Updated header and added not found page

src/app/not-found.tsx

@@ -0,0 +1,22 @@
+import Header from "@/components/header"
+import { Button } from "@/components/ui/button"
+import { ArrowLeftIcon } from "lucide-react"
+import Link from "next/link"
+
+export default function NotFound() {
+    return (
+        <div>
+            <Header searchBar />
+            <main className="flex flex-col items-center pt-header">
+                <Button className="self-start mt-4 ml-4" variant="secondary" asChild>
+                    <Link href="/">
+                        <ArrowLeftIcon />
+                        Back to Main page
+                    </Link>
+                </Button>
+                <h1 className="pt-20 text-3xl font-bold max-w-fit">404</h1>
+                <h1 className="text-3xl font-bold max-w-fit">Page not found</h1>
+            </main>
+        </div>
+    )
+}