chore: do new design mockup

src/app.html

@@ -8,7 +8,7 @@
   %sveltekit.head%
 </head>
 
-<body data-sveltekit-preload-data="hover">
+<body class="bg-theme-950" data-sveltekit-preload-data="hover">
   <div style="display: contents">%sveltekit.body%</div>
 </body>