<title>响应式布局</title>
<link rel="stylesheet" href="apple-pc.css" media="only screen and (min-width:1000px)">
<link rel="stylesheet" href="apple-pad.css" media="only screen and (min-width: 760px) and (max-width:1000px)">
<link rel="stylesheet" href="apple-phone.css" media="only screen and (max-width: 760px)">
使网页适用于不同屏幕的大小主要取决于宽度
在设定样式的时候,不要忘了在每个样式当中将其他端口的样式隐藏掉