fix: default theme

index.html

@@ -4,6 +4,20 @@
     <meta charset="UTF-8" />
     <link rel="icon" type="image/svg+xml" href="/vite.svg" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <script>
+      (function() {
+        const storageKey = 'vite-ui-theme';
+        const theme = localStorage.getItem(storageKey) || 'system';
+        const root = document.documentElement;
+        
+        if (theme === 'system') {
+          const systemTheme = window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
+          root.classList.add(systemTheme);
+        } else {
+          root.classList.add(theme);
+        }
+      })();
+    </script>
     <link
       rel="stylesheet"
       href="https://cdn.jsdelivr.net/gh/lipis/flag-icons@7.0.0/css/flag-icons.min.css"