@mixin sprite($filename) {

  &:before {
    content: "";
    display: inline-block;

    @if $filename == sprite1 {
      background-image: url(sprite.png);
      background-position: 0px 0px;
      height: 50px;
      width: 50px;
    }
    @if $filename == sprite2 {
      background-image: url(sprite.png);
      background-position: 0px -50px;
      height: 50px;
      width: 50px;
    }
    @if $filename == sprite3 {
      background-image: url(sprite.png);
      background-position: 0px -100px;
      height: 200px;
      width: 100px;
    }
  }
}