.iframe-container {
    position: relative;
    padding-bottom: 56.25%;
    padding-top: 75px;
    height: 0;
}

.iframe-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

<div class="iframe-container">
  <!-- embed-code -->
</div>