JSFiddle - React, Tailwind, and code Playground
HTML
<div id="banner" class="light">
</div>
<a href="#" id="change">Change</a>
CSS
.light {color: #ddd}
.dark {color: #eee}
JavaScript
$(function() {
$('#banner').addClass('light');
$('a#change').on('click', function(e) {
e.preventDefault();
$('#banner').removeClass('light').addClass('dark');
});
})