User blog comment:BertH/Fluid layout has arrived/@comment-3361105-20131205002147/@comment-957747-20131205003551

The lagging earlier was due to an issue with updating code earlier today and that has since been resolved.

As far as the text size, you can size that back in your personal CSS page (Special:MyPage/global.css). If you wish to do this wiki-wide, it's suggested that you start a discussion with your users as the increased font size was done for readability for users with larger monitors.