A new change rolled out to replace the vote count colors from hardcoded CSS values to branded colors.
However, these new colors are not in compliance with WCAG accessibility guidelines. In particular, the upvote color is way too bright:
(ignore the percentage above the downvote arrow; that's a user script)
In particular, the upvote number has a contrast ratio of just 2.38:1, which is below the 4.5:1 minimum for main text or even the 3:1 minimum for large text in WCAG 2 Level AA. The downvote contrast ratio is 3.81:1, which is above the minimum for large text but below that for main text. Still, though, it would be nicer if it was darker as well.
It's worth noting that accessibility is required under the U.S. Americans with Disabilities Act, so this color may be in violation of that law.