chaging the background - no configuration file

[manuelcaeiro]

Greetings,
I've been looking for a way to change the background to dark/black, butI couldn't find a configuration file.
I would really like to make the changes myself, but altough I can read Python, I know nothing of QT.
I'm reasonably sure it's a QT thing because the GUI initiates with dark background on my Plasma desktop, without any extra configuration. However this does not happen on other DE, and on the Xubuntu laptop, which I use more often.
I wonder if you could create configuration file, or some other option to get a dark background on the argos-gui myeyeswould be very grateful (and so would I :)
Kudos.