BuddyPress.org

hum, do you know what is the usage of z-index?!… not related to where the things are going or the interaction with other parts of the site… http://www.w3schools.com/Css/pr_pos_z-index.asp stack does not mean push others below.

you need to manage the margin of your #header and give it a !important; to make it fit with your adminbar.