.button--loading.x-btn-inner {
  visibility: hidden;
  opacity: 0;
}

.button--loading::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  margin: auto;
  border: 4px solid transparent;
  border-top-color: #000000;
  border-radius: 50%;
  animation: button-loading-spinner 1s ease infinite;
}

@keyframes button-loading-spinner {
  from { transform: rotate(0turn); }
  to { transform: rotate(1turn); }
}