@media (max-width: 767px) {


  .modal {
    position: fixed;
    top: 20px;
    right: 20px;
    left: 20px;
    width: auto;
    margin: 0;
  }
  .modal.fade {
    top: -100px;
  }
  .modal.fade.in {
    top: 20px;
  }
}

@media (max-width: 480px) {
 
  .modal {
    top: 10px;
    right: 10px;
    left: 10px;
  }
  .modal-header .close {
    padding: 10px;
    margin: -10px;
  }
  
}