.youtube-embedder {

position: relative;
padding-bottom: 56.25%;
height: 0;
overflow: hidden;
max-width: 100%;
margin: 1em 0;

}

.youtube-embedder iframe, .youtube-embedder object, .youtube-embedder embed {

position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;

}