JSFiddle - React, Tailwind, and code Playground

HTML

<span onclick="show(this)">Click me</span>

CSS

.wide {
    width: 500px;
}

span {
    border: 1px solid black;
    padding: 5px;
    display: inline-block;
}

JavaScript

function show(elem) {
    elem.classList.toggle('wide');
}