:root {
    --paper: #ece7da;
    --surface: #f8f5ec;
    --surface-2: #f1ecdf;
    --ink: #211f1b;
    --ink-soft: #5b564a;
    --ink-faint: #8b8474;
    --indigo: #223a5e;
    --indigo-soft: #dbe3ea;
    --shu: #a23829;
    --shu-soft: #f1ddd7;
    --line: #d6cfbc;
    --n2: #6b4f9c;
    --n2-soft: #e5dcf1;
    --n3: #2f7a5c;
    --n3-soft: #dcece4;
    --n4: #8a6a3a;
    --n4-soft: #ece3d3;
  }
  @media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
      --paper: #171511;
      --surface: #201d18;
      --surface-2: #262319;
      --ink: #ece7da;
      --ink-soft: #b9b2a0;
      --ink-faint: #837c6c;
      --indigo: #8fabd4;
      --indigo-soft: #26344a;
      --shu: #e2846f;
      --shu-soft: #3a2620;
      --line: #3a362c;
      --n2: #c1a8e8;
      --n2-soft: #302947;
      --n3: #7fcaa6;
      --n3-soft: #1f3b2d;
      --n4: #c9ab7a;
      --n4-soft: #3a3122;
    }
  }
  :root[data-theme="dark"] {
    --n4: #c9ab7a;
    --n4-soft: #3a3122;
  }
  :root[data-theme="dark"] {
    --paper: #171511;
    --surface: #201d18;
    --surface-2: #262319;
    --ink: #ece7da;
    --ink-soft: #b9b2a0;
    --ink-faint: #837c6c;
    --indigo: #8fabd4;
    --indigo-soft: #26344a;
    --shu: #e2846f;
    --shu-soft: #3a2620;
    --line: #3a362c;
    --n2: #c1a8e8;
    --n2-soft: #302947;
    --n3: #7fcaa6;
    --n3-soft: #1f3b2d;
  }

  * { box-sizing: border-box; }
  body {
    background: var(--paper);
    color: var(--ink);
    font-family: "Noto Sans JP", "Hiragino Sans", sans-serif;
    line-height: 1.75;
  }
  .page {
    max-width: 760px;
    margin: 0 auto;
    padding: 0 20px 80px;
  }
  ruby { ruby-position: over; }
  rt {
    font-size: 0.55em;
    color: var(--ink-soft);
    font-weight: 400;
    letter-spacing: 0;
  }

  .breadcrumb {
    margin: 20px 0 0;
    font-size: 13px;
    color: var(--ink-faint);
  }
  .breadcrumb a { color: var(--indigo); text-decoration: none; }
  .breadcrumb a:hover { text-decoration: underline; }
  .breadcrumb span[id="breadcrumbTitle"] { color: var(--ink-soft); }

  /* Chyron header, echoing the broadcast subtitle bar */
  .chyron {
    margin: 28px 0 0;
    padding: 22px 24px 24px;
    background: var(--indigo);
    color: var(--surface);
    border-radius: 4px;
  }
  .tag-row { display: flex; gap: 8px; align-items: center; margin-bottom: 14px; }
  .tag-live {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: var(--shu);
    color: #fff;
    font-family: "Noto Sans JP", sans-serif;
    font-weight: 700;
    font-size: 12px;
    letter-spacing: 0.08em;
    padding: 3px 9px;
    border-radius: 2px;
  }
  .tag-live::before {
    content: "";
    width: 6px; height: 6px; border-radius: 50%;
    background: #fff;
  }
  .eyebrow {
    font-size: 12px;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--indigo-soft);
    font-weight: 500;
  }
  h1.title-jp {
    font-family: "Shippori Mincho", serif;
    font-weight: 700;
    font-size: clamp(24px, 5vw, 32px);
    margin: 4px 0 6px;
    text-wrap: balance;
    line-height: 1.5;
  }
  .title-en {
    font-size: 14.5px;
    color: var(--indigo-soft);
    margin: 0;
  }
  .source-line {
    margin-top: 16px;
    padding-top: 14px;
    border-top: 1px solid rgba(255,255,255,0.18);
    font-size: 13px;
    display: flex;
    flex-wrap: wrap;
    gap: 6px 14px;
    color: var(--indigo-soft);
  }
  .source-line a { color: var(--surface); }

