/* スマホ（画面幅767px以下）は 16:9 で表示 */
@media screen and (max-width: 767px) {
  .mv-movie {
    position: relative;
    width: 100%;
    padding-top: 56.25%; /* 16:9の比率 */
    height: 0;
    overflow: hidden;
  }

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

/* PC（画面幅768px以上）は 画面一杯（全画面）で表示 */
@media screen and (min-width: 768px) {
  .mv-movie,
  #ytArea iframe {
    width: 100%;
    height: 100vh; /* 画面高さ一杯 */
    object-fit: cover;
    border: 0;
  }
}

/* スマホ（幅767px以下）の表示エリアを強制固定 */
@media screen and (max-width: 767px) {
  #ytArea.mv-movie {
    position: relative !important;
    width: 100% !important;
    padding-top: 56.25% !important; /* 16:9比率 */
    height: 0 !important;
    overflow: hidden !important;
  }

  #ytArea.mv-movie iframe {
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    width: 100% !important;
    height: 100% !important;
    border: 0 !important;
  }
}