.iframe-wrapper {
  position: relative;
  padding-bottom: 75%;
  height: 0;
  overflow: hidden;
}
.iframe-wrapper iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.zoom a {
    display: block;
    line-height: 20px;
    text-decoration: none;
    margin: 0.5rem auto;
    padding-left: 5px;
    font-size: 16px;
}