feat: add native styling support for fenced div blocks (:::classname)

csharp-version/src/MarkdownToDocx.CLI/Helpers.cs

@@ -1,3 +1,4 @@
+using Markdig.Extensions.CustomContainers;
 using Markdig.Extensions.Tables;
 using Markdig.Syntax;
 using Markdig.Syntax.Inlines;
@@ -175,6 +176,51 @@ public static string ResolveRelativePath(string path, string basePath)
     public static TableData GetTableData(Table table) =>
         MarkdownToDocx.Core.Markdown.TableExtractor.Extract(table);
 
+    /// <summary>
+    /// Extracts structured child blocks from a Markdig CustomContainer (:::classname ... :::).
+    /// Supports paragraphs, headings, tables, and lists within the div.
+    /// Unrecognized child block types are silently skipped.
+    /// </summary>
+    public static FencedDivContent GetFencedDivContent(CustomContainer container)
+    {
+        var blocks = new List<FencedDivBlock>();
+
+        foreach (var child in container)
+        {
+            switch (child)
+            {
+                case ParagraphBlock paragraph:
+                    var runs = new List<InlineRun>();
+                    if (paragraph.Inline != null)
+                        ExtractInlineRuns(paragraph.Inline, runs, bold: false, italic: false);
+                    if (runs.Count > 0)
+                        blocks.Add(new FencedDivParagraph { Runs = runs });
+                    break;
+
+                case HeadingBlock heading:
+                    var headingText = GetBlockText(heading);
+                    if (!string.IsNullOrEmpty(headingText))
+                        blocks.Add(new FencedDivHeading { Level = heading.Level, Text = headingText });
+                    break;
+
+                case Table table:
+                    blocks.Add(new FencedDivTable { Data = GetTableData(table) });
+                    break;
+
+                case ListBlock list:
+                    var items = GetListItems(list).ToList();
+                    if (items.Count > 0)
+                    {
+                        var startNumber = int.TryParse(list.OrderedStart, out var parsed) ? parsed : 1;
+                        blocks.Add(new FencedDivList { Items = items, IsOrdered = list.IsOrdered, StartNumber = startNumber });
+                    }
+                    break;
+            }
+        }
+
+        return new FencedDivContent { Blocks = blocks };
+    }
+
     private static void ExtractInlineRuns(Inline? inline, List<InlineRun> runs, bool bold, bool italic)
     {
         if (inline == null) return;

csharp-version/src/MarkdownToDocx.CLI/Program.cs

@@ -1,3 +1,4 @@
+using Markdig.Extensions.CustomContainers;
 using Markdig.Extensions.Tables;
 using Markdig.Syntax;
 using MarkdownToDocx.CLI;
@@ -135,6 +136,15 @@
                     builder.AddTable(tableData, tableStyle);
                     break;
 
+                case CustomContainer container:
+                    var className = container.Info ?? string.Empty;
+                    if (!config.Styles.FencedDivs.TryGetValue(className, out var divConfig))
+                        divConfig = new MarkdownToDocx.Styling.Models.FencedDivClassConfig();
+                    var divStyle = styleApplicator.ApplyFencedDivStyle(divConfig, config.Styles);
+                    var divContent = Helpers.GetFencedDivContent(container);
+                    builder.AddFencedDiv(divContent, divStyle);
+                    break;
+
                 case ThematicBreakBlock:
                     builder.AddThematicBreak();
                     break;

csharp-version/src/MarkdownToDocx.Core/Interfaces/IDocumentBuilder.cs

@@ -75,6 +75,14 @@ public interface IDocumentBuilder : IDisposable
     /// <param name="style">Table style configuration</param>
     void AddTable(TableData tableData, TableStyle style);
 
+    /// <summary>
+    /// Adds a fenced div block to the document.
+    /// Renders child blocks with background shading and optional top/bottom separator borders.
+    /// </summary>
+    /// <param name="content">Structured child blocks extracted from the fenced div</param>
+    /// <param name="style">Fenced div visual style</param>
+    void AddFencedDiv(FencedDivContent content, FencedDivStyle style);
+
     /// <summary>
     /// Adds a thematic break (horizontal rule) to the document
     /// </summary>

