css3@media 兼容ios4，ios5，ios6,6plus

//device-height  设备可视高度//-webkit-min-device-pixel-ratio    是设备上物理像素和设备独立像素,设备像素比率@media (device-height:480px) and (-webkit-min-device-pixel-ratio:2) {                /* 兼容iphone4/4s */                html{}            }            @media (max-device-width:621px) and (-webkit-min-device-pixel-ratio:3) {                /* 兼容iphone6p */                html{}            }            @media (device-height:667px) and (-webkit-min-device-pixel-ratio:2) {                /* 兼容iphone6 */                html{}            }/*魅族*/@media only screen and (min-device-width :1080px) and (-webkit-min-device-pixel-ratio : 2.5){ }/*mate7*/@media only screen and (min-device-width :1080px) and (-webkit-min-device-pixel-ratio : 3){ }