JSFiddle - React, Tailwind, and code Playground

HTML

<div><code>DIV</code>s on this page have an original CSS rule: <code>div:hover {background: #00f;}</code>. However, looks like JS has overridden this rule...</div>

CSS

div:hover {
  background: #00f;
}

JavaScript

var	changeRule = function(selector, property, value){
		var styles = document.styleSheets,
			n, sheet, rules, m, done = false;
        selector = selector.toLowerCase();
		for(n = 0; n < styles.length; n++) {
			sheet = styles[n];		
			rules = sheet.cssRules || sheet.rules;
			for(m = 0; m < rules.length; m++) {
				if (rules[m].selectorText.toLowerCase() === selector) {
					done = true;
					rules[m].style[property] = value;
					break;
				}
			}
			if (done) {
				break;
			}
		}
	};
changeRule('div:hover', 'background', '#f00');