:root {
  --color-primary: #1a365d;
  --color-primary-light: #2c5282;
  --color-accent: #e53e3e;
  --color-accent-light: #fc8181;
  --color-bg: #ffffff;
  --color-bg-alt: #f7fafc;
  --color-bg-dark: #1a202c;
  --color-text: #2d3748;
  --color-text-light: #718096;
  --color-border: #e2e8f0;
  --color-highlight: #ebf8ff;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif: 'Source Serif 4', Georgia, serif;
  --max-width: 960px;
  --nav-height: 64px;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  line-height: 1.7;
  background: var(--color-bg);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* Navigation */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-primary);
  box-shadow: none;
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
}

.nav-logo {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.25rem;
  color: #fff;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-logo-img {
  height: 36px;
  width: 36px;
  border-radius: 50%;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 0.25rem;
}

.nav-links a {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  transition: all 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  color: #fff;
  background: rgba(255, 255, 255, 0.15);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: #fff;
  margin: 5px 0;
  transition: 0.3s;
}

/* Hero */
.hero {
  background: var(--color-primary);
  color: #fff;
  text-align: center;
  margin: 0;
  padding: 0;
  line-height: 0;
}

.hero-banner {
  width: 100%;
  line-height: 0;
  font-size: 0;
  background: var(--color-primary);
  margin: 0;
  padding: 0;
  overflow: hidden;
}

.hero-banner-img {
  width: 100%;
  display: block;
  vertical-align: bottom;
  margin: 0;
  padding: 0;
  border: 0;
}

.hero-badges {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  padding: 0.6rem 1.5rem;
  background: var(--color-primary);
  line-height: 1;
  margin: 0;
  border: 0;
}

.hero-meta {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.hero-badge {
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.25);
  padding: 0.5rem 1.25rem;
  border-radius: 50px;
  font-size: 0.9rem;
  font-weight: 500;
}

/* Page Header */
.page-header {
  background: var(--color-primary);
  color: #fff;
  padding: 3rem 0 2rem;
}

.page-header h1 {
  font-family: var(--font-serif);
  font-size: 2.25rem;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Content */
main h2 {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  color: var(--color-primary);
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-border);
}

main h2:first-child {
  margin-top: 0;
}

main h3 {
  font-size: 1.15rem;
  color: var(--color-primary-light);
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
}

main p {
  margin-bottom: 1rem;
}

main ul, main ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

main li {
  margin-bottom: 0.4rem;
}

main a {
  color: var(--color-primary-light);
  text-decoration: underline;
  text-underline-offset: 2px;
}

main a:hover {
  color: var(--color-accent);
}

/* Highlight box */
.highlight-box {
  background: var(--color-highlight);
  border-left: 4px solid var(--color-primary);
  padding: 1.25rem 1.5rem;
  border-radius: 0 8px 8px 0;
  margin: 1.5rem 0;
}

.highlight-box p:last-child {
  margin-bottom: 0;
}

/* Info card */
.info-card {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.5rem;
  margin: 1.5rem 0;
}

/* Dates table */
.dates-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
}

.dates-table th,
.dates-table td {
  padding: 0.875rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.dates-table th {
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.dates-table tr:hover {
  background: var(--color-highlight);
}

.dates-table .date-highlight {
  font-weight: 600;
  color: var(--color-accent);
}

/* Topics grid */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.topic-item {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  font-size: 0.95rem;
  transition: border-color 0.2s;
}

.topic-item:hover {
  border-color: var(--color-primary);
}

/* Speaker / Organizer cards */
.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.person-card {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 1.75rem;
  text-align: center;
  transition: box-shadow 0.2s;
}

.person-card:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.person-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  font-weight: 700;
  font-family: var(--font-serif);
  margin: 0 auto 1rem;
}

.person-photo {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 1rem;
  display: block;
  border: 3px solid var(--color-border);
}

.person-card h3 {
  margin-top: 0;
  margin-bottom: 0.25rem;
  color: var(--color-text);
}

.person-card p {
  color: var(--color-text-light);
  font-size: 0.9rem;
  margin-bottom: 0;
}

.person-card .person-affiliation {
  font-weight: 500;
  color: var(--color-primary-light);
  margin-bottom: 0.5rem;
}

.person-card .person-bio {
  font-size: 0.85rem;
  text-align: left;
  line-height: 1.6;
  color: var(--color-text);
  margin-top: 0.75rem;
}

.person-card .person-links {
  margin-top: 0.75rem;
  display: flex;
  justify-content: center;
  gap: 0.5rem;
}

.person-card .person-links a {
  font-size: 0.8rem;
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 50px;
  text-decoration: none;
  color: var(--color-primary-light);
  transition: all 0.2s;
}

.person-card .person-links a:hover {
  background: var(--color-highlight);
  border-color: var(--color-primary);
}

.topic-item strong {
  color: var(--color-primary);
}

.topic-item p {
  margin: 0.25rem 0 0;
  font-size: 0.88rem;
  color: var(--color-text-light);
}

/* TBD badge */
.tbd-badge {
  display: inline-block;
  background: var(--color-accent);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.2rem 0.75rem;
  border-radius: 50px;
  letter-spacing: 0.05em;
}

/* Social links */
.social-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin: 1rem 0;
}

.social-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9rem;
  color: var(--color-text);
  transition: all 0.2s;
}

.social-link:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-highlight);
}

.icon {
  width: 14px;
  height: 14px;
  vertical-align: -2px;
  flex-shrink: 0;
}

.footer-links .icon {
  width: 13px;
  height: 13px;
  vertical-align: -1px;
  margin-right: 0.3rem;
}

/* Footer */
.footer {
  background: var(--color-bg-dark);
  color: rgba(255, 255, 255, 0.8);
  margin-top: 3rem;
}

.footer .container {
  padding-top: 2.5rem;
  padding-bottom: 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer h3 {
  color: #fff;
  font-size: 1rem;
  margin-bottom: 0.75rem;
}

.footer p {
  font-size: 0.9rem;
  line-height: 1.6;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 0.4rem;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.7);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 1.25rem;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.5);
}

/* Responsive */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-primary);
    flex-direction: column;
    padding: 1rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .nav-toggle.active span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }

  .hero-content {
    padding: 1rem 1rem 1.5rem;
  }

  .hero-meta {
    flex-direction: column;
    align-items: center;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .topics-grid {
    grid-template-columns: 1fr;
  }

  .people-grid {
    grid-template-columns: 1fr;
  }
}