/* NT'27 Nanjing Conference Website - Styles */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&family=Roboto:wght@300;400;500;700&display=swap');

:root {
  --primary: #1a2744;
  --primary-light: #2a3d5c;
  --accent: #c08a30;
  --accent-light: #d4a84a;
  --white: #ffffff;
  --off-white: #f5f7fa;
  --text: #333333;
  --text-light: #666666;
  --text-muted: #999999;
  --border: #e0e4ea;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
  --radius: 20px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Roboto', sans-serif;
  color: var(--text);
  background: var(--white);
  line-height: 1.6;
}
h1, h2, h3, h4, h5, h6 {
  font-family: 'Poppins', sans-serif;
  color: var(--primary);
}
a { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-light); }
img { max-width: 100%; height: auto; }

/* ===== NAVIGATION BAR ===== */
.navbar-wrapper {
  background: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

/* Countdown bar */
.navbar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 40px;
}
.navbar-top {
  display: flex !important;
  justify-content: space-between !important;
  align-items: center !important;
  padding: 12px 0 4px !important;
}
.countdown-bar {
  font-family: 'Poppins', sans-serif;
  font-size: 13px;
  letter-spacing: 1px;
  color: var(--text-light);
  text-transform: uppercase;
}
.countdown-bar .days-num {
  font-size: 22px;
  font-weight: 700;
  color: var(--primary);
  margin: 0 4px;
  text-transform: none;
}
.nav-logo {
  height: 40px !important;
  width: auto !important;
  flex-shrink: 0 !important;
}

/* Tab navigation */
.nav-tabs {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  gap: 2px;
  padding: 8px 0 14px;
  flex-wrap: wrap;
}

.nav-tab {
  display: inline-block;
  padding: 8px 18px;
  font-family: 'Roboto', sans-serif;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-light);
  border-radius: var(--radius);
  transition: all 0.2s;
  white-space: nowrap;
  text-decoration: none;
}

.nav-tab:hover {
  color: var(--primary);
  background: var(--off-white);
}

.nav-tab.active {
  background: var(--primary);
  color: var(--white);
  font-weight: 600;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  color: var(--primary);
}

/* ===== HERO BANNER ===== */
.hero {
  background: linear-gradient(135deg, #1a3a5c 0%, #2563a0 50%, #3b82c4 100%);
  padding: 60px 40px;
  text-align: left;
}

.hero-content {
  max-width: 1100px;
  margin: 0 auto;
}

.hero h1 {
  color: var(--white);
  font-size: 42px;
  font-weight: 700;
  margin-bottom: 6px;
}

.hero .subtitle {
  font-size: 18px;
  color: #d0dce8;
  margin-bottom: 4px;
  font-family: 'Poppins', sans-serif;
}

.hero .full-name {
  font-size: 13px;
  color: #a8b8c8;
  margin-bottom: 24px;
  max-width: 700px;
}

.hero .btn {
  display: inline-block;
  background: var(--white);
  color: var(--primary);
  padding: 10px 28px;
  border-radius: 24px;
  font-weight: 600;
  font-size: 14px;
  transition: all 0.3s;
}

.hero .btn:hover {
  background: var(--accent);
  color: var(--white);
}

/* ===== SECTIONS ===== */
.section { padding: 50px 20px; }
.section-container { max-width: 1100px; margin: 0 auto; }
.section-title {
  font-size: 26px;
  margin-bottom: 24px;
  padding-bottom: 8px;
  border-bottom: 3px solid var(--primary);
  display: inline-block;
}
.section-title.center {
  display: block;
  text-align: center;
  border-bottom: none;
  padding-bottom: 0;
}
.section-title.center::after {
  content: '';
  display: block;
  width: 50px;
  height: 3px;
  background: var(--accent);
  margin: 10px auto 0;
}
.section.bg-light { background: var(--off-white); }

/* ===== ABOUT CARDS ===== */
.about-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 20px;
}
.about-card {
  background: var(--white);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.2s;
}
.about-card:hover { transform: translateY(-3px); }
.about-card-img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}
.about-card-body { padding: 18px; }
.about-card-body h3 { font-size: 16px; margin-bottom: 6px; }
.about-card-body p { font-size: 13px; color: var(--text-light); line-height: 1.7; }

