From a6c3546ef893479225961b1576dfd71cff3a9c15 Mon Sep 17 00:00:00 2001
From: Olivier Nizet <onizet@hotmail.com>
Date: Wed, 26 Nov 2025 23:53:40 +0100
Subject: [PATCH 1/3] Further optimisation to generalise the usage of
 ReadOnlySpan and short-cicruit in complex GetStyle attributes.

---
 .../Collections/HtmlAttributeCollection.cs    | 30 ++++++++++++++++--
 .../Expressions/BlockElementExpression.cs     |  8 ++---
 .../Expressions/BodyExpression.cs             |  7 +++--
 .../Expressions/Numbering/ListExpression.cs   |  8 ++---
 .../Table/TableCaptionExpression.cs           |  5 +--
 .../Expressions/Table/TableCellExpression.cs  | 31 +++++++++----------
 .../Expressions/Table/TableColExpression.cs   |  2 +-
 .../Table/TableElementExpressionBase.cs       |  2 +-
 .../Expressions/Table/TableRowExpression.cs   |  2 +-
 .../Primitives/HtmlColor.Named.cs             |  1 -
 .../Utilities/AngleSharpExtensions.cs         |  8 +++--
 src/Html2OpenXml/Utilities/Converter.cs       | 24 ++++++--------
 .../Primitives/StyleParserTests.cs            | 13 ++++----
 test/HtmlToOpenXml.Tests/StyleTests.cs        | 10 +++---
 14 files changed, 86 insertions(+), 65 deletions(-)

diff --git a/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs b/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs
index 1ea4cc03..0f0aacb0 100755
--- a/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs
+++ b/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs
@@ -107,16 +107,34 @@ public static HtmlAttributeCollection ParseStyle(string? htmlStyles)
     /// <summary>
     /// Gets the named attribute.
     /// </summary>
-    public string? this[string name]
+    public ReadOnlySpan<char> this[string name]
     {
         get 
         {
             if (attributes.TryGetValue(name, out var range))
-                return rawValue.AsSpan().Slice(range).ToString().Trim();
-            return null;
+                return rawValue.AsSpan().Slice(range).Trim();
+            return [];
         }
     }
 
+    /// <summary>
+    /// Determines whether the collection contains the specified key.
+    /// </summary>
+    public bool ContainsKey(string name)
+    {
+        return attributes.ContainsKey(name);
+    }
+
+    /// <summary>
+    /// Efficient way to determine if a style is equals to a value.
+    /// </summary>
+    public bool HasKeyEqualsTo(string name, ReadOnlySpan<char> value)
+    {
+        if (attributes.TryGetValue(name, out var range))
+            return rawValue.AsSpan().Slice(range).Trim().Equals(value, StringComparison.InvariantCultureIgnoreCase);
+        return false;
+    }
+
     /// <summary>
     /// Gets an attribute representing a color (named color, hexadecimal or hexadecimal 
     /// without the preceding # character).
@@ -147,6 +165,8 @@ public Unit GetUnit(string name, UnitMetric defaultMetric = UnitMetric.Unitless)
     public Margin GetMargin(string name)
     {
         Margin margin = Margin.Empty;
+        if (IsEmpty) return margin;
+
         if (attributes.TryGetValue(name, out var range))
             margin = Margin.Parse(rawValue.AsSpan().Slice(range));
 
@@ -194,6 +214,8 @@ public HtmlBorder GetBorders()
     public SideBorder GetSideBorder(string name)
     {
         SideBorder border = SideBorder.Empty;
+        if (IsEmpty) return border;
+
         if (attributes.TryGetValue(name, out Range range))
             border = SideBorder.Parse(rawValue.AsSpan().Slice(range));
 
