (ICssValue)Activator.CreateInstance(x.GetType(), result);
             }
 
-            // TOOD INVALID
-            return this;
+            return null;
         }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
+
+        #endregion
     }
 }

src/AngleSharp.Css/Values/Expressions/CssCalcBracketExpression.cs

@@ -8,8 +8,14 @@ namespace AngleSharp.Css.Values
     /// </summary>
     sealed class CssCalcBracketExpression : ICssCompositeValue
     {
+        #region Fields
+
         private readonly ICssValue _content;
 
+        #endregion
+
+        #region ctor
+
         /// <summary>
         /// Creates a new calc bracket expression.
         /// </summary>
@@ -19,6 +25,10 @@ namespace AngleSharp.Css.Values
             _content = content;
         }
 
+        #endregion
+
+        #region Properties
+
         /// <summary>
         /// Gets the bracket's content.
         /// </summary>
@@ -29,9 +39,14 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public String CssText => String.Concat("(", _content.CssText, ")");
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return _content.Compute(context);
-        }
+        #endregion
+
+        #region Methods
+
+        ICssValue ICssValue.Compute(ICssComputeContext context) => _content.Compute(context);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
+
+        #endregion
     }
 }

src/AngleSharp.Css/Values/Expressions/CssCalcDivExpression.cs

@@ -8,9 +8,15 @@ namespace AngleSharp.Css.Values
     /// </summary>
     sealed class CssCalcDivExpression : ICssCompositeValue
     {
+        #region Fields
+
         private readonly ICssValue _left;
         private readonly ICssValue _right;
 
+        #endregion
+
+        #region ctor
+
         /// <summary>
         /// Creates a new calc division expression.
         /// </summary>
@@ -22,6 +28,10 @@ namespace AngleSharp.Css.Values
             _right = right;
         }
 
+        #endregion
+
+        #region Properties
+
         /// <summary>
         /// Gets the left operand.
         /// </summary>
@@ -37,6 +47,10 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public String CssText => String.Concat(_left.CssText, " / ", _right.CssText);
 
+        #endregion
+
+        #region Methods
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var left = _left.Compute(context);
@@ -48,8 +62,11 @@ namespace AngleSharp.Css.Values
                 return (ICssValue)Activator.CreateInstance(x.GetType(), result);
             }
 
-            // TOOD INVALID
-            return this;
+            return null;
         }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
+
+        #endregion
     }
 }

src/AngleSharp.Css/Values/Expressions/CssCalcMulExpression.cs

@@ -8,9 +8,15 @@ namespace AngleSharp.Css.Values
     /// </summary>
     sealed class CssCalcMulExpression : ICssCompositeValue
     {
+        #region Fields
+
         private readonly ICssValue _left;
         private readonly ICssValue _right;
 
+        #endregion
+
+        #region ctor
+
         /// <summary>
         /// Creates a new calc multiplication expression.
         /// </summary>
@@ -22,6 +28,10 @@ namespace AngleSharp.Css.Values
             _right = right;
         }
 
+        #endregion
+
+        #region Properties
+
         /// <summary>
         /// Gets the left operand.
         /// </summary>
@@ -37,6 +47,10 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public String CssText => String.Concat(_left.CssText, " * ", _right.CssText);
 
+        #endregion
+
+        #region Methods
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var left = _left.Compute(context);
@@ -48,8 +62,11 @@ namespace AngleSharp.Css.Values
                 return (ICssValue)Activator.CreateInstance(x.GetType(), result);
             }
 
-            // TOOD INVALID
-            return this;
+            return null;
         }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
+
+        #endregion
     }
 }

src/AngleSharp.Css/Values/Expressions/CssCalcSubExpression.cs

@@ -8,9 +8,15 @@ namespace AngleSharp.Css.Values
     /// </summary>
     sealed class CssCalcSubExpression : ICssCompositeValue
     {
+        #region Fields
+
         private readonly ICssValue _left;
         private readonly ICssValue _right;
 
+        #endregion
+
+        #region ctor
+
         /// <summary>
         /// Creates a new calc subtraction expression.
         /// </summary>
@@ -22,6 +28,10 @@ namespace AngleSharp.Css.Values
             _right = right;
         }
 
+        #endregion
+
+        #region Properties
+
         /// <summary>
         /// Gets the left operand.
         /// </summary>
@@ -37,6 +47,10 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public String CssText => String.Concat(_left.CssText, " - ", _right.CssText);
 
+        #endregion
+
+        #region Methods
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var left = _left.Compute(context);
@@ -48,8 +62,11 @@ namespace AngleSharp.Css.Values
                 return (ICssValue)Activator.CreateInstance(x.GetType(), result);
             }
 
-            // TOOD INVALID
-            return this;
+            return null;
         }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
+
+        #endregion
     }
 }

src/AngleSharp.Css/Values/Functions/CssAttrValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS attr function call.
     /// </summary>
-    public sealed class CssAttrValue : ICssFunctionValue
+    public sealed class CssAttrValue : ICssFunctionValue, IEquatable<CssAttrValue>
     {
         #region Fields
 
@@ -54,6 +54,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssAttrValue other)
+        {
+            return _attribute.Equals(other._attribute);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssAttrValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             return this;

src/AngleSharp.Css/Values/Functions/CssCalcValue.cs

@@ -59,10 +59,9 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return _expression.Compute(context);
-        }
+        ICssValue ICssValue.Compute(ICssComputeContext context) => _expression.Compute(context);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
 
         #endregion
     }

src/AngleSharp.Css/Values/Functions/CssConicGradientValue.cs

@@ -9,11 +9,11 @@ namespace AngleSharp.Css.Values
     /// Represents a linear gradient:
     /// https://drafts.csswg.org/css-images-4/#conic-gradients
     /// </summary>
-    sealed class CssConicGradientValue : ICssGradientFunctionValue
+    sealed class CssConicGradientValue : ICssGradientFunctionValue, IEquatable<CssConicGradientValue>
     {
         #region Fields
 
-        private readonly CssGradientStopValue[] _stops;
+        private readonly ICssValue[] _stops;
         private readonly ICssValue _center;
         private readonly ICssValue _angle;
         private readonly Boolean _repeating;
@@ -29,7 +29,7 @@ namespace AngleSharp.Css.Values
         /// <param name="center">The center to use.</param>
         /// <param name="stops">The stops to use.</param>
         /// <param name="repeating">Indicates if the gradient is repeating.</param>
-        public CssConicGradientValue(ICssValue angle, ICssValue center, CssGradientStopValue[] stops, Boolean repeating = false)
+        public CssConicGradientValue(ICssValue angle, ICssValue center, ICssValue[] stops, Boolean repeating = false)
         {
             _stops = stops;
             _center = center;
@@ -76,7 +76,7 @@ namespace AngleSharp.Css.Values
         {
             get
             {
-                var defaultAngle = _angle as Angle?;
+                var defaultAngle = _angle as CssAngleValue?;
                 var defaultPosition = _center as CssPoint2D?;
                 var offset = (defaultAngle.HasValue ? 1 : 0) + (defaultPosition.HasValue ? 1 : 0);
                 var args = new String[_stops.Length + offset];
@@ -103,7 +103,7 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets the angle of the conic gradient.
         /// </summary>
-        public ICssValue Angle => _angle ?? Values.Angle.Half;
+        public ICssValue Angle => _angle ?? Values.CssAngleValue.Half;
 
         /// <summary>
         /// Gets the position of the conic gradient.
@@ -113,7 +113,7 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets all stops.
         /// </summary>
-        public CssGradientStopValue[] Stops => _stops;
+        public ICssValue[] Stops => _stops;
 
         /// <summary>
         /// Gets if the gradient is repeating.
@@ -124,6 +124,36 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssConicGradientValue other)
+        {
+            var l = _stops.Length;
+
+            if (_angle.Equals(other._angle) && _center.Equals(other._center) && _repeating == other._repeating && l == other._stops.Length)
+            {
+                for (var i = 0; i < l; i++)
+                {
+                    var a = _stops[i];
+                    var b = other._stops[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssConicGradientValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var center = _center.Compute(context);

src/AngleSharp.Css/Values/Functions/CssContentValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS content function call.
     /// </summary>
-    public sealed class CssContentValue : ICssFunctionValue
+    public sealed class CssContentValue : ICssFunctionValue, IEquatable<CssContentValue>
     {
         #region Fields
 
