[aria-busy] {
  --loading-size: 64px;
  --loading-stroke: 6px;
  --loading-duration: 1s;
  position: relative;
  opacity: .75
}

[aria-busy]:before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: var(--loading-size);
  height: var(--loading-size);
  margin-top: calc(var(--loading-size) / 2 * -1);
  margin-left: calc(var(--loading-size) / 2 * -1);
  border: var(--loading-stroke) solid rgba(0, 0, 0, 0.15);
  border-radius: 50%;
  border-top-color: rgba(0, 0, 0, 0.5);
  animation: rotate calc(var(--loading-duration)) linear infinite;
}

@keyframes rotate {
  100% {
    transform: rotate(360deg);
  }
}