@media
only screen and (-webkit-min-device-pixel-ratio : 2),
only screen and (min-device-pixel-ratio : 2) {

#nav {background-image:url(../images/icon@2x.gif);}
.title {background-image:url(../images/titles@2x.gif);}
#author {background-image: url(../images/pexcil@2x.png);}

}