Almost finish implementing client side

Client/app/components/NotFound.tsx

@@ -0,0 +1,9 @@
+export function NotFound() {
+    return (
+        <div className="flex flex-col items-center justify-center min-h-screen bg-gray-100">
+            <h1 className="text-6xl font-bold text-gray-800 mb-4">404</h1>
+            <p className="text-xl text-gray-600 mb-8">The page you are looking for does not exist.</p>
+            <a href="/" className="text-blue-500 hover:underline">Go back to Home</a>
+        </div>
+    );
+}