<div class="video-responsive">
    <iframe width="853" height="480" src="https://www.youtube.com/embed/YOUR_VIDEO_ID" frameborder="0" allowfullscreen></iframe>
</div>
<style>
.video-responsive {
    position: relative;
    overflow: hidden;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
}

.video-responsive iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}
</style>