@@ -54,10 +54,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssContentValue other) => _type.Equals(other._type);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssContentValue value && Equals(value);
+
+        ICssValue ICssValue.Compute(ICssComputeContext context) => this;
 
         #endregion
     }

src/AngleSharp.Css/Values/Functions/CssCubicBezierValue.cs

@@ -13,10 +13,10 @@ namespace AngleSharp.Css.Values
     {
         #region Fields
 
-        private readonly Double _x1;
-        private readonly Double _y1;
-        private readonly Double _x2;
-        private readonly Double _y2;
+        private readonly ICssValue _x1;
+        private readonly ICssValue _y1;
+        private readonly ICssValue _x2;
+        private readonly ICssValue _y2;
 
         /// <summary>
         /// The pre-configured ease function.
@@ -56,7 +56,7 @@ namespace AngleSharp.Css.Values
         /// <param name="y1">The y-coordinate of P1.</param>
         /// <param name="x2">The x-coordinate of P2.</param>
         /// <param name="y2">The y-coordinate of P2.</param>
-        public CssCubicBezierValue(Double x1, Double y1, Double x2, Double y2)
+        public CssCubicBezierValue(ICssValue x1, ICssValue y1, ICssValue x2, ICssValue y2)
         {
             _x1 = x1;
             _y1 = y1;
@@ -64,6 +64,20 @@ namespace AngleSharp.Css.Values
             _y2 = y2;
         }
 
+        /// <summary>
+        /// The four values specify points P1 and P2 of the curve as (x1, y1, x2, y2). Both
+        /// x values must be in the range [0, 1] or the definition is invalid. The y values
+        /// can exceed this range.
+        /// </summary>
+        /// <param name="x1">The x-coordinate of P1.</param>
+        /// <param name="y1">The y-coordinate of P1.</param>
+        /// <param name="x2">The x-coordinate of P2.</param>
+        /// <param name="y2">The y-coordinate of P2.</param>
+        public CssCubicBezierValue(Double x1, Double y1, Double x2, Double y2)
+            : this(new CssNumberValue(x1), new CssNumberValue(y1), new CssNumberValue(x2), new CssNumberValue(y2))
+        {
+        }
+
         #endregion
 
         #region Properties
@@ -78,10 +92,10 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public ICssValue[] Arguments => new ICssValue[]
         {
-            new CssLengthValue(_x1, CssLengthValue.Unit.None),
-            new CssLengthValue(_y1, CssLengthValue.Unit.None),
-            new CssLengthValue(_x2, CssLengthValue.Unit.None),
-            new CssLengthValue(_y2, CssLengthValue.Unit.None),
+            _x1,
+            _y1,
+            _x2,
+            _y2,
         };
 
         /// <summary>
@@ -119,22 +133,22 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets the x-coordinate of the p1.
         /// </summary>
-        public Double X1 => _x1;
+        public ICssValue X1 => _x1;
 
         /// <summary>
         /// Gets the y-coordinate of the p1.
         /// </summary>
-        public Double Y1 => _y1;
+        public ICssValue Y1 => _y1;
 
         /// <summary>
         /// Gets the x-coordinate of the p2.
         /// </summary>
-        public Double X2 => _x2;
+        public ICssValue X2 => _x2;
 
         /// <summary>
         /// Gets the y-coordinate of the p2.
         /// </summary>
-        public Double Y2 => _y2;
+        public ICssValue Y2 => _y2;
 
         #endregion
 
@@ -146,13 +160,19 @@ namespace AngleSharp.Css.Values
         /// <param name="other">The cubic bezier to compare to.</param>
         /// <returns>True if both have the same parameters, otherwise false.</returns>
         public Boolean Equals(CssCubicBezierValue other) =>
-            _x1 == other._x1 && _x2 == other._x2 && _y1 == other._y1 && _y2 == other._y2;
+            _x1.Equals(other._x1) && _x2.Equals(other._x2) && _y1.Equals(other._y1) && _y2.Equals(other._y2);
 
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
-            return this;
+            var x1 = _x1.Compute(context);
+            var x2 = _x2.Compute(context);
+            var y1 = _y1.Compute(context);
+            var y2 = _y2.Compute(context);
+            return new CssCubicBezierValue(x1, y1, x2, y2);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssCubicBezierValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Functions/CssFitContentValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS fit-content function call.
     /// </summary>
-    sealed class CssFitContentValue : ICssFunctionValue
+    sealed class CssFitContentValue : ICssFunctionValue, IEquatable<CssFitContentValue>
     {
         #region Fields
 
@@ -54,6 +54,15 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssFitContentValue other) => _dim.Equals(other._dim);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssFitContentValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var dim = _dim.Compute(context);

src/AngleSharp.Css/Values/Functions/CssFontFormatValue.cs

@@ -5,7 +5,7 @@ namespace AngleSharp.Css.Values
     using AngleSharp.Text;
     using System;
 
-    sealed class CssFontFormatValue : ICssFunctionValue
+    sealed class CssFontFormatValue : ICssFunctionValue, IEquatable<CssFontFormatValue>
     {
         #region Fields
 
@@ -34,10 +34,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssFontFormatValue other) => _fontFormat.Equals(other._fontFormat);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssFontFormatValue value && Equals(value);
+
+        ICssValue ICssValue.Compute(ICssComputeContext context) => this;
 
         #endregion
     }

src/AngleSharp.Css/Values/Functions/CssLinearGradientValue.cs

@@ -9,11 +9,11 @@ namespace AngleSharp.Css.Values
     /// Represents a linear gradient:
     /// http://dev.w3.org/csswg/css-images-3/#linear-gradients
     /// </summary>
-    sealed class CssLinearGradientValue : ICssGradientFunctionValue
+    sealed class CssLinearGradientValue : ICssGradientFunctionValue, IEquatable<CssLinearGradientValue>
     {
         #region Fields
 
-        private readonly CssGradientStopValue[] _stops;
+        private readonly ICssValue[] _stops;
         private readonly ICssValue _angle;
         private readonly Boolean _repeating;
 
@@ -27,7 +27,7 @@ namespace AngleSharp.Css.Values
         /// <param name="angle">The angle of the linear gradient.</param>
         /// <param name="stops">The stops to use.</param>
         /// <param name="repeating">Indicates if the gradient is repeating.</param>
-        public CssLinearGradientValue(ICssValue angle, CssGradientStopValue[] stops, Boolean repeating = false)
+        public CssLinearGradientValue(ICssValue angle, ICssValue[] stops, Boolean repeating = false)
         {
             _stops = stops;
             _angle = angle;
@@ -68,7 +68,7 @@ namespace AngleSharp.Css.Values
         {
             get
             {
-                var defaultAngle = _angle as Angle?;
+                var defaultAngle = _angle as CssAngleValue?;
                 var offset = defaultAngle.HasValue ? 1 : 0;
                 var args = new String[_stops.Length + offset];
 
@@ -100,12 +100,12 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets the angle of the linear gradient.
         /// </summary>
-        public ICssValue Angle => _angle ?? Values.Angle.Half;
+        public ICssValue Angle => _angle ?? Values.CssAngleValue.Half;
 
         /// <summary>
         /// Gets all stops.
         /// </summary>
-        public CssGradientStopValue[] Stops => _stops;
+        public ICssValue[] Stops => _stops;
 
         /// <summary>
         /// Gets if the gradient is repeating.
@@ -116,6 +116,36 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssLinearGradientValue other)
+        {
+            var l = _stops.Length;
+
+            if (_angle.Equals(other._angle) && _repeating == other._repeating && l == other._stops.Length)
+            {
+                for (var i = 0; i < l; i++)
+                {
+                    var a = _stops[i];
+                    var b = other._stops[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssLinearGradientValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var angle = _angle.Compute(context);

src/AngleSharp.Css/Values/Functions/CssLocalFontValue.cs

@@ -5,7 +5,7 @@ namespace AngleSharp.Css.Values
     using AngleSharp.Text;
     using System;
 