@@ -224,6 +246,8 @@ public SideBorder GetSideBorder(string name)
     public HtmlFont GetFont(string name)
     {
         HtmlFont font = HtmlFont.Empty;
+        if (IsEmpty) return font;
+
         if (attributes.TryGetValue(name, out Range range))
             font = HtmlFont.Parse(rawValue.AsSpan().Slice(range));
 
diff --git a/src/Html2OpenXml/Expressions/BlockElementExpression.cs b/src/Html2OpenXml/Expressions/BlockElementExpression.cs
index bf5de423..54eb692c 100644
--- a/src/Html2OpenXml/Expressions/BlockElementExpression.cs
+++ b/src/Html2OpenXml/Expressions/BlockElementExpression.cs
@@ -90,7 +90,7 @@ protected override IEnumerable<OpenXmlElement> Interpret (
     {
         return ComposeChildren(context, childNodes, paraProperties,
             (runs) => {
-                if ("always".Equals(styleAttributes!["page-break-before"], StringComparison.OrdinalIgnoreCase))
+                if (styleAttributes.HasKeyEqualsTo("page-break-before", "always"))
                 {
                     runs.Add(
                         new Run(
@@ -102,7 +102,7 @@ protected override IEnumerable<OpenXmlElement> Interpret (
                 }
             },
             (runs) => {
-                if ("always".Equals(styleAttributes!["page-break-after"], StringComparison.OrdinalIgnoreCase))
+                if (styleAttributes.HasKeyEqualsTo("page-break-after", "always"))
                 {
                     runs.Add(new Run(
                         new Break() { Type = BreakValues.Page }));
@@ -186,7 +186,7 @@ protected override void ComposeStyles (ParsingContext context)
             };
         }
 
-        JustificationValues? align = Converter.ToParagraphAlign(styleAttributes!["text-align"]);
+        JustificationValues? align = Converter.ToParagraphAlign(styleAttributes["text-align"]);
         if (!align.HasValue) align = Converter.ToParagraphAlign(node.GetAttribute("align"));
         if (!align.HasValue) align = Converter.ToParagraphAlign(styleAttributes["justify-content"]);
         if (align.HasValue)
@@ -256,7 +256,7 @@ protected override void ComposeStyles (ParsingContext context)
 
         var lineHeight = styleAttributes.GetUnit("line-height");
         if (!lineHeight.IsValid 
-            && "normal".Equals(styleAttributes["line-height"], StringComparison.OrdinalIgnoreCase))
+            && styleAttributes.HasKeyEqualsTo("line-height", "normal"))
         {
             // if `normal` is specified, reset any values
             lineHeight = new Unit(UnitMetric.Unitless, 1);
diff --git a/src/Html2OpenXml/Expressions/BodyExpression.cs b/src/Html2OpenXml/Expressions/BodyExpression.cs
index 462d375d..9b86a3a4 100644
--- a/src/Html2OpenXml/Expressions/BodyExpression.cs
+++ b/src/Html2OpenXml/Expressions/BodyExpression.cs
@@ -69,10 +69,11 @@ protected override void ComposeStyles(ParsingContext context)
 
         // Unsupported W3C attribute but claimed by users. Specified at <body> level, the page
         // orientation is applied on the whole document
-        string? attr = styleAttributes!["page-orientation"];
-        if (attr != null)
+        if (styleAttributes.ContainsKey("page-orientation"))
         {
-            PageOrientationValues orientation = Converter.ToPageOrientation(attr);
+            PageOrientationValues orientation = PageOrientationValues.Portrait;
+            if (styleAttributes.HasKeyEqualsTo("page-orientation", "landscape"))
+                orientation = PageOrientationValues.Landscape;
 
             var sectionProperties = mainPart.Document.Body!.GetFirstChild<SectionProperties>();
             if (sectionProperties == null || sectionProperties.GetFirstChild<PageSize>() == null)
diff --git a/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs b/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs
index 2d071b43..a2a14798 100644
--- a/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs
+++ b/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs
@@ -214,14 +214,14 @@ private static string GetListName(IElement listNode, string? parentName = null)
     {
         var styleAttributes = listNode.GetStyles();
         bool orderedList = listNode.NodeName.Equals("ol", StringComparison.OrdinalIgnoreCase);
-        string? type = styleAttributes["list-style-type"];
+        var type = styleAttributes["list-style-type"];
 
