/**
* Get the url to retrieve the css
*
* @return string
*/
public function get_css_url()
{
$time = (int) $this->db_adapter->get(self::QUERY_STRING_PARAM);
$template_helper = $this->_registry->get('template.link.helper');
return add_query_arg(array(self::QUERY_STRING_PARAM => $time), trailingslashit($template_helper->get_site_url()));
}
