Change default white background in Firefox

[Jason]

I'm trying to figure out how to make the default white background on most websites to something off-white, basically, a little less glaringly white so it's easier on the eyes. I'm using Firefox Quantum. I've been searching, and although I see various possibilities, it occurred to me that this is probably a problem one of our users here has fixed already. If so, can you let me know what you specifically did?

[Jason]

Not sure if anybody cares, but I found a solution that seems to work decently. It doesn't work on all websites but it works on enough to make it useful. You need to install the GreaseMonkey extension and add a script. No idea if this works in Chrome or any other browsers.

Here you go:
https://superuser.com/a/808537/1104920

[dougal]

Jason, I wonder if you are finding this more 'enjoyable' than using something such as Redshift or f.lux  ?

[Jason]

I have used Redshift and f.lux in he past. The Plasma desktop has its own plugin that does the same thing as those apps and I've already been using it for a few months. Although they kind of appear to darken the whites, they aren't really, they're just increasing the amount of red (or decreasing mostly the blue, I don't remember) during the evening. I don't find the result of that very satisfactory. It might help me sleep better but since I started working out and am on the new meds, I sleep better anyways.

What I'm talking about doesn't even touch the blue level in the default setting, it turns down the red and green levels a little bit. You could even user another colour by fiddling with the RGB settings to another colour but that would likely look weird. It just looks less stark to me.