@media only screen and (-webkit-min-device-pixel-ratio: 1.5), only screen and (min-device-pixel-ratio: 1.5) {  .logo {    background-image: url(img/logo@2x.png);    -moz-background-size: 50px 35px;    -o-background-size: 50px 35px;    -webkit-background-size: 50px 35px;    background-size: 50px 35px;    margin-top:19px;  }}