So I noticed that Opera was like the only browser on MacOS High Sierra 10.13.6 without the first implementation of the Universal Dark Mode to have a dark themed, MacOS Style context menu across the whole application in it's dark theme. So it is possible for the browser to have MacOS Style dark context menu on non-native apps. I was wondering if this could ever happen on Firefox? If this isn't possible via UserChrome.css, I will be giving some feedback to the Firefox Dev team through Nightly... video showing proof. https://drive.google.com/file/d/1wNbugnKmxVT7ECWLPcwB4h6_lJTO6pvI/view?usp=sharing PS if you want my UserChrome setup for translucent menubar here you go! https://pastebin.com/RfwqWRGp