JSFiddle - React, Tailwind, and code Playground

HTML

<button onclick="onclickBut()">открыть</button> <span id="idSid" class="qw"> текст</span>

CSS

.qw {
color: aqua;
}
.xc{
color: red;
}

JavaScript

function onclickBut() {
    $('#idSid').toggleClass('xc');
}