csharp-version/src/MarkdownToDocx.Core/Models/FencedDivContent.cs

@@ -0,0 +1,77 @@
+namespace MarkdownToDocx.Core.Models;
+
+/// <summary>
+/// Structured content extracted from a fenced div block.
+/// Contains an ordered list of typed child blocks ready for rendering.
+/// </summary>
+public sealed class FencedDivContent
+{
+    /// <summary>
+    /// Ordered sequence of child blocks within the fenced div.
+    /// </summary>
+    public IReadOnlyList<FencedDivBlock> Blocks { get; init; } = [];
+}
+
+/// <summary>
+/// Base type for all child blocks within a fenced div.
+/// </summary>
+public abstract class FencedDivBlock { }
+
+/// <summary>
+/// A paragraph (with inline formatting) inside a fenced div.
+/// </summary>
+public sealed class FencedDivParagraph : FencedDivBlock
+{
+    /// <summary>
+    /// Structured inline runs with bold/italic/code formatting.
+    /// </summary>
+    public IReadOnlyList<InlineRun> Runs { get; init; } = [];
+}
+
+/// <summary>
+/// A heading inside a fenced div.
+/// </summary>
+public sealed class FencedDivHeading : FencedDivBlock
+{
+    /// <summary>
+    /// Heading level (1–6).
+    /// </summary>
+    public int Level { get; init; }
+
+    /// <summary>
+    /// Plain text content of the heading.
+    /// </summary>
+    public string Text { get; init; } = string.Empty;
+}
+
+/// <summary>
+/// A table inside a fenced div.
+/// </summary>
+public sealed class FencedDivTable : FencedDivBlock
+{
+    /// <summary>
+    /// Structured table data with rows, cells, and alignment.
+    /// </summary>
+    public TableData Data { get; init; } = new();
+}
+
+/// <summary>
+/// A list (ordered or unordered) inside a fenced div.
+/// </summary>
+public sealed class FencedDivList : FencedDivBlock
+{
+    /// <summary>
+    /// List items.
+    /// </summary>
+    public IReadOnlyList<ListItem> Items { get; init; } = [];
+
+    /// <summary>
+    /// True for numbered list, false for bullet list.
+    /// </summary>
+    public bool IsOrdered { get; init; }
+
+    /// <summary>
+    /// First number for ordered lists.
+    /// </summary>
+    public int StartNumber { get; init; } = 1;
+}

csharp-version/src/MarkdownToDocx.Core/Models/FencedDivStyle.cs

@@ -0,0 +1,79 @@
+namespace MarkdownToDocx.Core.Models;
+
+/// <summary>
+/// Styling configuration for a fenced div block (:::classname ... :::).
+/// Background color is applied to all child paragraphs.
+/// Top/bottom separator lines appear on the first and last paragraph-like elements.
+/// </summary>
+public sealed record FencedDivStyle
+{
+    /// <summary>
+    /// Background fill color in hex (e.g., "F2F2F2"). Empty = no shading.
+    /// </summary>
+    public string BackgroundColor { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Top separator line color in hex (e.g., "AAAAAA"). Empty = no top border.
+    /// </summary>
+    public string BorderTopColor { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Top separator line thickness in eighths of a point (default: 4 = 0.5pt).
+    /// </summary>
+    public uint BorderTopSize { get; init; } = 4;
+
+    /// <summary>
+    /// Bottom separator line color in hex (e.g., "AAAAAA"). Empty = no bottom border.
+    /// </summary>
+    public string BorderBottomColor { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Bottom separator line thickness in eighths of a point (default: 4 = 0.5pt).
+    /// </summary>
+    public uint BorderBottomSize { get; init; } = 4;
+
+    /// <summary>
+    /// Space between separator line and text in points (default: 0).
+    /// </summary>
+    public uint BorderSpace { get; init; } = 0;
+
+    /// <summary>
+    /// Spacing before the first block in the div in twips.
+    /// </summary>
+    public string SpaceBefore { get; init; } = "0";
+
+    /// <summary>
+    /// Spacing after the last block in the div in twips.
+    /// </summary>
+    public string SpaceAfter { get; init; } = "0";
+
+    /// <summary>
+    /// Left indent for div paragraphs in twips.
+    /// </summary>
+    public string LeftIndent { get; init; } = "0";
+
+    /// <summary>
+    /// Font size in half-points (inherited from paragraph style).
+    /// </summary>
+    public int FontSize { get; init; }
+
+    /// <summary>
+    /// Text color in hex (inherited from paragraph style).
+    /// </summary>
+    public string Color { get; init; } = string.Empty;
+
+    /// <summary>
+    /// Line spacing in twips (inherited from paragraph style).
+    /// </summary>
+    public string LineSpacing { get; init; } = "360";
+
+    /// <summary>
+    /// Monospace font for inline code ASCII characters.
+    /// </summary>
+    public string InlineCodeFontAscii { get; init; } = "Courier New";
+
+    /// <summary>
+    /// Monospace font for inline code East Asian characters.
+    /// </summary>
+    public string InlineCodeFontEastAsia { get; init; } = "Noto Sans Mono CJK JP";
+}

csharp-version/src/MarkdownToDocx.Core/Models/TableStyle.cs

@@ -75,4 +75,11 @@ public sealed record TableStyle
     /// Values below 100 leave horizontal space around the table.
     /// </summary>
     public int WidthPercent { get; init; } = 90;
+
+    /// <summary>
+    /// Background color applied to all body cells in hex (e.g., "F2F2F2").
+    /// When set (e.g., when the table is inside a fenced div), overrides the default
+    /// transparent body cell background. Null or empty means no shading.
+    /// </summary>
+    public string? BodyCellBackgroundColor { get; init; }
 }