I am searching for a way to inv´crease the visibility of days off in the workload chart. Days off are standard marked as light grey (see screenshot for the week view with one day off). Unfortunately some people have problems to see this coloring as the background and the light grey are very similar and one day in a week is bery small.
How can I change the colors to a higher contrast (e.g. a more black coloring or a completely other color)?