public static function downloadCssFile(\core_kernel_classes_resource $item, $lang, $styleSheetPath){

        $directory = \taoItems_models_classes_ItemsService::singleton()->getItemDirectory($item, $lang);
        $file = $directory->getFile($styleSheetPath);
        if ($file->exists()) {
            return $file->read();
        }
        return null;
    }