As for your main navbar, I assume that this is the one just below the image?
If so, the div DOES go fully across the page but I’m not sure you want the navbar full page width. Won’t this interfere with your sidebar?
If you only want it to be the width of the content section then it make sense to either bring it inside that div or give it the same width.
If you want the list items to be wider then you’ll have to give them greater widths or more padding. In fact, I wouldn’t set a width on the li, let their size be dictated by the ‘a’ links.