Add dark mode

[lafouledesbarbares]

Could you add dark mode as an option? The "cozy" mode is hardly "easy on my eyes".
By dark mode, I mean dark gray background, slightly grayish text, not black background, white text.

[iProgramMC]

Duplicate of #71.

Also, use a dark mode system theme and Discord Messenger will follow it. Discord Messenger follows your Win32 system theme.

Demo:

[OneBigLotus]

I'm on windows 11 using dark mode and this feature does not seem to be working natively, although I understand I'm not using the intended OS for this type program