4.1 dark mode issue SOLVED

User Support
3

Most of the Qubes OS UI in dom0 is now Qt5 based and doesn’t by default adhere to the selected theme, which is especially annoying when using a dark theme. Luckily this can easily be remedied by installing qt5-qtstyleplugins and exporting QT_QPA_PLATFORMTHEME=gtk2 (e.g. in /etc/environment ).

From my post in another thread.