JSFiddle - React, Tailwind, and code Playground

HTML

<a class="btn-100" href="#">100</a>
<a class="btn-500" href="#">500</a>
<a class="btn-1250" href="#">1250</a>

CSS

a {
      padding: 6px;
    display: block;
    width: 50px;
    font-size: 17px;
    margin: 10px auto;
    border: 2px solid;
    text-decoration: none;
    box-shadow: 0 0 0 rgba(204,169,44, 0.4);
    animation: pulse 2s infinite;
}
.btn-500 {
    animation-delay: 0.6s;
}

.btn-1250 {
    animation-delay: 1.3s;
}
@keyframes pulse {
  0% {
    -moz-box-shadow: 0 0 0 0 rgba(204,169,44, 0.4);
    box-shadow: 0 0 0 0 rgba(204,169,44, 0.4);
  }
  70% {
      -moz-box-shadow: 0 0 0 10px rgba(255,208,0, 0.2);
      box-shadow: 00 0 0 10px rgba(255,208,0, 0.2);
  }
  100% {
      -moz-box-shadow: 0 0 0 0 rgba(204,169,44, 0);
      box-shadow: 0 0 0 0 rgba(204,169,44, 0);
  }
}