refactor: remove flutter_highlight dependency and enhance code block styling

- Removed flutter_highlight as a dependency to streamline the codebase.
- Updated CodeBlockHeader to improve styling based on the current theme, enhancing visual consistency.
- Adjusted code block background and text colors to match GitHub/Atom themes for better readability.
- Refactored markdown processing logic to eliminate reliance on deprecated highlight features, improving maintainability.

lib/shared/widgets/markdown/code_block_header.dart

@@ -14,16 +14,30 @@ class CodeBlockHeader extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = context.conduitTheme;
-    final label = language.isEmpty ? 'code' : language;
+    final materialTheme = Theme.of(context);
+    final isDark = materialTheme.brightness == Brightness.dark;
+    final label = language.isEmpty ? 'plaintext' : language;
+
+    // Match GitHub/Atom theme colors
+    final backgroundColor = isDark
+        ? const Color(0xFF282c34) // Atom One Dark header
+        : const Color(0xFFf6f8fa); // GitHub light header
+    final textColor = isDark
+        ? const Color(0xFF9da5b4) // Muted text for dark
+        : const Color(0xFF57606a); // GitHub gray for light
+
     return Container(
       padding: const EdgeInsets.symmetric(
-        horizontal: Spacing.sm,
+        horizontal: Spacing.md,
         vertical: Spacing.xs,
       ),
       decoration: BoxDecoration(
-        color: theme.surfaceContainer.withValues(alpha: 0.35),
+        color: backgroundColor,
-        borderRadius: const BorderRadius.vertical(
+        border: Border(
-          top: Radius.circular(AppBorderRadius.sm),
+          bottom: BorderSide(
+            color: theme.cardBorder.withValues(alpha: 0.15),
+            width: 1,
+          ),
         ),
       ),
       child: Row(
@@ -31,16 +45,26 @@ class CodeBlockHeader extends StatelessWidget {
           Text(
             label,
             style: AppTypography.codeStyle.copyWith(
-              color: theme.textSecondary,
+              color: textColor,
-              fontWeight: FontWeight.w600,
+              fontSize: 12,
+              fontWeight: FontWeight.w500,
             ),
           ),
           const Spacer(),
-          IconButton(
+          Material(
-            icon: const Icon(Icons.copy_rounded, size: 18),
+            color: Colors.transparent,
-            color: theme.iconPrimary,
+            child: InkWell(
-            tooltip: 'Copy code',
+              onTap: onCopy,
-            onPressed: onCopy,
+              borderRadius: BorderRadius.circular(4),
+              child: Padding(
+                padding: const EdgeInsets.all(6),
+                child: Icon(
+                  Icons.content_copy_rounded,
+                  size: 16,
+                  color: textColor,
+                ),
+              ),
+            ),
           ),
         ],
       ),

lib/shared/widgets/markdown/markdown_config.dart

@@ -6,9 +6,6 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:flutter_highlight/flutter_highlight.dart';
-import 'package:flutter_highlight/themes/a11y-dark.dart';
-import 'package:flutter_highlight/themes/a11y-light.dart';
 import 'package:flutter_markdown_plus/flutter_markdown_plus.dart';
 import 'package:flutter_math_fork/flutter_math.dart';
 import 'package:markdown/markdown.dart' as md;
@@ -283,91 +280,54 @@ class _CodeBlockBuilder extends MarkdownElementBuilder {
     final isDark = Theme.of(context).brightness == Brightness.dark;
     final code = element.textContent;
     final language = element.attributes['class']?.replaceFirst('language-', '') ?? 'plaintext';
-
-    final highlightTheme = _getCodeHighlightTheme(theme, isDark: isDark);
     final normalizedLanguage = language.trim().isEmpty ? 'plaintext' : language.trim();
 
-    final highlight = HighlightView(
+    // Match GitHub/Atom theme colors for code block container
-      code,
+    final codeBackground = isDark
-      language: normalizedLanguage == 'plaintext' ? null : normalizedLanguage,
+        ? const Color(0xFF282c34) // Atom One Dark background
-      theme: highlightTheme,
+        : const Color(0xFFfafbfc); // GitHub light background
-      textStyle: AppTypography.codeStyle.copyWith(color: theme.codeText),
-      padding: EdgeInsets.zero,
-    );
 
