body {
    margin: 0;
    padding: 0;
}

.responsive_video {
    position: relative;
    padding-bottom: 56.25%;
}

.responsive_video video,
.responsive_video iframe,
.responsive_video object,
.responsive_video embed {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}