private function parseCssShorthandValue($value)
    {
        $values = preg_split('/\\s+/', $value);

        $css = [];
        $css['top'] = $values[0];
        $css['right'] = (count($values) > 1) ? $values[1] : $css['top'];
        $css['bottom'] = (count($values) > 2) ? $values[2] : $css['top'];
        $css['left'] = (count($values) > 3) ? $values[3] : $css['right'];

        return $css;
    }