但是当你新建一个vue项目时，需要重新安装stylus，否则报错：
This dependency was not found:
* !!vue-style-loader!css-loader?{"minimize":false,"sourceMap":false}!../../node_modules/vue-loader/lib/style-compiler/index?{"vue":true,"id":"data-v-1d57e5ea","scoped":false,"hasInlineConfig":false}!stylus-loader?{"sourceMap":false}!../../node_modules/vue-loader/lib/selector?type=styles&index=0!./a.vue in ./src/components/a.vue
To install it, you can run: npm install --save !!vue-style-loader!css-loader?{"minimize":false,"sourceMap":false}!../../node_modules/vue-loader/lib/style-compiler/index?{"vue":true,"id":"data-v-1d57e5ea","scoped":false,"hasInlineConfig":false}!stylus-loader?{"sourceMap":false}!../../node_modules/vue-loader/lib/selector?type=styles&index=0!./a.vue
解决步骤：
当前目录（项目）下：
npm install stylus-loader css-loader style-loader --save-dev
npm run dev 。
