This does exactly what it says, but I wish it had one extra feature: a black text on white background theme. I have an eye disease so I work with my entire computer screen inverted. The simplified CSS of the add-on looks fantastic, but having the background turn to black in your theme selector makes it white on my screen. If wish there was a minimalist black text on white background theme, but maybe this is not what this add-on is for.

At least - working diming light - not only reverse whinte with black - like in others addons.

The first thing that catched my eye was the support to Firefox 57+.
It has all the features that I need specially at night when I need to change the brightness of a firefox page. I tend to disable it on youtube and enable it on google or other page that has a lot of white.
Night mode is ok, but it does seem weird when you combine it with the brightness lowering.
Excellent work!

I was worried that there would not be a dimming addon for web extensions. This one comes through with shining colors. It needs one little adjustment to make it perfect, a right-click to exclude site function. This would make excluding sites from dimming so much easier. The ability to fine tune the amount of shading is great and works flawlessly. A 5 Star if not for the lack of right-click to exclude. Hope that can be added.

Update. The developer added that feature and it is indeed perfect now. Thank you!