  /* Overview */
  .overview {
    padding: 26px 0 6px;
    color: var(--ink-soft);
    font-size: 15px;
  }
  .overview strong { color: var(--ink); font-weight: 500; }
  .note {
    margin-top: 14px;
    padding: 10px 14px;
    background: var(--surface-2);
    border-left: 3px solid var(--shu);
    border-radius: 2px;
    font-size: 13px;
    color: var(--ink-soft);
  }

  /* Quiz toggle */
  .quiz-toggle {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    margin-top: 18px;
    padding: 8px 12px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 20px;
    font-size: 13px;
    color: var(--ink-soft);
    cursor: pointer;
    user-select: none;
  }
  .quiz-toggle input { accent-color: var(--indigo); width: 15px; height: 15px; cursor: pointer; }
  body.quiz-mode .hideable {
    filter: blur(5px);
    transition: filter 0.12s ease;
  }
  body.quiz-mode .hideable:hover,
  body.quiz-mode .hideable:focus-within {
    filter: none;
  }

  /* Sections */
  section { margin-top: 46px; }
  .section-head {
    display: flex;
    align-items: baseline;
    gap: 10px;
    border-bottom: 1px solid var(--line);
    padding-bottom: 10px;
    margin-bottom: 20px;
  }
  .section-head h2 {
    font-family: "Shippori Mincho", serif;
    font-size: 21px;
    font-weight: 700;
    margin: 0;
  }
  .section-head .jp {
    font-size: 14px;
    color: var(--ink-faint);
  }

  .group-label {
    font-size: 12.5px;
    font-weight: 700;
    letter-spacing: 0.06em;
    color: var(--indigo);
    margin: 26px 0 10px;
    display: flex;
    align-items: center;
    gap: 8px;
  }
  .group-label:first-child { margin-top: 0; }
  .group-label::after {
    content: "";
    flex: 1;
    height: 1px;
    background: var(--line);
  }

  .vocab-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(228px, 1fr));
    gap: 10px;
  }
  .vocab-card {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 6px;
    padding: 13px 14px;
    cursor: pointer;
  }
  .vocab-card:hover, .grammar-card:hover { border-color: var(--indigo); }
  .vocab-head {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 8px;
  }
  .vocab-word {
    font-family: "Shippori Mincho", serif;
    font-size: 19px;
    font-weight: 700;
  }
  .badge {
    flex: none;
    font-size: 10.5px;
    font-weight: 700;
    letter-spacing: 0.04em;
    padding: 2px 6px;
    border-radius: 3px;
    white-space: nowrap;
  }
  .badge.n2 { background: var(--n2-soft); color: var(--n2); }
  .badge.n3 { background: var(--n3-soft); color: var(--n3); }
  .badge.n4 { background: var(--n4-soft); color: var(--n4); }
  .badge.n1 { background: var(--shu-soft); color: var(--shu); }
  .vocab-meaning {
    font-size: 13.5px;
    color: var(--ink-soft);
    margin-top: 4px;
  }
  .vocab-example {
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px dashed var(--line);
    font-size: 12.5px;
    color: var(--ink-faint);
  }
  .vocab-example .jp { color: var(--ink-soft); }
  .timestamp {
    display: inline-flex;
    align-items: center;
    gap: 3px;
    font-size: 11px;
    font-variant-numeric: tabular-nums;
    color: var(--indigo);
    text-decoration: none;
    font-weight: 700;
    white-space: nowrap;
  }
  .timestamp:hover { text-decoration: underline; }
  .timestamp::before { content: "▶"; font-size: 8px; }

