vue-loader安装后在.vue里的<style></style>里面写样式就报错?

Question

提问:请问下,vue-loader也安装了为何在.vue的style标签了 还是不能写样式呢?webpack4,使用webpack-dev-server命令打包时就报错.应该如何解决?
我已经尝试卸载vue-loader重新安装,删除node-modules重新跑环境,但并没有解决掉.难到是某个加载器的版本的问题吗?
main.js

import Vue from 'vue';
import app from './App.vue';
import { Header } from 'mint-ui';
Vue.component(Header.name, Header);
var vm=new Vue({
  el:'#app',
  render:c=>c(app)
});

App.vue

<template>
  <div class="box">
<!--header-->
    <mt-header fixed title="固定在顶部"></mt-header>
<!--body-->
<!--foot-->
    <h1>这是 App 组件</h1>
  </div>
</template>
<script>
</script>
<style lang="sass" scoped>
  .box{
    padding-top:40px;
  }
</style>

package.json

  "devDependencies": {
    "babel-core": "^6.26.0",
    "babel-loader": "^7.1.2",
    "babel-plugin-component": "^0.10.1",
    "babel-plugin-transform-runtime": "^6.23.0",
    "babel-preset-env": "^1.6.1",
    "babel-preset-stage-0": "^6.24.1",
    "css-loader": "^0.28.7",
    "file-loader": "^1.1.5",
    "html-webpack-plugin": "^2.30.1",
    "less": "^2.7.3",
    "less-loader": "^4.0.5",
    "node-sass": "^4.5.3",
    "sass-loader": "^6.0.6",
    "style-loader": "^0.19.0",
    "url-loader": "^0.6.2",
    "vue-loader": "^13.3.0",
    "vue-template-compiler": "^2.5.2",
    "webpack": "^3.8.1",
    "webpack-dev-server": "^2.9.3"
  },
  "dependencies": {
    "bootstrap": "^3.3.7",
    "mint-ui": "^2.2.9",
    "vue": "^2.5.2",
    "vue-router": "^3.0.1"
  }
}

错误提示:

ERROR in ./node_modules/css-loader!./node_modules/vue-loader/lib/style-compiler?{"vue":true,"id":"data-v-7ba5bd90","scoped":

true,"hasInlineConfig":false}!./node_modules/sass-loader/lib/loader.js?indentedSyntax!./node_modules/vue-loader/lib/selector

.js?type=styles&index=0!./src/App.vue

Module build failed: 
  .box{
    ^
      Invalid CSS after ".box{": expected "}", was "{"
      in F:\vuetest\day7\src\App.vue (line 19, column 6)
 @ ./node_modules/vue-style-loader!./node_modules/css-loader!./node_modules/vue-loader/lib/style-compiler?{"vue":true,"id":"
data-v-7ba5bd90","scoped":true,"hasInlineConfig":false}!./node_modules/sass-loader/lib/loader.js?indentedSyntax!./node_modul
es/vue-loader/lib/selector.js?type=styles&index=0!./src/App.vue 4:14-331 13:3-17:5 14:22-339
 @ ./src/App.vue
 @ ./src/main.js
 @ multi (webpack)-dev-server/client?http://localhost:3000 webpack/hot/dev-server ./src/main.js

Answer 1

找到问题所在了. 因为用了 sass 是不能用{}语法的. </p>

Answer 2

啥意思啊，我用的less，还是不行，心态炸了