移动端rem

注意@media only screen写在需要操控的样式后面，对已声明样式才可以重新赋予新样式，媒体查询@media写在style靠前是不规范的写法，切记。
如果懒得不愿动手可直接将@media的代码放置style尾部。

/*iphone 4  screen-width:320px*/
@media only screen and (min-width: 320px) and (max-width: 360px) {}

/*三星Galaxy S5  screen-width:360px*/
@media only screen and (min-width: 360px) and (max-width: 375px) {}

/*iphone 6  screen-width:375px*/
@media only screen and (min-width: 375px) and (max-width: 414px) {}

/*iphone 6plus  screen-width:414px*/
@media only screen and (min-width: 414px) and (max-width: 768px) {}

/*iPad Mini  screen-width:768px*/
@media only screen and (min-width: 768px){}