-    sealed class CssLocalFontValue : ICssFunctionValue
+    sealed class CssLocalFontValue : ICssFunctionValue, IEquatable<CssLocalFontValue>
     {
         #region Fields
 
@@ -34,10 +34,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssLocalFontValue other) => _fontName.Equals(other._fontName);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssLocalFontValue value && Equals(value);
+
+        ICssValue ICssValue.Compute(ICssComputeContext context) => this;
 
         #endregion
     }

src/AngleSharp.Css/Values/Functions/CssMatrixValue.cs

@@ -4,21 +4,22 @@ namespace AngleSharp.Css.Values
     using AngleSharp.Css.Dom;
     using AngleSharp.Text;
     using System;
+    using System.Linq;
 
     /// <summary>
     /// Represents the matrix3d transformation.
     /// </summary>
-    sealed class CssMatrixValue : ICssTransformFunctionValue
+    sealed class CssMatrixValue : ICssTransformFunctionValue, IEquatable<CssMatrixValue>
     {
         #region Fields
 
-        private readonly Double[] _values;
+        private readonly ICssValue[] _values;
 
         #endregion
 
         #region ctor
 
-        internal CssMatrixValue(Double[] values)
+        internal CssMatrixValue(ICssValue[] values)
         {
             _values = values;
         }
@@ -35,20 +36,7 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets the arguments.
         /// </summary>
-        public ICssValue[] Arguments
-        {
-            get
-            {
-                var args = new ICssValue[_values.Length];
-
-                for (var i = 0; i < args.Length; i++)
-                {
-                    args[i] = new CssLengthValue(_values[i], CssLengthValue.Unit.None);
-                }
-
-                return args;
-            }
-        }
+        public ICssValue[] Arguments => _values;
 
         /// <summary>
         /// Gets the CSS text representation.
@@ -60,37 +48,69 @@ namespace AngleSharp.Css.Values
         /// </summary>
         /// <param name="index">The index to look for.</param>
         /// <returns>The value.</returns>
-        public Double this[Int32 index] => _values[index];
+        public ICssValue this[Int32 index] => _values[index];
 
         #endregion
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssMatrixValue other)
+        {
+            var count = _values.Length;
+
+            if (count == other._values.Length)
+            {
+                for (var i = 0; i < count; i++)
+                {
+                    var a = _values[i];
+                    var b = other._values[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssMatrixValue value && Equals(value);
+
         /// <summary>
         /// Returns the stored matrix.
         /// </summary>
         /// <returns>The current transformation.</returns>
         public TransformMatrix ComputeMatrix(IRenderDimensions dimensions)
         {
-            var values = _values;
+            var values = _values.Select(v => v.AsDouble()).ToList();
 
-            if (values.Length == 6)
+            if (values.Count == 6)
             {
-                values = new Double[]
-                {
-                    _values[0], _values[2], 0.0, _values[4],
-                    _values[1], _values[3], 0.0, _values[5],
-                    1.0, 0.0, 0.0, 0.0,
-                    0.0, 0.0, 0.0, 1.0
-                };
+                values.Add(1.0);
+                values.Add(0.0);
+                values.Add(0.0);
+                values.Add(0.0);
+                values.Add(0.0);
+                values.Add(0.0);
+                values.Add(0.0);
+                values.Add(1.0);
             }
 
-            return new TransformMatrix(values);
+            return new TransformMatrix(values.ToArray());
         }
 
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
-            return this;
+            var values = _values.Select(v => v.Compute(context)).ToArray();
+            return new CssMatrixValue(values);
         }
 
         #endregion

src/AngleSharp.Css/Values/Functions/CssMinMaxValue.cs

@@ -8,7 +8,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS minmax function call.
     /// </summary>
-    sealed class CssMinMaxValue : ICssFunctionValue
+    sealed class CssMinMaxValue : ICssFunctionValue, IEquatable<CssMinMaxValue>
     {
         #region Fields
 
@@ -63,6 +63,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssMinMaxValue other)
+        {
+            return _min.Equals(other._min) && _max.Equals(other._max);
+        }
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var min = _min.Compute(context);
@@ -70,6 +80,8 @@ namespace AngleSharp.Css.Values
             return new CssMinMaxValue(min, max);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssMinMaxValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Functions/CssNoneValue.cs

@@ -17,10 +17,9 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
+
+        ICssValue ICssValue.Compute(ICssComputeContext context) => this;
 
         #endregion
     }

src/AngleSharp.Css/Values/Functions/CssPerspectiveValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents the distance transformation.
     /// </summary>
-    sealed class CssPerspectiveValue : ICssTransformFunctionValue
+    sealed class CssPerspectiveValue : ICssTransformFunctionValue, IEquatable<CssPerspectiveValue>
     {
         #region Fields
 
@@ -50,6 +50,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssPerspectiveValue other)
+        {
+            return _distance.Equals(other._distance);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssPerspectiveValue value && Equals(value);
+
         /// <summary>
         /// Computes the matrix for the given transformation.
         /// </summary>

src/AngleSharp.Css/Values/Functions/CssRadialGradientValue.cs

@@ -11,11 +11,11 @@ namespace AngleSharp.Css.Values
     /// Represents a radial gradient:
     /// http://dev.w3.org/csswg/css-images-3/#radial-gradients
     /// </summary>
-    public sealed class CssRadialGradientValue : ICssGradientFunctionValue
+    public sealed class CssRadialGradientValue : ICssGradientFunctionValue, IEquatable<CssRadialGradientValue>
     {
         #region Fields
 
-        private readonly CssGradientStopValue[] _stops;
+        private readonly ICssValue[] _stops;
         private readonly CssPoint2D _center;
         private readonly ICssValue _width;
         private readonly ICssValue _height;
@@ -37,7 +37,7 @@ namespace AngleSharp.Css.Values
         /// <param name="sizeMode">The size mode of the ellipsoid.</param>
         /// <param name="stops">A collection of stops to use.</param>
         /// <param name="repeating">The repeating setting.</param>
-        public CssRadialGradientValue(Boolean circle, CssPoint2D center, ICssValue width, ICssValue height, SizeMode sizeMode, CssGradientStopValue[] stops, Boolean repeating = false)
+        public CssRadialGradientValue(Boolean circle, CssPoint2D center, ICssValue width, ICssValue height, SizeMode sizeMode, ICssValue[] stops, Boolean repeating = false)
         {
             _stops = stops;
             _center = center;
@@ -64,7 +64,8 @@ namespace AngleSharp.Css.Values
         {
             get
             {
-                var isDefault = _center == CssPoint2D.Center && !_circle && _height == null && _width == null && _sizeMode == SizeMode.None;
+                var center = CssPoint2D.Center;
+                var isDefault = _center.X == center.X && _center.Y == center.Y && !_circle && _height == null && _width == null && _sizeMode == SizeMode.None;
                 var args = new List<ICssValue>();
 
                 if (!isDefault)
@@ -145,7 +146,7 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets all stops.
         /// </summary>
-        public CssGradientStopValue[] Stops => _stops;
+        public ICssValue[] Stops => _stops;
 
         /// <summary>
         /// Gets if the gradient is repeating.
@@ -156,6 +157,37 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssRadialGradientValue other)
+        {
+            if (_center.Equals(other._center) && _width.Equals(other._width) && _height.Equals(other._height) && _repeating == other._repeating && _sizeMode == other._sizeMode && _circle == other._circle)
+            {
+                var count = _stops.Length;
+
+                if (count == other._stops.Length)
+                {
+                    for (var i = 0; i < count; i++)
+                    {
+                        var a = _stops[i];
+                        var b = other._stops[i];
+
+                        if (!a.Equals(b))
+                        {
+                            return false;
+                        }
+                    }
+
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var center = (CssPoint2D)((ICssValue)_center).Compute(context);
@@ -165,6 +197,8 @@ namespace AngleSharp.Css.Values
             return new CssRadialGradientValue(_circle, center, width, height, _sizeMode, stops, _repeating);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssRadialGradientValue value && Equals(value);
+
         #endregion
 
         #region Sizes

src/AngleSharp.Css/Values/Functions/CssRepeatValue.cs

@@ -8,7 +8,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS repeat function call.
     /// </summary>
-    sealed class CssRepeatValue : ICssFunctionValue
+    sealed class CssRepeatValue : ICssFunctionValue, IEquatable<CssRepeatValue>
     {
         #region Fields
 
