:root {
  --primary-color: #0974AA;
  --primary-dark: #075a85;
  --primary-light: #e6f2f8;
  --secondary-color: #334155;
  --accent-color: #0ea5e9;
  --bg-color: #ffffff;
  --bg-offset: #f8fafc;
  --text-main: #1e293b;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --font-serif: 'Playfair Display', serif;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
}

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

body {
  font-family: var(--font-sans);
  color: var(--text-main);
  background-color: var(--bg-color);
  line-height: 1.6;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.2;
}

a {
  text-decoration: none;
  color: inherit;
  transition: all 0.2s ease;
}

ul {
  list-style: none;
}

img {
  max-width: 100%;
  display: block;
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 5rem 0;
}

/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  height: 4.5rem;
  display: flex;
  align-items: center;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.logo {
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--primary-color);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-link {
  font-weight: 500;
  font-size: 0.9375rem;
  color: var(--text-muted);
}

.nav-link:hover, .nav-link.active {
  color: var(--primary-color);
}

/* Hero Section */
.hero {
  position: relative;
  height: 85vh;
  min-height: 600px;
  display: flex;
  align-items: center;
  color: white;
  overflow: hidden;
  background: linear-gradient(rgba(0, 0, 0, 0.3), rgba(0, 0, 0, 0.5)), url('../assets/hero-bg.png');
  background-size: cover;
  background-position: center;
}

.hero-content {
  max-width: 800px;
  position: relative;
  z-index: 10;
}

.hero-tag {
  display: inline-block;
  background: var(--accent-color);
  padding: 0.5rem 1.25rem;
  border-radius: 2rem;
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 1.5rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.hero h1 {
  font-size: 4rem;
  margin-bottom: 1.5rem;
  line-height: 1.1;
}

.hero p {
  font-size: 1.25rem;
  margin-bottom: 2.5rem;
  opacity: 0.9;
  max-width: 600px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(9, 116, 170, 0.3);
}

.btn-outline {
  background: transparent;
  color: white;
  border: 2px solid white;
}

.btn-outline:hover {
  background: white;
  color: var(--primary-color);
}

/* Agenda Styling */
.agenda-tabs {
  display: flex;
  gap: 1rem;
  margin-bottom: 3rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0px;
}

.tab-btn {
  padding: 1rem 2rem;
  font-weight: 600;
  border: none;
  background: none;
  cursor: pointer;
  color: var(--text-muted);
  position: relative;
  font-family: var(--font-sans);
}

.tab-btn.active {
  color: var(--primary-color);
}

.tab-btn.active::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--primary-color);
}

.agenda-day {
  display: none;
}

.agenda-day.active {
  display: block;
}

.agenda-item {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 2rem;
  padding: 2.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

.agenda-time {
  font-weight: 700;
  color: var(--primary-color);
  font-size: 1.1rem;
}

.agenda-details h3 {
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
  color: var(--text-main);
}

.agenda-speakers {
  color: var(--text-muted);
  font-style: italic;
  margin-bottom: 1rem;
}

.agenda-type {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background: var(--primary-light);
  color: var(--primary-color);
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
}

/* Participants Grid */
.participants-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 2.5rem;
  margin-top: 3rem;
}

.participant-card {
  background: white;
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  text-align: center;
}

.participant-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.participant-avatar {
  width: 100px;
  height: 100px;
  background: var(--primary-light);
  border-radius: 50%;
  margin: 0 auto 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary-color);
  font-size: 2.5rem;
  font-weight: 700;
}

.participant-info h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.participant-info p {
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Library Section */
.doc-list {
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.doc-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.5rem 2rem;
  border-bottom: 1px solid var(--border-color);
}

.doc-item:last-child {
  border-bottom: none;
}

.doc-info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.doc-icon {
  color: var(--primary-color);
}

/* Footer */
footer {
  background: var(--secondary-color);
  color: white;
  padding: 4rem 0;
  margin-top: 5rem;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 4rem;
}

.footer-logo {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 1.5rem;
}

.footer-desc {
  opacity: 0.7;
  max-width: 400px;
}

.footer-links h4 {
  margin-bottom: 1.5rem;
  font-family: var(--font-sans);
  text-transform: uppercase;
  font-size: 0.875rem;
  letter-spacing: 0.1em;
}

.footer-links ul li {
  margin-bottom: 0.75rem;
}

.footer-links ul li a {
  opacity: 0.7;
}

.footer-links ul li a:hover {
  opacity: 1;
  color: var(--accent-color);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  margin-top: 4rem;
  padding-top: 2rem;
  text-align: center;
  opacity: 0.5;
  font-size: 0.875rem;
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-fade-in {
  animation: fadeInUp 0.8s ease-out forwards;
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.5rem;
  }
  .nav-links {
    display: none;
  }
  .agenda-item {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }
  .footer-content {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

.participant-card, .agenda-day {
  scroll-margin-top: 6rem;
}