我app.vue打开不一样

<template>

  <div id="app">

    <img src="./assets/logo.png">

    <router-view/>

  </div>

</template>

<script>

export default {

  name: 'App'

}

</script>

<style>

#app {

  font-family: 'Avenir', Helvetica, Arial, sans-serif;

  -webkit-font-smoothing: antialiased;

  -moz-osx-font-smoothing: grayscale;

  text-align: center;

  color: #2c3e50;

  margin-top: 60px;

}

</style>

它是这样的，字体也都是黑色的