Ah, thanks - I guess I should just get rid of the fixed header...

But to your first point, I don't think it's just learning HTML and CSS syntax. For example, I've never seen a SE break out XScope and measure the exact pixels between two elements, obsess about the opacity of a drop shadow, or spend a few hours to tweak the bezier curve of an animation. It's like saying that SEs will just struggle with design initially.