Custom Twitter Stylesheet
Modified from @tealtan's original for a lighter touch. Doesn't interfere with font faces or hide UI elements, except promoted tweets and trends.
Does equalise all the tweets on your profile page to the same font size and weight.
You can add this CSS in Safari with this extension. The URL to target is twitter.com/*.
Updated 2014-09-27 to undo Twitter's hiding of pic.twitter.com links.