fix

frontend/src/services/api.ts

@@ -1,5 +1,9 @@
+// Use empty string for same-origin requests in production (HF Spaces)
+// Only fallback to localhost:8000 if VITE_API_BASE_URL is truly undefined
 const baseURL =
-  import.meta.env.VITE_API_BASE_URL || "http://localhost:8000";
+  import.meta.env.VITE_API_BASE_URL !== undefined
+    ? import.meta.env.VITE_API_BASE_URL
+    : "http://localhost:8000";
 
 export interface ResearchRequest {
   topic: string;