-    final codeBackground = theme.surfaceContainer.withValues(alpha: 0.55);
+    return Container(
-    final borderColor = theme.cardBorder.withValues(alpha: 0.25);
+      margin: const EdgeInsets.symmetric(vertical: Spacing.sm),
-
+      decoration: BoxDecoration(
-    return LayoutBuilder(
+        color: codeBackground,
-      builder: (context, constraints) {
+        borderRadius: BorderRadius.circular(6),
-        final width = constraints.maxWidth.isFinite
+      ),
-            ? constraints.maxWidth
+      clipBehavior: Clip.antiAlias,
-            : MediaQuery.sizeOf(context).width;
+      child: Column(
-
+        mainAxisSize: MainAxisSize.min,
-        return Container(
+        crossAxisAlignment: CrossAxisAlignment.stretch,
-          margin: const EdgeInsets.symmetric(vertical: Spacing.xs),
+        children: [
-          decoration: BoxDecoration(
+          CodeBlockHeader(
-            color: codeBackground,
+            language: normalizedLanguage,
-            borderRadius: BorderRadius.circular(AppBorderRadius.sm),
+            onCopy: () async {
-            border: Border.all(color: borderColor, width: BorderWidth.micro),
+              await Clipboard.setData(ClipboardData(text: code));
+              if (!context.mounted) {
+                return;
+              }
+              ScaffoldMessenger.of(context).hideCurrentSnackBar();
+              ScaffoldMessenger.of(context).showSnackBar(
+                const SnackBar(
+                  content: Text('Code copied to clipboard.'),
+                ),
+              );
+            },
           ),
-          child: ClipRect(
+          SingleChildScrollView(
-            child: Column(
+            scrollDirection: Axis.horizontal,
-              mainAxisSize: MainAxisSize.min,
+            padding: const EdgeInsets.all(Spacing.md),
-              crossAxisAlignment: CrossAxisAlignment.stretch,
+            child: SelectableText(
-              children: [
+              code,
-                CodeBlockHeader(
+              style: AppTypography.codeStyle.copyWith(
-                  language: normalizedLanguage,
+                color: theme.codeText,
-                  onCopy: () async {
+                fontFamily: AppTypography.monospaceFontFamily,
-                    await Clipboard.setData(ClipboardData(text: code));
+              ),
-                    if (!context.mounted) {
-                      return;
-                    }
-                    ScaffoldMessenger.of(context).hideCurrentSnackBar();
-                    ScaffoldMessenger.of(context).showSnackBar(
-                      const SnackBar(
-                        content: Text('Code copied to clipboard.'),
-                      ),
-                    );
-                  },
-                ),
-                SingleChildScrollView(
-                  scrollDirection: Axis.horizontal,
-                  child: IntrinsicWidth(
-                    child: ConstrainedBox(
-                      constraints: BoxConstraints(minWidth: width),
-                      child: Padding(
-                        padding: const EdgeInsets.all(Spacing.sm),
-                        child: highlight,
-                      ),
-                    ),
-                  ),
-                ),
-              ],
             ),
           ),
-        );
+        ],
-      },
+      ),
     );
   }
-
-  Map<String, TextStyle> _getCodeHighlightTheme(
-    ConduitThemeExtension theme, {
-    required bool isDark,
-  }) {
-    final baseTheme = isDark ? a11yDarkTheme : a11yLightTheme;
-    final codeStyle = AppTypography.codeStyle.copyWith(color: theme.codeText);
-
-    return {
-      for (final entry in baseTheme.entries)
-        entry.key: entry.value.copyWith(
-          color: entry.value.color ?? theme.codeText,
-          fontFamily: AppTypography.monospaceFontFamily,
-          fontSize: codeStyle.fontSize,
-          height: codeStyle.height,
-        ),
-    };
-  }
 }
 
 // Custom image builder

lib/shared/widgets/markdown/markdown_preprocessor.dart

@@ -1,5 +1,5 @@
 /// Utility helpers for normalising markdown content before handing it to
-/// [GptMarkdown]. The goal is to keep streaming responsive while smoothing
+/// [ConduitMarkdown]. The goal is to keep streaming responsive while smoothing
 /// out troublesome edge-cases (e.g. nested fences inside lists).
 class ConduitMarkdownPreprocessor {
   const ConduitMarkdownPreprocessor._();

pubspec.lock

@@ -430,14 +430,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.4.1"
-  flutter_highlight:
-    dependency: "direct main"
-    description:
-      name: flutter_highlight
-      sha256: "7b96333867aa07e122e245c033b8ad622e4e3a42a1a2372cbb098a2541d8782c"
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.7.0"
   flutter_lints:
     dependency: "direct dev"
     description:
@@ -621,14 +613,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.3.2"
-  highlight:
-    dependency: transitive
-    description:
-      name: highlight
-      sha256: "5353a83ffe3e3eca7df0abfb72dcf3fa66cc56b953728e7113ad4ad88497cf21"
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.7.0"
   hive_ce:
     dependency: "direct main"
     description:

pubspec.yaml

@@ -31,7 +31,6 @@ dependencies:
   
   # UI Components - Markdown Rendering
   cached_network_image: ^3.3.1
-  flutter_highlight: ^0.7.0
   flutter_markdown_plus: ^1.0.5
   markdown: ^7.3.0
   webview_flutter: ^4.7.0