From f793cf3c074a7937a7f98ec563971de02add5a1c Mon Sep 17 00:00:00 2001
From: Steven Giesel <stgiesel35@gmail.com>
Date: Sun, 13 Sep 2026 18:37:13 +0200
Subject: [PATCH 1/2] feat: External link support and language indicator

---
 .../CopyCodeBlockToClipboardExtension.cs      | 10 +++
 .../Features/ExternalLinkExtension.cs         | 40 ++++++++++++
 .../Features/MarkdownConverter.cs             |  1 +
 src/LinkDotNet.Blog.Web/wwwroot/css/basic.css |  5 ++
 .../Web/Features/MarkdownConverterTests.cs    | 62 +++++++++++++++++++
 5 files changed, 118 insertions(+)
 create mode 100644 src/LinkDotNet.Blog.Web/Features/ExternalLinkExtension.cs

diff --git a/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs b/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs
index a45561f5..72c69826 100644
--- a/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs
+++ b/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs
@@ -24,6 +24,12 @@ public static MarkdownPipelineBuilder UseLazyLoadImages(this MarkdownPipelineBui
         pipeline.Extensions.Add(new LazyLoadImageExtension());
         return pipeline;
     }
+
+    public static MarkdownPipelineBuilder UseExternalLinks(this MarkdownPipelineBuilder pipeline)
+    {
+        pipeline.Extensions.Add(new ExternalLinkExtension());
+        return pipeline;
+    }
 }
 
 internal sealed class CopyCodeBlockToClipboardExtension : IMarkdownExtension
@@ -55,6 +61,10 @@ internal sealed class CustomCodeBlockRenderer : CodeBlockRenderer
     protected override void Write(HtmlRenderer renderer, CodeBlock obj)
     {
         renderer.Write("""<div class="position-relative">""");
+        if (obj is FencedCodeBlock { Info.Length: > 0 } fenced)
+        {
+            renderer.Write($"""<span class="badge bg-secondary position-absolute top-0 start-0 m-2 code-lang-badge">{fenced.Info}</span>""");
+        }
         renderer.Write("""
                        <button class="btn btn-sm position-absolute top-0 end-0 m-2 border border-primary text-primary copy-btn"
                                type="button"
diff --git a/src/LinkDotNet.Blog.Web/Features/ExternalLinkExtension.cs b/src/LinkDotNet.Blog.Web/Features/ExternalLinkExtension.cs
new file mode 100644
index 00000000..b0e08bc1
--- /dev/null
+++ b/src/LinkDotNet.Blog.Web/Features/ExternalLinkExtension.cs
@@ -0,0 +1,40 @@
+using System;
+using Markdig;
+using Markdig.Renderers;
+using Markdig.Renderers.Html;
+using Markdig.Syntax;
+using Markdig.Syntax.Inlines;
+
+namespace LinkDotNet.Blog.Web.Features;
+
+internal sealed class ExternalLinkExtension : IMarkdownExtension
+{
+    public void Setup(MarkdownPipelineBuilder pipeline)
+    {
+        pipeline.DocumentProcessed -= MarkExternalLinks;
+        pipeline.DocumentProcessed += MarkExternalLinks;
+    }
+
+    public void Setup(MarkdownPipeline pipeline, IMarkdownRenderer renderer)
+    {
+    }
+
+    private static void MarkExternalLinks(MarkdownDocument document)
+    {
+        foreach (var link in document.Descendants<LinkInline>())
+        {
+            if (link.IsImage
+                || !Uri.TryCreate(link.Url, UriKind.Absolute, out var uri)
+                || (uri.Scheme != Uri.UriSchemeHttp && uri.Scheme != Uri.UriSchemeHttps))
+            {
+                continue;
+            }
+
+            var attributes = link.GetAttributes();
+            attributes.AddPropertyIfNotExist("target", "_blank");
+            attributes.AddPropertyIfNotExist("rel", "noopener noreferrer");
+            attributes.AddClass("external-link");
+            link.AppendChild(new HtmlInline("""<i class="bi bi-box-arrow-up-right ms-1" aria-hidden="true"></i>"""));
+        }
+    }
+}
diff --git a/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs b/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs
index 12fee356..fbf79e08 100644
--- a/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs
+++ b/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs
@@ -21,6 +21,7 @@ public static class MarkdownConverter
         .UseCopyCodeBlock()
         .UseCallouts()
         .UseLazyLoadImages()
+        .UseExternalLinks()
         .Build();
 
     public static MarkupString ToMarkupString(string markdown)
diff --git a/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css b/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css
index bcc9225d..2b242713 100644
--- a/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css
+++ b/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css
@@ -132,6 +132,11 @@ code {
 	}
 }
 
