.sf-whatsapp-bubble {
  position: fixed;
  right: 20px;
  bottom: 20px;

  width: 64px;          /* MÁS GRANDE */
  height: 64px;

  background-color: #25D366;
  color: #fff;
  border-radius: 50%;

  display: flex;
  align-items: center;
  justify-content: center;

  box-shadow: 0 4px 12px rgba(0,0,0,.3);
  z-index: 9999;
  text-decoration: none;

  transition: transform .2s ease, box-shadow .2s ease;
}

.sf-whatsapp-bubble:hover {
  transform: scale(1.1);
  box-shadow: 0 6px 16px rgba(0,0,0,.4);
}

@media (max-width: 768px) {
  .sf-whatsapp-bubble {
    width: 48px;     /* ↓ 25% aprox */
    height: 48px;
    right: 16px;
    bottom: 16px;
  }

  .sf-whatsapp-icon {
    width: 40px;
    height: 40px;
  }
}