@mixin device-pixel-ratio($ratio: 2) {
@media only screen and (-webkit-min-device-pixel-ratio: $ratio), only screen and (min--moz-device-pixel-ratio: $ratio), only screen and ( -o-min-device-pixel-ratio: #{($ratio*10)}/10), only screen and ( min-device-pixel-ratio: $ratio), only screen and ( min-resolution: #{($ratio*96)}dpi), only screen and ( min-resolution: #{$ratio}dppx) { @content; }
}