JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
    <li>Aliquam Lorem tincidunt mauris lorem eu risus.</li>
    <li>Vestibulum auctor dapibus neque.</li>
</ul>
<section>
    <article>
        <p>Lorem ipsum</p>
    </article>
    <article>
        <p>None here</p>
        <p>Or here</p>
    </article>
</section>

CSS

.look-at-me {
    background: #999;
}

JavaScript

$('body > *').each(function() {
    $(this).html($(this).html().replace(/Lorem/ig, "<mark>$&</mark>"));
});

$('mark').parent().addClass('look-at-me');