update styling

frontend/src/App.svelte

@@ -8,9 +8,9 @@
   let url: string = $state("/");
 </script>
 
-<main class="flex-col h-screen items-center bg-gray-50 dark:bg-gray-800">
+<main class="flex-col h-screen items-center bg-gray-50 dark:bg-gray-900">
   <Router bind:url>
-    <Navbar color="form">
+    <Navbar class="border-b">
       <button
         class="grid grid-cols-3 items-center"
         onclick={() => navigate("/")}