Basically, it looks as though the header bit with the menus in takes its width from the advert - I am one of many people who uses adblocking and tracker blocking addons in my browsers, and it's not making it look very good!
This is how the top looks for me in Firefox with Ghostery (tracker blocker) fully enabled (I also get the same when I disable Ghostery and enable Adblock, which I previously had disabled on WCR):
Note the small size and the messed up CensusPlus addon menu button.
This is how it looks when I tell Ghostery to allow Google Adsense:
The ad is still blocked by Ghostery, but the layout looks much better, so I think this is the origin of the problem.
By the way, as a paid member of the site I'm supposed to not see ads at all (and I do see the ad when I disable Ghostery/Adblock entirely), so that may also be a glitch, unless that feature's being dropped now - fair enough if so, can't imagine there's that many of us who've bothered paying! I'll continue to block them though and just donate occasionally instead - I do not trust ad suppliers
I like the look of it overall btw (although the ad does hide the poor troll a bit
), looks good!