@@ -63,6 +63,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssRepeatValue other)
+        {
+            return _count.Equals(other._count) && _value.Equals(other._value);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssRepeatValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var count = _count.Compute(context);

src/AngleSharp.Css/Values/Functions/CssRotateValue.cs

@@ -8,13 +8,13 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents the rotate3d transformation.
     /// </summary>
-    sealed class CssRotateValue : ICssTransformFunctionValue
+    sealed class CssRotateValue : ICssTransformFunctionValue, IEquatable<CssRotateValue>
     {
         #region Fields
 
-        private readonly Double _x;
-        private readonly Double _y;
-        private readonly Double _z;
+        private readonly ICssValue _x;
+        private readonly ICssValue _y;
+        private readonly ICssValue _z;
         private readonly ICssValue _angle;
 
         #endregion
@@ -28,7 +28,7 @@ namespace AngleSharp.Css.Values
         /// <param name="y">The y coordinate.</param>
         /// <param name="z">The z coordinate.</param>
         /// <param name="angle">The angle of rotation.</param>
-        public CssRotateValue(Double x, Double y, Double z, ICssValue angle)
+        public CssRotateValue(ICssValue x, ICssValue y, ICssValue z, ICssValue angle)
         {
             _x = x;
             _y = y;
@@ -47,19 +47,19 @@ namespace AngleSharp.Css.Values
         {
             get
             {
-                if (Double.IsNaN(_x) && Double.IsNaN(_y) && Double.IsNaN(_z))
+                if (_x is null && _y is null && _z is null)
                 {
                     return FunctionNames.Rotate;
                 }
-                else if (_x == 1f && _y == 0f && _z == 0f)
+                else if (_x is not null && _y is null && _z is null)
                 {
                     return FunctionNames.RotateX;
                 }
-                else if (_x == 0f && _y == 1f && _z == 0f)
+                else if (_x is null && _y is not null && _z is null)
                 {
                     return FunctionNames.RotateY;
                 }
-                else if (_x == 0f && _y == 0f && _z == 1f)
+                else if (_x is null && _y is null && _z is not null)
                 {
                     return FunctionNames.RotateY;
                 }
@@ -73,9 +73,9 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public ICssValue[] Arguments => new ICssValue[]
         {
-            new CssLengthValue(_x, CssLengthValue.Unit.None),
-            new CssLengthValue(_y, CssLengthValue.Unit.None),
-            new CssLengthValue(_z, CssLengthValue.Unit.None),
+            _x,
+            _y,
+            _z,
             _angle,
         };
 
@@ -101,17 +101,17 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets the value of the x-component of the rotation vector.
         /// </summary>
-        public Double X => _x;
+        public ICssValue X => _x;
 
         /// <summary>
         /// Gets the value of the y-component of the rotation vector.
         /// </summary>
-        public Double Y => _y;
+        public ICssValue Y => _y;
 
         /// <summary>
         /// Gets the value of the z-component of the rotation vector.
         /// </summary>
-        public Double Z => _z;
+        public ICssValue Z => _z;
 
         /// <summary>
         /// Gets the angle.
@@ -122,19 +122,34 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssRotateValue other)
+        {
+            return _angle.Equals(other._angle) && _x.Equals(other._x) && _y.Equals(other._y) && _z.Equals(other._z);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssRotateValue value && Equals(value);
+
         /// <summary>
         /// Computes the matrix for the given transformation.
         /// </summary>
         /// <returns>The transformation matrix representation.</returns>
         public TransformMatrix ComputeMatrix(IRenderDimensions renderDimensions)
         {
-            var norm = 1.0 / Math.Sqrt(_x * _x + _y * _y + _z * _z);
-            var alpha = _angle as Angle ? ?? Values.Angle.Zero;
-            var sina = Math.Sin(alpha.ToRadian());
-            var cosa = Math.Cos(alpha.ToRadian());
-            var l = _x * norm;
-            var m = _y * norm;
-            var n = _z * norm;
+            var x = _x.AsDouble();
+            var y = _x.AsDouble();
+            var z = _x.AsDouble();
+            var norm = 1.0 / Math.Sqrt(x * x + y * y + z * z);
+            var alpha = _angle.AsRad();
+            var sina = Math.Sin(alpha);
+            var cosa = Math.Cos(alpha);
+            var l = x * norm;
+            var m = y * norm;
+            var n = z * norm;
             var omc = (1.0 - cosa);
             return new TransformMatrix(
                 l * l * omc + cosa, m * l * omc - n * sina, n * l * omc + m * sina,
@@ -145,8 +160,11 @@ namespace AngleSharp.Css.Values
 
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
+            var x = _x?.Compute(context);
+            var y = _y?.Compute(context);
+            var z = _z?.Compute(context);
             var angle = _angle.Compute(context);
-            return new CssRotateValue(_x, _y, _z, angle);
+            return new CssRotateValue(x, y, z, angle);
         }
 
         #endregion

src/AngleSharp.Css/Values/Functions/CssRunningValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS running function call.
     /// </summary>
-    public sealed class CssRunningValue : ICssFunctionValue
+    public sealed class CssRunningValue : ICssFunctionValue, IEquatable<CssRunningValue>
     {
         #region Fields
 
@@ -54,10 +54,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssRunningValue other) => _ident.Equals(other._ident);
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssRunningValue value && Equals(value);
+
+        ICssValue ICssValue.Compute(ICssComputeContext context) => this;
 
         #endregion
     }

src/AngleSharp.Css/Values/Functions/CssScaleValue.cs

@@ -3,18 +3,17 @@ namespace AngleSharp.Css.Values
     using AngleSharp.Css.Dom;
     using AngleSharp.Text;
     using System;
-    using System.Globalization;
 
     /// <summary>
     /// Represents the scale3d transformation.
     /// </summary>
-    sealed class CssScaleValue : ICssTransformFunctionValue
+    sealed class CssScaleValue : ICssTransformFunctionValue, IEquatable<CssScaleValue>
     {
         #region Fields
 
-        private readonly Double _sx;
-        private readonly Double _sy;
-        private readonly Double _sz;
+        private readonly ICssValue _sx;
+        private readonly ICssValue _sy;
+        private readonly ICssValue _sz;
 
         #endregion
 
@@ -26,7 +25,7 @@ namespace AngleSharp.Css.Values
         /// <param name="sx">The x scaling factor.</param>
         /// <param name="sy">The y scaling factor.</param>
         /// <param name="sz">The z scaling factor.</param>
-        public CssScaleValue(Double sx, Double sy, Double sz)
+        public CssScaleValue(ICssValue sx, ICssValue sy, ICssValue sz)
         {
             _sx = sx;
             _sy = sy;
@@ -44,24 +43,26 @@ namespace AngleSharp.Css.Values
         {
             get
             {
-                if (_sz == 1f)
+                if (_sx is null && _sz is null)
+                {
+                    return FunctionNames.ScaleY;
+                }
+                else if (_sy is null && _sz is null)
+                {
+                    return FunctionNames.ScaleX;
+                }
+                else if (_sx is null && _sy is null)
+                {
+                    return FunctionNames.ScaleX;
+                }
+                else if (_sz is null)
                 {
-                    if (_sx != _sy)
-                    {
-                        if (_sx == 1f)
-                        {
-                            return FunctionNames.ScaleY;
-                        }
-                        else if (_sy == 1f)
-                        {
-                            return FunctionNames.ScaleX;
-                        }
-                    }
-
                     return FunctionNames.Scale;
                 }
-
-                return FunctionNames.Scale3d;
+                else
+                {
+                    return FunctionNames.Scale3d;
+                }
             }
         }
 
@@ -70,9 +71,9 @@ namespace AngleSharp.Css.Values
         /// </summary>
         public ICssValue[] Arguments => new ICssValue[]
         {
-            new CssLengthValue(_sx, CssLengthValue.Unit.None),
-            new CssLengthValue(_sy, CssLengthValue.Unit.None),
-            new CssLengthValue(_sz, CssLengthValue.Unit.None),
+            _sx,
+            _sy,
+            _sz,
         };
 
