// HTML
<div class="video_wrapper">
<iframe frameborder="0" width="100%" height="100%" src="https://www.dailymotion.com/embed/video/Your_dailymotion_embed_URL" allowfullscreen allow="autoplay">
</iframe></div>
// CSS
.video_wrapper {
position: relative;
padding-bottom: 56.25%; /* 16:9 */
}
iframe{
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}