@media only screen and (-webkit-min-device-pixel-ratio: 2),
       only screen and (-moz-min-device-pixel-ratio: 2),
       only screen and (-o-min-device-pixel-ratio: 2/1),
       only screen and (min-device-pixel-ratio: 2) {
       .hotsec{background-image:url(../macidea/hotsec@2x.gif);background-size: 41px 14px}
       .newsection{background-image:url(../macidea/newsec@2x.gif);background-size: 41px 14px}
       .postbtn, .replybtn {background-size:93px 24px}
       .postbtn{background-image:url(../macidea/newtopic@2x.png)}
       .replybtn{background-image:url(../macidea/newreply@2x.png)}
}