Red warning colour extremely hard to see for colourblind people
Prior to the move to GTK4, I was able to use Gnome Sudoku easily despite suffering from mild red-green colour-blindness. Since the UI update, I find it almost impossible to see the difference between the black and red numbers in cells. The removal of the clear "X" marks over incorrect cells makes this worse. In general, it is a violation of good UX accessibility design to rely purely on colour to communicate information - especially colours that are particularly problematic for deuteranopia or protanopia. Possible resolutions:
- Provide some customisation options for the colours so that colour-blind people can adjust them to provide distinctions they can see
- Add some other visual feedback for hints that doesn't rely purely on colour