JSFiddle - React, Tailwind, and code Playground

HTML

<div class="cart_over1">

      <div id="close_box1">X</div>

      <iframe width="1024" height="600" src="//www.youtube.com/embed/zDnVDyVYiv8?autoplay=1" frameborder="0" allowfullscreen id="clearmySound"></iframe>

  </div>

CSS

.full_page_overlay1 {
    width: 100%;
    height: 100%;
    position: fixed;
    top: 0px;
    left: 0px;
    background: #626262;
    opacity: 0.9;
    z-index: 2147483646;
}

.cart_over1 {
    width: 1024px;
    position: fixed;
    float: left;
    border: 1px solid black;
    box-shadow: 1px 1px 10px black;
    background: white;
    z-index: 2147483647;
    border-radius: 10px;
}

#close_box1 {
    float: left;
    top: 0px;
    left: 0px;
    display: table-cell;
    vertical-align: middle;
    width: 40px;
    height: 40px;
    font-size: 40px;
    text-align: center;
    color: black;
    text-shadow: 1px 1px 3px black;
    font-weight: bolder;
    cursor: pointer;
    margin-bottom: 10px;
}

JavaScript

$( document ).ready(function() {
    $("#close_box1").click(function(){
    $(".cart_over1").fadeOut();
    $("#clearmySound").attr('src','');      
})
});