/* ─── Reset & Base ─────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --red:       #A41E22;
  --red-light: #C0393D;
  --gold:      #C9A84C;
  --gold-light:#E8CC80;
  --dark:      #1A1A1A;
  --mid:       #555;
  --light:     #F7F5F0;
  --white:     #FFFFFF;
  --card-bg:   #FFFFFF;
  --border:    #E5E0D8;
  --shadow:    0 4px 20px rgba(0,0,0,0.08);
  --radius:    12px;
  --nav-h:     64px;
  --font-en:   'Inter', sans-serif;
  --font-zh:   'Noto Sans SC', sans-serif;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-en);
  color: var(--dark);
  background: var(--white);
  line-height: 1.7;
  font-size: 16px;
}

/* Chinese font for ZH mode */
body.zh-mode {
  font-family: var(--font-zh);
}

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

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ─── Navigation ───────────────────────────────────────────────────── */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  transition: box-shadow 0.3s;
}
#navbar.scrolled { box-shadow: 0 2px 12px rgba(0,0,0,0.10); }

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 18px;
  color: var(--dark);
  text-decoration: none;
  white-space: nowrap;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 4px;
  margin-left: auto;
}
.nav-links a {
  color: var(--mid);
  font-size: 14px;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
  text-decoration: none;
}
.nav-links a:hover {
  color: var(--red);
  background: rgba(164,30,34,0.07);
}

.lang-switcher {
  display: flex;
  align-items: center;
  gap: 4px;
  background: var(--light);
  border-radius: 20px;
  padding: 4px 8px;
  white-space: nowrap;
}
.lang-divider { color: var(--border); font-size: 13px; }
.lang-btn {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 13px;
  font-weight: 600;
  color: var(--mid);
  padding: 3px 8px;
  border-radius: 14px;
  transition: background 0.2s, color 0.2s;
}
.lang-btn.active {
  background: var(--red);
  color: #fff;
}

.hamburger {
  display: none;
  background: none;
  border: none;
  font-size: 22px;
  cursor: pointer;
  color: var(--dark);
  margin-left: auto;
}

/* ─── Hero ─────────────────────────────────────────────────────────── */
.hero {
  min-height: 100vh;
  background: linear-gradient(135deg, #1A0405 0%, #3D0A0D 40%, #6B1519 70%, #8B2020 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  padding: calc(var(--nav-h) + 40px) 24px 80px;
}

.hero-bg-pattern {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 20% 80%, rgba(201,168,76,0.08) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(201,168,76,0.06) 0%, transparent 50%);
  pointer-events: none;
}

/* Decorative circles */
.hero-decoration { position: absolute; inset: 0; pointer-events: none; overflow: hidden; }
.deco-circle {
  position: absolute;
  border-radius: 50%;
  border: 1px solid rgba(201,168,76,0.15);
}
.c1 { width: 600px; height: 600px; top: -200px; right: -200px; }
.c2 { width: 400px; height: 400px; bottom: -150px; left: -100px; border-color: rgba(201,168,76,0.10); }
.c3 { width: 200px; height: 200px; top: 30%; right: 10%; border-color: rgba(201,168,76,0.20); }

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-block;
  background: rgba(201,168,76,0.15);
  color: var(--gold-light);
  border: 1px solid rgba(201,168,76,0.30);
  padding: 6px 18px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.5px;
  margin-bottom: 28px;
}

.hero-title {
  font-size: clamp(2.4rem, 6vw, 4rem);
  font-weight: 700;
  color: #fff;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.5px;
}
.title-zh-char {
  color: var(--gold);
  font-family: var(--font-zh);
}

.hero-venue {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  margin-bottom: 20px;
}
.venue-name {
  font-size: clamp(1.3rem, 3vw, 1.8rem);
  font-weight: 700;
  color: var(--gold);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.venue-detail {
  font-size: clamp(0.78rem, 1.8vw, 0.95rem);
  color: rgba(255,255,255,0.6);
  font-weight: 300;
}
.hero-subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  color: rgba(255,255,255,0.75);
  margin-bottom: 36px;
  font-weight: 300;
}

.hero-ctas {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 0;
  flex-wrap: wrap;
}
.cta-primary {
  background: var(--gold);
  color: #1A0405;
  padding: 13px 32px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 15px;
  transition: background 0.2s, transform 0.2s;
  text-decoration: none;
}
.cta-primary:hover { background: var(--gold-light); transform: translateY(-1px); text-decoration: none; }

