Glad you liked it! Re: perf tips for authors: I don't think so, the tracking is pretty central to fundamental features of fonts (i.e. the default font size) I

Glad you liked it! Re: perf tips for authors: I don't think so, the tracking is pretty central to fundamental features of fonts (i.e. the default font size) I guess using absolute font sizes as close to the top of the DOM tree as possible will help a tiny bit. But it also means that folks with custom default font size settings wont have the settings get respected. I think this has a pretty minor perf impact overall as well.