<div class="box">
<div class="box1">1</div>
<div class="box2">2</div>
<div class="box3">3</div>
</div>
css
<style type="text/css">
*{margin: 0px;padding: 0px;}
.box{display: flex;flex: 3;}
.box1{flex: 1;border: 1px solid red;order: 1;}
.box2{flex: 1;border:1px solid blue;order: 3;}
.box3{flex: 1; border:1px solid yellow;order:2;}
</style>
排序：order