// http://qiita.com/orangemittoo/items/1c9f32296836d3ea125e

$sprite-map: sprite-map("sprites/*.png", $layout: smart)
$map-img: sprite-url($sprite-map)

=sprite-background($name, $background-size: null, $background-repeat: null)
  // block;
  background-image: $map-img
  $pos: sprite-position($sprite-map, $name)
  background-position: nth($pos, 1) / 2 nth($pos, 2) / 2
  @if $background-size
    +background-size($background-size)
  @else
    +background-size(ceil(image-width(sprite-path($sprite-map)) / 2) auto)
  @if $background-repeat
    background-repeat: $background-repeat
  @else
    background-repeat: no-repeat