body#schedule .section .nav {
  margin-bottom: 1.25em;
  text-align: center;
}
body#schedule .section .calendar {
  position: relative;
}
body#schedule .section .calendar::before {
  content: '';
  display: block;
  padding-top: calc(100% * 3 / 4);
}
body#schedule .section .calendar iframe {
  position: absolute;
  top: 0;
  width: 100%;
  height: 100%;
}

/* RWD
---------------------------------------------------------------- */
@media only screen and (max-width: 768px) {
  body#schedule .section .nav a {
    font-size: 75%;
  }
  body#schedule .section .calendar::before {
    padding-top: 100%;
  }
}