@media  only screen and (-webkit-min-device-pixel-ratio: 1.5),
        only screen and (   min--moz-device-pixel-ratio: 1.5),
        only screen and (        min-device-pixel-ratio: 1.5),
        only screen and (-webkit-min-device-pixel-ratio: 2),
        only screen and (min-resolution: 192dpi) {

            body {
                background-image: url("../img/left_top_banner@2x.png"), url("../img/right_top_banner@2x.png"), url("../img/right_bottom_bg@2x.png"), url("../img/left_bottom_bg@2x.png");
            }
}