diff --git a/app/static/js/chat.js b/app/static/js/chat.js
index 2ba829f..a804e8e 100644
--- a/app/static/js/chat.js
+++ b/app/static/js/chat.js
@@ -1,5 +1,6 @@
 // ── Chat Widget JavaScript ──
-const BASE_PATH = window.BASE_PATH || '';
+// BASE_PATH is declared in main.js (loaded first on index.html)
+if (typeof BASE_PATH === 'undefined') var BASE_PATH = window.BASE_PATH || '';
 
 let chatSessionId = sessionStorage.getItem('chat_session');
 if (!chatSessionId) {