src/app/not-found.tsx

export default function NotFound() {
  return (
    <div className="container-px max-w-wrapper py-24">
      <h1 className="text-3xl font-semibold">Not found</h1>
      <p className="mt-2 text-muted">The page you’re looking for doesn’t exist.</p>
    </div>
  );
}