#whatsapp-button {
  position: fixed;
  bottom: -80px; /* oculto inicialmente */
  left: 20px;
  z-index: 9999;
  transition: bottom 0.6s ease;
}

#whatsapp-button.show {
  bottom: 20px;
}

#whatsapp-button img {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  box-shadow: 0 2px 6px rgba(0,0,0,0.3);
}

@keyframes vibrar {
  0% { transform: translate(0,0); }
  20% { transform: translate(-2px,2px); }
  40% { transform: translate(2px,-2px); }
  60% { transform: translate(-2px,2px); }
  80% { transform: translate(2px,-2px); }
  100% { transform: translate(0,0); }
}

#whatsapp-button img.vibrar {
  animation: vibrar 0.15s linear 3;
}