I've been toying with a CRT theme with scanline effects in CSS. Since this is an effect that would apply to the whole viewport it would need to be above everyth

I've been toying with a CRT theme with scanline effects in CSS. Since this is an effect that would apply to the whole viewport it would need to be above everything else... I'm currently using z-index. Well, since I control the whole content and know there's no dialog or anything else like that on my blog I could put it in toplevel, but what if I had? What if multiple stacked dialogs were to be opened (Win 3.1 style)? Is it possible to order things inside this toplevel? Maybe using z-index? In any case, I'm just discovering this but it seems to be more about having a container with specific positioning than just replacing z-index (which is merely a consequence of that container loving outside of the <html> object). Also makes me want to have a bottom-level as well (e.g implementing cool effects on the background, think X11 root window).