I checked Firefox Nightly and seems that dark theme for in-content pages is comming. Its already working great but the options page of my extension is still in light mode and looks terrible.
I already tried to not define colors, but its not working. Same for media queries because it seems to be disabled because of fingerprinting(?) If i am not wrong, there are no CSS vars etc. too or?
How i can detect it to show the options page in dark mode as well as the rest of the UI?
Dark mode works well for my extension’s Option page (Flickr Fixr). And no nightly browser needed, works fine with current Firefox 68 release-version and with Strict Content blocking enabled in browser settings (including blocking fingerprinters).
You can discuss if it is pretty what I have made, but it definitely works as intended.
All I have made is a CSS media declaration for my Options page:
It sure does. But it is defined to open in a new tab. Apparently in latest Firefox versions you have to open it via the the three-dots menu to the right in your screenshot.