新增导航栏样式控制

src/App.vue

@@ -1,5 +1,5 @@
 <template>
-  <div>
+  <div :class="{ fullscreen: isFullscreen }">
     <template>
       <transition name="router-fade" mode="out-in">
         <keep-alive>
@@ -17,7 +17,9 @@
 export default {
   name: "app",
   data() {
-    return {};
+    return {
+      isFullscreen: false // 是否全屏
+    };
   }
 };
 </script>
@@ -30,4 +32,9 @@ export default {
 .router-fade-leave-to {
   opacity: 0;
 }
+.fullscreen {
+  .van-nav-bar {
+    background-color: red;
+  }
+}
 </style>