针对Retina屏幕的CSS，From http://www.qianduan.net/optimized-for-high-resolution-screen-style.html

retina.css

@media only screen and (-webkit-min-device-pixel-ratio: 1.5), only screen and ( min--moz-device-pixel-ratio: 1.5), only screen and ( -o-min-device-pixel-ratio: 3/2), only screen and ( min-device-pixel-ratio: 1.5), only screen and (min-resolution: 192dpi) {
 /* Style Rules */ 
}