Videos youtube responsive

<style type=»text/css»>
.iframe-container{
position: relative;
width: 100%;
padding-bottom: 56.25%;
height: 0;
text-align: center;
}
.iframe-container iframe{
position: absolute;
top:0;
left: 0;
width: 100%;
height: 100%;
}
</style>

<div class=»iframe-container»>[código iframe youtube]</ div>