/* v50: geographic artwork, the teaching product's title face, and balanced navigation. */
:is(.video-dialog, .viewer-page) {
  --viewer-ink: #173e34;
  --viewer-muted: #53645a;
  --viewer-line: #a5b4a8;
  --viewer-hover: #e5eddf;
  --viewer-button-surface: #f8faf5;
  --viewer-title-font: 'Noto Serif CJK SC Local Black', serif;
  --viewer-reading-font: 'LXGW WenKai Local', cursive;
  --viewer-gap: 18px;
  --viewer-touch: 48px;
  --viewer-close-icon: 22px;
  --viewer-series-size: 17px;
  --viewer-position-size: 20px;
  --viewer-title-size: 26px;
  --viewer-gutter: 24px;
  --viewer-nav-width: 400px;
  --viewer-nav-height: 50px;
  --viewer-nav-gap: 14px;
  --viewer-nav-count: 90px;
  --viewer-nav-size: 18px;
  --viewer-nav-radius: 8px;
  --viewer-portrait-reserve: 272px;
}
.video-dialog {
  color: var(--viewer-ink);
  background: transparent;
  border: 0;
  border-radius: 0;
  box-shadow: none;
  padding: 4px;
  margin: auto;
  width: min(470px, calc(100vw - 2 * var(--viewer-gutter)), calc((100dvh - var(--viewer-portrait-reserve)) * 9 / 16 + 8px));
  max-width: none;
  max-height: calc(100dvh - 24px);
  overflow: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  font-family: var(--font-body, var(--buy-body));
}
.video-modal-open, html:has(.video-dialog[open]) { overflow: hidden !important; }
.video-dialog::backdrop, .viewer-page { background: #f2f4ef url('assets/viewer-v50/landscape.webp') center / cover no-repeat; }
.video-dialog::backdrop { backdrop-filter: none; }
.video-dialog.tool-video-dialog {
  width: min(1120px, calc(100vw - 2 * var(--viewer-gutter)), calc((100dvh - 184px) * 16 / 9));
}
.modal-video-header { display: flex; align-items: center; justify-content: space-between; gap: var(--viewer-gap); margin-bottom: var(--viewer-gap); }
.modal-video-heading { min-width: 0; }
.modal-series { font: 400 var(--viewer-series-size)/1.5 var(--viewer-reading-font); color: var(--viewer-muted); margin: 0 0 6px; letter-spacing: .04em; }
.modal-video-header h2 { margin: 0; font-family: var(--viewer-title-font); font-size: var(--viewer-title-size); font-weight: 900; line-height: 1.4; letter-spacing: 0; text-wrap: balance; }
.video-dialog .modal-close { position: static; display: grid; place-items: center; flex: none; width: var(--viewer-touch); height: var(--viewer-touch); padding: 0; border: 1px solid var(--viewer-line); border-radius: var(--viewer-nav-radius); color: var(--viewer-ink); background: var(--viewer-button-surface); }
.viewer-icon { display: block; width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.video-dialog .modal-close .viewer-icon { width: var(--viewer-close-icon); height: var(--viewer-close-icon); stroke-width: 1.6; }
.modal-video-stage { display: flex; justify-content: center; background: transparent; }
.modal-video-stage video { display: block; width: 100%; height: auto; max-width: 100%; aspect-ratio: 16 / 9; object-fit: contain; background: #000; border-radius: 4px; }
.video-dialog:not(.tool-video-dialog) .modal-video-stage video { width: min(100%, calc((100dvh - var(--viewer-portrait-reserve)) * 9 / 16)); aspect-ratio: 9 / 16; }
.modal-sequence { display: grid; grid-template-columns: minmax(0, 1fr) var(--viewer-nav-count) minmax(0, 1fr); align-items: center; width: min(100%, var(--viewer-nav-width)); gap: var(--viewer-nav-gap); margin: var(--viewer-gap) auto 0; padding: 0; border: 0; }
.modal-sequence button { display: flex; align-items: center; justify-content: center; gap: 10px; min-width: 0; width: 100%; height: var(--viewer-nav-height); padding: 0 12px; border: 1px solid var(--viewer-line); border-radius: var(--viewer-nav-radius); background: var(--viewer-button-surface); color: var(--viewer-ink); font: 400 var(--viewer-nav-size)/1 var(--viewer-reading-font); white-space: nowrap; box-shadow: 0 1px 2px #173e3408; }
.modal-sequence .viewer-icon { width: 18px; height: 18px; flex: none; stroke-width: 1.75; }
.modal-sequence .sequence-label { display: block; line-height: 1; }
.modal-position { display: flex; align-items: center; justify-content: center; gap: 8px; height: var(--viewer-nav-height); color: var(--viewer-ink); font: 400 var(--viewer-position-size)/1 var(--viewer-reading-font); font-variant-numeric: tabular-nums; white-space: nowrap; }
