Is it possible to recolour everything on the screen, every application, web pages, menus, everything, in two colours (with intermediate shades, i.e. monochromatic)?
Some document viewers support this. For example, Zathura (a document viewer) can be configured as follows:
set recolor true set recolor-darkcolor "#93a1a1" set recolor-lightcolor "#002b36"
I have explored f.lux and similar programs, which seem to change the gamma to redden everything, but that isn't quite the same.
I use X11 and i3wm on Arch Linux, but this question is relevant to most Unix-like platforms.