rem

app.js

require('./index.scss');

//获取屏幕宽度(viewport)

let htmlWidth=document.documentElement.clientWidth || document.body.clientWidth;

//获取html的dom

let htmlDom = document.getElementsByTagName('html')[0];

//设置html的fontSize

htmlDom.style.fontSize=htmlWidth/10+'px';

 window.addEventListener('resize',(e)=>{

　　let htmlWidth=document.documentElement.clientWidth || document.body.clientWidth;

　　htmlDom.style.fontSize=htmlWidth/10+'px';

});

npm install node-sass

 node-sass a.css b.css

@function px2rem($px){

　　$rem : 37.5px;

　　@return ( $px / $rem ) + rem　　

}

<meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,minimum-scale=1,user-scalable=no">