<!DOCTYPE html>
<html lang="en">
<head>
  <title>Bootstrap Example</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet">
  <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js"></script>
</head>
<body>

<div class="container mt-3">
  <h3>Responsive Fullscreen Modal Example</h3>
  <p>The modal-fullscreen-sm-down class will display a modal that is in fullscreen below 576px.</p>
  <p>Click the button and resize the browser window to see the effect.</p>

  <button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#myModal">
    Open modal
  </button>
</div>

<!-- The Modal -->
<div class="modal" id="myModal">
  <div class="modal-dialog modal-fullscreen-sm-down">
    <div class="modal-content">

      <!-- Modal Header -->
      <div class="modal-header">
        <h4 class="modal-title">Modal Heading</h4>
        <button type="button" class="btn-close" data-bs-dismiss="modal"></button>
      </div>

      <!-- Modal body -->
      <div class="modal-body">
        Modal body..
      </div>

      <!-- Modal footer -->
      <div class="modal-footer">
        <button type="button" class="btn btn-danger" data-bs-dismiss="modal">Close</button>
      </div>

    </div>
  </div>
</div>


</body>
</html>