-        if(orderedList && string.IsNullOrEmpty(type))
+        if(orderedList && type.IsEmpty)
         {
             type = ListTypeToListStyleType(listNode.GetAttribute("type"));
         }
 
-        if (string.IsNullOrEmpty(type) || !supportedListTypes.Contains(type!))
+        if (type.IsEmpty || !supportedListTypes.Contains(type.ToString()))
         {
             if (parentName != null && IsCascadingStyle(parentName))
                 return parentName!;
@@ -229,7 +229,7 @@ private static string GetListName(IElement listNode, string? parentName = null)
             type = orderedList? "decimal" : "disc";
         }
 
-        return type!;
+        return type.ToString();
     }
 
     /// <summary>
diff --git a/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs b/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs
index 8a05e34e..2c7e3346 100644
--- a/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs
@@ -54,8 +54,9 @@ public override IEnumerable<OpenXmlElement> Interpret (ParsingContext context)
         }
         p.Append(childElements);
 
-        string? att = styleAttributes!["text-align"] ?? node.GetAttribute("align");
-        if (!string.IsNullOrEmpty(att))
+        var att = styleAttributes["text-align"];
+        if (att.IsEmpty) att = node.GetAttribute("align");
+        if (!att.IsEmpty)
         {
             JustificationValues? align = Converter.ToParagraphAlign(att);
             if (align.HasValue)
diff --git a/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs b/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs
index 6a4f94cb..0cf036ec 100644
--- a/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs
@@ -62,7 +62,7 @@ protected override void ComposeStyles(ParsingContext context)
     {
         base.ComposeStyles(context);
 
-        Unit width = styleAttributes!.GetUnit("width");
+        Unit width = styleAttributes.GetUnit("width");
         if (!width.IsValid)
         {
             var widthValue = cellNode.GetAttribute("width");
@@ -84,23 +84,22 @@ protected override void ComposeStyles(ParsingContext context)
         }
 
         // Manage vertical text (only for table cell)
-        string? direction = styleAttributes!["writing-mode"];
-        if (direction != null)
+        var direction = styleAttributes["writing-mode"];
+        if (!direction.IsEmpty)
         {
-            switch (direction)
+            if (direction.Equals("tb-lr", StringComparison.InvariantCultureIgnoreCase) ||
+                direction.Equals("vertical-lr", StringComparison.InvariantCultureIgnoreCase))
             {
-                case "tb-lr":
-                case "vertical-lr":
-                    cellProperties.TextDirection = new() { Val = TextDirectionValues.BottomToTopLeftToRight };
-                    cellProperties.TableCellVerticalAlignment = new() { Val = TableVerticalAlignmentValues.Center };
-                    paraProperties.Justification = new() { Val = JustificationValues.Center };
-                    break;
-                case "tb-rl":
-                case "vertical-rl":
-                    cellProperties.TextDirection = new() { Val = TextDirectionValues.TopToBottomRightToLeft };
-                    cellProperties.TableCellVerticalAlignment = new() { Val = TableVerticalAlignmentValues.Center };
-                    paraProperties.Justification = new() { Val = JustificationValues.Center };
-                    break;
+                cellProperties.TextDirection = new() { Val = TextDirectionValues.BottomToTopLeftToRight };
+                cellProperties.TableCellVerticalAlignment = new() { Val = TableVerticalAlignmentValues.Center };
+                paraProperties.Justification = new() { Val = JustificationValues.Center };
+            }
+            else if (direction.Equals("tb-rl", StringComparison.InvariantCultureIgnoreCase) ||
+                direction.Equals("vertical-rl", StringComparison.InvariantCultureIgnoreCase))
+            {
+                cellProperties.TextDirection = new() { Val = TextDirectionValues.TopToBottomRightToLeft };
+                cellProperties.TableCellVerticalAlignment = new() { Val = TableVerticalAlignmentValues.Center };
+                paraProperties.Justification = new() { Val = JustificationValues.Center };
             }
         }
     }
diff --git a/src/Html2OpenXml/Expressions/Table/TableColExpression.cs b/src/Html2OpenXml/Expressions/Table/TableColExpression.cs
index c51269de..6edf0d1b 100644
--- a/src/Html2OpenXml/Expressions/Table/TableColExpression.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableColExpression.cs
@@ -35,7 +35,7 @@ public override IEnumerable<OpenXmlElement> Interpret(ParsingContext context)
         ComposeStyles(context);
 