/* ===== VENUE INFO ===== */
.venue-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 20px;
  align-items: start;
}
.venue-details {
  background: var(--white);
  border-radius: 8px;
  padding: 20px;
  box-shadow: var(--shadow);
}
.venue-details h3 { font-size: 18px; margin-bottom: 12px; }
.info-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.info-table tr:nth-child(even) { background: var(--off-white); }
.info-table td { padding: 8px 12px; border: 1px solid var(--border); }
.info-table td:first-child { font-weight: 600; color: var(--primary); width: 150px; }
.venue-map { border-radius: 8px; overflow: hidden; box-shadow: var(--shadow); }
.venue-map iframe { width: 100%; height: 320px; border: none; }

/* ===== PARTNERS ===== */
.partners-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 36px;
  margin-top: 24px;
}
.partner-item { text-align: center; max-width: 160px; }
.partner-item img { height: 55px; width: auto; object-fit: contain; margin-bottom: 6px; }
.partner-item p { font-size: 12px; color: var(--text-light); font-weight: 500; }

/* ===== GALLERY ===== */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 18px 0 24px;
}
.gallery-item {
  text-align: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  background: var(--white);
}
.gallery-item img { width: 100%; height: 170px; object-fit: cover; }
.gallery-item .caption { padding: 8px; }
.gallery-item .caption strong { display: block; color: var(--primary); font-size: 12px; }
.gallery-item .caption span { font-size: 11px; color: var(--text-muted); }

/* ===== DATA TABLE ===== */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: 18px 0 24px;
  font-size: 13px;
  background: var(--white);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.data-table th { background: var(--primary); color: var(--white); padding: 10px 14px; text-align: left; font-weight: 600; }
.data-table td { padding: 8px 14px; border-bottom: 1px solid var(--border); }
.data-table tr:nth-child(even) { background: var(--off-white); }
.data-table tr:hover { background: #eef2f7; }

/* ===== FAQ ===== */
.faq-item { background: var(--white); border: 1px solid var(--border); border-radius: 8px; margin-bottom: 8px; overflow: hidden; }
.faq-q { padding: 12px 16px; font-weight: 600; color: var(--primary); cursor: pointer; display: flex; justify-content: space-between; align-items: center; font-size: 13px; }
.faq-q::after { content: '+'; font-size: 18px; color: var(--accent); transition: transform 0.2s; }
.faq-item.open .faq-q::after { content: '−'; }
.faq-a { padding: 0 16px; max-height: 0; overflow: hidden; transition: max-height 0.3s ease, padding 0.3s ease; font-size: 13px; color: var(--text-light); line-height: 1.7; }
.faq-item.open .faq-a { padding: 0 16px 14px; max-height: 300px; }

/* ===== TRANSPORT ===== */
.transport-section { margin-bottom: 36px; }
.transport-section h2 { font-size: 18px; padding-bottom: 5px; border-bottom: 2px solid var(--primary); margin-bottom: 6px; }
.transport-section .distance { font-size: 12px; color: var(--text-muted); margin-bottom: 14px; }
.transport-mode h3 { font-size: 15px; color: var(--accent); margin: 16px 0 8px; }
.step-table { width: 100%; border-collapse: collapse; font-size: 13px; margin-bottom: 14px; }
.step-table td { padding: 8px 12px; border: 1px solid var(--border); vertical-align: top; }
.step-table td:first-child { background: var(--off-white); font-weight: 600; color: var(--accent); width: 70px; }
.step-table .label-cell { background: var(--off-white); font-weight: 600; color: var(--text-light); width: 90px; }
.step-table strong { color: var(--primary); }

/* ===== PAGE HERO ===== */
.page-hero { background: var(--primary); color: var(--white); padding: 40px 20px 35px; text-align: center; }
.page-hero h1 { color: var(--white); font-size: 32px; margin-bottom: 6px; }
.page-hero p { color: #c8d8e8; font-size: 13px; }

