bg(bg,forceResetIeFilter=false)
	if bg
		if length(bg)==1
			background:bg
			if forceResetIeFilter and $IE_COMPATIBILITY
				@css{ filter:progid:DXImageTransform.Microsoft.gradient(enabled=false) }
		else
			bg-gradient-tb bg[0] bg[1]
	//@if typeof($background)=='list'{ @include bg-gradient-tb(nth($background,1),nth($background,2)); }
	//@else if $background{ background:$background; @if $forceResetIeFilter { @if $IE_COMPATIBILITY{; } } }

bg-gradient-tb($top,$bottom=true)
	if $top == true
		$top=lighten($bottom,$amount)
	else if $bottom == true
		$bottom=lighten($top,$amount)
	
	/* Old browsers */
	if lightness($top) > lightness($bottom)
		background: $top;
	else
		background: $bottom;
	
	/* IE6-9 */
	if $IE_COMPATIBILITY
		filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr='%s',endColorstr='%s',GradientType=0)" % $top $bottom 
	background: -moz-linear-gradient(top, $top 0%, $bottom 100%); /* FF3.6+ */
	background: '-webkit-gradient(linear, left top, left bottom, color-stop(0%,%s), color-stop(100%,%s))' % $top $bottom; /* Chrome,Safari4+ */
	background: -webkit-linear-gradient(top, $top 0%,$bottom 100%); /* Chrome10+,Safari5.1+ */
	background: -o-linear-gradient(top, $top 0%,$bottom 100%); /* Opera11.10+ */
	background: -ms-linear-gradient(top, $top 0%,$bottom 100%); /* IE10+ */
	background: linear-gradient(top, $top 0%,$bottom 100%); /* W3C */