         var column = new GridColumn();
-        var width = styleAttributes!.GetUnit("width");
+        var width = styleAttributes.GetUnit("width");
         if (width.IsValid)
         {
             if (width.IsFixed)
diff --git a/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs b/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs
index 27bef6f4..a90e8382 100644
--- a/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs
@@ -71,7 +71,7 @@ protected override void ComposeStyles(ParsingContext context)
     {
         base.ComposeStyles(context);
 
-        var valign = Converter.ToVAlign(styleAttributes!["vertical-align"]);
+        var valign = Converter.ToVAlign(styleAttributes["vertical-align"]);
         if (!valign.HasValue) valign = Converter.ToVAlign(node.GetAttribute("valign"));
         if (!valign.HasValue)
         {
diff --git a/src/Html2OpenXml/Expressions/Table/TableRowExpression.cs b/src/Html2OpenXml/Expressions/Table/TableRowExpression.cs
index 25c7ce1d..8b1223b9 100644
--- a/src/Html2OpenXml/Expressions/Table/TableRowExpression.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableRowExpression.cs
@@ -101,7 +101,7 @@ protected override void ComposeStyles(ParsingContext context)
     {
         base.ComposeStyles(context);
 
-        Unit unit = styleAttributes!.GetUnit("height", UnitMetric.Pixel);
+        Unit unit = styleAttributes.GetUnit("height", UnitMetric.Pixel);
         if (!unit.IsValid) unit = Unit.Parse(rowNode.GetAttribute("height").AsSpan(), UnitMetric.Pixel);
 
         switch (unit.Metric)
diff --git a/src/Html2OpenXml/Primitives/HtmlColor.Named.cs b/src/Html2OpenXml/Primitives/HtmlColor.Named.cs
index b8301893..400463db 100755
--- a/src/Html2OpenXml/Primitives/HtmlColor.Named.cs
+++ b/src/Html2OpenXml/Primitives/HtmlColor.Named.cs
@@ -15,7 +15,6 @@ private static HtmlColor GetNamedColor (ReadOnlySpan<char> name)
     {
         // the longest built-in Color's name is much lower than this check, so we should not allocate here in a typical usage
         Span<char> loweredValue = name.Length <= 128 ? stackalloc char[name.Length] : new char[name.Length];
-
         name.ToLowerInvariant(loweredValue);
 
