The so-called "content container" is purely a device for centering things on the page. It is necessary because of a bug in IE 5, which is still used by about 5% of the population as of 2006. Inside the content container, we have a navigation bar on the left (outlined in green) and a "right container" (outlined in blue) and a "news" bar on the right (outlined in green).
Site Index
The navigation bar is an unordered list that has been stylized so that it looks mor-or-less like buttons. You can pretty much click anywhere inside the button and get the link to fire.
Hot News!
The hot news here over on the right, is a place where I could put ads or further navigaton aids, or even quick links to downloads or something. It and the nav bar have a width fixed in ems so that if one resizes one's font size, the box will "breathe" with the resizing. That keeps things from looking too weird.
The sole purpose of the right container is to keep the main content (inside the lime box) centered in the available space to the right of the navigation bar and to the left of the "hot news" section. This is another accomodation for an IE bug. Actually, it's not so much a bug as a lack of standards compliant features.
The primary content goes inside the "center content" div (outlined in lime). In a small screen it will stretch to be the size of the right container. In a larger screen, it will have a fixed width and be centered in the right container. IE has a strange bug that would cause this content to disappear completely should I fix the center content so that it was too large to fit inside the right container. So to keep this from happening and to keep things from looking otherwise funny, I had to make up my dynamic style sheet switcher that sizes things based upon one's screen resolution.
The purpose of the horizontal rule is to make sure we've cleared the navigation bar should the main content be minimal. In a good browser, the horizontal rule won't show up. In IE it does and therefore, makes things uglier. I'll put up with some ugliness so that I don't have to do (and later undo) hacks to accommodate IEs outdatedness.
Below the content container block, we have a bottom navigation division. This is again an unordered list, but this time styled to be horizontal.