The best practice is to associate a single skin with your application.
By default, a portal points to the skin specified in the application, ensuring that all portals in your application have the same look and feel. If desired, you can associate your portal with a different skin.
If you do not specify a skin for your application, the default Pega end user skin, pyEndUser, is applied.
To associate a skin with your application:
In the Skin field in the User Interface area, select the skin that you want to apply to this application.
The list of available skins is based upon your profile and may include skins not available within the current application. If you save an application with a skin that is not available within the RuleSets of the application, then the default Pega end user skin, pyEndUser, is applied at run time. To avoid this, log in using the application.
For upgraded applications, the skin defaults to pyEndUser, the default Pega end user skin, when the application rule is opened and saved.
User Interface category