Render ==highlight== via delimiter pairing rewriter

README.md

@@ -113,12 +113,14 @@ The renderer targets the subset of CommonMark + GitHub-flavored Markdown that LL
 - [x] Inline LaTeX math via `\( … \)`
 - [x] Display LaTeX math via `$$ … $$`
 - [x] Inline citation pills
+- [x] Inline HTML formatting tags — `<br>`, `<b>`/`<strong>`, `<i>`/`<em>`, `<s>`/`<del>`/`<strike>`, `<u>`/`<ins>`, `<mark>`, `<sub>`/`<sup>`, `<code>`/`<kbd>`/`<samp>`/`<tt>`, `<a href>`, `<wbr>` (comments are dropped; unsupported or unmatched tags render as literal text)
+- [x] Highlight (`==text==`)
 
 ### Not yet supported
 
 - [ ] Footnotes (`[^1]`)
-- [ ] Highlight (`==text==`), superscript (`^x^`), subscript (`~x~`)
-- [ ] Raw HTML (`<details>`, `<kbd>`, `<aside>`, …) — kept inline as text
+- [ ] Superscript (`^x^`), subscript (`~x~`)
+- [ ] Block-level raw HTML (`<details>`, `<aside>`, …) — kept inline as text
 - [ ] GitHub alerts (`> [!NOTE]`) — rendered as plain block quotes
 - [ ] Container directives (`::: warning … :::`) and admonitions (`!!! note`)
 - [ ] Mermaid / PlantUML diagrams — rendered as fenced code

Sources/MarkdownText/Inline/Markdown+InlineConvertible.swift

@@ -187,6 +187,51 @@ extension Markdown.InlineCode: InlineConvertible {
   }
 }
 
+extension Markdown.InlineAttributes: InlineConvertible {
+
+  /// Attribute keys this renderer understands inside `attributes`. Produced by
+  /// `InlineHTMLRewriter` for tags that have no dedicated Markdown node
+  /// (`<u>`/`<ins>`, `<mark>`, `<sub>`, `<sup>`).
+  private static let enabledKeyRegex = try? Regex(#"(?:^|[,{}\s])([a-zA-Z]+)\s*:\s*true\b"#)
+
+  private var enabledKeys: Set<String> {
+    guard let regex = Self.enabledKeyRegex else { return [] }
+    var keys = Set<String>()
+    for match in attributes.matches(of: regex) {
+      if let key = match.output[1].substring {
+        keys.insert(String(key))
+      }
+    }
+    return keys
+  }
+
+  func convert(attributeContainer: NSAttributeContainer, config: MarkdownRenderConfig) -> NSMutableAttributedString {
+    var container = attributeContainer
+    let font = attributeContainer[.font] as? MDFont ?? config.paragraphStyle.textFonts.normal
+    let keys = enabledKeys
+    if keys.contains("subscript") {
+      container[.font] = font.scaled(by: 0.75)
+      container[.baselineOffset] = -font.pointSize * 0.2
+    }
+    if keys.contains("superscript") {
+      container[.font] = font.scaled(by: 0.75)
+      container[.baselineOffset] = font.pointSize * 0.35
+    }
+    if keys.contains("underline") {
+      container[.underlineStyle] = NSUnderlineStyle.single.rawValue
+      container[.underlineColor] = container[.foregroundColor]
+    }
+    if keys.contains("highlight") {
+      container[.backgroundColor] = MDColor.systemYellow.withAlphaComponent(0.45)
+    }
+    let str = NSMutableAttributedString()
+    self.inlineConvertibleChildren.forEach { convertible in
+      str.append(convertible.convert(attributeContainer: container, config: config))
+    }
+    return str
+  }
+}
+
 extension Markdown.Table.Cell: InlineConvertible {
 
   func convert(attributeContainer: NSAttributeContainer, config: MarkdownRenderConfig) -> NSMutableAttributedString {

Sources/MarkdownText/Parser/MarkdownParserImpl.swift

@@ -13,6 +13,10 @@ public final class MarkdownParserImpl: MarkdownParser {
     PartialTableMarkupPostParsingRewriter()
   ]
 
+  private let inlineHTMLRewriter = InlineHTMLMarkupPostParsingRewriter()
+
+  private let delimiterRewriter = InlineDelimiterMarkupPostParsingRewriter()
+
   private let imageBlockRewriter = ImageBlockMarkupPostParsingRewriter()
 
   private let latexPreprocessor: LaTexPreProcessor
@@ -39,6 +43,20 @@ public final class MarkdownParserImpl: MarkdownParser {
       }
     }
 
+    if let rewrittenDoc = inlineHTMLRewriter.rewriteIfApplicable(document: result.document) {
+      result = MarkdownParseResult(
+        document: rewrittenDoc,
+        speculativeRewritten: result.speculativeRewritten
+      )
+    }
+
+    if let rewrittenDoc = delimiterRewriter.rewriteIfApplicable(document: result.document) {
+      result = MarkdownParseResult(
+        document: rewrittenDoc,
+        speculativeRewritten: result.speculativeRewritten
+      )
+    }
+
     if option.imageSupport {
       if let rewrittenDoc = imageBlockRewriter.rewriteIfApplicable(document: result.document) {
         result = MarkdownParseResult(