JSFiddle - React, Tailwind, and code Playground

HTML

<div class="fixed-panel">fixed panel</div>

CSS

.fixed-panel{
    position:fixed;
    top:-50px;
    left:0;
    height:50px;
    width:100%;
    background:green;
}

JavaScript

jQuery(function(){
    setTimeout(function(){
        jQuery('.fixed-panel').animate({top:0}, 500);
    },3000)
});