JSFiddle - React, Tailwind, and code Playground

HTML

<label>Click me twice
    <input onchange="document.getElementById('brick').innerHTML = this.checked ? 'FALL!!!' : ''" type='checkbox'></input>
</label>
<div id='pit'>
    <div>
        <div>
        </div>
    </div>
    <div id='contrail'>
        <div>
            <div id='brick'></div>
        </div>
    </div>
</div>

CSS

#brick {
    background-color: lightgray;
    border: solid black medium;
    border-radius: 1em;
    color: red;
    font-size: 2em;
    height: 100%;
    text-align: center;
}
#contrail { background-color: lightblue; width: 20em; }
#pit { display: table; }
#pit>* { display: table-cell; }
#pit>*>* { height: 4em; }