         namedColors.TryGetValue(loweredValue.ToString(), out var color);
diff --git a/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs b/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs
index 4caed8b9..21cb8e96 100644
--- a/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs
+++ b/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs
@@ -156,9 +156,11 @@ public static string CollapseLineBreaks(this string str)
     /// Determines whether the layout mode is inline vs block or flex.
     /// </summary>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static bool IsInlineLayout(string? displayMode, string defaultLayout)
+    public static bool IsInlineLayout(ReadOnlySpan<char> displayMode, string defaultLayout)
     {
-        return (displayMode ?? defaultLayout)
-            .StartsWith("inline", StringComparison.OrdinalIgnoreCase) == true;
+        if (displayMode.IsEmpty)
+            displayMode = defaultLayout.AsSpan();
+
+        return displayMode.StartsWith("inline", StringComparison.InvariantCultureIgnoreCase);
     }
 }
\ No newline at end of file
diff --git a/src/Html2OpenXml/Utilities/Converter.cs b/src/Html2OpenXml/Utilities/Converter.cs
index 9d5907d2..4d2290c1 100755
--- a/src/Html2OpenXml/Utilities/Converter.cs
+++ b/src/Html2OpenXml/Utilities/Converter.cs
@@ -22,12 +22,13 @@ static class Converter
     /// <summary>
     /// Convert the Html text align attribute (horizontal alignement) to its corresponding OpenXml value.
     /// </summary>
-    public static JustificationValues? ToParagraphAlign(string? htmlAlign)
+    public static JustificationValues? ToParagraphAlign(ReadOnlySpan<char> span)
     {
-        if (htmlAlign == null) return null;
-        return htmlAlign.ToLowerInvariant() switch
+        Span<char> loweredValue = span.Length <= 128 ? stackalloc char[span.Length] : new char[span.Length];
+        span.ToLowerInvariant(loweredValue);
+        return loweredValue switch
         {
-            "left" => JustificationValues.Left,
+           "left" => JustificationValues.Left,
             "right" => JustificationValues.Right,
             "center" => JustificationValues.Center,
             "justify" => JustificationValues.Both,
@@ -38,10 +39,11 @@ static class Converter
     /// <summary>
     /// Convert the Html vertical-align attribute to its corresponding OpenXml value.
     /// </summary>
-    public static TableVerticalAlignmentValues? ToVAlign(string? htmlAlign)
+    public static TableVerticalAlignmentValues? ToVAlign(ReadOnlySpan<char> span)
     {
-        if (htmlAlign == null) return null;
-        return htmlAlign.ToLowerInvariant() switch
+        Span<char> loweredValue = span.Length <= 128 ? stackalloc char[span.Length] : new char[span.Length];
+        span.ToLowerInvariant(loweredValue);
+        return loweredValue switch
         {
             "top" => TableVerticalAlignmentValues.Top,
             "middle" => TableVerticalAlignmentValues.Center,
@@ -159,14 +161,6 @@ public static BorderValues ToBorderStyle(ReadOnlySpan<char> span)
         };
     }
 
-    public static PageOrientationValues ToPageOrientation(string? orientation)
-    {
-        if ( "landscape".Equals(orientation,StringComparison.OrdinalIgnoreCase))
-            return PageOrientationValues.Landscape;
-
-        return PageOrientationValues.Portrait;
-    }
-
     public static ICollection<TextDecoration> ToTextDecoration(ReadOnlySpan<char> values)
     {
         // this style could take multiple values separated by a space
diff --git a/test/HtmlToOpenXml.Tests/Primitives/StyleParserTests.cs b/test/HtmlToOpenXml.Tests/Primitives/StyleParserTests.cs
index 73f02e82..ebdce137 100644
--- a/test/HtmlToOpenXml.Tests/Primitives/StyleParserTests.cs
+++ b/test/HtmlToOpenXml.Tests/Primitives/StyleParserTests.cs
@@ -9,21 +9,22 @@ namespace HtmlToOpenXml.Tests.Primitives
     public class StyleParserTests
     {
         [TestCase("text-decoration:underline; color: red ")]
-        [TestCase("text-decoration&#58;underline&#59;color:red")]
+        [TestCase("text-decoration &#58; underline &#59;color :red")]
         public void ParseStyle_ShouldSucceed(string htmlStyle)
         {
             var styles = HtmlAttributeCollection.ParseStyle(htmlStyle);
             Assert.Multiple(() => {
-                Assert.That(styles["text-decoration"], Is.EqualTo("underline"));
-                Assert.That(styles["color"], Is.EqualTo("red"));
+                Assert.That(styles.HasKeyEqualsTo("text-decoration", "underline"), Is.True);
+                Assert.That(styles.HasKeyEqualsTo("color", "red"), Is.True);
+                Assert.That(styles["color"].ToString(), Is.EqualTo("red"));
             });
         }
 
         [Test(Description = "Parser should consider the last occurence of a style")]
         public void DuplicateStyle_ReturnsLatter()
         {
-            var styleAttributes = HtmlAttributeCollection.ParseStyle("color:red;color:blue");
-            Assert.That(styleAttributes["color"], Is.EqualTo("blue"));
+            var styleAttributes = HtmlAttributeCollection.ParseStyle("color:red;color:BLUE");
+            Assert.That(styleAttributes.HasKeyEqualsTo("color", "blue"), Is.True);
         }
 
