JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-1.11.3.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<div class="panel-collapse" role="tabpanel">
  <div class="panel-body">
    <ul class="treeview">
      <li>
        <a data-toggle="collapse" class="collapse1" href=".collapse1-1">Item 1</a>
        <ul class="collapse collapse1-1">
          <li>
            <a data-toggle="collapse" href=".collapse1-1-1">Item 1-1</a>
            <ul class="collapse collapse1-1-1">
              <li>Item 1-1-1
                <ul>
                  <li>Item 1-1-1-1</li>
                  <li>Item 1-1-1-2</li>
                  <li>Item 1-1-1-3</li>
                </ul>
              </li>
            </ul>
          </li>
          <li>Item 1-2</li>
          <li>Item 1-3</li>
        </ul>
      </li>
      <li>Item 2</li>
      <li>Item 3</li>
    </ul>
  </div>
</div>