Iframe video responsive.Youtube.

Iframe video responsive.

<div class="video-container"> </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%;
}

http://ksesocss.blogspot.com/2013/08/aspect-ratios-css.html