code: public function getCssClassesForContainer() {
          $colsXl = $this->getWidth() >= 100 ? 12 : ceil(12 * ($this->getWidth() / 100));
          $colsXlLeft = floor((12 - $colsXl) / 2);
          $colsLg = $colsXl >= 10 ? 12 : $colsXl + 2;
          $colsLgLeft = floor((12 - $colsLg) / 2);
          return "col-xs-12 col-xl-{$colsXl} col-lg-{$colsLg} col-xl-offset-{$colsXlLeft} col-lg-offset-{$colsLgLeft}";
      }
docs: Get css classes for content container.
  Uses witdh to collect col-??-?? and col-??-offset?? classes
  @return string