i_love_sass.scss

@mixin slider-nav($sprite, $total-width) {
  position:absolute;
  $sprite-height:slider-sprite-height($sprite);
  $sprite-width:slider-sprite-width($sprite);
  $margin:($base-line-height/2) - ($sprite-height/2);
  margin-top: $margin;
  margin-bottom: $margin;
  left: (($total-width - $sprite-width) / 2);
  @include slider-sprite($sprite, true);
}