diff --git a/libs/tiptap-editor/src/__tests__/highlight.test.ts b/libs/tiptap-editor/src/__tests__/highlight.test.ts
index 6546a6c..397c380 100644
--- a/libs/tiptap-editor/src/__tests__/highlight.test.ts
+++ b/libs/tiptap-editor/src/__tests__/highlight.test.ts
@@ -14,6 +14,8 @@ describe('extractLang', () => {
     ['  python  ', 'python', '前后空格(trim)'],
     ['', '', '空字符串'],
     ['   ', '', '纯空格'],
+    ['PYTHON', 'python', '大写小写化（与后端对齐）'],
+    ['Python Runnable', 'python', '混合大小写'],
   ])('%s → %s (%s)', (input, expected) => {
     expect(extractLang(input)).toBe(expected);
   });
diff --git a/libs/tiptap-editor/src/highlight.ts b/libs/tiptap-editor/src/highlight.ts
index ce7a524..e0b0d54 100644
--- a/libs/tiptap-editor/src/highlight.ts
+++ b/libs/tiptap-editor/src/highlight.ts
@@ -3,13 +3,15 @@ import { common, createLowlight } from 'lowlight';
 const base = createLowlight(common);
 
 /**
- * 从完整 fence info string 提取语言名（首个 token）。
+ * 从完整 fence info string 提取语言名（首个 token，小写化）。
  *
- * 与后端 parse_fence_info（src/api/code_runner/languages.rs:80）对齐：
- * info string 形如 `python runnable {"timeout_secs":10}`，语言是首个空白分隔的 token。
+ * 与后端 parse_fence_info（src/api/code_runner/languages.rs:85）对齐：
+ * info string 形如 `python runnable {"timeout_secs":10}`，语言是首个空白分隔的 token，
+ * 再 to_lowercase（lowlight 注册名均为小写，大写会导致 Unknown language 抛错）。
  */
 export function extractLang(info: string): string {
-  return info.trim().split(/\s+/)[0] || '';
+  const first = info.trim().split(/\s+/)[0];
+  return first ? first.toLowerCase() : '';
 }
 
 /**
diff --git a/libs/tiptap-editor/src/style.css b/libs/tiptap-editor/src/style.css
index 2d6a77c..10d7656 100644
--- a/libs/tiptap-editor/src/style.css
+++ b/libs/tiptap-editor/src/style.css
@@ -903,7 +903,7 @@
 }
 .dark .tiptap-editor pre code .hljs-type,
 .dark .tiptap-editor pre code .hljs-title.class_ {
-  color: #8839ef;
+  color: #f9e2af;
 }
 .dark .tiptap-editor pre code .hljs-built_in,
 .dark .tiptap-editor pre code .hljs-doctag {