  /* Grammar cards */
  .grammar-card {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 18px 20px;
    margin-bottom: 14px;
    display: grid;
    grid-template-columns: 34px 1fr;
    cursor: pointer;
    gap: 14px;
  }
  .grammar-num {
    font-family: "Shippori Mincho", serif;
    font-size: 15px;
    color: var(--ink-faint);
    font-variant-numeric: tabular-nums;
    padding-top: 2px;
  }
  .grammar-head {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 6px;
  }
  .grammar-pattern {
    font-family: "Shippori Mincho", serif;
    font-size: 20px;
    font-weight: 700;
    color: var(--indigo);
  }
  .grammar-gloss {
    font-size: 13.5px;
    color: var(--ink-soft);
  }
  .grammar-form {
    display: inline-block;
    margin: 4px 0 10px;
    font-size: 12.5px;
    color: var(--ink-faint);
    background: var(--surface-2);
    padding: 3px 8px;
    border-radius: 4px;
    font-family: "Noto Sans JP", sans-serif;
  }
  .grammar-example {
    font-size: 15px;
    line-height: 1.9;
    margin-bottom: 4px;
  }
  .grammar-example b { color: var(--shu); font-weight: 700; }
  .grammar-translation {
    font-size: 13px;
    color: var(--ink-faint);
    font-style: italic;
  }
  .grammar-foot {
    margin-top: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  footer {
    margin-top: 50px;
    padding-top: 18px;
    border-top: 1px solid var(--line);
    font-size: 12.5px;
    color: var(--ink-faint);
  }

  @media (max-width: 480px) {
    .grammar-card { grid-template-columns: 1fr; }
    .grammar-num { display: none; }
  }

  /* Lesson page tabs — same heading + jp-caption look as .section-head
     below, just as clickable per-tab controls instead of a static
     heading repeated inside every section. */
  .lesson-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 4px 26px;
    margin-top: 30px;
    border-bottom: 1px solid var(--line);
  }
  .tab-btn {
    appearance: none;
    -webkit-appearance: none;
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    display: flex;
    align-items: baseline;
    gap: 8px;
    font-family: "Shippori Mincho", serif;
    font-size: 18px;
    font-weight: 700;
    color: var(--ink-faint);
    padding: 10px 0;
    cursor: pointer;
  }
  .tab-btn .jp {
    font-family: "Noto Sans JP", sans-serif;
    font-size: 13px;
    font-weight: 400;
    color: var(--ink-faint);
  }
  .tab-btn:hover { color: var(--ink-soft); }
  .tab-btn.active { color: var(--ink); border-bottom-color: var(--indigo); }
  .tab-btn.active .jp { color: var(--ink-faint); }

  /* Jump nav (index.html's static chyron only) */
  .jumpnav {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 10px;
    margin-top: 14px;
    font-size: 12.5px;
  }
  .jumpnav a {
    color: var(--indigo-soft);
    text-decoration: none;
    padding: 3px 0;
    border-bottom: 1px dotted rgba(255,255,255,0.35);
  }
  .jumpnav a:hover { color: var(--surface); }

  /* Highlight legend + inline highlights used in the transcript */
  .legend {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 12.5px;
    color: var(--ink-soft);
    margin-bottom: 22px;
  }
  .legend span { display: inline-flex; align-items: center; gap: 6px; }
  .legend .voc, .legend .gram { padding: 1px 6px; border-radius: 3px; }
  .voc {
    font-weight: 700;
    color: var(--shu);
    background: var(--shu-soft);
    padding: 0 3px;
    border-radius: 3px;
  }
  .gram {
    font-weight: 700;
    color: var(--indigo);
    border-bottom: 2px dotted var(--indigo);
  }

  /* Transcript */
  .transcript-block {
    padding: 14px 0;
    border-bottom: 1px dashed var(--line);
  }
  .transcript-block:last-child { border-bottom: none; }
  .transcript-time { margin-bottom: 6px; }
  .transcript-jp {
    font-size: 16px;
    line-height: 2;
  }
  .transcript-vi {
    font-size: 13.5px;
    color: var(--ink-soft);
    line-height: 1.7;
    margin-top: 6px;
  }

