I have noticed that when you access the site using the HTTPS link to the site (https://area51.stackexchange.com) that it doesn't render properly, like its missing a reference to CSS or just missing the file completely.
We do not support HTTPS yet, we are working on performance problems associated with it before it is enabled. We do not link you to this anywhere yet, for a reason.
If you use
https://area51.stackexchange.com then be prepared for breaks until we're ready.