.intrinsic-container {
position: relative;
height: 0;
overflow: hidden;
}

/* 16x9 Aspect Ratio */
.intrinsic-container-16x9 {
padding-bottom: 56.25%;
}

/* 4x3 Aspect Ratio */
.intrinsic-container-4x3 {
padding-bottom: 75%;
}

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