Appearance; black text on white


How do I change the appearence of the client and this forum to something sensible and useful like Black text on white/lighy-gray background.?

Where are the config files?

Feedback, Second install of Tribler. 1st was 7.0.0 on win7 but stopped using it to frequent crashing. Now trying the linux version 7.0.2; Actually on Devuan.
The install failed (dpkg -i package.deb). Ran tribler; error message about libtorrent being missing. so apt-get seasrch libtorrent, then apt-get install libtorrent followed by helpfull info msg to try “apt-get --fix-broken install” and all was well, aka it started. Now to see how reliable it is.