// From thoughtbot/bourbon
@mixin position ($position: relative, $coordinates: 0 0 0 0) {
	@if type-of($position) == list {
		$coordinates: $position;
		$position: relative;
	}

	$top: nth($coordinates, 1);
	$right: nth($coordinates, 2);
	$bottom: nth($coordinates, 3);
	$left: nth($coordinates, 4);
  	position: $position;

	@if not(unitless($top)){ top: $top; }
	@if not(unitless($right)) { right: $right; }
  	@if not(unitless($bottom)) { bottom: $bottom; }
	@if not(unitless($left)) { left: $left; }
}