.Polaris-Collapsible {
  overflow: hidden;
  height: 0;
  padding-top: 0;
  padding-bottom: 0;
  opacity: 0;
  will-change: opacity, height;
}

.Polaris-Collapsible--animating {
  transition-property: opacity, height;
  transition-duration: duration(slow);
  transition-timing-function: easing(out);
}

.Polaris-Collapsible--open {
  opacity: 1;
}