BuddyPress.org

There are two sets of files you need to work with… One for the home page and main blog and another for the member/group/admin pages.

The home theme is found here: /wordpress-mu/wp-content/themes/bphome

The member theme is here: /wordpress-mu/wp-content/bp-themes/bpmember

If you don’t have a member theme in the above location, upload it there. The bpmember base.css is similar and you will have to make most of your CSS tweaks to both. v1.1 uses only one theme for both. More info:https://buddypress.org/blog/news/the-new-buddypress-theme-architecture/