.css {  background-image: url(img@1x.png);}@media only screen and(-webkit-min-device-pixel-ratio: 2) {  .css {    background-image: url(img@2x.png);  }}@media only screen and(-webkit-min-device-pixel-ratio: 3) {  .css {    background-image: url(img@3x.png);  }}

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