@import url('https://fonts.googleapis.com/css2?family=Be+Vietnam+Pro:wght@400;500;600;700;800&family=Noto+Serif:wght@500;600;700;900&family=Noto+Serif+SC:wght@700;900&family=JetBrains+Mono:wght@400;600&display=swap');

:root {
  --wood-dark: #2c1e14;
  --wood: #6b4226;
  --wood-light: #96693f;
  --paper: #f1e7d0;
  --paper-2: #e8d9b8;
  --paper-3: #fbf6e9;
  --ink: #211b15;
  --ink-soft: #55493c;
  --seal: #a3272c;
  --seal-dark: #7c1d21;
  --jade: #3f6b52;
  --gold: #b5892c;
  --shadow: 0 8px 24px rgba(43, 30, 18, 0.16);
  --radius: 4px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

::selection { background: var(--seal); color: #fff; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: 'Be Vietnam Pro', sans-serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  /* subtle paper grain, no image assets required */
  background-image:
    radial-gradient(rgba(43,30,18,0.035) 1px, transparent 1px),
    radial-gradient(rgba(43,30,18,0.025) 1px, transparent 1px);
  background-size: 3px 3px, 7px 7px;
  background-position: 0 0, 2px 3px;
}

.js body {
  opacity: 0;
  transition: opacity 0.4s ease;
}
.js body.loaded { opacity: 1; }

/* Visible keyboard focus everywhere */
a:focus-visible, button:focus-visible, [tabindex]:focus-visible {
  outline: 3px solid var(--gold);
  outline-offset: 2px;
  border-radius: 2px;
}

h1, h2, h3, h4 {
  font-family: 'Noto Serif', serif;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 0.5em;
}

h1 { font-size: clamp(2.1rem, 4vw, 3.4rem); font-weight: 900; }
h2 { font-size: clamp(1.6rem, 3vw, 2.3rem); }
h3 { font-size: 1.3rem; }

p { margin: 0 0 1em; color: var(--ink-soft); }

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

.cjk { font-family: 'Noto Serif SC', serif; }

.mono {
  font-family: 'JetBrains Mono', monospace;
  letter-spacing: 0.02em;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Seal badge, the site's signature motif ---------- */
.seal-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--seal);
  color: var(--paper-3);
  font-family: 'Noto Serif SC', serif;
  font-weight: 900;
  font-size: 20px;
  border-radius: 6px;
  transform: rotate(-3deg);
  box-shadow: 0 3px 0 rgba(0,0,0,0.25);
  flex-shrink: 0;
}
.seal-badge.lg { width: 84px; height: 84px; font-size: 42px; border-radius: 10px; }

/* ---------- Header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--wood-dark);
  background-image: linear-gradient(180deg, rgba(255,255,255,0.03), rgba(0,0,0,0.08));
  border-bottom: 3px solid var(--seal-dark);
  transition: box-shadow 0.25s ease;
}
.site-header.scrolled {
  box-shadow: 0 6px 20px rgba(0,0,0,0.35);
}
.header-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--paper-3);
  font-family: 'Noto Serif', serif;
  font-weight: 700;
  font-size: 1.25rem;
}
.brand:hover { text-decoration: none; }
.brand-dot { color: var(--gold); }

.main-nav {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}
.main-nav a {
  color: #e8dabd;
  font-size: 0.94rem;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: var(--radius);
  transition: background 0.15s ease, color 0.15s ease;
}
.main-nav a:hover { background: rgba(255,255,255,0.08); text-decoration: none; }
.main-nav a.active { color: #fff; background: var(--seal); }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid rgba(255,255,255,0.3);
  color: var(--paper-3);
  font-size: 1.1rem;
  padding: 6px 10px;
  border-radius: var(--radius);
  cursor: pointer;
}