  /* Quiz */
  .quiz-progress {
    font-size: 13px;
    color: var(--ink-faint);
    margin-bottom: 18px;
  }
  .quiz-card {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 16px 18px;
    margin-bottom: 14px;
  }
  .quiz-card-head {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 10px;
    margin-bottom: 10px;
  }
  .quiz-q {
    font-size: 15px;
    font-weight: 500;
  }
  .quiz-q .jp { color: var(--indigo); font-weight: 700; }
  .quiz-tag {
    flex: none;
    font-size: 10.5px;
    font-weight: 700;
    padding: 2px 6px;
    border-radius: 3px;
    background: var(--shu-soft);
    color: var(--shu);
    white-space: nowrap;
  }
  .quiz-options {
    display: grid;
    gap: 8px;
  }
  .quiz-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 9px 12px;
    border: 1px solid var(--line);
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    background: var(--paper);
  }
  .quiz-option:hover { border-color: var(--indigo); }
  .quiz-option input { accent-color: var(--indigo); }
  .quiz-option.correct { border-color: var(--n3); background: var(--n3-soft); }
  .quiz-option.incorrect { border-color: var(--shu); background: var(--shu-soft); }
  .quiz-actions {
    display: flex;
    align-items: center;
    gap: 14px;
    margin: 24px 0 8px;
  }
  .quiz-btn {
    font-family: "Noto Sans JP", sans-serif;
    font-size: 14px;
    font-weight: 700;
    color: var(--surface);
    background: var(--indigo);
    border: none;
    border-radius: 20px;
    padding: 10px 22px;
    cursor: pointer;
  }
  .quiz-btn:hover { opacity: 0.9; }
  .quiz-btn.secondary {
    background: none;
    color: var(--indigo);
    border: 1px solid var(--line);
  }
  .quiz-score {
    font-size: 15px;
    font-weight: 700;
    color: var(--indigo);
  }
  .quiz-result-banner {
    display: none;
    padding: 14px 18px;
    border-radius: 8px;
    background: var(--indigo-soft);
    color: var(--ink);
    margin-bottom: 20px;
    font-size: 14.5px;
  }

  /* Sticky YouTube player */
  .player-wrap {
    position: sticky;
    top: 12px;
    z-index: 5;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 10px;
    padding: 10px;
    margin-bottom: 20px;
    box-shadow: 0 6px 18px rgba(0,0,0,0.12);
  }
  .player-frame {
    position: relative;
    width: 100%;
    max-width: 480px;
    aspect-ratio: 16 / 9;
    border-radius: 6px;
    overflow: hidden;
    background: #000;
    margin: 0 auto;
  }
  .player-frame #player,
  .player-frame iframe {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    border: 0;
  }
  .player-controls {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    margin-top: 10px;
  }
  #playerStatus {
    font-size: 12.5px;
    color: var(--ink-soft);
    text-align: center;
  }
  .player-btns { display: flex; gap: 8px; flex-wrap: nowrap; justify-content: center; }
  .player-btns .quiz-btn { padding: 7px 16px; font-size: 12.5px; white-space: nowrap; }
  .player-btns .quiz-btn:disabled { opacity: 0.4; cursor: default; }
  @media (max-width: 420px) {
    .player-btns { gap: 4px; }
    .player-btns .quiz-btn { padding: 6px 8px; font-size: 11px; }
  }

  .loop-btn {
    font-family: "Noto Sans JP", sans-serif;
    font-size: 11px;
    font-weight: 700;
    color: var(--indigo);
    background: var(--indigo-soft);
    border: none;
    border-radius: 12px;
    padding: 3px 10px;
    cursor: pointer;
    margin-left: 8px;
  }
  .loop-btn:hover { opacity: 0.85; }
  .loop-btn.active { background: var(--shu); color: #fff; }

  .transcript-block.active {
    background: var(--surface-2);
    border-radius: 8px;
    margin-left: -12px;
    margin-right: -12px;
    padding-left: 12px;
    padding-right: 12px;
    border-bottom: 1px dashed var(--line);
  }
  .transcript-block.active .transcript-jp { color: var(--indigo); }

  @media (max-width: 560px) {
    .player-wrap { position: static; }
  }