title: Vue-cli import css not work
body: <pre><code>&lt;style src="@/assets/css/base.css"&gt; -&gt;ok
  &lt;style src="./assets/css/base.css"&gt; -&gt;error
  
  This dependency was not found:
  * !!vue-style-loader!css-loader?{"sourceMap":true}!../../node_modules/vue-loader/lib/style-compiler/index?{"vue":true,"id":"data-v-656039f0","scoped":false,"hasInlineConfig":false}!./assets/css/base.css in ./src/components/HelloWorld.vue
  
  To install it, you can run: npm install --save !!vue-style-loader!css-loader?{"sourceMap":true}!../../node_modules/vue-loader/lib/style-compiler/index?{"vue":true,"id":"data-v-656039f0","scoped":false,"hasInlineConfig":false}!./assets/css/base.css
  
  @import '@/assets/css/base.css' -&gt;error
  @import './assets/css/base.css' -&gt;error
  
  Module build failed: Error: Failed to find '@/assets/css/base.css'
  @ ./node_modules/vue-style-loader!./node_modules/css-loader?{"sourceMap":true}!./node_modules/vue-loader/lib/style-compiler?{"vue":true,"id":"data-v-656039f0","scoped":false,"hasInlineConfig":false}!./node_modules/vue-loader/lib/selector.js?type=styles&amp;index=0!./src/components/HelloWorld.vue 4:14-312 13:3-17:5 14:22-320
  </code></pre>
  
  <p>I search a lot of methods, and I tried, but it doesn't work.
  I do't know which method can solute my problem.</p>