Autoprefixer takes care of adding -webkit-min-device-pixel-ratio and -o-min-device-pixel-ratio,\n  // but doesn't convert dppx=>dpi.\n  // There's no such thing as unprefixed min-device-pixel-ratio since it's nonstandard.\n  // Compatibility info: https://caniuse.com/css-media-resolution\n  @media only screen and (min-resolution: 192dpi), // IE9-11 don't support dppx\n    only screen and (min-resolution: 2dppx) { // Standardized\n    background-image: url($file-2x);\n    background-size: $width-1x $height-1x;\n...