npm install --save-dev sass-loader
//sass-loader依赖于node-sass
npm install --save-dev node-sass

{
 test: /\.sass$/,
 loaders: ['style', 'css', 'sass']
}

<style lang="scss"></style>

$ npm run dev

npm install --save-dev sass-resources-loader

// 全局文件引入 当然只想编译一个文件的话可以省去这个函数
function resolveResource(name) {
 return path.resolve(__dirname, '../src/style/' + name);
}
function generateSassResourceLoader() {
 var loaders = [
  cssLoader,
  'sass-loader',
  {
   loader: 'sass-resources-loader',
   options: {
    // 多个文件时用数组的形式传入，单个文件时可以直接使用 path.resolve(__dirname, '../static/style/common.scss'
    resources: [resolveResource('theme.scss')] 
   }
  }
  ];
  if (options.extract) {
   return ExtractTextPlugin.extract({
    use: loaders,
    fallback: 'vue-style-loader'
   })
  } else {
   return ['vue-style-loader'].concat(loaders)
  }
 }

return {
  css: generateLoaders(),
  postcss: generateLoaders(),
  less: generateLoaders('less'),
  // vue-cli默认sass配置
  // sass: generateLoaders('sass', { indentedSyntax: true }), 
  // scss: generateLoaders('sass'),
  // 新引入的sass-resources-loader
  sass: generateSassResourceLoader(),
  scss: generateSassResourceLoader(),
  stylus: generateLoaders('stylus'),
  styl: generateLoaders('stylus')
 }

$c-primary: #fd7a00;
$theme-blue: #3296fa;
$theme-red: #da3838;