There are already a few theme options available in the Theme tab of System Settings, but you might want to have a few other color schemes available for users to choose from. To look at the themes currently available in your instance, navigate to System UI | Themes. If you're in a Geneva or Helsinki instance, you'll notice quite a few themes that are not listed in System Settings: the additional themes are for UI15 or UI11. Here's how you can tell: Each theme has a field labeled Device that identifies the UI version that the theme applies to. A device value of Browser indicates a UI11 theme, while Doctype indicates a UI15 theme, and Concourse indicates a UI16 theme.
I know that sounds very odd, so I'll re-state it another way: ...