         /// <summary>
@@ -82,68 +83,84 @@ namespace AngleSharp.Css.Values
         {
             get
             {
-                var args = String.Empty;
-
-                if (_sz == 1.0)
+                if (_sx is null && _sz is null)
                 {
-                    if (_sx == _sy || _sy == 1.0)
-                    {
-                        args = _sx.ToString(CultureInfo.InvariantCulture);
-                    }
-                    else if (_sx == 1.0)
-                    {
-                        args = _sy.ToString(CultureInfo.InvariantCulture);
-                    }
-                    else
-                    {
-                        args = String.Concat(
-                            _sx.ToString(CultureInfo.InvariantCulture), ", ",
-                            _sy.ToString(CultureInfo.InvariantCulture));
-                    }
+                    return FunctionNames.ScaleY.CssFunction(_sy.CssText);
                 }
-                else if (_sx != _sy || _sx != _sz)
+                else if (_sy is null && _sz is null)
                 {
-                    args = String.Concat(
-                        _sx.ToString(CultureInfo.InvariantCulture), ", ",
-                        _sy.ToString(CultureInfo.InvariantCulture), ", ",
-                        _sz.ToString(CultureInfo.InvariantCulture));
+                    return FunctionNames.ScaleX.CssFunction(_sx.CssText);
+                }
+                else if (_sx is null && _sy is null)
+                {
+                    return FunctionNames.ScaleZ.CssFunction($"{_sz.CssText}");
+                }
+                else if (_sz is null && _sx.Equals(_sy))
+                {
+                    return FunctionNames.Scale.CssFunction(_sx.CssText);
+                }
+                else if (_sz is null)
+                {
+                    return FunctionNames.Scale.CssFunction($"{_sx.CssText}, {_sy.CssText}");
+                }
+                else
+                {
+                    return FunctionNames.Scale3d.CssFunction($"{_sx.CssText}, {_sy.CssText}, {_sz.CssText}");
                 }
-
-                return Name.CssFunction(args);
             }
         }
 
         /// <summary>
         /// Gets the scaling in x-direction.
         /// </summary>
-        public Double ScaleX => _sx;
+        public ICssValue ScaleX => _sx;
 
         /// <summary>
         /// Gets the scaling in y-direction.
         /// </summary>
-        public Double ScaleY => _sy;
+        public ICssValue ScaleY => _sy;
 
         /// <summary>
         /// Gets the scaling in z-direction.
         /// </summary>
-        public Double ScaleZ => _sz;
+        public ICssValue ScaleZ => _sz;
 
         #endregion
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssScaleValue other)
+        {
+            return _sx.Equals(other._sx) && _sy.Equals(other._sy) && _sz.Equals(other._sz);
+        }
+
         /// <summary>
         /// Computes the matrix for the given transformation.
         /// </summary>
         /// <returns>The transformation matrix representation.</returns>
-        public TransformMatrix ComputeMatrix(IRenderDimensions renderDimensions) =>
-            new(_sx, 0f, 0f, 0f, _sy, 0f, 0f, 0f, _sz, 0f, 0f, 0f, 0f, 0f, 0f);
+        public TransformMatrix ComputeMatrix(IRenderDimensions renderDimensions)
+        {
+            var sx = _sx?.AsDouble() ?? 1.0;
+            var sy = _sy?.AsDouble() ?? 1.0;
+            var sz = _sz?.AsDouble() ?? 1.0;
+            return new TransformMatrix(sx, 0f, 0f, 0f, sy, 0f, 0f, 0f, sz, 0f, 0f, 0f, 0f, 0f, 0f);
+        }
 
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
-            return new CssScaleValue(_sx, _sy, _sz);
+            var sx = _sx?.Compute(context);
+            var sy = _sy?.Compute(context);
+            var sz = _sz?.Compute(context);
+            return new CssScaleValue(sx, sy, sz);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssScaleValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Functions/CssShapeValue.cs

@@ -9,7 +9,7 @@ namespace AngleSharp.Css.Values
     /// Represents a CSS shape.
     /// https://developer.mozilla.org/en-US/docs/Web/CSS/shape
     /// </summary>
-    public sealed class CssShapeValue : ICssValue, ICssFunctionValue
+    public sealed class CssShapeValue : ICssValue, ICssFunctionValue, IEquatable<CssShapeValue>
     {
         #region Fields
 
@@ -86,6 +86,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssShapeValue other)
+        {
+            return _top.Equals(other._top) && _right.Equals(other._right) && _bottom.Equals(other._bottom) && _left.Equals(other._left);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssShapeValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             var top = _top.Compute(context);

src/AngleSharp.Css/Values/Functions/CssSkewValue.cs

@@ -7,7 +7,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents the skew transformation.
     /// </summary>
-    public sealed class CssSkewValue : ICssTransformFunctionValue
+    public sealed class CssSkewValue : ICssTransformFunctionValue, IEquatable<CssSkewValue>
     {
         #region Fields
 
@@ -100,14 +100,26 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssSkewValue other)
+        {
+            return _alpha.Equals(other._alpha) && _beta.Equals(other._beta);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssSkewValue value && Equals(value);
+
         /// <summary>
         /// Computes the matrix for the given transformation.
         /// </summary>
         /// <returns>The transformation matrix representation.</returns>
         public TransformMatrix ComputeMatrix(IRenderDimensions renderDimensions)
         {
-            var a = Math.Tan((_alpha as Angle ? ?? Angle.Zero).ToRadian());
-            var b = Math.Tan((_beta as Angle? ?? Angle.Zero).ToRadian());
+            var a = Math.Tan((_alpha as CssAngleValue ? ?? CssAngleValue.Zero).ToRadian());
+            var b = Math.Tan((_beta as CssAngleValue? ?? CssAngleValue.Zero).ToRadian());
             return new TransformMatrix(1.0, a, 0.0, b, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0);
         }
 

src/AngleSharp.Css/Values/Functions/CssStepsValue.cs

@@ -10,7 +10,7 @@ namespace AngleSharp.Css.Values
     /// Represents a steps timing-function object.
     /// https://developer.mozilla.org/en-US/docs/Web/CSS/timing-function
     /// </summary>
-    sealed class CssStepsValue : ICssTimingFunctionValue
+    sealed class CssStepsValue : ICssTimingFunctionValue, IEquatable<CssStepsValue>
     {
         #region Fields
 
@@ -101,6 +101,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssStepsValue other)
+        {
+            return _start == other._start && _intervals == other._intervals;
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssStepsValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             return this;

src/AngleSharp.Css/Values/Functions/CssSymbolsValue.cs

@@ -9,7 +9,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS symbols function call.
     /// </summary>
-    public sealed class CssSymbolsValue : ICssFunctionValue
+    public sealed class CssSymbolsValue : ICssFunctionValue, IEquatable<CssSymbolsValue>
     {
         #region Fields
 
@@ -59,6 +59,36 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssSymbolsValue other)
+        {
+            var l = _entries.Count;
+
+            if (_type.Equals(other._type) && l == other._entries.Count)
+            {
+                for (var i = 0; i < l; i++)
+                {
+                    var a = _entries[i];
+                    var b = other._entries[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssSymbolsValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             if (_type == null)

src/AngleSharp.Css/Values/Functions/CssTranslateValue.cs

@@ -8,7 +8,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents the translate3d transformation.
     /// </summary>
-    sealed class CssTranslateValue : ICssTransformFunctionValue
+    sealed class CssTranslateValue : ICssTransformFunctionValue, IEquatable<CssTranslateValue>
     {
         #region Fields
 
