Fix UI — CSS variables, sidebar toggle with chevron, settings panel pushes content

components/Sidebar.tsx

@@ -27,7 +27,7 @@ function groupConversations(convs: { id: string; title: string; updated_at: stri
   return groups;
 }
 
-export default function Sidebar() {
+export default function Sidebar({ onClose }: { onClose?: () => void }) {
   const { conversations, currentId, setCurrentId, setMessages, setConversations, setSidebarOpen } = useStore();
 
   async function newConversation() {
@@ -36,7 +36,7 @@ export default function Sidebar() {
     setConversations(updated);
     setCurrentId(conv.id);
     setMessages([]);
-    setSidebarOpen(false);
+    if (onClose) onClose();
   }
 
   async function loadConversation(id: string) {