console 命令行工具 X clear
console
<style>
#flex{
    flex-direction: column;
    display:-webkit-flex;display:flex;width:400px;border:1px green solid;margin:0;padding:0;list-style:none;}
#flex li:nth-child(1){flex:1 0 100px;background:#888;}
#flex li:nth-child(2){flex:2 0 100px;background:#ccc;}
#flex li:nth-child(3){flex:3 0 300px;background:#aaa;}
</style>
</head>
<body>
<ul id="flex">
    <li>a</li>
    <li>b</li>
    <li>c</li>
</ul>