<div class="video-container">
<iframe width="560" height="315" src="https://www.youtube.com/embed/QGsxW6m5Dec" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe></iframe>
</div>
.video-container {
position: relative;
padding-bottom: 56.25%;
padding-top: 30px;
height: 0;
overflow: hidden;
}
.video-container iframe,
.video-container object,
.video-container embed {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
This Pen doesn't use any external CSS resources.