JSFiddle - React, Tailwind, and code Playground

HTML

<body>
		<div id="testCSS"></div>
		<div id="message"></div>

	</body>

CSS

#testCSS {width: 3px;}

JavaScript

jQuery(document).ready(function(){
    if (jQuery("#testCSS").width() != 3) {
        jQuery("#message").html("CSS Disabled");
    } else {
        jQuery("#message").html("CSS Enabled");        
    }
});