@media (max-width: 860px) {
  .nav-toggle { display: inline-block; }
  .main-nav {
    display: flex;
    max-height: 0;
    overflow: hidden;
    position: absolute;
    left: 0; right: 0; top: 100%;
    background: var(--wood-dark);
    flex-direction: column;
    padding: 0 24px;
    border-bottom: none;
    transition: max-height 0.3s ease, padding 0.3s ease;
  }
  .main-nav.open {
    max-height: 400px;
    padding: 8px 24px 16px;
    border-bottom: 3px solid var(--seal-dark);
  }
}

/* ---------- Footer ---------- */
.site-footer {
  background: var(--wood-dark);
  color: #cbb98f;
  margin-top: 80px;
}
.footer-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 40px 24px;
  text-align: center;
}
.footer-seal {
  font-family: 'Noto Serif SC', serif;
  font-size: 2rem;
  color: var(--seal);
  margin-bottom: 8px;
}
.footer-links {
  display: flex;
  gap: 18px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 14px;
}
.footer-links a { color: #cbb98f; font-size: 0.9rem; }
.footer-links a:hover { color: #fff; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.98rem;
  cursor: pointer;
  border: none;
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}
.btn:hover { text-decoration: none; }
.btn-primary {
  background: var(--seal);
  color: #fff;
  box-shadow: 0 4px 0 var(--seal-dark);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 0 var(--seal-dark); }
.btn-primary:active { transform: translateY(1px); box-shadow: 0 2px 0 var(--seal-dark); }
.btn-outline {
  background: transparent;
  color: var(--ink);
  border: 1.5px solid var(--wood);
}
.btn-outline:hover { background: var(--wood); color: #fff; }

/* ---------- Hero ---------- */
.hero {
  padding: 64px 0 40px;
  position: relative;
  overflow: hidden;
}
.hero-inner {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
  align-items: center;
}
.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  color: var(--seal-dark);
  background: rgba(163,39,44,0.08);
  border: 1px solid rgba(163,39,44,0.25);
  padding: 5px 12px;
  border-radius: 999px;
  margin-bottom: 18px;
}
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 26px; }

@media (max-width: 860px) {
  .hero-inner { grid-template-columns: 1fr; }
}

/* ---------- Sections & cards ---------- */
.section { padding: 56px 0; }
.section-head { max-width: 640px; margin-bottom: 36px; }
.section-head .kicker {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  color: var(--seal);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  display: block;
  margin-bottom: 10px;
}

.grid { display: grid; gap: 22px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 900px) { .grid-3, .grid-4 { grid-template-columns: repeat(2,1fr); } }
@media (max-width: 620px) { .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; } }

.card {
  background: var(--paper-3);
  border: 1px solid rgba(43,30,18,0.1);
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--shadow);
  position: relative;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 16px 32px rgba(43,30,18,0.22);
}
.card h3 { margin-bottom: 10px; }
.card p:last-child { margin-bottom: 0; }
.card-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 12px;
  font-weight: 600;
  font-size: 0.92rem;
  transition: gap 0.15s ease;
}
.card-link:hover { gap: 10px; text-decoration: none; }

/* Scroll-reveal: only applies once JS confirms it can animate them back in */
.js .card,
.js .roadmap-step,
.js .media-card,
.js .piece-row {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.js .card.is-visible,
.js .roadmap-step.is-visible,
.js .media-card.is-visible,
.js .piece-row.is-visible {
  opacity: 1;
  transform: none;
}

.corner-seal {
  position: absolute;
  top: -10px;
  right: 18px;
  background: var(--seal);
  color: #fff;
  font-family: 'Noto Serif SC', serif;
  font-size: 1rem;
  font-weight: 900;
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
  transform: rotate(6deg);
  box-shadow: 0 3px 0 rgba(0,0,0,0.2);
}

/* ---------- Divider with river motif ---------- */
.river-divider {
  display: flex;
  align-items: center;
  gap: 18px;
  color: var(--wood);
  font-family: 'Noto Serif SC', serif;
  font-size: 1.1rem;
  margin: 48px 0;
}
.river-divider::before, .river-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--wood-light), transparent);
}

