flyLong/app2/src/App.vue

<template>
  <div id="app">
    <router-view/>
  </div>
</template>

<script>
export default {
  name: 'App'
}
</script>

<style>
    #app {
        position: absolute;
        top: 0;
        bottom: 0;
        left: 0;
        right: 0;
        width: 100%;
        overflow: hidden;
        display: block;
        margin: 0 auto;
    }
</style>