.video-wrap
  position: relative

  &:before
    content: ''
    display: block
    padding-top: 56.25%

.video-wrap .iframe-box
  position: absolute
  top: 0
  left: 0
  bottom: 0
  right: 0

.video-wrap .iframe-box iframe
  width: 100%
  height: 100%

.ratio16-9:before
  padding-top: 56.25%

.ratio4-3:before
  padding-top: 75%

.ratio3-2:before
  padding-top: 50%

.ratio1-1:before
  padding-top: 100%