Literally the only theme that is compatible with my version of Firefox apparently.
The Firefox logo makes the icons a little hard to see, but otherwise it looks good.

Can't believe it's simply impossible to find a dark theme for Firefox nowadays. Why is this not a commodity?
This particular theme flunks phenomenally by making most of your nice toolbar icons impossible to discern from the theme background image. How could the creator fail so big at something that seems to be a relatively simple job?

Looks good. Works on the latest Firefox Quantum. The FIrefox logo might make things hard to see. I have the downloads icon in-between the head and the tail and I have the search bar out and it looks good.