section.style1 iframe.slider {
  width: 100%;
  height: auto;
  max-width: 900px;
  min-height: 610px;
  margin: 0 0 30px 0;
}

/* スマホ向けのレイアウトの指定 */
@media only screen and (max-width: 769px) {
  section.style1 iframe.slider {
    min-height: 280px;
  }
}