fix: 代码块显式设置浅色文字+高亮颜色，不再依赖 highlight.js 主题自动配色

src/styles/globals.css

@@ -1,5 +1,5 @@
 @import "tailwindcss";
-@import "highlight.js/styles/atom-one-dark.css";
+@import "highlight.js/styles/github-dark.css";
 
 /* ===== MetonaAI Desktop — 全局样式 ===== */
 
@@ -220,22 +220,39 @@ code, pre, .font-mono { font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', mo
 }
 
 .prose-metona pre {
-  background: #252836;
+  background: #1e1e2e;
   border: 1px solid #2a2d3a;
   border-radius: 8px;
   padding: 16px;
   overflow-x: auto;
   margin-bottom: 1em;
+  color: #cdd6f4;
 }
 
 .prose-metona pre code {
-  color: inherit;
+  color: #cdd6f4;
   background: transparent;
   padding: 0;
   font-size: 13px;
   line-height: 1.6;
 }
 
+/* highlight.js 语法高亮覆盖 — 浅色关键字/字符串/数字 */
+.prose-metona .hljs-keyword { color: #cba6f7; }
+.prose-metona .hljs-string  { color: #a6e3a1; }
+.prose-metona .hljs-number  { color: #fab387; }
+.prose-metona .hljs-comment { color: #6c7086; font-style: italic; }
+.prose-metona .hljs-function { color: #89b4fa; }
+.prose-metona .hljs-title   { color: #89b4fa; }
+.prose-metona .hljs-params  { color: #f9e2af; }
+.prose-metona .hljs-built_in { color: #f38ba8; }
+.prose-metona .hljs-type    { color: #f9e2af; }
+.prose-metona .hljs-literal  { color: #fab387; }
+.prose-metona .hljs-attr    { color: #89b4fa; }
+.prose-metona .hljs-selector-class { color: #a6e3a1; }
+.prose-metona .hljs-selector-tag   { color: #cba6f7; }
+.prose-metona .hljs-variable { color: #cdd6f4; }
+
 .prose-metona blockquote {
   border-left: 3px solid #818cf8;
   padding-left: 16px;