响应式布局
<link rel="stylesheet" href="css1.css" media="screen and (min-width:800px)"/>
<link rel="stylesheet" href="css2.css" media="screen and (min-width:600px) and (max-width:800px)"/>
<link rel="stylesheet" href="css3.css" media="screen and (max-width:400px)"/>
横屏portrait竖屏landscape
<link rel="stylesheet" href="css3.css" media="screen and (orientation:portrait)"/>
<link rel="stylesheet" href="css1.css" media="screen and (orientation:landscape)"/>
行内样式
@media screen and (min-width: 800px){}
@media screen and (min-width: 400px) and (max-width: 800px){}
@media screen and (max-width: 400px){}
Css3分栏布局
column-width 栏目宽度
column-count 栏目列数
column-gap 栏目距离
column-rule 栏目间隔线
