Vue：Backcolor没有变化

Question

我第一次尝试使用Vue-Material，当我尝试更改默认主题的背景颜色时，它根本不会改变颜色，背景颜色总是变白。我正在做以下事情：

 <div class="panel panel-default" ng-init="getBook()">
 <div class="panel-heading">
<h3 class="panel-title">{{book.title}}</h3>
</div>
<div class="panel-body">
<div class "row">
    <div class ="col-md-4">
            <img src="{{book.image_url}}">
    </div>
    <div class ="col-md-8">
        <p>{{book.description}}</p>
        <ul class="list-group">
            <li class="list-group-item">Genre: {{book.genre}}</li>
            <li class="list-group-item">Author: {{book.author}}</li>
            <li class="list-group-item">Publisher: {{book.publisher}}
</li>


        </ul>
    </div>
</div>
</div>
</div>

我也尝试过，如Vue-Material文档中所示：

import Vue from 'vue'

import VueMaterial from 'vue-material'

import App from './App'

Vue.use(VueMaterial)

Vue.material.registerTheme({
  default: {
    primary: 'red',
    accent: 'red',
    background: {
      color: 'blue-grey',
      hue: 800
    }
  },
  green: {
    primary: 'green',
    accent: 'pink'
  },
  orange: {
    primary: 'orange',
    accent: 'green'
  }
})

new Vue({
  el: '#app',
  render: h => h(App)
})

有什么问题？