Bug 483502

SUMMARY
When you're retired and thus have configured no workdays since you don't work, all the days in the month view are shown in red with no good way to change that.

STEPS TO REPRODUCE
1. uncheck all days so no days are configured as work days
2. look at the month view
3. try to configure a spefic colour for non-workdays

OBSERVED RESULT
All the days in every month are shown in red as if they were suddenly dangerous.  They also seem to be bold which doesn't exactly improve readability.  There doesn't seem to be a way in the settings to change this.

EXPECTED RESULT
Use a more harmless colour as default and allow to customize colour and font (boldness) for non-workdays.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 39
KDE Plasma Version: 5.27.10
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.12
Kernel Version: 6.7.7-200.fc39.x86_64 (64-bit)
Graphics Platform: X11
Processors: 16 × Intel® Xeon® CPU E5-2637 v4 @ 3.50GHz
Memory: 125.6 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1080 Ti/PCIe/SSE2
Manufacturer: Dell Inc.
Product Name: Precision Rack 7910

ADDITIONAL INFORMATION
Oh!  I just found out by chance that the holiday colour is being used for the non-workdays.  That means that normal days (i. e. non-workdays) can not be distinguished from holidays.  Of course I do want to use a different colour for holidays than the one for non-workdays.  Even when one doesn't work on a day that doesn't mean that that day is a holiday.  Obviously, that doesn't only go for retired people but for everyone who doesn't work every day.

This also as has an effect on weekends.  Weekends need their own colour because some people are working on weekends, and not all weekends are holidays, either.  And normal days (i. e. non-workdays) should be distinguished from weekends, so that requires yet another colour for weekends (which mostly aren't holidays).

Once we have enough colours for the types of days, we'll need to be able to set priorities for the colours of the days.  For example, I would prefer holidays always shown in holiday colour even when they are weekends while other users may prefer to keep showing them in weekend colour, etc. ...