Answered
Firefox Linux bug with rotation
(Note: while Firefox on Windows has a similar issue, it is not nearly as pronounced as this is)
I'm not really sure where to put this, but I've noticed a strange issue on Linux Firefox: when I rotate text, the letters lose alignment.
It's kind of difficult to explain, so I just made a video of it in action, with a Chrome demonstration for comparison.
Thanks for your help!
I'll let the developer know, thanks!