I’m mostly satisfied with inverting colours through Advanced Options to obtain a pseudo-dark mode, but for some documents(especially those with images), it can be useful to toggle this on and off quickly, it’s really rather tedious to go into the text editor each time I want to do this.
Most I could find was this (but this requires altering and compiling the source, right?) and this (this seems to be exactly what I want, but shift+I does nothing for me).
I would really appreciate some help on this. Sumatra is otherwise absolutely perfect for all my needs.