Very simple horizontal nav with fixed margins

Hello! Does anyone know how to make a simple, one-level horizontal navigation? All I want is to give it the same width as the page. That is, I want the row of page names to be exactly as long as the page is wide, so that the leftmost button aligns with the left page, while the rightmost button is aligned with the right edge, and all items beween are disbributed evenly.

Tips or maybe a link to a theme that does this would be very appreciated!
Cheers!