.reponsive-iframe {
  position: relative;
  padding-bottom: 56.25%; /* 16:9 */
  padding-top: 25px;
  height: 0;
}

.reponsive-iframe--parent-calendar {
  padding-bottom: 160%; /* 3:5 */
}

.reponsive-iframe__iframe {
  height: 100%;
  left: 0;
  position: absolute;
  top: 0;
  width: 100%;
}