client/style/scss/modules/_mixins.scss
@mixin image-2x($image, $width, $height) {
@media (min--moz-device-pixel-ratio: 1.3),
(-o-min-device-pixel-ratio: 2.6/2),
(-webkit-min-device-pixel-ratio: 1.3),
(min-device-pixel-ratio: 1.3),
(min-resolution: 1.3dppx) {
/* on retina, use image that's scaled by 2 */
background-image: url($image);
background-size: $width $height;
}
}