init: add project files

src/app/not-found.tsx

@@ -0,0 +1,23 @@
+import { Button } from '@/components/Button'
+import { Container } from '@/components/Container'
+
+export default function NotFound() {
+  return (
+    <Container className="flex h-full items-center pt-16 sm:pt-32">
+      <div className="flex flex-col items-center">
+        <p className="text-base font-semibold text-zinc-400 dark:text-zinc-500">
+          404
+        </p>
+        <h1 className="mt-4 text-4xl font-bold tracking-tight text-zinc-800 dark:text-zinc-100 sm:text-5xl">
+          Page not found
+        </h1>
+        <p className="mt-4 text-base text-zinc-600 dark:text-zinc-400">
+          Sorry, we couldn’t find the page you’re looking for.
+        </p>
+        <Button href="/" variant="secondary" className="mt-4">
+          Go back home
+        </Button>
+      </div>
+    </Container>
+  )
+}