a.whatsapp-header-button {
  display: inline-block;
  background-color: #000000 !important;
  color: #ffffff !important;
  padding: 12px 20px;
  border: 2px solid #000000;
  font-weight: 700;
  text-decoration: none;
  transition: all 0.3s ease;
  font-size: 1rem;
  border-radius: 2px;
}

a.whatsapp-header-button:hover {
  background-color: #ffffff !important;
  color: #000000 !important;
}