Prado\Web\UI\WebControls\TStyle::setCssClass PHP Method

    public function setCssClass($value)
    {
        $this->_class = $value;
    }

 /**
  * @return TStyle the style for the active tab div
  */
 public function getActiveTabStyle()
 {
     if (($style = $this->getViewState('ActiveTabStyle', null)) === null) {
         $style = new TStyle();
         $style->setCssClass('tab-active');
         $this->setViewState('ActiveTabStyle', $style, null);
     }
     return $style;
 }