fix: hide empty MobileDrawers overlays that covered real sidebar content on mobile

- MobileDrawers component rendered empty drawer-left/drawer-right overlays
- These had drawer-body with 0 children, covering the real leftbar/rightbar
- Real sidebars with actual content now visible as slide-in overlays

frontend/src/styles.css

@@ -1268,6 +1268,9 @@ a:hover { text-decoration: underline; }
   }
   .leftbar.open { transform: translateX(0); }
   .rightbar.open { transform: translateX(0); }
+  /* Hide empty MobileDrawers overlays — real sidebars are used as slide-in overlays */
+  .drawer { display: none !important; }
+  body.drawer-open { overflow: auto !important; }
   /* Mobile sidebars: scrollable content, visible labels */
   .leftbar { overflow-y: auto; -webkit-overflow-scrolling: touch; }
   .leftbar-title { display: block; }