Responsive Design for Motion, a.k.a. "prefers-reduced-motion" Media Query

WebKit now supports the prefers-reduced-motion media feature, part of CSS Media Queries Level 5, User Preferences. The feature can be used in a CSS @media block or through the window.matchMedia() interface in JavaScript. Web designers and developers can use this feature to serve alternate animations that avoid motion sickness triggers experienced by some site visitors.

To explain who this media feature is for, and how it’s intended to work, we’ll cover some background. Skip directly to the code samples or prefers-reduced-motion demo if you wish.