JSFiddle - React, Tailwind, and code Playground

HTML

<button>Go</button>
<div>Hello World</div>

CSS

body { text-align: center; }
div {
    position: fixed; 
    top: 0; 
    width: 200px; 
    border: 1px solid gray; 
    background: lightgray; 
    border-radius: 0px 0px 5px 5px; 
    padding: 5px; 
    left: 50%;
    margin-left: -100px;
}
button { float: left; }

JavaScript

$('button').click( function() {
    $('div').slideToggle();
});