.btn-12 {
  background-color: #007bff;
  color: white;
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

.btn-12:hover {
  animation: pulse 0.5s infinite alternate;
  background-color: #b30000;
}

@keyframes pulse {
  0% {
    transform: scale(1);
  }
  100% {
    transform: scale(1.1);
  }
}