Project Quantum is Mozilla’s attempt to revitalise Firefox by replacing components one at a time with components written in Rust. In the latest Nightly builds of Firefox, Quantum CSS, also known as Stylo, is present but disabled by default. By flicking a switch in the configuration menu, though, you can easily enable Stylo.
Explaining Stylo, Mozilla’s Wiki reads:
“Stylo will integrate Servo’s CSS style system into Gecko, such that the style system code can be shared by Gecko and Servo. Stylo V1 will support Firefox on Windows, macOS, and Linux. Android support may ship in a later release. Stylo is a core part of Project Quantum.”
In order to test out Stylo simply download the latest Nightly build of Firefox; from there, enter about:config into the URL bar. Accept the warning message upon entering the configuration menu. Now you should see a search bar in the configuration menu; type layout.css.servo.enabled and flick the setting to true.
According to users that have tested out the new CSS engine, there is not a noticeable difference when performing day-to-day activities; however, web apps and other dynamic web pages are speedier. Let us know your experience using Stylo and don’t forget to report bugs to Mozilla.