Like many others,According to Wikimedia Analytics, in May of 2025, only about 5.83% of all traffic used Firefox, which is less than I expected. I too use Firefox as my primary web browser, and have been for quite some time, and have, unfortunately, fallen into the rabbit whole of customizing it with FirefoxCSS.
This is not inherently a bad thing. However, it means that every now and again, Mozilla will update Firefox, causing the CSS to break. And I do not like fixing these issues: I do not fully understand CSS, hence why I used a pre-existing stylesheet for my website, and oftentimes these updates occur when I am already occupied, such as during exam season.
Now that I have finished my semester, I have some time that can be spent tinkering and fixing my Firefox theme, and I figured that I'd document both a) my experience trying to recreate my previous theme and b) the settings and my process so I can recreate the theme in the future when something else (inevitably) breaks.