         [TestCase("color;color;")]
@@ -33,7 +34,7 @@ public void InvalidStyle_ShouldBeEmpty(string htmlStyle)
         {
             var styles = HtmlAttributeCollection.ParseStyle(htmlStyle);
             Assert.That(styles.IsEmpty, Is.True);
-            Assert.That(styles["color"], Is.Null);
+            Assert.That(styles.ContainsKey("color"), Is.False);
         }
 
         [Test]
diff --git a/test/HtmlToOpenXml.Tests/StyleTests.cs b/test/HtmlToOpenXml.Tests/StyleTests.cs
index 855b071c..61b1d0fd 100644
--- a/test/HtmlToOpenXml.Tests/StyleTests.cs
+++ b/test/HtmlToOpenXml.Tests/StyleTests.cs
@@ -163,23 +163,23 @@ public void ManualAddStyle_ThenRefreshStyles_ShouldSucceed()
         public void DuplicateStyle_ReturnsLatter()
         {
             var styleAttributes = HtmlAttributeCollection.ParseStyle("color:red;color:blue");
-            Assert.That(styleAttributes["color"], Is.EqualTo("blue"));
+            Assert.That(styleAttributes["color"].ToString(), Is.EqualTo("blue"));
         }
 
         [Test(Description = "Encoded ':' and ';' characters are valid")]
         public void EncodedStyle_ShouldSucceed()
         {
             var styleAttributes = HtmlAttributeCollection.ParseStyle("text-decoration&#58;underline&#59;color:red");
-            Assert.That(styleAttributes["text-decoration"], Is.EqualTo("underline"));
-            Assert.That(styleAttributes["color"], Is.EqualTo("red"));
+            Assert.That(styleAttributes["text-decoration"].ToString(), Is.EqualTo("underline"));
+            Assert.That(styleAttributes["color"].ToString(), Is.EqualTo("red"));
         }
 
         [Test(Description = "Key style with no value should be ignored")]
         public void EmptyStyle_ShouldBeIgnored()
         {
             var styleAttributes = HtmlAttributeCollection.ParseStyle("text-decoration;color:red");
-            Assert.That(styleAttributes["text-decoration"], Is.Null);
-            Assert.That(styleAttributes["color"], Is.EqualTo("red"));
+            Assert.That(styleAttributes.ContainsKey("text-decoration"), Is.False);
+            Assert.That(styleAttributes["color"].ToString(), Is.EqualTo("red"));
         }
     }
 }

From 731e44ffe0bca38b4e0f748a49d906e0ce8ce2a4 Mon Sep 17 00:00:00 2001
From: Olivier Nizet <onizet@hotmail.com>
Date: Thu, 27 Nov 2025 00:05:50 +0100
Subject: [PATCH 2/3] Deal with net462 and the not implicit cast to Span

---
 src/Html2OpenXml/Collections/HtmlAttributeCollection.cs  | 7 +++++--
 src/Html2OpenXml/Expressions/Numbering/ListExpression.cs | 8 ++++----
 src/Html2OpenXml/Utilities/AngleSharpExtensions.cs       | 2 +-
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs b/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs
index 0f0aacb0..f1492673 100755
--- a/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs
+++ b/src/Html2OpenXml/Collections/HtmlAttributeCollection.cs
@@ -128,10 +128,13 @@ public bool ContainsKey(string name)
     /// <summary>
     /// Efficient way to determine if a style is equals to a value.
     /// </summary>
-    public bool HasKeyEqualsTo(string name, ReadOnlySpan<char> value)
+    public bool HasKeyEqualsTo(string name, string value)
     {
         if (attributes.TryGetValue(name, out var range))
-            return rawValue.AsSpan().Slice(range).Trim().Equals(value, StringComparison.InvariantCultureIgnoreCase);
+        {
+            var span = rawValue.AsSpan().Slice(range).Trim();
+            return span.Equals(value.AsSpan(), StringComparison.InvariantCultureIgnoreCase);
+        }
         return false;
     }
 
