<link rel="stylesheet" href="css/1.css" media="(max-width:479px)"/>
<link rel="stylesheet" href="css/1.css" media="(min-width: 480px) and (max-width: 767px)"/>
<link rel="stylesheet" href="css/1.css" media="(min-width: 768px) and (max-width: 959px)"/>
<link rel="stylesheet" href="css/1.css" media="(min-width: 960px) and (max-width: 1199px)"/>
<link rel="stylesheet" href="css/1.css" media="(min-width:1200px)"/>
原文：http://www.cnblogs.com/jayruan/p/7291572.html