Krita ignores system theme if it's not in a prefilled list. Steps to reproduce: Install KDE Theme such as Gently Use newly installed theme for KDE Start Krita Expected result: Krita respects the system theme or at least has option to use it Actual result: Krita stands out like a sore thumb.
This is not a bug, but intentional. There are very few themes that actually work with Krita, so we have a checklist of known good themes, and by default block all others. Start krita as KRITA_NO_STYLE_OVERRIDE=TRUE krita --style your_theme and your style will be used.