.spinner {
  border: 7px solid #f3f3f3;
  border-radius: 50%;
  border-top: 7px solid #3498db;
  width: 75px;  
  height: 75px;
  -webkit-animation: spin 2s linear infinite;
  animation: spin 2s linear infinite;  
  position: fixed;
  top: 40%;
  left: 50%;
}

@-webkit-keyframes spin {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}