JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://i.imgur.com/zAD2y29.gif"></script>
<div id="loader" class="loader"></div>
<div style="display:none" id="tudo_page"> CONTEUDO DA PÁGINA <div>

CSS

.loader {
	position: fixed;
	left: 0px;
	top: 0px;
	width: 100%;
	height: 100%;
	z-index: 9999;
	background: url('http://i.imgur.com/zAD2y29.gif') 50% 50% no-repeat white;
}

JavaScript

jQuery(window).load(function () {
      $(".loader").delay(1500).fadeOut("slow"); //retire o delay quando for copiar!
    $("#tudo_page").toggle("fast");
});