public function getThemeEditorClasses()
{
   // Doc:https://documentation.concrete5.org/tutorials/adding-ckeditor-custom...
   return [
      [
         'title' => t('Card Title'),
         'element' => ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'],
         'attributes' => ['class' => 'card-title']
      ],
      [
         'title' => t('Card Text'),
         'element' => ['p'],
         'attributes' => ['class' => 'card-text']
      ],
      [
         'title' => t('Card Link'),
         'element' => ['p'],
         'attributes' => ['class' => 'card-link']
      ],
      [
         'title' => t('Side outline'),
         'element' => 'p',
         'attributes' => ['class' => 'sideoutline']
      ],
   ];
 
   // Old code for Redactor (concrete5 5.7):
   // Doc:http://documentation.concrete5.org/tutorials/adding-redactor-custom...
   /*return [
      ['title' => t('Card Title'), 'menuClass' => 'card-title', 'spanClass' => 'card-title', 'forceBlock' => 1],
      ['title' => t('Card Text'), 'menuClass' => 'card-text', 'spanClass' => 'card-text', 'forceBlock' => 1],
      ['title' => t('Card Link'), 'menuClass' => 'card-link', 'spanClass' => 'card-link', 'forceBlock' => 1],
      ['title' => t('Side outline'), 'menuClass' => 'sideoutline', 'spanClass' => 'sideoutline', 'forceBlock' => 1],
   ];*/
}