I can’t figure out why my NAV list on the right is not nested inside the black HEADER. I know I could declare a height on the HEADER so that the NAV appears to be inside the header, but I shouldn’t have to do that. Must be something wrong with my CSS. Any suggestions?
This is a common issue. The reason is that parent elements don’t wrap around floated elements by default. (The floats hang out of the parent unless you force the parent to contain or wrap around them.)
You can easily fix this by adding this to your CSS: