1：彈性盒子 流式布局 CSS:

main

{ flex: 1; border-top: 5px solid #f5f5f9; display: flex; flex-direction: row; flex-wrap: wrap; align-content: flex-start; overflow: auto; background-color: #000000; }

main div{

            width: 25%;
            height: 24vw;
            background: deepskyblue;
            border-bottom: 1px solid #e6e6e6;
            border-right: 1px solid #e6e6e6;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
        }
        #main div em{
            color: #dd2727;
            font-size: 6.67vw!important;
        }
        #main div a{
            color: #dd2727;
            font-size: 3.2vw;
        }