I seem to have clicked on something that changed my display preferences. The main site is now very minimalistic, with fewer controls and different fonts, and I want to change it back, but I can't find where! Help?
Did you click on the "mobile" link shown in the footer? It could be you clicked on it by mistake.
If that is what happened, then the site would appear similarly to the following screenshot, taken for this very site. (The screenshot shows just part of the page.)
If this is the case, you just need to click on the "full site" link that is present in the footer. In a browser that is not for a mobile device, it could seem the "full site" link is not really a link because the cursor shape is different, but clicking it changes back the site to the normal design.