diff --git a/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs b/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs
index a2a14798..548ed09f 100644
--- a/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs
+++ b/src/Html2OpenXml/Expressions/Numbering/ListExpression.cs
@@ -214,14 +214,14 @@ private static string GetListName(IElement listNode, string? parentName = null)
     {
         var styleAttributes = listNode.GetStyles();
         bool orderedList = listNode.NodeName.Equals("ol", StringComparison.OrdinalIgnoreCase);
-        var type = styleAttributes["list-style-type"];
+        string? type = styleAttributes["list-style-type"].ToString();
 
-        if(orderedList && type.IsEmpty)
+        if(orderedList && string.IsNullOrEmpty(type))
         {
             type = ListTypeToListStyleType(listNode.GetAttribute("type"));
         }
 
-        if (type.IsEmpty || !supportedListTypes.Contains(type.ToString()))
+        if (string.IsNullOrEmpty(type) || !supportedListTypes.Contains(type!))
         {
             if (parentName != null && IsCascadingStyle(parentName))
                 return parentName!;
@@ -229,7 +229,7 @@ private static string GetListName(IElement listNode, string? parentName = null)
             type = orderedList? "decimal" : "disc";
         }
 
-        return type.ToString();
+        return type!;
     }
 
     /// <summary>
diff --git a/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs b/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs
index 21cb8e96..31763e87 100644
--- a/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs
+++ b/src/Html2OpenXml/Utilities/AngleSharpExtensions.cs
@@ -161,6 +161,6 @@ public static bool IsInlineLayout(ReadOnlySpan<char> displayMode, string default
         if (displayMode.IsEmpty)
             displayMode = defaultLayout.AsSpan();
 
-        return displayMode.StartsWith("inline", StringComparison.InvariantCultureIgnoreCase);
+        return displayMode.StartsWith("inline".AsSpan(), StringComparison.InvariantCultureIgnoreCase);
     }
 }
\ No newline at end of file

From 8532595da20c8a12b053fe39fb94d3240ddf9d1e Mon Sep 17 00:00:00 2001
From: Olivier Nizet <onizet@hotmail.com>
Date: Thu, 27 Nov 2025 00:12:25 +0100
Subject: [PATCH 3/3] More implicit cast

---
 src/Html2OpenXml/Expressions/BlockElementExpression.cs    | 2 +-
 .../Expressions/Table/TableCaptionExpression.cs           | 2 +-
 src/Html2OpenXml/Expressions/Table/TableCellExpression.cs | 8 ++++----
 .../Expressions/Table/TableElementExpressionBase.cs       | 4 ++--
 src/Html2OpenXml/Expressions/Table/TableExpression.cs     | 2 +-
 5 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/Html2OpenXml/Expressions/BlockElementExpression.cs b/src/Html2OpenXml/Expressions/BlockElementExpression.cs
index 54eb692c..79731535 100644
--- a/src/Html2OpenXml/Expressions/BlockElementExpression.cs
+++ b/src/Html2OpenXml/Expressions/BlockElementExpression.cs
@@ -187,7 +187,7 @@ protected override void ComposeStyles (ParsingContext context)
         }
 
         JustificationValues? align = Converter.ToParagraphAlign(styleAttributes["text-align"]);
-        if (!align.HasValue) align = Converter.ToParagraphAlign(node.GetAttribute("align"));
+        if (!align.HasValue) align = Converter.ToParagraphAlign(node.GetAttribute("align").AsSpan());
         if (!align.HasValue) align = Converter.ToParagraphAlign(styleAttributes["justify-content"]);
         if (align.HasValue)
         {
diff --git a/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs b/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs
index 2c7e3346..509be4c2 100644
--- a/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableCaptionExpression.cs
@@ -55,7 +55,7 @@ public override IEnumerable<OpenXmlElement> Interpret (ParsingContext context)
         p.Append(childElements);
 
