fix: use standard style tag for responsive layout

Replace styled-jsx with standard style tag to avoid TypeScript errors.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/index.tsx

@@ -67,13 +67,16 @@ export default function Index() {
         </div>
 
         {/* 快捷操作卡片区域 */}
-        <div style={{
+        <div
+          className="quick-actions-grid"
+          style={{
             display: 'grid',
             gridTemplateColumns: 'repeat(auto-fit, minmax(280px, 1fr))',
             gap: 24,
             maxWidth: 900,
             margin: '0 auto',
-        }}>
+          }}
+        >
           {quickActions.map((action) => (
             <QuickActionCard
               key={action.path}
@@ -87,10 +90,10 @@ export default function Index() {
         </div>
 
         {/* 移动端响应式样式 */}
-        <style jsx>{`
+        <style>{`
           @media (max-width: 768px) {
-            div[style*="gridTemplateColumns"] {
-              gridTemplateColumns: 1fr !important;
+            .quick-actions-grid {
+              grid-template-columns: 1fr !important;
             }
           }
         `}</style>