+.code-lang-badge {
+	font-size: 0.7rem;
+	opacity: 0.85;
+}
+
 /* Template defined css */
 .valid.modified:not([type=checkbox]) {
     outline: 1px solid #26b050;
diff --git a/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs b/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs
index bbe6a554..db1d618d 100644
--- a/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs
+++ b/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs
@@ -99,4 +99,66 @@ public void ShouldNotAddLazyLoadingToLinks()
 
         html.ShouldNotContain("loading=");
     }
+
+    [Fact]
+    public void ShouldMarkAbsoluteLinksAsExternal()
+    {
+        var html = MarkdownConverter.ToMarkupString("[link](https://localhost)").Value;
+
+        html.ShouldContain("target=\"_blank\"");
+        html.ShouldContain("rel=\"noopener noreferrer\"");
+        html.ShouldContain("class=\"external-link\"");
+        html.ShouldContain("""<i class="bi bi-box-arrow-up-right ms-1" aria-hidden="true"></i>""");
+    }
+
+    [Fact]
+    public void ShouldNotMarkRelativeLinksAsExternal()
+    {
+        var html = MarkdownConverter.ToMarkupString("[post](/blogPost/1)").Value;
+
+        html.ShouldNotContain("external-link");
+        html.ShouldNotContain("target=");
+    }
+
+    [Fact]
+    public void ShouldNotMarkFragmentLinksAsExternal()
+    {
+        var html = MarkdownConverter.ToMarkupString("[jump](#section)").Value;
+
+        html.ShouldNotContain("external-link");
+        html.ShouldNotContain("target=");
+    }
+
+    [Fact]
+    public void ShouldNotMarkExternalImagesAsExternalLinks()
+    {
+        var html = MarkdownConverter.ToMarkupString("![alt](https://localhost/image.png)").Value;
+
+        html.ShouldNotContain("external-link");
+        html.ShouldNotContain("bi-box-arrow-up-right");
+    }
+
+    [Fact]
+    public void ShouldRenderLanguageBadgeForFencedCodeBlock()
+    {
+        var html = MarkdownConverter.ToMarkupString("```csharp\nvar x = 1;\n```").Value;
+
+        html.ShouldContain("""<span class="badge bg-secondary position-absolute top-0 start-0 m-2 code-lang-badge">csharp</span>""");
+    }
+
+    [Fact]
+    public void ShouldNotRenderLanguageBadgeWithoutLanguage()
+    {
+        var html = MarkdownConverter.ToMarkupString("```\nvar x = 1;\n```").Value;
+
+        html.ShouldNotContain("code-lang-badge");
+    }
+
+    [Fact]
+    public void ShouldNotRenderLanguageBadgeForIndentedCodeBlock()
+    {
+        var html = MarkdownConverter.ToMarkupString("    var x = 1;").Value;
+
+        html.ShouldNotContain("code-lang-badge");
+    }
 }

From 2297b8a815f36c7ee7bfbb2d72ebddd05f8f431c Mon Sep 17 00:00:00 2001
From: Steven Giesel <stgiesel35@gmail.com>
Date: Sun, 13 Sep 2026 19:44:04 +0200
Subject: [PATCH 2/2] feat: Style task list checkboxes and wrap tables
 responsively

---
 .../CopyCodeBlockToClipboardExtension.cs      |  6 +++
 .../Features/MarkdownConverter.cs             |  3 ++
 .../Features/ResponsiveTableExtension.cs      | 41 +++++++++++++++++++
 src/LinkDotNet.Blog.Web/wwwroot/css/basic.css | 15 +++++++
 .../Web/Features/MarkdownConverterTests.cs    | 29 +++++++++++++
 5 files changed, 94 insertions(+)
 create mode 100644 src/LinkDotNet.Blog.Web/Features/ResponsiveTableExtension.cs

diff --git a/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs b/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs
index 72c69826..4d115bf2 100644
--- a/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs
+++ b/src/LinkDotNet.Blog.Web/Features/CopyCodeBlockToClipboardExtension.cs
@@ -30,6 +30,12 @@ public static MarkdownPipelineBuilder UseExternalLinks(this MarkdownPipelineBuil
         pipeline.Extensions.Add(new ExternalLinkExtension());
         return pipeline;
     }
+
+    public static MarkdownPipelineBuilder UseResponsiveTables(this MarkdownPipelineBuilder pipeline)
+    {
+        pipeline.Extensions.Add(new ResponsiveTableExtension());
+        return pipeline;
+    }
 }
 
 internal sealed class CopyCodeBlockToClipboardExtension : IMarkdownExtension
diff --git a/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs b/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs
index fbf79e08..bca398d7 100644
--- a/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs
+++ b/src/LinkDotNet.Blog.Web/Features/MarkdownConverter.cs
@@ -22,6 +22,7 @@ public static class MarkdownConverter
         .UseCallouts()
         .UseLazyLoadImages()
         .UseExternalLinks()
+        .UseResponsiveTables()
         .Build();
 
