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？