JSFiddle - React, Tailwind, and code Playground

HTML

login: <a href="#" class="blink">_</a>

CSS

@keyframes blink_keys {
  50% { opacity: 0; }
}
.blink {
  animation: blink_keys 1s step-start infinite;
}

body {
  background: black;
  color: #7cCF5A;
  font: bold 20px monospace;
}
a {
  color: red;
}