/****************************
 HIGH PPI DISPLAY BACKGROUNDS
*****************************/

@mixin background-2x($path, $file, $ext: "png", $w: auto, $h: auto, $pos: center center, $repeat: no-repeat) {

    $at1x_path: "#{$path}/scale-1/#{$file}.#{$ext}";
    $at2x_path: "#{$path}/scale-2/#{$file}.#{$ext}";
   
    background-image: url("#{$at1x_path}");
    background-size: cover;
    background-position: $pos;
    background-repeat: $repeat;
   
    @media all and (-webkit-min-device-pixel-ratio : 1.5),
    all and (-o-min-device-pixel-ratio: 3/2),
    all and (min--moz-device-pixel-ratio: 1.5),
    all and (min-device-pixel-ratio: 1.5) {
      background-image: url("#{$at2x_path}"); 
    }
  }