JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://fancyapps.com/fancybox/source/jquery.fancybox.js"></script>
<link rel="stylesheet" href="http://fancyapps.com/fancybox/source/jquery.fancybox.css">
<a rel="gallery" class="fancybox" href="http://fancyapps.com/fancybox/demo/1_b.jpg"><img src="http://fancyapps.com/fancybox/demo/1_s.jpg" alt=""/></a>

<a rel="gallery" class="fancybox" href="http://fancyapps.com/fancybox/demo/2_b.jpg"><img src="http://fancyapps.com/fancybox/demo/2_s.jpg" alt=""/></a>

CSS

.myClose {
    height: 50px;
    width: 50px;
    background: #ff0000;
}

JavaScript

$(".fancybox").fancybox({
    tpl: {
        closeBtn: '<a title="Close" class="fancybox-item fancybox-close myClose" href="javascript:;"></a>'
    }
});