chore(playground): dark mode [ci skip]

playground/src/App.vue

@@ -65,8 +65,6 @@ const log = (arg: any) => {
 }
 
 html {
-  color-scheme: dark;
-  background-color: #000;
   padding: 10px;
 }
 </style>

playground/src/main.ts

@@ -1,4 +1,5 @@
 import { render, unmountComponent } from 'vue/vapor'
+import './style.css'
 
 const modules = import.meta.glob<any>('./*.(vue|js)')
 const mod = (modules['.' + location.pathname] || modules['./App.vue'])()

playground/src/style.css

@@ -0,0 +1,5 @@
+@media (prefers-color-scheme: dark) {
+  html {
+    color-scheme: dark;
+  }
+}