margin-left: 210px;
border: 1px solid #000;
height: 500px;
父元素中设置
position: relative;
左侧栏脱离文档流,但高度仍然跟随父元素高度变化
position: absolute;
top: 0;
left: 0;
bottom: 0;
width: 200px;
border: 1px solid pink;
margin-left: 210px;
border: 1px solid #000;
height: 500px;
父元素中设置
position: relative;