Give your portal a look that is different from the rest of the application. By setting up a separate skin for a portal, you ensure that the portal does not share the design of the application, which gives you greater creative freedom.
You can associate each of your portals with a different skin, but a single skin for the entire application is a best practice, because it helps you maintain a single, consistent source of branding information.
In the navigation pane of Dev Studio, click Records.
Expand the User Interface category, and then click Portal.
Open the record of the portal with which you want to associate a skin.
On the Details tab, in the User interface section, select Other skin.
In the field that appears, enter the name of the skin that you want to use.If you set a skin for a portal that is different from the application skin, you cannot adjust the portal skin settings in the App Studio Theme menu.