JSFiddle - React, Tailwind, and code Playground

HTML

<h2 class="title">1</h2>
<div>
    <h2 class="title">2</h2>
    <p>
        world
        <h2 class="title">3</h2>
    </p>
</div>
<h2>untitled</h2>
<div>
    <div>abc</div>
    <p>
        <h2 class="title">4</h2>
    </p>
</div>

CSS

h2.title {
    color: green;
}

JavaScript

// select fourth h2.title in entire document
$("h2.title:eq(3)").css("color", "red");