JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div id="openModal" class="modalDialog">
        <div>
            <a href="#close" title="Close" class="close">X</a>
            <h2>
                Modal Box</h2>
            <p>
                This is a sample modal box that can be created using the powers of CSS3.</p>
            <p>
                You could do a lot of things here like have a pop-up ad that shows when your website
                loads, or create a login/register form for users.</p>
        </div>
    </div>
</body>

CSS

.modalDialog
        {
            position: fixed;
            font-family: Arial, Helvetica, sans-serif;
            top: 0;
            right: 0;
            bottom: 0;
            left: 0;
            background: rgba(0,0,0,0.8);
            z-index: 99999;
            opacity: 0;
            -webkit-transition: opacity 400ms ease-in;
            -moz-transition: opacity 400ms ease-in;
            transition: opacity 400ms ease-in;
            pointer-events: none;
   
        }
        .modalDialog:target
        {
            opacity: 1;
            pointer-events: auto;
        }
        .modalDialog > div
        {
            width: 400px;
            position: relative;
            margin: 10% auto;
            padding: 5px 20px 13px 20px;
            border-radius: 10px;
            background: #fff;
            background: -moz-linear-gradient(#fff, #999);
            background: -webkit-linear-gradient(#fff, #999);
            background: -o-linear-gradient(#fff, #999);
        }
        .close
        {
            background: #606061;
            color: #FFFFFF;
            line-height: 25px;
            position: absolute;
            right: -12px;
            text-align: center;
            top: -10px;
            width: 24px;
            text-decoration: none;
            font-weight: bold;
            -webkit-border-radius: 12px;
            -moz-border-radius: 12px;
            border-radius: 12px;
            -moz-box-shadow: 1px 1px 3px #000;
            -webkit-box-shadow: 1px 1px 3px #000;
            box-shadow: 1px 1px 3px #000;
        }
        .close:hover
        {
            background: #00d9ff;
        }
    </style>

JavaScript

$(document).ready(function() {
    $("#openModal").fadeTo(1, 1);
    console.log($("#openModal"));
    console.log($("#openModal").is(':visible'));
});