diff --git a/frontend/src/components/ChatPanel.vue b/frontend/src/components/ChatPanel.vue
index 6ce9ef4..5678756 100644
--- a/frontend/src/components/ChatPanel.vue
+++ b/frontend/src/components/ChatPanel.vue
@@ -128,7 +128,7 @@ const hasContextData = computed(
 // ── Narrow-viewport sidebar toggle ────────────────────────────────────────────
 const NARROW_BREAKPOINT = 1200
 const isNarrow = ref(typeof window !== 'undefined' && window.innerWidth < NARROW_BREAKPOINT)
-const sidebarOpen = ref(!isNarrow.value)
+const sidebarOpen = ref(false)
 
 function onResize() {
   isNarrow.value = window.innerWidth < NARROW_BREAKPOINT