JSFiddle - React, Tailwind, and code Playground

HTML

<ul class='product_list'>
<li>Item 1
    <ul>
        <li>Item 1.1</li>
        <li>Item 1.2
            <ul>
                <li>Item 1.2.1</li>
                <li>Item 1.2.2
                    <ul>
                        <li>Item 1.2.2.1</li>
                        <li>Item 1.2.2.2</li>
                    </ul>
                </li>
            </ul>
        </li>
        <li>Item 1.3</li>
    </ul>
</li>
<li>Item 2</li>

JavaScript

$("li:last-child > ul").css("border", "1px solid red");