JSFiddle - React, Tailwind, and code Playground

HTML

<div id="blackbox"></div>

CSS

#blackbox {
    background:pink;
    width:10px;
    height:10px;
}

JavaScript

var b = $('#blackbox');
b.css('background', (b.css('backgroundColor') === 'rgb(255, 192, 203)' ? 'black' : 'pink'));