Would it be possible to allow finer color settings? There are lots of calculations to get subtle shades of the entered color codes and not all of them work great for some scenarios. I would normally do it in custom CSS but I set up Horizon theme and it has no way to edit CSS. So I realized it anyway belongs to the color palette setting.
Actually the best would be to add a custom CSS option in here (obviously one would only play with colors) and to also allow Horizon to edit color palette CSS.