Flatpak Electron Menu Dark Mode

Hello,

is there a way to get a dark menu with electron apps from Flatpak?
I recently switched some app from AUR to Flatpak.

But in the Flatpak app, the menu bar is in light mode instead of the system dark mode.
Everyting else in the app is in dark mode.
Tried some tutorials, installed theme for Flatpak but nothing worked.

Example:
AUR app:
image

Flatpak:
image

Thanks for the help!