Lent.

I can't live without this plug-in. It darkens every single page and it detects if some pages have a dark mode as option (regardless often Dark Reader does a better job).

works like a charm; love the schedule function

コントラストも設定されていて使いやすいです。

slow down Firefox. Can't change per website, only global.

Works like a charm and the dark theme is of the right contrast

My eyes are saved.
I would like to have a "dark-ish" mode so as to not have white on black (which also strains my eyes), but I manage with just making everything sorta greyscale and increasing the sepia value.
Would recommend.