css布局一屏幕的自适应高度

css

 *{margin: 0; padding: 0;list-style: none;} 
 .top{height: 100px;background-color:orange;}
 .max{width: 100%;position:absolute;top: 100px;bottom:0;background-color:skyblue;}

html

 <div class="top">
       top
 </div>

<div class="max">
       main
 </div>