JSFiddle - React, Tailwind, and code Playground

HTML

<div class="video-responsive">
    <iframe width="420" height="315" src="https://www.youtube.com/embed/2SUqC8PGrtU" frameborder="0" allowfullscreen></iframe>
</div>

CSS

.video-responsive{
    overflow:hidden;
    padding-bottom:56.25%;
    position:relative;
    height:0;
}
.video-responsive iframe{
    left:0;
    top:0;
    height:100%;
    width:100%;
    position:absolute;
}