Every Kartris must have at least two skins - one called 'Kartris' which is the default front end skin. And another called 'Admin' which is used by the back end admin area. You can also add new skins to change the appearance of the front end.

If you wish to support browsers below IE8, and have a modern responsive skin on your site, you can also add a non-responsive skin for older browsers. Please see @13.2.3.3. Old IE support.