@@ -99,18 +99,27 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssTranslateValue other)
+        {
+            return _x.Equals(other._x) && _y.Equals(other._y) && _z.Equals(other._z);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssTranslateValue value && Equals(value);
+
         /// <summary>
         /// Computes the matrix for the given transformation.
         /// </summary>
         /// <returns>The transformation matrix representation.</returns>
         public TransformMatrix ComputeMatrix(IRenderDimensions renderDimensions)
         {
-            var x = _x as CssLengthValue? ?? CssLengthValue.Zero;
-            var y = _y as CssLengthValue? ?? CssLengthValue.Zero;
-            var z = _z as CssLengthValue? ?? CssLengthValue.Zero;
-            var dx = x.ToPixel(renderDimensions, RenderMode.Horizontal);
-            var dy = y.ToPixel(renderDimensions, RenderMode.Vertical);
-            var dz = z.ToPixel(renderDimensions, RenderMode.Undefined);
+            var dx = _x.AsPx(renderDimensions, RenderMode.Horizontal);
+            var dy = _y.AsPx(renderDimensions, RenderMode.Vertical);
+            var dz = _z.AsPx(renderDimensions, RenderMode.Undefined);
             return new TransformMatrix(1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, dx, dy, dz, 0.0, 0.0, 0.0);
         }
 

src/AngleSharp.Css/Values/Functions/CssUrlValue.cs

@@ -8,7 +8,7 @@ namespace AngleSharp.Css.Values
     /// Represents an URL object.
     /// https://developer.mozilla.org/en-US/docs/Web/CSS/uri
     /// </summary>
-    public sealed class CssUrlValue : ICssImageValue, ICssFunctionValue
+    public sealed class CssUrlValue : ICssImageValue, ICssFunctionValue, IEquatable<CssUrlValue>
     {
         #region Fields
 
@@ -55,6 +55,18 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssUrlValue other)
+        {
+            return _path.Equals(other._path);
+        }
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssUrlValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             return this;

src/AngleSharp.Css/Values/Functions/CssVarValue.cs

@@ -8,7 +8,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS var replacement.
     /// </summary>
-    public sealed class CssVarValue : ICssFunctionValue
+    public sealed class CssVarValue : ICssFunctionValue, IEquatable<CssVarValue>
     {
         #region Fields
 
@@ -96,6 +96,16 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssVarValue other)
+        {
+            return _defaultValue.Equals(other._defaultValue) && _variableName.Equals(other._variableName);
+        }
+
         /// <summary>
         /// Resolves the value of the referenced variable. Returns null
         /// if the reference is invalid or cannot be resolved.
@@ -114,6 +124,8 @@ namespace AngleSharp.Css.Values
             return _defaultValue?.Compute(context);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssVarValue value && Equals(value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/ICssGradientFunctionValue.cs

@@ -1,5 +1,6 @@
 namespace AngleSharp.Css.Values
 {
+    using AngleSharp.Css.Dom;
     using System;
 
     /// <summary>
@@ -10,7 +11,7 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Gets an enumeration of all stops.
         /// </summary>
-        CssGradientStopValue[] Stops { get; }
+        ICssValue[] Stops { get; }
 
         /// <summary>
         /// Gets if the gradient is repeating.

src/AngleSharp.Css/Values/Multiples/CssFlowRelativeValue.cs

@@ -10,7 +10,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a flow relative CSS value.
     /// </summary>
-    public class CssFlowRelativeValue<T> : ICssMultipleValue
+    public class CssFlowRelativeValue<T> : ICssMultipleValue, IEquatable<CssFlowRelativeValue<T>>
         where T : ICssValue
     {
         #region Fields
@@ -84,6 +84,34 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssFlowRelativeValue<T> other)
+        {
+            var count = _values.Length;
+
+            if (count == other._values.Length)
+            {
+                for (var i = 0; i < count; i++)
+                {
+                    var a = _values[i];
+                    var b = other._values[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
         IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator()
         {
             yield return Start;
@@ -98,6 +126,8 @@ namespace AngleSharp.Css.Values
             return new CssFlowRelativeValue<T>(values);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssFlowRelativeValue<T> value && Equals(value);
+
         #endregion
     }
 

src/AngleSharp.Css/Values/Multiples/CssListValue.cs

@@ -10,7 +10,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a CSS value list.
     /// </summary>
-    public class CssListValue<T> : ICssMultipleValue
+    public class CssListValue<T> : ICssMultipleValue, IEquatable<CssListValue<T>>
         where T : ICssValue
     {
         #region Fields
@@ -50,6 +50,34 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssListValue<T> other)
+        {
+            var count = _items.Length;
+
+            if (count == other._items.Length)
+            {
+                for (var i = 0; i < count; i++)
+                {
+                    var a = _items[i];
+                    var b = other._items[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
         IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator() =>
             _items.OfType<ICssValue>().GetEnumerator();
 
@@ -61,6 +89,8 @@ namespace AngleSharp.Css.Values
             return new CssListValue<T>(items);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssListValue<T> value && Equals(value);
+
         #endregion
     }
 

src/AngleSharp.Css/Values/Multiples/CssPeriodicValue.cs

@@ -10,7 +10,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a periodic CSS value.
     /// </summary>
-    public class CssPeriodicValue<T> : ICssMultipleValue
+    public class CssPeriodicValue<T> : ICssMultipleValue, IEquatable<CssPeriodicValue<T>>
         where T : ICssValue
     {
         #region Fields
@@ -104,6 +104,34 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssPeriodicValue<T> other)
+        {
+            var count = _values.Length;
+
+            if (count == other._values.Length)
+            {
+                for (var i = 0; i < count; i++)
+                {
+                    var a = _values[i];
+                    var b = other._values[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
         IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator()
         {
             yield return Top;
@@ -120,6 +148,8 @@ namespace AngleSharp.Css.Values
             return new CssPeriodicValue<T>(values);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssPeriodicValue<T> value && Equals(value);
+
         #endregion
     }
 

src/AngleSharp.Css/Values/Multiples/CssRadiusValue.cs

@@ -10,7 +10,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a periodic CSS value.
     /// </summary>
-    public class CssRadiusValue<T> : ICssMultipleValue
+    public class CssRadiusValue<T> : ICssMultipleValue, IEquatable<CssRadiusValue<T>>
         where T : ICssValue
     {
         #region Fields
@@ -84,6 +84,34 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssRadiusValue<T> other)
+        {
+            var count = _values.Length;
+
+            if (count == other._values.Length)
+            {
+                for (var i = 0; i < count; i++)
+                {
+                    var a = _values[i];
+                    var b = other._values[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
         IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator()
         {
             yield return Width;
@@ -98,6 +126,8 @@ namespace AngleSharp.Css.Values
             return new CssRadiusValue<T>(values);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssRadiusValue<T> value && Equals(value);
+
         #endregion
     }
 

src/AngleSharp.Css/Values/Multiples/CssTupleValue.cs

@@ -10,7 +10,7 @@ namespace AngleSharp.Css.Values
     /// <summary>
     /// Represents a tuple of CSS values.
     /// </summary>
-    public class CssTupleValue<T> : ICssMultipleValue
+    public class CssTupleValue<T> : ICssMultipleValue, IEquatable<CssTupleValue<T>>
         where T : ICssValue
     {
         #region Fields
@@ -58,6 +58,34 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
+        /// <summary>
+        /// Checks if the current value is equal to the provided one.
+        /// </summary>
+        /// <param name="other">The value to check against.</param>
+        /// <returns>True if both are equal, otherwise false.</returns>
+        public Boolean Equals(CssTupleValue<T> other)
+        {
+            var count = _items.Length;
+
+            if (_separator.Equals(other._separator) && count == other._items.Length)
+            {
+                for (var i = 0; i < count; i++)
+                {
+                    var a = _items[i];
+                    var b = other._items[i];
+
+                    if (!a.Equals(b))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            return false;
+        }
+
         IEnumerator<ICssValue> IEnumerable<ICssValue>.GetEnumerator() =>
             _items.OfType<ICssValue>().GetEnumerator();
 
@@ -69,6 +97,8 @@ namespace AngleSharp.Css.Values
             return new CssTupleValue<T>(items, _separator);
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssTupleValue<T> value && Equals(value);
+
         #endregion
     }
 

src/AngleSharp.Css/Values/Primitives/CssAngleValue.cs

@@ -7,34 +7,34 @@ namespace AngleSharp.Css.Values
     /// Represents an angle object.
     /// https://developer.mozilla.org/en-US/docs/Web/CSS/angle
     /// </summary>
-    public readonly struct Angle : IEquatable<Angle>, IComparable<Angle>, ICssMetricValue
+    public readonly struct CssAngleValue : IEquatable<CssAngleValue>, IComparable<CssAngleValue>, ICssMetricValue
     {
         #region Basic angles
 
