Great idea and works in practice!

This stopped working on latest Firefox version. Please fix it ASAP.
ISSUE: System theme cannot be detected by the extension.

This recently stopped working on newest Firefox

Does exactly what it says! Question for the developer: would it be possible in a future update to include a toolbar button that could be clicked to toggle back and forth between the two set themes? On very dark winter days, even though sunset is still several hours away, my office gets so dark that I find that I need to activate the dark theme early. A one-click solution for that scenario would be highly appreciated! Either way, thank you for this wonderful extension.