Adding styling to bbPress site wide forums in a WPMU DEV theme

Delirium Comics Inactive
Just Getting Started

I've noticed in many WPMU themes that the theme has support for bbPress Group forums but that does not extend to site wide forums. Case in point, I am currently testing BuddyPress Business 4.1.6 and the Demo site clearly shows group base forums.

How do I, or can I, get that styling to work on site wide forums?