mimipile/firefoxCSS ? reverse-engineered prompt

Build me a simple Firefox theme that makes the browser feel super minimal and keyboard focused.

I want a single userChrome.css file I can drop into my Firefox profile to hide most of the visible browser chrome by default, while keeping the main menu button available. Please make it easy to turn individual controls back on by commenting or removing CSS rules, especially the back and forward buttons, tab controls, extensions button, window controls, and the icons in the address bar like bookmarks, permissions, tracking protection, reader mode, picture in picture, and translations.

The goal is a clean, one line style browser with as little clutter as possible, but still usable day to day. If you can, include clear comments in the CSS so it is obvious what each block controls. Keep the implementation lightweight and focused on Firefox userChrome.css only. If you need to check current Firefox UI selectors or compatibility details, look up the latest docs or examples online first.