.ms-dos-cursor {
  display: inline-block;
  width: 10px;
  height: 1.2em;
  background-color: #00ff00;
  animation: blink 1s step-end infinite;
  vertical-align: bottom;
  margin-left: 2px;
}

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