@keyframes flasher {
  0%, 100% { box-shadow: none; }
  50% { box-shadow: 0 0 2em 1px #ff0000; }
}

@keyframes pulsating {
  0%, 50% { opacity: 1; }
  100% { opacity: 0; }
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}