Calendar event colors display incorrectly in web interface

I’m experiencing a visual issue with the calendar in the mailbox.org web interface that started a couple of days ago.

Description of problem:

• The event colors are displayed strangely and are very hard to read.
• The colors are not the ones I normally see and selected before.
• In many cases, the event text and background lack contrast, making it difficult to view my schedule.

Has anyone else seen this problem with calendar colors?
Is it related to a recent interface update or theme change on mailbox.org?
And, if so, is there a known fix or workaround?

Thanks in advance!