JSFiddle - React, Tailwind, and code Playground

HTML

<div class='invert-link dark'> </div>

CSS

.invert-link {
    width: 100px;
    height: 100px;
    background-color: pink; 
}

JavaScript

$(".invert-link").click(function() {

    if ($(this).hasClass('dark')) {
        //alert("a");
        $("link[class='THEME']").attr("href", "http://link-to-site/wp-content/themes/HM/light-style.css");
        $(".invert-link").removeClass("dark");
    } else {
        //alert("b");
        $("link[class='THEME']").attr("href", "http://link-to-site/wp-content/themes/HM/dark-style.css");
        $(".invert-link").addClass("dark");

    }
});