diff --git a/app/_not-found/page.tsx b/app/_not-found/page.tsx
new file mode 100644
index 000000000..a6006221a
--- /dev/null
+++ b/app/_not-found/page.tsx
@@ -0,0 +1,9 @@
+// app/_not-found/page.tsx
+export default function InternalNotFound() {
+  return (
+    <div style={{ padding: 40, textAlign: 'center' }}>
+      <h1 style={{ fontSize: 48, marginBottom: 16 }}>404</h1>
+      <p style={{ fontSize: 18 }}>Page not found.</p>
+    </div>
+  )
+}