媒体查询技术

screen 媒介类型 print and 条件 not only
@media screen and (max-width: 1200px){
/*常规CSS*/
body{
background-color: red;
}
.box1{
width: 200px;
height: 200px;
background-color: yellow;
}
}

<link rel="stylesheet" href="global1.css" media="screen and (max-width: 1200px)">
<link rel="stylesheet" href="global2.css" media="screen and (max-width: 800px)">