Just downloaded this about 5mins ago & it appears to solve all my immediate problems - gotta say; I love it!

Update:
6th Dec '19 ~ Experiencing some issues with Firefox 71.0

Update:
24th Apr '20 ~ This App doesn't play well with Gmail & for sometime now ~ I hope you are aware of such?

Update:
25thMay'20 ~ 👍Still slow with Gmail but one can change one's settings to be specific to individual sites & that workaround works.

excelente

This is my favorite Dark Mode Add-on for Firefox and Firefox for Android. It works fine and every website looks wonderful.

Excellent

thanku so much

NICE WORK