:root {
  --bg: #f2ecdf;
  --bg-strong: #e6dcc8;
  --ink: #1e221d;
  --muted: #5e6058;
  --line: rgba(30, 34, 29, 0.12);
  --card: rgba(255, 252, 245, 0.92);
  --accent: #4f6a50;
  --accent-strong: #314533;
  --gold: #a27b40;
  --shadow: 0 18px 40px rgba(49, 69, 51, 0.10);
  --radius: 24px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(162, 123, 64, 0.10), transparent 28%),
    radial-gradient(circle at right 10% top 10%, rgba(79, 106, 80, 0.12), transparent 24%),
    linear-gradient(180deg, #f8f3e9 0%, var(--bg) 44%, #efe6d3 100%);
  font-family: "Songti SC", "STSong", "Noto Serif SC", serif;
  line-height: 1.7;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(49, 69, 51, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(49, 69, 51, 0.03) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: linear-gradient(180deg, rgba(0,0,0,0.4), transparent 85%);
}

a { color: var(--accent-strong); text-decoration: none; }
a:hover { text-decoration: underline; }

.site-top {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: center;
  padding: 18px 32px;
  border-bottom: 1px solid var(--line);
  background: rgba(248, 243, 233, 0.86);
  backdrop-filter: blur(12px);
}

.site-brand a {
  font-size: 1.1rem;
  font-weight: 700;
}

.site-brand p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
  max-width: 760px;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.nav-link {
  padding: 10px 14px;
  border-radius: 999px;
  color: var(--muted);
  background: rgba(255,255,255,0.55);
  border: 1px solid transparent;
}

.nav-link.active {
  color: white;
  background: var(--accent-strong);
  border-color: rgba(255,255,255,0.1);
}

.page-shell {
  width: min(1180px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 28px 0 72px;
}

.hero-panel, .chapter-hero, .section-block, .viewer-panel, .chapter-index-card, .chapter-card, .card, .plate-card, .plate-card-home, .glossary-row, .hero-note, .route-note {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero-panel {
  display: grid;
  grid-template-columns: 1.3fr 0.9fr;
  gap: 24px;
  padding: 32px;
}

.hero-copy h1, .chapter-hero h1, .page-head h1 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 3.3rem);
  line-height: 1.12;
}

.lead {
  font-size: 1.14rem;
  color: #2f322d;
}

.body-copy, .subtitle, .summary, .muted, .source-snippet, .hero-note p, .route-note p, .route-note li, .page-head p {
  color: var(--muted);
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--gold);
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.76rem;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-top: 28px;
}

.hero-metrics div {
  padding: 16px;
  border-radius: 18px;
  background: rgba(79, 106, 80, 0.07);
  border: 1px solid rgba(79, 106, 80, 0.12);
}

.hero-metrics strong {
  display: block;
  font-size: 1.4rem;
}

.route-note, .hero-note {
  padding: 22px;
}

.route-note ul {
  padding-left: 18px;
  margin: 0;
}

.section-block {
  margin-top: 24px;
  padding: 24px;
}

.section-head {
  margin-bottom: 18px;
}

.chapter-grid, .card-grid, .plate-grid-home, .plate-grid, .glossary-grid, .chapter-index-grid {
  display: grid;
  gap: 18px;
}

.chapter-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.card-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.plate-grid-home { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.plate-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.glossary-grid { grid-template-columns: 1fr; }
.chapter-index-grid { grid-template-columns: 1fr; }

.chapter-card, .card, .plate-card-home, .plate-card, .chapter-index-card {
  padding: 22px;
}

.index-thumb {
  margin-bottom: 14px;
}

.chapter-card h3, .card h3, .plate-card h2, .plate-card-home h3, .chapter-index-card h2 {
  margin: 0 0 8px;
}

.tag-row, .path-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.chip-link, .path-card {
  display: inline-flex;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(162, 123, 64, 0.11);
  border: 1px solid rgba(162, 123, 64, 0.18);
}

.path-card {
  background: rgba(79, 106, 80, 0.08);
  border-color: rgba(79, 106, 80, 0.15);
}

.plate-band {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 18px;
}

.plate-band img,
.plate-card-home img,
.plate-card img,
.index-thumb,
.viewer-thumb img,
.plate-mini-card img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: contain;
  background: #fcf7ef;
  border-radius: 16px;
  padding: 10px;
  border: 1px solid rgba(30, 34, 29, 0.10);
}

.plate-card-home {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 18px;
  align-items: start;
}

.glossary-preview, .bullet-list, .mini-list, .route-list {
  margin: 0;
  padding-left: 20px;
}

.glossary-preview li {
  margin-bottom: 10px;
}

.glossary-preview span {
  display: inline-block;
  margin-left: 8px;
  color: var(--gold);
}

.path-panel {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 16px;
  color: var(--muted);
}

.chapter-hero {
  display: grid;
  grid-template-columns: 1.25fr 0.9fr;
  gap: 24px;
  padding: 28px;
}

.chapter-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.72fr);
  gap: 22px;
  margin-top: 24px;
  align-items: start;
}

.viewer-panel {
  position: sticky;
  top: 96px;
  padding: 20px;
}

.viewer-main, .plate-full {
  width: 100%;
  border-radius: 18px;
  border: 1px solid rgba(30, 34, 29, 0.12);
  background: #fffdf8;
}

.viewer-main {
  object-fit: contain;
  padding: 12px;
}

.viewer-caption {
  margin-top: 14px;
}

.viewer-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 14px;
}

.viewer-thumb {
  padding: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
}

