Quark

Personal collection of userChrome tweaks to trim down Firefox Quantum's bloated UI. Great for small form-factor screens like the 13" Macbook Pro, these tweaks remove most UI elements that already have keyboard shortcuts or menu items. Other elements are hidden until they are contextually relevant.

Original styling and inspiration borrowed from user GiantSpeck on Reddit with additional changes borrowed from lr-tech:
My Two-Line Firefox Setup - Reddit
Original Source
Additional Tweaks

Installation

1. (Firefox v69+) Open about:config in the URL bar and change toolkit.legacyUserProfileCustomizations.stylesheets to TRUE by double-clicking the line item
2. Create a "Chrome" folder inside your Firefox profile directory
3. Download and place the userChrome.css file from this repo into the "Chrome" folder
4. Restart Firefox

Preview