diff --git a/frontend/src/constants/app.ts b/frontend/src/constants/app.ts
index 4223c76b3..c83cffcfd 100644
--- a/frontend/src/constants/app.ts
+++ b/frontend/src/constants/app.ts
@@ -7,7 +7,8 @@ export const getBaseUrl = (): string => {
 };
 
 // Base path from Vite config - build-time constant, normalized (no trailing slash)
-export const BASE_PATH = (import.meta.env.BASE_URL || '/').replace(/\/$/, '');
+// When no subpath, use empty string instead of '.' to avoid relative path issues
+export const BASE_PATH = (import.meta.env.BASE_URL || '/').replace(/\/$/, '').replace(/^\.$/, '');
 
 /** For in-app navigations when you must touch window.location (rare). */
 export const withBasePath = (path: string): string => {