diff --git a/vite.config.ts b/vite.config.ts
index d32eba1..c255a02 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -3,5 +3,9 @@ import { svelte } from '@sveltejs/vite-plugin-svelte'
 
 // https://vite.dev/config/
 export default defineConfig({
+  // Hosted as a sub-app under chess.sethpc.xyz/duplicate/ alongside blind_chess.
+  // Setting `base` makes Vite emit asset URLs with the /duplicate/ prefix so they
+  // stay inside the Caddy static handler instead of falling through to blind_chess.
+  base: '/duplicate/',
   plugins: [svelte()],
 })