JSFiddle - React, Tailwind, and code Playground

HTML

<div class="class1">
    <div class="class2">
        <div class="class3">
        </div>
    </div>
</div>

CSS

div{
    padding: 5px;
    border: 1px solid #f00
}
.class1 .class2 .class3 {
    background-color: #000;
}