.text-header{
    color:black;
}

.whatsapp-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: green;
  color: white;
  padding: 10px 20px;
  border-radius: 50px; 
  text-decoration: none;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.portfolio-item:hover .whatsapp-btn {
  opacity: 1;
}