Responsive Vimeo, Youtube video
<style>
.embed-container {
position: relative;
padding-bottom: 56.25%;
height: 0;
overflow: hidden;
max-width: 100%;
height: auto;
}
.embed-container iframe,
.embed-container object,
.embed-container embed {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
}
</style>
<div class='embed-container'>
<iframe src='https://player.vimeo.com/video/11712103' frameborder='0' webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>
</div>