[site/pages][xs]: create 404 page with an image

site/pages/404.js

@@ -0,0 +1,8 @@
+export default function () {
+    return (
+      <div className="flex flex-col items-center justify-center mt-12 sm:mt-20 xl:mt-36 space-y-8">
+        <img src="/img/undraw_page_not_found.svg" alt="404" className="px-8 sm:px-0 max-w-xs m-auto" />
+        <p className="text-lg">Page not found</p>
+      </div>
+    );
+}