Skinning was all the rage back in the '90s. I remember installing LiteStep (which seems to still be around!) on Windows 98 to get a custom look-and-feel. Winamp3 was all about crazy skins, and theming in general was just part of the hobby that was using a computer. Fast forward 20 years, and the newest feature I see in every app and operating system is 'Dark Mode'. I think the change is partly because we became more thoughtful about the security impact that cosmetic changes could have. As with all rules, there are valid cases that get prohibited, and developing a consistent, high-quality dark theme for Firefox is of them. Luckily, ShadowFox adopts an unorthodox approach that side-steps some of those security measures by distributing itself as a script, rather than a browser addon. This is clever, and result is quite beautiful to my eye, particularly the consistency across the 'protected' pages like 'about:addons' and 'about:profile'. I'm very happy some folks took the time to work on it!