https://www.americanhousing.com/fouc.js

1function showContent() {
2	document.documentElement.classList.add('ready');
3}
4
5var isShown = false;
6
7function show() {
8	if (isShown === true) {
9		return;
10	}
11
12	isShown = true;
13	showContent();
14}
15
16var timeout = setTimeout(show, 3000);
17
18if (document.fonts && document.fonts.ready) {
19	document.fonts.ready.then(function () {
20		clearTimeout(timeout);
21		show();
22	});
23} else {
24	clearTimeout(timeout);
25	show();
26}