feat: 更新样式和功能，优化徽章、登录页面和文章页面的布局，增强可访问性和用户体验

frontend/src/components/Header.astro

@@ -48,7 +48,7 @@ const currentNavLabel =
 
 <header data-ai-search-enabled={aiEnabled ? 'true' : 'false'} class="sticky top-0 z-50 border-b border-[var(--border-color)] backdrop-blur-xl" style="background-color: color-mix(in oklab, var(--bg) 88%, transparent);">
   <div class="max-w-6xl mx-auto px-4 sm:px-6 lg:px-8 py-2.5">
-    <div class="terminal-toolbar-shell">
+    <div class="terminal-toolbar-shell overflow-visible">
       <div class="flex flex-col gap-2.5">
         <div class="flex items-center gap-2 lg:flex-nowrap">
           <a href="/" class="terminal-toolbar-module shrink-0 min-w-[9.5rem] px-2.5 py-1.5 hover:border-[var(--primary)] transition-all">
@@ -101,7 +101,7 @@ const currentNavLabel =
             </p>
             <div
               id="search-results"
-              class="hidden absolute right-0 top-[calc(100%+12px)] z-20 w-[26rem] overflow-hidden rounded-2xl border border-[var(--border-color)] bg-[var(--terminal-bg)] shadow-[0_20px_40px_rgba(15,23,42,0.08)]"
+              class="hidden absolute left-0 top-[calc(100%+12px)] z-40 w-[min(34rem,calc(100vw-4rem))] overflow-hidden rounded-[24px] border border-[var(--border-color)]/80 bg-[color-mix(in_oklab,var(--terminal-bg)_94%,white)] shadow-[0_24px_60px_rgba(15,23,42,0.14)] backdrop-blur-xl"
             ></div>
           </div>