JSFiddle - React, Tailwind, and code Playground

HTML

<h1>20 best dudes</h1>

CSS

span {
    color:Red;
}

JavaScript

$('h1').each(function (_, el) {
    var $this = $(el);
    var h1Content = $this.html();
    $this.html(h1Content.replace(/(\d+)/, '<span>$1</span>'));
});