         var att = styleAttributes["text-align"];
-        if (att.IsEmpty) att = node.GetAttribute("align");
+        if (att.IsEmpty) att = node.GetAttribute("align").AsSpan();
         if (!att.IsEmpty)
         {
             JustificationValues? align = Converter.ToParagraphAlign(att);
diff --git a/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs b/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs
index 0cf036ec..05c471f9 100644
--- a/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableCellExpression.cs
@@ -87,15 +87,15 @@ protected override void ComposeStyles(ParsingContext context)
         var direction = styleAttributes["writing-mode"];
         if (!direction.IsEmpty)
         {
-            if (direction.Equals("tb-lr", StringComparison.InvariantCultureIgnoreCase) ||
-                direction.Equals("vertical-lr", StringComparison.InvariantCultureIgnoreCase))
+            if (direction.Equals("tb-lr".AsSpan(), StringComparison.InvariantCultureIgnoreCase) ||
+                direction.Equals("vertical-lr".AsSpan(), StringComparison.InvariantCultureIgnoreCase))
             {
                 cellProperties.TextDirection = new() { Val = TextDirectionValues.BottomToTopLeftToRight };
                 cellProperties.TableCellVerticalAlignment = new() { Val = TableVerticalAlignmentValues.Center };
                 paraProperties.Justification = new() { Val = JustificationValues.Center };
             }
-            else if (direction.Equals("tb-rl", StringComparison.InvariantCultureIgnoreCase) ||
-                direction.Equals("vertical-rl", StringComparison.InvariantCultureIgnoreCase))
+            else if (direction.Equals("tb-rl".AsSpan(), StringComparison.InvariantCultureIgnoreCase) ||
+                direction.Equals("vertical-rl".AsSpan(), StringComparison.InvariantCultureIgnoreCase))
             {
                 cellProperties.TextDirection = new() { Val = TextDirectionValues.TopToBottomRightToLeft };
                 cellProperties.TableCellVerticalAlignment = new() { Val = TableVerticalAlignmentValues.Center };
diff --git a/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs b/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs
index a90e8382..f7614ced 100644
--- a/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableElementExpressionBase.cs
@@ -72,7 +72,7 @@ protected override void ComposeStyles(ParsingContext context)
         base.ComposeStyles(context);
 
         var valign = Converter.ToVAlign(styleAttributes["vertical-align"]);
-        if (!valign.HasValue) valign = Converter.ToVAlign(node.GetAttribute("valign"));
+        if (!valign.HasValue) valign = Converter.ToVAlign(node.GetAttribute("valign").AsSpan());
         if (!valign.HasValue)
         {
             // in Html, table cell are vertically centered by default
@@ -92,7 +92,7 @@ protected override void ComposeStyles(ParsingContext context)
         }
 
         var halign = Converter.ToParagraphAlign(styleAttributes["text-align"]);
-        if (!halign.HasValue) halign = Converter.ToParagraphAlign(node.GetAttribute("align"));
+        if (!halign.HasValue) halign = Converter.ToParagraphAlign(node.GetAttribute("align").AsSpan());
         if (halign.HasValue)
         {
             paraProperties.KeepNext = new();
diff --git a/src/Html2OpenXml/Expressions/Table/TableExpression.cs b/src/Html2OpenXml/Expressions/Table/TableExpression.cs
index dd0e54db..abcf010b 100644
--- a/src/Html2OpenXml/Expressions/Table/TableExpression.cs
+++ b/src/Html2OpenXml/Expressions/Table/TableExpression.cs
@@ -278,7 +278,7 @@ protected override void ComposeStyles (ParsingContext context)
             }
         }
 
-        var align = Converter.ToParagraphAlign(tableNode.GetAttribute("align"))
+        var align = Converter.ToParagraphAlign(tableNode.GetAttribute("align").AsSpan())
             ?? Converter.ToParagraphAlign(styleAttributes["justify-self"]);
         if (!align.HasValue)
         {