[animations] motion animations aren't disabled when using `prefers-reduced-motion: reduce`

[yukijoou]

Bug Report

Motion animations aren't disabled when the accessibility setting prefers-reduced-motion is turned on. Reduced motion needs to be supported to provide usable UIs to motion-sensitive people like me. No movement animation should be played when this setting is enabled.

More information on the related MDN article

Steps to reproduce

1. Turn on reduced motion according to the guide on the MDN article
2. Go on a website using fomantic-ui (here, https://fomantic-ui.com/)
3. Interact with a UI element that has a motion animation (here, the menu sidebar)

Expected result

The interaction should not make anything move on the page (here, the menubar should pop in or fade in)

Actual result

The interaction results in a motion animation (here, the menubar slides)

Testcase

N/A

Screenshot (if possible)

N/A

Version

all