Is there some sort of scaling going on? I keep getting these mangled scroll bar buttons. Other sites never show this behaviour at the same zoom and resolution level (magnified 4 times):
This only affects Firefox, and it wouldn't happen at all if we hadn't been experimenting with using community-themed colours for `scrollbar-color`.
It seems to be a bug with Firefox — I've confirmed this is visible even on [the MDN page about scrollbar-color](https://developer.mozilla.org/en-US/docs/Web/CSS/scrollbar-color) itself and reported it their BugZilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1611854
We can workaround this bug in three ways:
1. Ignore it until Firefox fixes the bug, as it is cosmetic.
2. Stop using `scrollbar-color`.
3. Use `scrollbar-width: thin;`, which doesn't display the arrows at all.
We are trialling option (3) at the moment, please let us know whether you think one of the other options would be a better bet.