.source-grid, .plate-group-list {
  display: grid;
  gap: 16px;
}

.source-item-deep {
  padding: 18px;
  border-radius: 20px;
  background: rgba(255,255,255,0.7);
  border: 1px solid rgba(30, 34, 29, 0.08);
}

.source-item-deep dl {
  margin: 12px 0 0;
}

.source-item-deep dt {
  font-weight: 700;
  margin-bottom: 4px;
}

.source-item-deep dd {
  margin: 0 0 12px;
  color: var(--muted);
}

.qa-box {
  padding: 14px 18px;
  border-radius: 18px;
  background: rgba(79, 106, 80, 0.06);
  border: 1px solid rgba(79, 106, 80, 0.12);
}

.qa-box summary {
  cursor: pointer;
  font-weight: 700;
}

.plate-mini-card {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 16px;
  align-items: start;
}

.prev-next {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 22px;
}

.prev-next a, .plate-mini-card a {
  color: var(--accent-strong);
  font-weight: 700;
}

.glossary-row {
  display: grid;
  grid-template-columns: 180px 220px 1fr;
  gap: 18px;
  align-items: start;
  padding: 18px 20px;
}

.fade-up {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-up.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 980px) {
  .site-top,
  .hero-panel,
  .chapter-hero,
  .chapter-layout,
  .plate-card-home,
  .plate-mini-card,
  .glossary-row {
    grid-template-columns: 1fr;
    display: grid;
  }

  .site-top {
    padding: 16px 20px;
  }

  .page-shell {
    width: min(100vw - 20px, 980px);
  }

  .viewer-panel {
    position: static;
  }

  .chapter-grid, .card-grid, .plate-grid-home, .plate-grid {
    grid-template-columns: 1fr;
  }

  .hero-metrics {
    grid-template-columns: repeat(2, 1fr);
  }
}


.page-head { margin-bottom: 16px; }
.meta-line {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 12px;
}
.meta-pill {
  display: inline-flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(49, 69, 51, 0.08);
  border: 1px solid rgba(49, 69, 51, 0.14);
  color: var(--muted);
}
.two-col {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(280px, 0.9fr);
  gap: 22px;
}
.deep-grid, .concept-grid, .plate-learning-grid {
  display: grid;
  gap: 16px;
}
.deep-card, .concept-card, .qa-card, .stat-card, .plate-learning-group, .plate-mini-card, .concept-panel, .chapter-panel {
  background: rgba(255, 252, 245, 0.92);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 18px;
}
.deep-card h3, .concept-card h3, .qa-card h2, .plate-learning-group h3, .concept-panel h2, .chapter-panel h2 {
  margin: 0 0 8px;
}
.label {
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--gold);
}
.viewer-shell {
  display: grid;
  gap: 14px;
}
.viewer-hero {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: contain;
  background: #fcf7ef;
  border-radius: 20px;
  border: 1px solid rgba(30, 34, 29, 0.10);
  padding: 16px;
}
.viewer-thumb-grid, .mini-thumb-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}
.thumb-card {
  display: grid;
  gap: 8px;
  background: transparent;
  border: none;
  padding: 0;
  text-align: left;
  cursor: pointer;
}
.thumb-card img, .plate-mini-card img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: contain;
  background: #fcf7ef;
  border-radius: 14px;
  border: 1px solid rgba(30, 34, 29, 0.10);
  padding: 8px;
}
.thumb-card strong, .plate-mini-card strong {
  font-size: 0.96rem;
}
.plate-hero img {
  width: 100%;
  max-height: 70vh;
  object-fit: contain;
  background: #fcf7ef;
  border-radius: 20px;
  border: 1px solid rgba(30, 34, 29, 0.10);
  padding: 16px;
}
.rule-list, .mistake-list, .chapter-list, .action-list, .reading-list {
  margin: 0;
  padding-left: 20px;
}
.question-answer {
  margin-top: 12px;
  padding: 14px 16px;
  border-radius: 14px;
  background: rgba(79, 106, 80, 0.08);
  border: 1px solid rgba(79, 106, 80, 0.12);
}
.ghost-button {
  display: inline-flex;
  padding: 9px 14px;
  border-radius: 999px;
  border: 1px solid rgba(49, 69, 51, 0.18);
  background: rgba(255,255,255,0.65);
  color: var(--accent-strong);
  cursor: pointer;
}
.learning-path {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
.path-button {
  display: grid;
  gap: 4px;
  padding: 16px;
  border-radius: 18px;
  background: rgba(79, 106, 80, 0.08);
  border: 1px solid rgba(79, 106, 80, 0.15);
}
.path-button span {
  color: var(--gold);
  font-size: 0.82rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.cover-frame {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: contain;
  background: #fcf7ef;
  border-radius: 18px;
  border: 1px solid rgba(30, 34, 29, 0.10);
  padding: 14px;
}
.stat-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}
.stat-card strong {
  display: block;
  font-size: 1.35rem;
}
.fade-up {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.fade-up.is-visible {
  opacity: 1;
  transform: translateY(0);
}
@media (max-width: 980px) {
  .hero-panel, .two-col, .plate-card-home {
    grid-template-columns: 1fr;
  }
  .chapter-grid, .card-grid, .plate-grid-home, .plate-grid, .viewer-thumb-grid, .mini-thumb-grid, .hero-metrics, .learning-path, .stat-grid {
    grid-template-columns: 1fr;
  }
  .site-top {
    padding: 16px 18px;
  }
}