2栏布局 右侧自适应
flex
grid
table
float
<style >body{height: 400px;}.son1{width: 20%;height: 100%;float: left;}.son2{margin-left: 20%;height: 100%;}</style>
<body> <div class="son1" style="background-color: #d2e085;"> A </div><div class="son2" style="background-color: #7cdbe4;"> B </div></body>