.whatsapp-btn {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 60px;
  height: 60px;
  border-radius: 15px;
  text-align: center;
  font-size: 30px;
  z-index: 1000;
  overflow: hidden;
  transition: background-image 0.3s ease;
  background-color: #25D366;
  animation: crescendo 1.5s alternate infinite ease-in;
}

@keyframes crescendo {
  0% {
      transform: scale(0.8);
  }
  100% {
      transform: scale(1.0);
  }
}

.whatsapp-btn a {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
  line-height: 60px;
  text-decoration: none;
  color: white;
}