Fluid Layouts - CSS

For the site I'm currently working on, they would like it to be totally fluid, i've worked out mostly everything using css (even making the images fluid, which I thought was pretty nifty) but the site has dropdown menus and also a type of imagemap navigation bar, which doesn't work too well when resized (not fluid) so I thought maybe I could do a CSS image map & maybe make it fluid but I'm a bit stumped and not sure if that will even be the best idea anyway..

I found this tutorial for CSS image maps, but my problem is I actually need to somehow have my 'invisible buttons' set at a certain height % and left %, the left % works fine but height % will always change due to how much content is on a page.

Has anyone got any advice?