responsive web design with bootstrap code example

Example: how to make a responsive website boots

<ul class="nav nav-pills flex-column">
  <li class="nav-item">
    <a class="nav-link active" href="#">Active</a>
  </li>
  <li class="nav-item">
    <a class="nav-link" href="#">Link</a>
  </li>
  <!-- more links -->
</ul>