JSFiddle - React, Tailwind, and code Playground

HTML

<!-- HTML markup -->
<h2>Your score: <span id="YourScore">10</span></h2>

CSS

.high-score {
    color: green;
}

JavaScript

// Js to update a score to 20
var scoreEl = document.getElementById("YourScore");
scoreEl.innerHTML = "20";
scoreEl.className += " high-score";