         /// <summary>
         /// The zero angle.
         /// </summary>
-        public static readonly Angle Zero = new(0.0, Angle.Unit.Rad);
+        public static readonly CssAngleValue Zero = new(0.0, CssAngleValue.Unit.Rad);
 
         /// <summary>
         /// The 45° angle.
         /// </summary>
-        public static readonly Angle HalfQuarter = new(45.0, Angle.Unit.Deg);
+        public static readonly CssAngleValue HalfQuarter = new(45.0, CssAngleValue.Unit.Deg);
 
         /// <summary>
         /// The 90° angle.
         /// </summary>
-        public static readonly Angle Quarter = new(90.0, Angle.Unit.Deg);
+        public static readonly CssAngleValue Quarter = new(90.0, CssAngleValue.Unit.Deg);
 
         /// <summary>
         /// The 135° angle.
         /// </summary>
-        public static readonly Angle TripleHalfQuarter = new(135.0, Angle.Unit.Deg);
+        public static readonly CssAngleValue TripleHalfQuarter = new(135.0, CssAngleValue.Unit.Deg);
 
         /// <summary>
         /// The 180° angle.
         /// </summary>
-        public static readonly Angle Half = new(180.0, Angle.Unit.Deg);
+        public static readonly CssAngleValue Half = new(180.0, CssAngleValue.Unit.Deg);
 
         #endregion
 
@@ -51,7 +51,7 @@ namespace AngleSharp.Css.Values
         /// Creates a new angle value.
         /// </summary>
         /// <param name="value">The value of the angle in rad.</param>
-        public Angle(Double value)
+        public CssAngleValue(Double value)
             : this(value, Unit.Rad)
         {
         }
@@ -61,7 +61,7 @@ namespace AngleSharp.Css.Values
         /// </summary>
         /// <param name="value">The value of the angle.</param>
         /// <param name="unit">The unit of the angle.</param>
-        public Angle(Double value, Unit unit)
+        public CssAngleValue(Double value, Unit unit)
         {
             _value = value;
             _unit = unit;
@@ -111,7 +111,7 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Compares the magnitude of two angles.
         /// </summary>
-        public static Boolean operator >=(Angle a, Angle b)
+        public static Boolean operator >=(CssAngleValue a, CssAngleValue b)
         {
             var result = a.CompareTo(b);
             return result == 0 || result == 1;
@@ -120,12 +120,12 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Compares the magnitude of two angles.
         /// </summary>
-        public static Boolean operator >(Angle a, Angle b) => a.CompareTo(b) == 1;
+        public static Boolean operator >(CssAngleValue a, CssAngleValue b) => a.CompareTo(b) == 1;
 
         /// <summary>
         /// Compares the magnitude of two angles.
         /// </summary>
-        public static Boolean operator <=(Angle a, Angle b)
+        public static Boolean operator <=(CssAngleValue a, CssAngleValue b)
         {
             var result = a.CompareTo(b);
             return result == 0 || result == -1;
@@ -134,14 +134,14 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Compares the magnitude of two angles.
         /// </summary>
-        public static Boolean operator <(Angle a, Angle b) => a.CompareTo(b) == -1;
+        public static Boolean operator <(CssAngleValue a, CssAngleValue b) => 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 Int32 CompareTo(Angle other) => ToRadian().CompareTo(other.ToRadian());
+        public Int32 CompareTo(CssAngleValue other) => ToRadian().CompareTo(other.ToRadian());
 
         #endregion
 
@@ -152,7 +152,7 @@ namespace AngleSharp.Css.Values
             if (_unit != Unit.Rad)
             {
                 var rad = ToRadian();
-                return new Angle(rad, Unit.Rad);
+                return new CssAngleValue(rad, Unit.Rad);
             }
 
             return this;
@@ -164,13 +164,13 @@ namespace AngleSharp.Css.Values
         /// <param name="s">The string to convert.</param>
         /// <param name="result">The reference to the result.</param>
         /// <returns>True if successful, otherwise false.</returns>
-        public static Boolean TryParse(String s, out Angle result)
+        public static Boolean TryParse(String s, out CssAngleValue result)
         {
             var unit = GetUnit(s.CssUnit(out double value));
 
             if (unit != Unit.None)
             {
-                result = new Angle(value, unit);
+                result = new CssAngleValue(value, unit);
                 return true;
             }
 
@@ -225,12 +225,27 @@ namespace AngleSharp.Css.Values
             };
         }
 
+        /// <summary>
+        /// Converts the contained value to degree.
+        /// </summary>
+        /// <returns>The value in degree.</returns>
+        public Double ToDegree()
+        {
+            return _unit switch
+            {
+                Unit.Turn => _value * 360.0,
+                Unit.Grad => _value * (360.0 / 400.0),
+                Unit.Rad => _value / (180.0 / Math.PI),
+                _ => _value,
+            };
+        }
+
         /// <summary>
         /// Checks for equality with the other angle.
         /// </summary>
         /// <param name="other">The angle to compare with.</param>
         /// <returns>True if both represent the same angle in rad.</returns>
-        public Boolean Equals(Angle other) => ToRadian() == other.ToRadian();
+        public Boolean Equals(CssAngleValue other) => ToRadian() == other.ToRadian();
 
         #endregion
 
@@ -270,12 +285,12 @@ namespace AngleSharp.Css.Values
         /// <summary>
         /// Checks for equality of two angles.
         /// </summary>
-        public static Boolean operator ==(Angle a, Angle b) => a.Equals(b);
+        public static Boolean operator ==(CssAngleValue a, CssAngleValue b) => a.Equals(b);
 
         /// <summary>
         /// Checks for inequality of two angles.
         /// </summary>
-        public static Boolean operator !=(Angle a, Angle b) => !a.Equals(b);
+        public static Boolean operator !=(CssAngleValue a, CssAngleValue b) => !a.Equals(b);
 
         /// <summary>
         /// Tests if another object is equal to this object.
@@ -284,7 +299,7 @@ namespace AngleSharp.Css.Values
         /// <returns>True if the two objects are equal, otherwise false.</returns>
         public override Boolean Equals(Object obj)
         {
-            var other = obj as Angle?;
+            var other = obj as CssAngleValue?;
 
             if (other != null)
             {
@@ -294,6 +309,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssAngleValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current angle.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssColorValue.cs

@@ -585,6 +585,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssColorValue value && Equals(value);
+
         Int32 IComparable<CssColorValue>.CompareTo(CssColorValue other) => _hashcode - other._hashcode;
 
         /// <summary>

src/AngleSharp.Css/Values/Primitives/CssConstantValue.cs

@@ -62,6 +62,8 @@ namespace AngleSharp.Css.Values
         public override Boolean Equals(Object obj) =>
             obj is CssConstantValue<T> constant && Equals(constant);
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssConstantValue<T> value && Equals(value);
+
         /// <summary>
         /// Gets the computed hash code of the constant.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssCounterDefinitionValue.cs

@@ -72,6 +72,8 @@ namespace AngleSharp.Css.Values
             ListStyle.Is(other.ListStyle) &&
             DefinedSeparator.Is(other.DefinedSeparator);
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssCounterDefinitionValue value && Equals(value);
+
         /// <summary>
         /// Checks for equality against the given object, if
         /// the provided object is no counter definition the

src/AngleSharp.Css/Values/Primitives/CssCounterValue.cs

@@ -59,6 +59,8 @@ namespace AngleSharp.Css.Values
         /// <returns>True if both are equal, otherwise false.</returns>
         public Boolean Equals(CssCounterValue other) => Name.Is(other.Name) && Value == other.Value;
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssCounterValue value && Equals(value);
+
         /// <summary>
         /// Checks for equality against the given object,
         /// if the provided object is no counter value the

src/AngleSharp.Css/Values/Primitives/CssFractionValue.cs

@@ -175,6 +175,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssFractionValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current fraction.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssFrequencyValue.cs

@@ -228,6 +228,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssFrequencyValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current frequency.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssIdentifierValue.cs

@@ -61,6 +61,8 @@ namespace AngleSharp.Css.Values
         public override Boolean Equals(Object obj) =>
             obj is CssIdentifierValue ident && Equals(ident);
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssIdentifierValue value && Equals(value);
+
         /// <summary>
         /// Gets the hash code of the object.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssIntegerValue.cs

