vue-cli3.0 怎么配置px2rem-loader？放了几个位置都报错

Question

根据文档，px2rem-loader应该是配置在vue.config.js里的，我开始放在css.loaderOption里,yunq

---

  loaderOptions: {
    px2rem:{
      options:{
        remUnit:75,
        dpr:2
      }
    }
  },

---

然后就提示 Invalid options in vue.config.js: child "css" fails because [child "loaderOptions" fails because ["px2rem" is not allowed]]

放在chainWebpack也不行。有大神可以贴个代码我看下或者提供一个文档我看下么？