.cta-secondary {
  background: transparent;
  color: rgba(255,255,255,0.85);
  border: 1px solid rgba(255,255,255,0.30);
  padding: 13px 32px;
  border-radius: 8px;
  font-weight: 500;
  font-size: 15px;
  transition: background 0.2s, border-color 0.2s;
  text-decoration: none;
}
.cta-secondary:hover { background: rgba(255,255,255,0.08); border-color: rgba(255,255,255,0.5); text-decoration: none; }

.hero-stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 32px;
  flex-wrap: wrap;
}
.stat { text-align: center; }
.stat-num {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--gold);
  line-height: 1;
  margin-bottom: 4px;
}
.stat-label {
  font-size: 12px;
  color: rgba(255,255,255,0.55);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}
.stat-divider {
  width: 1px;
  height: 40px;
  background: rgba(255,255,255,0.15);
}

/* ─── Sections ─────────────────────────────────────────────────────── */
.section { padding: 88px 0; }
.section-alt { background: var(--light); }

.section-header {
  text-align: center;
  margin-bottom: 56px;
}
.section-tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--red);
  margin-bottom: 12px;
}
.section-header h2 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 16px;
}
.section-desc {
  max-width: 600px;
  margin: 0 auto;
  color: var(--mid);
  font-size: 1.05rem;
}

/* ─── Overview ─────────────────────────────────────────────────────── */
.overview-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}
.overview-text p {
  color: var(--mid);
  margin-bottom: 18px;
  font-size: 1.02rem;
}

.overview-goals {
  background: var(--light);
  border-radius: var(--radius);
  padding: 32px;
  border: 1px solid var(--border);
}
.overview-goals h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 20px;
  color: var(--dark);
}
.goals-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.goals-list li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  color: var(--mid);
  font-size: 0.95rem;
}
.goal-icon { font-size: 1.1rem; flex-shrink: 0; margin-top: 2px; }

/* ─── Tracks ───────────────────────────────────────────────────────── */
.tracks-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 32px;
}
.track-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 32px 28px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition: transform 0.2s, box-shadow 0.2s;
}
.track-card:hover { transform: translateY(-4px); box-shadow: 0 8px 32px rgba(0,0,0,0.12); }

.track-icon-wrap {
  width: 52px; height: 52px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
}
.t1 { background: rgba(164,30,34,0.10); }
.t2 { background: rgba(201,168,76,0.15); }
.t3 { background: rgba(40,100,180,0.10); }
.track-icon { font-family: var(--font-zh); }

.track-card h3 { font-size: 1.1rem; font-weight: 700; color: var(--dark); }
.track-card p { color: var(--mid); font-size: 0.93rem; flex: 1; }

.track-dataset-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 1px solid var(--border);
  padding-top: 14px;
  margin-top: 4px;
}
.track-dataset-item {
  display: flex;
  flex-direction: column;
  gap: 1px;
  padding: 8px 10px;
  background: var(--light);
  border-radius: 8px;
}
.track-dataset-name {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--dark);
}
.track-dataset-desc {
  font-size: 0.8rem;
  color: var(--mid);
}

.architecture-note {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 20px 24px;
  border: 1px solid var(--border);
}
.note-icon { font-size: 18px; flex-shrink: 0; margin-top: 2px; }
.architecture-note p { color: var(--mid); font-size: 0.95rem; }

/* ─── Data ─────────────────────────────────────────────────────────── */
.data-layout { max-width: 900px; margin: 0 auto; }
.data-main > p { color: var(--mid); margin-bottom: 28px; font-size: 1.02rem; }

.corpus-table-wrap {
  overflow-x: auto;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.corpus-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}
.corpus-table thead {
  background: var(--red);
  color: #fff;
}
.corpus-table thead th {
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.corpus-table tbody tr:nth-child(even) { background: var(--light); }
.corpus-table tbody tr:nth-child(odd) { background: var(--card-bg); }
.corpus-table tbody td {
  padding: 12px 16px;
  color: var(--mid);
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.corpus-table tbody td:first-child { color: var(--dark); font-weight: 500; }
.corpus-table tbody td:nth-child(3) { white-space: nowrap; font-weight: 600; color: var(--dark); }
.corpus-total td {
  border-top: 2px solid var(--border) !important;
  background: var(--light) !important;
}

