diff --git a/web/index.html b/web/index.html
index 934e76c..100d9fb 100644
--- a/web/index.html
+++ b/web/index.html
@@ -15,7 +15,13 @@
 
 <body>
   <div id="root"></div>
-  <script>window.__publicField = function(a, b, c) { a[b] = c; return c; };</script>
+  <script>
+    globalThis.__publicField = function(obj, key, value) {
+      Object.defineProperty(obj, typeof key !== 'symbol' ? key + '' : key, {
+        configurable: true, enumerable: true, writable: true, value: value
+      });
+    };
+  </script>
   <script type="module" src="/src/main.tsx"></script>
 </body>
 
diff --git a/web/vite.config.ts b/web/vite.config.ts
index fac8819..0e21f22 100644
--- a/web/vite.config.ts
+++ b/web/vite.config.ts
@@ -5,6 +5,12 @@ import { resolve } from 'path';
 
 // https://vitejs.dev/config/
 export default defineConfig({
+  define: {
+    // Some pre-compiled npm packages use __publicField (a TypeScript/esbuild helper)
+    // without bundling it. Rewrite bare references to a globalThis property that
+    // we polyfill in index.html before any module code runs.
+    '__publicField': 'globalThis.__publicField',
+  },
   plugins: [
     react(),
     TanStackRouterVite(),
