@wordpress/block-library/build-style/accordion-item/style.css

Block library for the WordPress editor.

.wp-block-accordion-item.is-open > .wp-block-accordion-heading .wp-block-accordion-heading__toggle-icon {
  transform: rotate(45deg);
}
.wp-block-accordion-item {
  /* Add transitions only for users who do not prefer reduced motion */
}
@media (prefers-reduced-motion: no-preference) {
  .wp-block-accordion-item {
    transition: grid-template-rows 0.3s ease-out;
  }
  .wp-block-accordion-item > .wp-block-accordion-heading .wp-block-accordion-heading__toggle-icon {
    transition: transform 0.2s ease-in-out;
  }
}