Calendar Text color mismatch on light backgrounds

[jschwalbe]

Specifically for All-day or Multi-day events, if the background is a light color, the text is unreadable (white). I cannot see a way to change it. Would be great if it automatically shifted to black text if the background is beyond a certain threshold of brightness.

[Szeraax]

Went ahead and introduced a color handler to look at the luminosity of calendars to pick whether to use white or black text. Seems to work pretty well on light mode and dark mode after I tried 5 levels of brightness on each.