JSFiddle - React, Tailwind, and code Playground

HTML

<p>I'm not dark</p>
<div class="dark">
    <div>
        <p>I'm dark</p>
        <div class="light">
            <div>
                <p>I should be light</p>
            </div>
        </div>
    </div>
</div>

CSS

body {
    color: #ccc;
}
.dark :not(.light) p {
    color: #000;
}