fix: 修复移动端副导航栏未隐藏的问题

web/src/App.vue

@@ -304,10 +304,12 @@ body {
 
 /* 默认隐藏侧边栏，小屏幕适配 */
 .left-sidebar { display: none; }
+.left-subnav { display: none; } /* 默认隐藏平板导航 */
 
 /* 平板及以上显示副导航 */
 @media (min-width: 768px) {
   .left-subnav {
+    display: flex;
     width: var(--subnav-width);
     min-width: var(--subnav-width);
     flex-shrink: 0;
@@ -369,12 +371,14 @@ body {
   background: rgba(0, 0, 0, 0.5);
   z-index: 1000;
   opacity: 0;
+  pointer-events: none;
   transition: opacity 0.3s;
 }
 
 .mobile-drawer.open {
   display: block;
   opacity: 1;
+  pointer-events: auto;
 }
 
 .drawer-content {
@@ -386,12 +390,20 @@ body {
   max-width: 80vw;
   transform: translateX(-100%);
   transition: transform 0.3s;
+  overflow: hidden;
 }
 
 .mobile-drawer.open .drawer-content {
   transform: translateX(0);
 }
 
+/* 确保抽屉内的 AppSidebar 有正确样式 */
+.drawer-content .sidebar {
+  width: 100%;
+  position: static;
+  height: 100%;
+}
+
 /* 移动端：小屏幕隐藏副导航，显示汉堡菜单按钮 */
 @media (max-width: 767px) {
   .content-wrapper {