website/sass/_pico/utilities/_reduce-motion.scss

@if $enable-transitions and $enable-important {
  /**
 * Reduce Motion Features
 */

  // Based on :
  // - sanitize.css v13.0.0 | CC0 1.0 Universal | github.com/csstools/sanitize.css
  // ––––––––––––––––––––

  // 1. Remove animations when motion is reduced (opinionated)
  // 2. Remove fixed background attachments when motion is reduced (opinionated)
  // 3. Remove timed scrolling behaviors when motion is reduced (opinionated)
  // 4. Remove transitions when motion is reduced (opinionated)
  @media (prefers-reduced-motion: reduce) {
    *:not([aria-busy="true"]),
    :not([aria-busy="true"])::before,
    :not([aria-busy="true"])::after {
      background-attachment: initial !important; // 2
      animation-duration: 1ms !important; // 1
      animation-delay: -1ms !important; // 1
      animation-iteration-count: 1 !important; // 1
      scroll-behavior: auto !important; // 3
      transition-delay: 0s !important; // 4
      transition-duration: 0s !important; // 4
    }
  }
}