.iframe-container {
overflow: hidden;
// Calculated from the aspect ration of the content (in case of 16:9 it is 9/16= 0.5625)
padding-top: 56.25%;
position: relative;
}
.iframe-container iframe {
border: 0;
height: 100%;
left: 0;
position: absolute;
top: 0;
width: 100%;
}