JSFiddle - React, Tailwind, and code Playground

HTML

<body>
        <br/><br/><br/>
        <div id="box1">
            <ul id="box2">
              <li>
                <div id="box3"/>
              </li>
            </ul>
        </div>
    </body>

CSS

/* Positioning */
            #box1 { position: absolute; }
            #box2 { position: relative }
            #box3 { position: absolute; top: 10px }

            /* Styling */
            #box1 { background: red; padding: 5px; width: 125px }
            #box2 { background: blue; padding: 2px; width: 125px; height: 100px }
            #box3 { background: green; padding: 2px; width: 500px; height: 150px }