#cursor {
  opacity: 1;
  -webkit-animation: blink 0.7s infinite;
  -moz-animation: blink 0.7s infinite;
  animation: blink 0.7s infinite;
}

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