CSS 弹性元素扩展比率

演示代码：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <link rel="stylesheet" type="text/css" href="reset.css"/>
        <style type="text/css">
            .box{
                width: 400px;height: 400px;background-color: aqua;
                margin: 100px auto;overflow: hidden;
                display: flex;/* 转成弹性盒子 */
                flex-wrap: wrap;
                justify-content: space-between;
                align-content: space-between;
            }
            .wyzx{
                width: 120px;height: 50px;line-height: 50px;
                background-color: red;text-align: center;color: white;
            }
            #n1{
                background-color: #FF0000;width: 50px;
                flex-grow: 1;/* 1/6 */
            }
            #n2{
                background-color: #00ff00;width: 70px;
                flex-grow: 2;/* 2/6 */
            }
            #n3{
                background-color: #0000ff;width: 90px;
                flex-grow: 3;/* 3/6 */
            }
        </style>
    </head>
    <body>
        <!-- 
        设置弹性元素扩展比flex-grow来分配剩余空间，默认值为0
         -->
        <!-- ul.box>li.wyzx{我要自学$}*3 -->
        <ul class="box">
            <li id="n1" class="wyzx">我要自学1</li>
            <li id="n2" class="wyzx">我要自学2</li>
            <li id="n3" class="wyzx">我要自学3</li>
        </ul>
    </body>
</html>