注意了，现在的谷歌不兼容响应式布局的
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<link rel="stylesheet" type="text/css" href="./index.css" media="only screen and (max-width:480px)"/>
<style type="text/css">
@media screen and (min-width: 490px) {
body {background: blue;}
}
</style>
</head>
<body>
</body>
</html>
换成IE或者火狐,Edge可以