/* ---------- Piece move-icon rows (used on rules & learn pages) ---------- */
.piece-row {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  padding: 22px 0;
  border-bottom: 1px solid rgba(43,30,18,0.1);
}
.piece-row:last-child { border-bottom: none; }
.piece-token {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--paper-3);
  border: 2px solid var(--ink);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Noto Serif SC', serif;
  font-weight: 900;
  font-size: 1.5rem;
  box-shadow: 1px 2px 2px rgba(0,0,0,0.2);
}
.piece-token.red { color: var(--seal); }
.piece-token.black { color: var(--ink); }
.piece-row h4 { margin: 0 0 4px; font-family: 'Noto Serif', serif; }
.piece-row .move-note {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  color: var(--seal-dark);
  background: rgba(163,39,44,0.08);
  padding: 2px 8px;
  border-radius: 3px;
  display: inline-block;
  margin-top: 6px;
}

/* ---------- Lesson roadmap (timeline; genuinely sequential) ---------- */
.roadmap { position: relative; padding-left: 34px; }
.roadmap::before {
  content: '';
  position: absolute;
  left: 11px; top: 6px; bottom: 6px;
  width: 2px;
  background: var(--wood-light);
}
.roadmap-step { position: relative; padding-bottom: 34px; }
.roadmap-step:last-child { padding-bottom: 0; }
.roadmap-step::before {
  content: '';
  position: absolute;
  left: -34px; top: 4px;
  width: 24px; height: 24px;
  border-radius: 50%;
  background: var(--seal);
  border: 3px solid var(--paper);
  box-shadow: 0 0 0 2px var(--wood-light);
}
.roadmap-step .step-label {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: var(--seal-dark);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* ---------- Accordion (rules page) ---------- */
.accordion-item {
  border: 1px solid rgba(43,30,18,0.14);
  border-radius: var(--radius);
  margin-bottom: 12px;
  background: var(--paper-3);
  overflow: hidden;
}
.accordion-btn {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 18px 22px;
  font-family: 'Noto Serif', serif;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--ink);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.accordion-btn .chevron { transition: transform 0.2s ease; color: var(--seal); }
.accordion-item.open .chevron { transform: rotate(180deg); }
.accordion-panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.25s ease;
  padding: 0 22px;
}
.accordion-item.open .accordion-panel { padding-bottom: 20px; }

/* ---------- Tag pills ---------- */
.pill {
  display: inline-block;
  font-size: 0.78rem;
  font-family: 'JetBrains Mono', monospace;
  padding: 3px 10px;
  border-radius: 999px;
  background: rgba(63,107,82,0.12);
  color: var(--jade);
  margin-right: 6px;
}
.pill.red { background: rgba(163,39,44,0.1); color: var(--seal); }

/* ---------- Video / article cards ---------- */
.media-card { overflow: hidden; padding: 0; }
.media-thumb {
  aspect-ratio: 16/9;
  background: linear-gradient(135deg, var(--wood), var(--wood-dark));
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0.85);
  font-size: 2.4rem;
  position: relative;
  transition: color 0.2s ease;
}
.media-card:hover .media-thumb { color: #fff; }
.media-thumb .platform-tag {
  position: absolute;
  top: 10px; left: 10px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  background: rgba(0,0,0,0.5);
  color: #fff;
  padding: 3px 8px;
  border-radius: 3px;
}
.media-body { padding: 18px 20px; }

/* ---------- Placeholder note ---------- */
.placeholder-note {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  color: var(--seal-dark);
  background: rgba(163,39,44,0.07);
  border: 1px dashed rgba(163,39,44,0.3);
  padding: 10px 14px;
  border-radius: var(--radius);
  margin-bottom: 28px;
}

/* ---------- Back to top ---------- */
.back-to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--seal);
  color: #fff;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(0,0,0,0.3);
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 0.25s ease, transform 0.2s ease;
  z-index: 60;
}
.back-to-top.show { opacity: 1; pointer-events: auto; transform: none; }
.back-to-top:hover { transform: translateY(-3px); }

/* ---------- Utility ---------- */
.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  .js .card, .js .roadmap-step, .js .media-card, .js .piece-row {
    opacity: 1 !important;
    transform: none !important;
  }
}