I often start my day early, and there is nothing worse, at least it feels that way at the moment, than opening a web page, where most of the page is white. So I do a little research and learn about dark themes. But wait that only affects a small aspect of Firefox, such as tabs. The web pages themselves haven’t changed. Opening Google, for example is visual torture. It’s like being snow blind. I need my sunglasses (which I have actually done). Long story short Dark Reader https://addons.mozilla.org/en-US/firefox/addon/darkreader/