public static function sanitize_color( $color = '', $mode = 'auto' ) {
		if ( is_string( $color ) && 'transparent' == trim( $color ) ) {
			return 'transparent';
		}
		$obj = ariColor::newColor( $color );
		if ( 'auto' == $mode ) {
			$mode = $obj->mode;
		}
		return $obj->toCSS( $mode );
	}