RFR: 8267606: Style classes not always working

[Alessandro Parisi]

 Hello Kevin,
I recently had time to review this issue and I created a new MRE. It's a
Gradle project but it has no dependencies as requested, there are just
two resources a .ttf font that has some font icons and a CSS for the custom
control user agent.

This time nothing works except for inline style (with setStyle()), I don't
know if I'm doing something wrong or it's a bug to be honest
The project is here:
https://drive.google.com/file/d/1oaUawMqg0QYcMmokYyocpFkBzutPNMLR/view?usp=sharing