/* ─── Evaluation ───────────────────────────────────────────────────── */
.eval-phases {
  display: flex;
  align-items: center;
  gap: 24px;
  margin-bottom: 40px;
}
.eval-phase {
  flex: 1;
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 36px 32px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  display: flex;
  gap: 20px;
  align-items: flex-start;
}
.phase-num {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--red);
  line-height: 1;
  flex-shrink: 0;
  opacity: 0.3;
}
.phase-content h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 10px; }
.phase-content p { color: var(--mid); font-size: 0.94rem; }

.eval-arrow {
  font-size: 2rem;
  color: var(--border);
  flex-shrink: 0;
}

.eval-details {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.eval-detail-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid var(--border);
  border-top: 3px solid var(--gold);
}
.eval-detail-card h4 { font-size: 0.95rem; font-weight: 700; margin-bottom: 10px; }
.eval-detail-card p { color: var(--mid); font-size: 0.88rem; }

/* ─── Timeline ─────────────────────────────────────────────────────── */
.timeline {
  position: relative;
  max-width: 700px;
  margin: 0 auto;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 28px;
  top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--red), var(--gold));
}

.timeline-item {
  display: grid;
  grid-template-columns: 56px 160px 1fr;
  gap: 0 20px;
  align-items: start;
  margin-bottom: 40px;
  position: relative;
}
.timeline-item:last-child { margin-bottom: 0; }

.tl-marker {
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--red);
  border: 3px solid var(--white);
  box-shadow: 0 0 0 2px var(--red);
  margin-top: 4px;
  justify-self: center;
}
.tl-star {
  background: var(--gold);
  box-shadow: 0 0 0 2px var(--gold);
  width: 20px; height: 20px;
}

.tl-date {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--red);
  padding-top: 2px;
  line-height: 1.4;
}

.tl-content {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 18px 20px;
  border: 1px solid var(--border);
}
.tl-content h4 { font-size: 0.95rem; font-weight: 700; margin-bottom: 6px; }
.tl-content p { color: var(--mid); font-size: 0.88rem; }

/* ─── Organizers ───────────────────────────────────────────────────── */
.organizers-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px 32px;
  margin-bottom: 48px;
}
.organizer-item {
  display: flex;
  flex-direction: column;
  gap: 3px;
}
.organizer-item strong {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--dark);
}
.organizer-item span {
  font-size: 0.85rem;
  color: var(--mid);
}

.contact-block {
  text-align: center;
  padding: 32px;
  background: var(--card-bg);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.contact-block p { color: var(--mid); margin-bottom: 10px; }
.contact-email {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--red);
}

/* ─── Footer ───────────────────────────────────────────────────────── */
.footer {
  background: var(--dark);
  color: rgba(255,255,255,0.7);
  padding: 40px 0;
}
.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  text-align: center;
}
.footer .nav-brand, .footer .footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 16px;
  color: #fff;
}
.footer-note { font-size: 0.85rem; }
.footer-links { display: flex; gap: 24px; margin-top: 4px; }
.footer-links a { color: rgba(255,255,255,0.5); font-size: 0.85rem; transition: color 0.2s; }
.footer-links a:hover { color: var(--gold); text-decoration: none; }

/* ─── Responsive ───────────────────────────────────────────────────── */
@media (max-width: 900px) {
  .nav-links { display: none; }
  .nav-links.open { display: flex; flex-direction: column; position: absolute; top: var(--nav-h); left: 0; right: 0; background: #fff; border-bottom: 1px solid var(--border); padding: 16px; gap: 4px; z-index: 999; }
  .hamburger { display: block; }
  .lang-switcher { margin-left: auto; }

  .overview-grid { grid-template-columns: 1fr; }
  .tracks-grid { grid-template-columns: 1fr; }
  .eval-phases { flex-direction: column; }
  .eval-arrow { transform: rotate(90deg); }
  .eval-details { grid-template-columns: 1fr; }
  .organizers-list { grid-template-columns: repeat(2, 1fr); }
  .timeline-item { grid-template-columns: 40px 1fr; grid-template-rows: auto auto; }
  .tl-date { grid-column: 2; grid-row: 1; }
  .tl-content { grid-column: 2; grid-row: 2; }
  .timeline::before { left: 20px; }
}

@media (max-width: 560px) {
  .hero-stats { gap: 20px; }
  .organizers-grid { grid-template-columns: 1fr 1fr; }
  .hero-ctas { flex-direction: column; align-items: center; }
  .cta-primary, .cta-secondary { width: 100%; max-width: 260px; text-align: center; }
}