Kmail - with a dark theme, icons are invisibly dark

Still new to KDE and not quite sure where all the various personalisation controls are found, but I’ve just tried switching to Kmail from Thunderbird and I’ve got an immediate UI usability issue - the icon colours are all clearly chosen for a light theme, and with a dark theme they’re all basically invisible. I can’t tell at a glance which emails are read vs unread, which have been replied to, etc.

How can I change the icons or their colours to get something more usable?

Which icons where? Can you post a screenshot that shows the issue?

Yes - here’s an example with the most problematic icons, which are the email status ones.


I cannot seem to find any settings inside Kmail or in Plasma’s wider theme settings that have any effect on these icons at all! I can neither change their colour nor replace them entirely. This is true of almost all icons inside Kmail; only the folder icons on the left change into the wider theme’s folder icons (I think) when set to maximum size. All else are the same dark grey under all circumstances.