body {
    display: block;
    margin: auto;
    max-width: 90%;
}

.video-container {
	position:relative;
	padding-top:25px;
	height:0;
}
.video-4-3 {padding-bottom:75%;}
.video-16-9 {padding-bottom:56.25%;}

.video-container iframe {
	position:absolute;
	top:0;
	left:0;
	width:100%;
	height:100%;
}