I like it very much - but there is one little flaw. :(
The scroll bar on the right side for up and down is hard to see as it is too bright if the mouse is not there!
So one has to search it each time you want to scroll up or down :(
Another problem exists with local web pages!
On one hand I see as selectable options: null, null/C:, null/C:/Users, null/C:/Users/cas ...
But none of these options being selected changes anything?
On the other hand I see the menu from: Disabled to Default but again none seems of them is selectable - at least the page is black.
Finally under Global Preferences I found null at the end and there was simple CSS defined but it wasn't applied (in this case foreground would be silver not bright white) applied was the default setting which wasn't changed.

After a lot of tests of other similar extensions, I find this one particularly well done, that's why i'm leaving this review. I love that it handles clicked links (different color once visited), contrarily to most of the other similar addons. I only found one doing this, and it's not open source, with less options. Here, you can choose several methods of darkening, and apply them to different part of the same website or domain (if the global setting breaks only some pages), by URL segments (domain, website, page, subpages, etc). I've not found this depth of settings in other addons. The customization of colors for different elements is easy and when some could say it's not as "fancy" as other addons, the interface is very clear and intuitive. And I also like that it is open source.
Developer, really well done. Your extension is the closest to perfection for what it does, imo.
Could you check if there is a way to darken the menu of firefox (left-click one, and when opening a folder of favorites in the favorites bar)? I'm afraid it's a limitation in Firefox Quantum, if you can't do anything about it, i totally understand. You have my 5 stars anyway :)

Edit: thanks for the reply and advice! I already have the dark themes enabled, I'll have to wait until Mozilla expand it to these areas of their browser.
Edit 2: oh, high contrast. Brutal, but indeed it works. Thank you for the tip! ;)

Ну наконец-то! изменяет цвета даже в локальных сохранённых страницах. Не хватает возможность хранить несколько пользовательских тем. Спасибо автору!

Rápido e eficaz!

Работает как в простых страницах типа google translate так и в сложных как Slack или Facebook! :)
Легкая интуитивная настройка схемы. Единственно - мне не хватило выбора из нескольких заданных схем. Но может не нашел в настройках? В итоге изменил ту что была по умолчанию на менее контрастную.
Пользоваться можно! Спасибо автору!
Thank you autor! Very well application!

wow awesome look

this is best dark background extension so far for me.
some dark background doesnt work when I already used dark mode. like stock price night mode twitter's night mode etc... but this totally fine.

Just GUI looks not awesome but other things is perfect for me.
I couldnt find like this extension.

Loved it, but not to be newly installed any longer on mobile although still working on other devices.

=)

I've been using this for some time, and I have to say it's made the web much easier on my eyes. I used to get headaches with all the bright white light some websites like to cram down people's throats. This works well, has minimal performance impact, and has multiple options so that even if a site has some breakage with one, you can pick another setting and still have nice black backgrounds and light text. I love this extension and it's a must have for me now.

Awesome! I was trying to find a dark theme extesnion that would still let me see what's on Pinterest! This extension is perfect!!! Turned out the lights works for every site but Pinterest(It completely blacks the site out where nothing can be seen at all). I can still see everything including videos on DailyMotion with this extension. The best of the dark theme extensions!!! Thank you Devs!!! :)

Casi perfecta, no ralentiza la navegacion, solo le falta la opcion de programar hora de inicio y de fin de el oscurecimiento

Bien

I hate bright screens. Normally I use Stylish but not everyone makes custom styles for each page and it's a real pain to make your own. This just does everything, everywhere. I gotta be honest though, some of these text color options are a bit weak and it'd be nice to customize a bit more. I'll probably edit the addon myself and do it but it works well right out of the box.

20180615-Fr., Used to use that Userstyles stuff (until some things changed).

I like being able to choose my own text and link colors a lot, in fact the only way to make this better, that I can think of, would be to set a custom background.

Easy to use and prolly the best addon of it's kind out of dozens. My eyes thank you. Good job.

Been using this for a while. Always will. GREAT Global settings. It's all good with this.

Very good.