     public static MarkupString ToMarkupString(string markdown)
@@ -124,6 +125,8 @@ static void ProcessInlineDelegate(Inline? inline, StringBuilder stringBuilder)
                     case HtmlEntityInline htmlEntity:
                         stringBuilder.Append(htmlEntity.Transcoded);
                         break;
+                    case HtmlInline:
+                        break;
                     default:
                         stringBuilder.Append(current);
                         break;
diff --git a/src/LinkDotNet.Blog.Web/Features/ResponsiveTableExtension.cs b/src/LinkDotNet.Blog.Web/Features/ResponsiveTableExtension.cs
new file mode 100644
index 00000000..8ddf6645
--- /dev/null
+++ b/src/LinkDotNet.Blog.Web/Features/ResponsiveTableExtension.cs
@@ -0,0 +1,41 @@
+using Markdig;
+using Markdig.Extensions.Tables;
+using Markdig.Renderers;
+using Markdig.Renderers.Html;
+
+namespace LinkDotNet.Blog.Web.Features;
+
+internal sealed class ResponsiveTableExtension : IMarkdownExtension
+{
+    public void Setup(MarkdownPipelineBuilder pipeline)
+    {
+    }
+
+    public void Setup(MarkdownPipeline pipeline, IMarkdownRenderer renderer)
+    {
+        if (renderer is not HtmlRenderer htmlRenderer)
+        {
+            return;
+        }
+
+        var originalTableRenderer = htmlRenderer.ObjectRenderers.FindExact<HtmlTableRenderer>();
+        if (originalTableRenderer is null)
+        {
+            return;
+        }
+
+        htmlRenderer.ObjectRenderers.Remove(originalTableRenderer);
+        htmlRenderer.ObjectRenderers.Add(new ResponsiveHtmlTableRenderer());
+    }
+}
+
+internal sealed class ResponsiveHtmlTableRenderer : HtmlTableRenderer
+{
+    protected override void Write(HtmlRenderer renderer, Table table)
+    {
+        renderer.Write("""<div class="table-container">""");
+        base.Write(renderer, table);
+        renderer.EnsureLine();
+        renderer.Write("</div>");
+    }
+}
diff --git a/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css b/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css
index 2b242713..a851d416 100644
--- a/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css
+++ b/src/LinkDotNet.Blog.Web/wwwroot/css/basic.css
@@ -671,6 +671,21 @@ code {
 	object-fit: cover;
 }
 
+.blogpost-content .contains-task-list {
+	list-style: none;
+	padding-left: 0.5rem;
+}
+
+.blogpost-content .task-list-item input[type="checkbox"] {
+	accent-color: var(--bs-primary);
+	margin-right: 0.4rem;
+}
+
+.blogpost-content .task-list-item:has(input:checked) {
+	color: var(--bs-secondary-color);
+	text-decoration: line-through;
+}
+
 @media only screen and (max-width: 700px) {
 	.blog-outer-box .blog-container {
 		width: 90%;
diff --git a/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs b/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs
index db1d618d..d062d0c8 100644
--- a/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs
+++ b/tests/LinkDotNet.Blog.UnitTests/Web/Features/MarkdownConverterTests.cs
@@ -78,6 +78,14 @@ public void ShouldNotAddHeadingAnchorToTableOfContents()
         toc.ShouldHaveSingleItem().Text.ShouldBe("Hello World");
     }
 
+    [Fact]
+    public void ShouldGenerateTocTextForHeadingWithExternalLink()
+    {
+        var toc = MarkdownConverter.GenerateToc("## [Markdig](https://github.com/xoofx/markdig)");
+
+        toc.ShouldHaveSingleItem().Text.ShouldBe("Markdig");
+    }
+
     [Fact]
     public void ShouldReturnEmptyMarkupForEmptyContentWithHeadingAnchors()
     {
@@ -161,4 +169,25 @@ public void ShouldNotRenderLanguageBadgeForIndentedCodeBlock()
 
         html.ShouldNotContain("code-lang-badge");
     }
+
+    [Fact]
+    public void ShouldRenderTaskListCheckboxes()
+    {
+        var html = MarkdownConverter.ToMarkupString("- [ ] Todo item\n- [x] Done item\n- Regular item").Value;
+
+        html.ShouldContain("contains-task-list");
+        html.ShouldContain("""<li class="task-list-item"><input disabled="disabled" type="checkbox" /> Todo item</li>""");
+        html.ShouldContain("""<li class="task-list-item"><input disabled="disabled" type="checkbox" checked="checked" /> Done item</li>""");
+        html.ShouldContain("<li>Regular item</li>");
+    }
+
+    [Fact]
+    public void ShouldWrapTablesInResponsiveContainer()
+    {
+        var html = MarkdownConverter.ToMarkupString("| A | B |\n|---|---|\n| 1 | 2 |").Value;
+
+        html.ShouldContain("""<div class="table-container">""");
+        html.ShouldContain("""<table class="table">""");
+        html.ShouldContain("</table>\n</div>");
+    }
 }