SOURCE

console 命令行工具 X clear

                    
>
console
<div class="box">
  <div class="content">内容</div>
  <div class="footer">底部</div>
</div>
*{
      margin: 0;
      padding: 0;
    }
    html,body{
      height: 100%;
    }
    .box{
      height: 100%;
      display: flex;
      flex-direction: column;
    }
    .box .content{
      flex: 1;
      border: 1px solid #f00;
    }