响应式布局设置--@media only screen and //各种浏览器的Hack写法(chrome firefox ie等)

http://chaofu200900.blog.163.com/blog/static/110119533201341102618140/

http://wow.techbrood.com/static/20150707/9704.html

http://bjango.com/articles/min-device-pixel-ratio/

http://www.wufangbo.com/css-hack/