JSFiddle - React, Tailwind, and code Playground

HTML

<div id='ModalId' class="Modal" > content <br> content </div> 
    <button>show</button>

CSS

.Modal {
    display: block;
    opacity: 0;
    transition: all 300ms ease 0s;
    height: 0px;
    overflow: hidden;
}
.ModalVisible {
    display: block;
    opacity: 1;
     height: 50px;
    
}

JavaScript

$('button').on('click', function () {
   
     $('#ModalId').addClass('ModalVisible');
});