JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#" class="open">Жми</a>

<div class="popup">
	<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Tempora provident sed ut ipsa voluptatum quisquam fugit iste incidunt numquam maxime impedit adipisci neque officiis nemo obcaecati quidem facere ullam! Dolore.</p>
</div>

<script src="http://dinbror.dk/bpopup/assets/jquery.bpopup-0.11.0.min.js"></script>

CSS

* {
    margin: 0;
    padding: 0;
}

html, body {
    height: 100%;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    background: url(http://goo.gl/50Xu6u) no-repeat;
    background-size: cover;
    font: 1em/1.2 Tahoma, sans-serif;
}

.open {
    position: relative;
    top: 0;
    margin: 100px;
    padding: 5px 25px;
    background: rgba(219,87,5,1);
    display: inline-block;
    border-radius: 8px;
    color: #fff;
    font-weight: bold;
    text-decoration: none;
    box-shadow: 0px 6px 0px rgba(219, 31, 5, 1);
    transition: all 0.1s linear
}
.open:active {
    box-shadow: none;
    top: 6px;
}

.popup {
    display: none;
    width: 50%;
    background: rgba(255, 255, 255, 0.5);
    padding: 10px;
    border-radius: 10px;
}

.new-bg {
    background: url(http://goo.gl/0virQo);
    background-size: cover;
}

JavaScript

$('.open').click(function() {
    $('.popup').bPopup({
        onOpen: function() {
            $('body').addClass('new-bg');
        }, 
        onClose: function() {
            $('body').removeClass('new-bg');
        }
    });
});