It was intentional.
https://github.com/Zarel/Pokemon-Showdown-Client/commit/9b6a9a7a5559b507e5194a20b892bff687a60c9fZarel said:Update color correction algorithm
The new algorithm is significantly more accurate to how lightness actually works.
Overall, colors should be a bit darker now.
This has two advantages:
- Better readability for light colors in light mode
- Less eyesore in dark mode
Also people were complaining about reds being too bright in the last change, which this change fixes.