why does it not working?!

Not bad, but needs some work.

The on/off switch is global which is not ideal, it should be site-based.
Editing the Include/exclude list is too much work, it should be done automatically via the main switch.

The settings are available from the 3-dot menu next to the addon toggle in the Addon page (Cmd+Shift+A). They're not straight forward though.

The Dark styles should be more easily accessible from the main addon button, and they should be editable.

"Dark mode simple 1" seems to work better than the default mode but if only there was a way to edit the background color to 10% brightness (dark grey).

Hopeully it will get better.
Cheers!

Switch on each time on each site separately or make it automatic and then see awful invert of already dark by default pages. Not handy.

One of the best around

gray background with black text awesome

I had to downgrade to 0.4.5 because this version works much better for me, even though I have the latest version of Firefox. In 0.53 I had difficulties on Amazon, Wikimedia and DeepL. For example, the Wikimedia page was displayed brightly in 0.53, but this was not the case until 0.4.5. In version 0.4.5 everything works again for me as I am used to. I wonder for how long, because there are constant Firefox updates and at some point version 0.4.5 will stop working. If it is updated again to 0.53 I will try to install 0.4.5 again.

Recently it broke reCaptcha and cloudflare captcha check, makes absolutely no sense.

dark mode toolbar button cannot be found, will not sync across devices. big waste of time to try to find any information on how to make it sync or even how to make it appear on the toolbar. not consistent, thus useless.

Do you also offer configuration seminars to configure the extension?
Wouldn't one have been able to define the basic setting for the new version in such a way that the expansion will at least continue to work as before?
It no longer works here because I don't understand all the new options. I am a user and not a developer!
Already in the previous version I didn't understand everything, but at least the necessary and could simply leave the others as they were.
I went to the old version and stopped the automatic update. Hence one star deduction.

DO NOT DOWNLOAD. FIND SOMETHING ELSE BY SOMEONE ELSE!!!!!!
Don't get it, it breaks most websites, there is no way to whitelist websites so it doesn't touch them, opening images in a new tab gets broken, key logging(beware), hasn't seen an update since it was released. Mozilla should just remove this add-on all together. developer is also inactive and does not give or provide support. DO NOT DOWNLOAD. FIND SOMETHING ELSE BY SOMEONE ELSE!!!!!!

Just recently, right-clicking on an image and "Open Image in New Tab" fails to open up an image. Turning off this extension solves this problem, so it's very likely Dark Mode.

Overall a great extension that allows me to read web pages far easier. I have only run into one issue. RealClearPolictics does not render properly when dark mode is active. The heading collapses down on some links until I turn DM off and refresh. It may be an issue with the website and not with DarkMode.