For your div#leaf styles, do:
Code:
position: absolute;
bottom: 0px;
z-index: 10;
width: 100%;
(make z-index value greater than the z-indexes of all other divs)
Maybe want to add a padding:0px or margin:0px or both if you still have issues.
EDIT: I know you said you don't want absolute positioning, but I'm assuming you want them to be at the bottom... if you positioned relative, it would be stuck to the bottom of the content and not the frame and it would look kinda bad...