add error page

src/error-page.tsx

@@ -0,0 +1,16 @@
+import { useRouteError } from "react-router-dom";
+
+export default function ErrorPage() {
+  const error: any = useRouteError();
+  console.error(error);
+
+  return (
+    <div id="error-page">
+      <h1>Oops!</h1>
+      <p>Sorry, an unexpected error has occurred.</p>
+      <p>
+        <i>{error.statusText || error.message}</i>
+      </p>
+    </div>
+  );
+}