.modal-position > :not(.sr-only) { display: block; font: inherit; color: inherit; }
.modal-sequence button, .modal-close { transition: background .15s ease, border-color .15s ease; }
@media (hover: hover) { .modal-sequence button:hover, .modal-close:hover { background: var(--viewer-hover); border-color: var(--viewer-ink); } }
.modal-sequence button:active, .modal-close:active { background: var(--viewer-hover); }
.video-dialog :is(button, video):focus-visible, .purchase-video :is(.modal-close, .tutorial-download):focus-visible { outline: 2px solid var(--viewer-ink); outline-offset: 3px; }
.modal-status { color: var(--viewer-muted); font-size: 14px; line-height: 1.6; text-align: center; margin: 10px 0 0; }
.modal-status:empty { display: none; }
.purchase-video.video-dialog {
  --tutorial-width: 980px;
  --tutorial-footer-gap: 16px;
  width: min(var(--tutorial-width), calc(100vw - 2 * var(--viewer-gutter)), calc((100dvh - 240px) * 16 / 9));
}
.purchase-video .modal-video-header { margin-bottom: 20px; }
.purchase-video .modal-video-header h2 { font-size: var(--viewer-title-size); }
.tutorial-subtitle { margin: 5px 0 0; color: var(--viewer-muted); font-size: 14px; line-height: 1.6; }
.tutorial-actions { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 16px; margin-top: var(--tutorial-footer-gap); }
.tutorial-format { font-size: 13px; line-height: 1.5; color: var(--viewer-muted); white-space: nowrap; }
.tutorial-download { display: inline-flex; flex: none; align-items: center; justify-content: center; gap: 10px; min-height: 46px; padding: 9px 17px; border: 1px solid var(--viewer-line); border-radius: 6px; color: var(--viewer-ink); background: var(--viewer-button-surface); font: 400 15px/1.5 var(--buy-body); white-space: nowrap; text-decoration: none; }
.tutorial-download:hover { background: var(--viewer-hover); border-color: var(--viewer-ink); }
.video-dialog .tutorial-download:focus-visible { outline: 2px solid var(--viewer-ink); outline-offset: 3px; }
.purchase-video .modal-video-stage video { border-radius: 6px; }
.viewer-page { color: var(--viewer-ink); background-attachment: fixed; }
.viewer-page .player-heading h1 { font-family: var(--viewer-title-font); font-size: var(--viewer-title-size); font-weight: 900; line-height: 1.4; }
.viewer-page .player-heading p { font-size: 16px; color: var(--viewer-muted); }
.viewer-page .player-stage { background: transparent; }
.viewer-page .player-stage video { border-radius: 4px; }
.viewer-page .player-status:empty { display: none; }
@media (max-width: 600px) {
  .video-dialog { --viewer-title-size: 22px; --viewer-gap: 16px; --viewer-gutter: 14px; --viewer-touch: 44px; --viewer-close-icon: 22px; --viewer-series-size: 16px; --viewer-position-size: 18px; --viewer-nav-height: 48px; --viewer-nav-width: 336px; --viewer-nav-count: 74px; --viewer-nav-gap: 8px; --viewer-nav-size: 16px; width: calc(100vw - 2 * var(--viewer-gutter)); }
  .modal-video-header { gap: 12px; }
  .modal-sequence button { gap: 6px; padding-inline: 7px; }
  .modal-position { gap: 6px; }
  .purchase-video .modal-video-header { margin-bottom: 16px; }
  .tutorial-actions { gap: 12px; }
  .tutorial-download { min-height: 44px; padding: 9px 13px; font-size: 14px; box-sizing: border-box; }
  .tutorial-format { font-size: 12px; }
}
@media (max-aspect-ratio: 4 / 5) { .video-dialog::backdrop, .viewer-page { background-image: url('assets/viewer-v50/portrait.webp'); } }
@media (max-height: 540px) and (min-aspect-ratio: 1 / 1) {
  .video-dialog { --viewer-title-size: 20px; --viewer-gap: 12px; --viewer-portrait-reserve: 188px; }
  .video-dialog:not(.tool-video-dialog) { width: min(520px, calc(100vw - 48px)); }
  .purchase-video.video-dialog { --tutorial-footer-gap: 12px; width: min(720px, calc(100vw - 48px), calc((100dvh - 168px) * 16 / 9)); }
  .purchase-video .modal-video-header { margin-bottom: 12px; }
}
@media (prefers-reduced-motion: reduce) { .video-dialog *, .video-dialog *::before { transition: none; animation: none; } }