/* ===== FOOTER ===== */
.footer { background: var(--primary); color: #c8d8e8; padding: 36px 20px; }
.footer-container { max-width: 1100px; margin: 0 auto; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; }
.footer h4 { color: var(--white); font-size: 15px; margin-bottom: 12px; }
.footer p, .footer a { font-size: 12px; color: #a0b4c8; line-height: 1.8; }
.footer a:hover { color: var(--accent); }
.footer-bottom { text-align: center; padding-top: 16px; margin-top: 16px; border-top: 1px solid rgba(255,255,255,0.1); font-size: 11px; color: #667788; }

/* ===== NANJING SECTION ===== */
.nanjing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 20px;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 900px) {
  .nav-tabs { gap: 0; padding: 6px 12px 10px; }
  .nav-tab { padding: 6px 12px; font-size: 12px; }
  .hero-overlay h1 { font-size: 28px; }
  .about-grid, .nanjing-grid { grid-template-columns: 1fr; }
  .venue-grid { grid-template-columns: 1fr; }
  .gallery-grid { grid-template-columns: 1fr 1fr; }
  .footer-container { grid-template-columns: 1fr; gap: 20px; }
}

@media (max-width: 600px) {
  .nav-toggle { display: block; }
  .nav-tabs { display: none; flex-direction: column; padding: 8px 16px; }
  .nav-tabs.open { display: flex; }
  .nav-tab { width: 100%; text-align: center; }
  .gallery-grid { grid-template-columns: 1fr; }
}

/* ===== DESKTOP REFINEMENTS ===== */
/* Use the available screen width while keeping a comfortable reading margin. */
.navbar-inner,
.hero-content,
.section-container,
.footer-container {
  max-width: 1400px;
}

.navbar-inner { padding-left: 32px; padding-right: 32px; }
.navbar-top { padding-top: 14px !important; padding-bottom: 6px !important; }
.nav-logo { height: 58px !important; width: auto !important; }
.countdown-bar { font-size: 15px; }
.countdown-bar .days-num { font-size: 26px; }
.nav-tabs { gap: 6px; padding-top: 8px; padding-bottom: 16px; }
.nav-tab { padding: 10px 20px; font-size: 15px; }

.hero { padding: 72px 32px; }
.hero h1 { font-size: 48px; }
.hero .subtitle { font-size: 20px; }
.hero .full-name { font-size: 15px; }
.hero .btn { font-size: 15px; padding: 12px 30px; }

.section { padding: 64px 24px; }
.section-title { font-size: 30px; }
.about-card-body { padding: 22px; }
.about-card-body h3 { font-size: 18px; }
.about-card-body p { font-size: 15px; }
.info-table { font-size: 15px; }
.data-table, .step-table { font-size: 15px; }
.gallery-item .caption strong { font-size: 14px; }
.gallery-item .caption span { font-size: 13px; }

/* Committee grid mirrors the PPT slide layout: 3 columns x 2 rows. */
.committee-grid {
  display: grid !important;
  grid-template-columns: repeat(3, minmax(150px, 1fr));
  gap: 24px !important;
  align-items: start;
  justify-items: center;
}
.committee-member {
  max-width: none !important;
  min-width: 0;
}
.committee-member img {
  width: 130px !important;
  height: 140px !important;
  object-fit: cover !important;
  object-position: top !important;
}
.committee-member p:first-of-type { font-size: 16px !important; }
.committee-member p:last-of-type { font-size: 13px !important; }


@media (max-width: 900px) {
  .navbar-inner { padding-left: 20px; padding-right: 20px; }
  .nav-tab { padding: 8px 14px; font-size: 14px; }
  .hero { padding: 56px 24px; }
  .hero h1 { font-size: 38px; }
  .section { padding: 52px 20px; }
  .section-container, .hero-content, .footer-container { max-width: 100%; }
}

@media (max-width: 600px) {
  .navbar-top { padding-top: 10px !important; }
  .nav-logo { height: 48px !important; }
  .countdown-bar { font-size: 12px; }
  .countdown-bar .days-num { font-size: 21px; }
  .hero h1 { font-size: 32px; }
  .hero .subtitle { font-size: 17px; }
  .section-title { font-size: 26px; }
  .committee-grid { grid-template-columns: repeat(2, minmax(120px, 1fr)); gap: 20px !important; }
}