This is a basic sidebar, for a menu/table of contents. You can see an example in this page.

<div class="sidebar-container">
    <label for="toggle-sidebar">Mobile toggle for the sidebar</label>
    <input type="checkbox" id="toggle-sidebar">

    <div class="sidebar">
        <ul class="nav">
            <li><a href="#">Go to the top</a></li>
            <li class="section">Section</li>
            <li><a href="#">A link</a></li>
        </ul>
    </div>
    <div class="content">
        <p>Hello world!</p>
    </div>
</div>