5.4 테마/다크모드 및 반응형 설정 o

src/app/components/AppHeader.tsx

@@ -1,3 +1,5 @@
+import { ThemeToggle } from "@/app/components/ThemeToggle";
+
 export function AppHeader() {
   return (
     <header style={{ display: "flex", justifyContent: "space-between", padding: 12 }}>
@@ -5,6 +7,7 @@ export function AppHeader() {
       <nav style={{ display: "flex", gap: 12 }}>
         <a href="/">홈</a>
         <a href="/boards">게시판</a>
+        <ThemeToggle />
       </nav>
     </header>
   );