JSFiddle - React, Tailwind, and code Playground

HTML

<div class="some-class">
        <div>
             <p>The background of this should be red.</p>
        </div>
    </div>
    
    <div class="some-class">
        <div>
             <p>The background of this should be blue.</p>
        </div>
        <div>
             <p>The background of this should be blue</p>
        </div>
    </div>

CSS

.some-class div {
    background: blue;
}

.some-class div:first-child:last-child {
    background: red;
}