1.

/*@media Rule*/

@media all and (max-width : 1024px){...}

2.

/*@imput Rule*/

@imput url(styles.css)  all and (max-width : 1024px){...}

3.

<link rel = "stylesheet" href = "http://www.mamicode.com/styles.css" media = " all and (max-width : 1024px)">

三种方式加入媒体样式