@@ -120,6 +120,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssIntegerValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current integer.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssLengthValue.cs

@@ -547,6 +547,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssLengthValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current length.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssLineNamesValue.cs

@@ -71,6 +71,8 @@ namespace AngleSharp.Css.Values
         /// <returns>The computed hash code.</returns>
         public override Int32 GetHashCode() => CssText.GetHashCode();
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssLineNamesValue value && Equals(value);
+
         ICssValue ICssValue.Compute(ICssComputeContext context)
         {
             return this;

src/AngleSharp.Css/Values/Primitives/CssNumberValue.cs

@@ -8,6 +8,20 @@ namespace AngleSharp.Css.Values
     /// </summary>
     public readonly struct CssNumberValue : IEquatable<CssNumberValue>, IComparable<CssNumberValue>, ICssMetricValue
     {
+        #region Basic lengths
+
+        /// <summary>
+        /// Gets the 0.0.
+        /// </summary>
+        public static readonly CssNumberValue Zero = new(0.0);
+
+        /// <summary>
+        /// Gets the 1.0.
+        /// </summary>
+        public static readonly CssNumberValue One = new(0.0);
+
+        #endregion
+
         #region Fields
 
         private readonly Double _value;
@@ -105,6 +119,7 @@ namespace AngleSharp.Css.Values
 
             return false;
         }
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssNumberValue value && Equals(value);
 
         /// <summary>
         /// Returns a hash code that defines the current number.

src/AngleSharp.Css/Values/Primitives/CssPercentageValue.cs

@@ -8,6 +8,25 @@ namespace AngleSharp.Css.Values
     /// </summary>
     public readonly struct CssPercentageValue : IEquatable<CssPercentageValue>, IComparable<CssPercentageValue>, ICssMetricValue
     {
+        #region Basic percentages
+
+        /// <summary>
+        /// Gets a zero percentage value.
+        /// </summary>
+        public static readonly CssPercentageValue Zero = new(0.0);
+
+        /// <summary>
+        /// Gets the half relative length, i.e. 50%.
+        /// </summary>
+        public static readonly CssPercentageValue Half = new(50.0);
+
+        /// <summary>
+        /// Gets the full relative length, i.e. 100%.
+        /// </summary>
+        public static readonly CssPercentageValue Full = new(100.0);
+
+        #endregion
+
         #region Fields
 
         private readonly Double _value;
@@ -175,6 +194,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssPercentageValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current percentage.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssQuoteValue.cs

@@ -73,6 +73,7 @@ namespace AngleSharp.Css.Values
         /// <returns>True if both are equal, otherwise false.</returns>
         public override Boolean Equals(Object obj) =>
             obj is CssQuoteValue quote && Equals(quote);
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssQuoteValue value && Equals(value);
 
         /// <summary>
         /// Gets the hash code of the object.

src/AngleSharp.Css/Values/Primitives/CssRatioValue.cs

@@ -1,107 +0,0 @@
-namespace AngleSharp.Css.Values
-{
-    using AngleSharp.Css.Dom;
-    using System;
-
-    /// <summary>
-    /// Represents a ratio (top to bottom) value.
-    /// </summary>
-    public readonly struct CssRatioValue : IEquatable<CssRatioValue>, IComparable<CssRatioValue>, ICssPrimitiveValue
-    {
-        #region Fields
-
-        private readonly Double _top;
-        private readonly Double _bottom;
-
-        #endregion
-
-        #region ctor
-
-        /// <summary>
-        /// Creates a new ratio value.
-        /// </summary>
-        /// <param name="top">The first number.</param>
-        /// <param name="bottom">The second number.</param>
-        public CssRatioValue(Double top, Double bottom)
-        {
-            _top = top;
-            _bottom = bottom;
-        }
-
-        #endregion
-
-        #region Properties
-
-        /// <summary>
-        /// Gets the CSS text representation.
-        /// </summary>
-        public String CssText => String.Concat(_top.CssStringify(), "/", _bottom.CssStringify());
-
-        /// <summary>
-        /// Gets the first number of the ratio.
-        /// </summary>
-        public Double Top => _top;
-
-        /// <summary>
-        /// Gets the second number of the ratio.
-        /// </summary>
-        public Double Bottom => _bottom;
-
-        /// <summary>
-        /// Gets the normalized (Top / Bottom) value.
-        /// </summary>
-        public Double Value => _top / _bottom;
-
-        #endregion
-
-        #region Methods
-
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
-
-        /// <summary>
-        /// Checks if the current resolution equals the given one.
-        /// </summary>
-        /// <param name="other">The given resolution to check for equality.</param>
-        /// <returns>True if both are equal, otherwise false.</returns>
-        public Boolean Equals(CssRatioValue other) => Value == other.Value;
-
-        #endregion
-
-        #region Equality
-
-        /// <summary>
-        /// Compares the current fraction against the given one.
-        /// </summary>
-        /// <param name="other">The fraction to compare to.</param>
-        /// <returns>The result of the comparison.</returns>
-        public Int32 CompareTo(CssRatioValue other) => Value.CompareTo(other.Value);
-
-        /// <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 Boolean Equals(Object obj)
-        {
-            var other = obj as CssRatioValue?;
-
-            if (other != null)
-            {
-                return Equals(other.Value);
-            }
-
-            return false;
-        }
-
-        /// <summary>
-        /// Returns a hash code that defines the current fraction.
-        /// </summary>
-        /// <returns>The integer value of the hashcode.</returns>
-        public override Int32 GetHashCode() => Value.GetHashCode();
-
-        #endregion
-    }
-}

src/AngleSharp.Css/Values/Primitives/CssResolutionValue.cs

@@ -225,6 +225,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssResolutionValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current resolution.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssStringValue.cs

@@ -66,6 +66,8 @@ namespace AngleSharp.Css.Values
         public override Boolean Equals(Object obj) =>
             obj is CssStringValue str && Equals(str);
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssStringValue value && Equals(value);
+
         /// <summary>
         /// Gets the hash code of the object.
         /// </summary>

src/AngleSharp.Css/Values/Primitives/CssTimeValue.cs

@@ -237,6 +237,8 @@ namespace AngleSharp.Css.Values
             return false;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssTimeValue value && Equals(value);
+
         /// <summary>
         /// Returns a hash code that defines the current time.
         /// </summary>

src/AngleSharp.Css/Values/Raws/CssAnyValue.cs

@@ -57,6 +57,8 @@ namespace AngleSharp.Css.Values
             return null;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssAnyValue o && _text.Equals(o.CssText);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Raws/CssInheritValue.cs

@@ -37,10 +37,9 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
+        ICssValue ICssValue.Compute(ICssComputeContext context) => this;
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
 
         #endregion
     }

src/AngleSharp.Css/Values/Raws/CssInitialValue.cs

@@ -43,10 +43,9 @@ namespace AngleSharp.Css.Values
 
         #region Methods
 
-        ICssValue ICssValue.Compute(ICssComputeContext context)
-        {
-            return this;
-        }
+        ICssValue ICssValue.Compute(ICssComputeContext context) => this;
+
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssInitialValue o && _value.Equals(o.Value);
 
         #endregion
     }

src/AngleSharp.Css/Values/Raws/CssReferenceValue.cs

@@ -76,6 +76,8 @@ namespace AngleSharp.Css.Values
             return null;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => Object.ReferenceEquals(this, other);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/Raws/CssUnsetValue.cs

@@ -48,6 +48,8 @@ namespace AngleSharp.Css.Values
             return this;
         }
 
+        Boolean IEquatable<ICssValue>.Equals(ICssValue other) => other is CssUnsetValue o && _value.Equals(o.Value);
+
         #endregion
     }
 }

src/AngleSharp.Css/Values/TransformMatrix.cs

@@ -6,7 +6,7 @@ namespace AngleSharp.Css.Values
     /// Represents a transformation matrix value.
     /// http://dev.w3.org/csswg/css-transforms/#mathematical-description
     /// </summary>
-    public class TransformMatrix : IEquatable<TransformMatrix>
+    public sealed class TransformMatrix : IEquatable<TransformMatrix>
     {
         #region Fields