fix: dark mode toggle not working - Tailwind requires class=dark

app/templates/base.html

@@ -70,17 +70,29 @@
     
     {# 主题切换脚本 #}
     <script>
-        // 初始化主题
+        // 初始化主题 - Tailwind darkMode: 'class' 需要 class="dark"
         const savedTheme = localStorage.getItem('theme') || 'light';
-        document.documentElement.setAttribute('data-theme', savedTheme);
+        applyTheme(savedTheme);
+        
+        // 应用主题
+        function applyTheme(theme) {
+            const html = document.documentElement;
+            if (theme === 'dark') {
+                html.classList.add('dark');
+                html.setAttribute('data-theme', 'dark');
+            } else {
+                html.classList.remove('dark');
+                html.setAttribute('data-theme', 'light');
+            }
+        }
         
         // 主题切换函数
         function toggleTheme() {
             const html = document.documentElement;
-            const current = html.getAttribute('data-theme');
-            const next = current === 'light' ? 'dark' : 'light';
+            const isDark = html.classList.contains('dark');
+            const next = isDark ? 'light' : 'dark';
             
-            html.setAttribute('data-theme', next);
+            applyTheme(next);
             localStorage.setItem('theme', next);
         }