1.安装以下包

 npm i lib-flexible sass-loader node-sass postcss-px2rem-exclude   --save

2.npm run eject 暴露webpack配置，添加以下代码

const px2rem = require('postcss-px2rem-exclude');
 px2rem({remUnit:75,exclude: /node_modules/i})

3.在index.js中引入

import "lib-flexible"

4.修改index.html

<meta content="width=device-width,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no" name="viewport" />

5.根据图纸太小修改node文件中的flexible.js配置文件