Heartbeat

.btn-heartbeat {
  display: inline-block;
  padding: 12px 26px;
  border: none;
  border-radius: 12px;
  background: #ef4444;
  color: #ffffff;
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  animation: btn-heartbeat-thump 1.6s ease-in-out infinite;
}
.btn-heartbeat:hover {
  animation-duration: 0.8s;
}
@keyframes btn-heartbeat-thump {
  0%, 28%, 70%, 100% {
    transform: scale(1);
  }
  14% {
    transform: scale(1.08);
  }
  42% {
    transform: scale(1.06);
  }
}