Why do I have a night theme turned on on all sites?

Question

Mozilla Firefox

FF 95.0 (64 bits) Since the day before yesterday, all my sites have the night theme enabled by default. It turns on only where it is. Google, peekaboo, github, etc. The same goes for incognito mode. What could be the problem? Plugin or add-on is not worth it.
upd I think I found it, I have a dark theme in ff, when I turn it on - it's dark on all sites too. I only need a dark theme, but on sites it needs to be light.

Answer 1

Googled a little, I'm not the only one https://dtf.ru/ask/974199-mozilla-i-temnye-temy
It helped:

change the layout.css.prefers-color-scheme.content-override parameter in about:config by setting it to 1

Answer 2

It seems like the ability to change colors was expected in release 96, but apparently they decided to add it to 95
Dark and light display modes have been added to Firefox ...
To change, go to Settings and set the default options

Go to Color Settings

Change to default values

Screenshot

If you have a dark theme enabled in your system, then the change could happen automatically, as there is a checkmark "Use system colors"