create basic layout

src/app.html

@@ -6,7 +6,7 @@
 		<meta name="viewport" content="width=device-width" />
 		%sveltekit.head%
 	</head>
-	<body data-sveltekit-preload-data="hover">
+	<body class="h-screen flex flex-col justify-between" data-sveltekit-preload-data="hover">
 		<div style="display: contents">%sveltekit.body%</div>
 	</body>
 </html>