[data-theme="light"] .spinner {
  --spinner-bg: #ccc;
  --spinner-border-color: #000;
}

[data-theme="dark"] .spinner {
  --spinner-bg: #222;
  --spinner-border-color: #CCC;
}

@keyframes spinner {
  to { transform: rotate(360deg); }
}

.spinner:before {
  display: block;
  width: 35px;
  height: 35px;
  content: '';
  border-radius: 50%;
  border: 3px solid var(--spinner-border-color);
  border-top-color: var(--spinner-bg);
  animation: spinner .6s linear infinite;
}