JSFiddle - React, Tailwind, and code Playground

HTML

<div id="notification">Page load complete...</div>

CSS

#notification {
    background-color: #F00;
    color: #FFF;
    height: 25px;
    position: absolute;
    top: -25px;
    width: 100%;
    transition: top 0.5s;
    -moz-transition: top 0.5s;
    -webkit-transition: top 0.5s;
    -o-transition: top 0.5s;
}

#notification.visible {
    top: 0px;
}

JavaScript

$(document).ready(function(){
    $("#notification").addClass("visible");
});