/* ============================================
   AIET IN STEM 2025 - Global Forum Website
   Modern, Clean, Accessible Design
   ============================================ */

/* CSS Variables */
:root {
  --primary: #2f616a;
  --primary-light: #3d7d8a;
  --secondary: #2563EB;
  --accent: #F59E0B;
  --accent-hover: #D97706;
  --background: #FAFAFA;
  --background-alt: #F3F4F6;
  --text: #1F2937;
  --text-light: #6B7280;
  --white: #FFFFFF;
  --border: #E5E7EB;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --transition: all 0.3s ease;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-display: 'Poppins', var(--font-sans);
}

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

html {
  scroll-behavior: smooth;
  font-size: 17px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--background);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.3;
  color: var(--text);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.25rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
  margin-bottom: 1rem;
  color: var(--text-light);
}

a {
  color: var(--secondary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--primary);
}

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

/* Navigation */
.navbar {
  background: var(--white);
  box-shadow: var(--shadow);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 90px;
}

.nav-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  display: flex;
  align-items: center;
}

.nav-logo-img {
  height: 34px;
  width: auto;
  max-width: 100%;
  object-fit: contain;
}

.nav-logo span {
  color: var(--secondary);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-link {
  color: var(--text);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.5rem 0;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: var(--transition);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

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

/* Mobile Menu Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 5px;
}

.nav-toggle span {
  width: 25px;
  height: 3px;
  background: var(--text);
  border-radius: 2px;
  transition: var(--transition);
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, #2f616a 0%, #3d7d8a 100%);
  color: var(--white);
  padding-top: 90px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image:
    url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="300" height="300" viewBox="0 0 300 300"><text x="30" y="240" font-size="40" fill="rgba(255,255,255,0.12)" font-family="serif" font-weight="bold">∑</text><g><line x1="218" y1="150" x2="192" y2="132" stroke="rgba(255,255,255,0.12)" stroke-width="2.5"/><line x1="218" y1="150" x2="244" y2="132" stroke="rgba(255,255,255,0.12)" stroke-width="2.5"/><circle cx="218" cy="150" r="9" fill="rgba(255,255,255,0.12)"/><circle cx="192" cy="132" r="6" fill="rgba(255,255,255,0.12)"/><circle cx="244" cy="132" r="6" fill="rgba(255,255,255,0.12)"/></g><text x="120" y="70" font-size="26" fill="rgba(255,255,255,0.12)" font-family="monospace" font-weight="bold">&lt;/&gt;</text><path d="M40,60 L40,70 L32,94 Q32,98 36,98 L58,98 Q62,98 62,94 L54,70 L54,60 Q54,58 50,58 L44,58 Q40,58 40,60 Z" fill="none" stroke="rgba(255,255,255,0.12)" stroke-width="2.5"/></svg>');
  background-size: 300px 300px;
  background-position: 0 0;
  background-repeat: repeat;
  opacity: 0.45;
  pointer-events: none;
  animation: float 60s ease-in-out infinite;
}

@keyframes float {
  0%, 100% {
    transform: translate(0, 0);
  }
  25% {
    transform: translate(20px, -20px);
  }
  50% {
    transform: translate(-10px, 10px);
  }
  75% {
    transform: translate(15px, -15px);
  }
}

.hero::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  pointer-events: none;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem;
}

.hero-badge {
  display: inline-block;
  background: rgba(255, 255, 255, 0.3);
  padding: 0.75rem 2.5rem;
  border-radius: 50px;
  font-size: 1.3rem;
  font-weight: 400;
  margin-bottom: 2rem;
  backdrop-filter: blur(10px);
  letter-spacing: 0.5px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.badge-year {
  font-weight: 700;
  font-size: 1.35rem;
}

.hero h1 {
  color: var(--white);
  font-size: 4.5rem;
  margin-bottom: 1rem;
  font-weight: 700;
}

.hero-year {
  font-size: 4.5rem;
  font-weight: 700;
  color: var(--white);
  font-family: var(--font-display);
  display: inline;
}

.hero-subtitle {
  font-size: 1.25rem;
  opacity: 0.9;
  margin-bottom: 2rem;
  color: var(--white);
}

.hero-date {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.hero-location {
  font-size: 1.1rem;
  opacity: 0.9;
  margin-bottom: 2rem;
}

/* Countdown Parallax Section */
.countdown-parallax {
  position: relative;
  height: 70vh;
  min-height: 500px;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.countdown-parallax-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.6)), url('../images/index/jeju.png') center/cover no-repeat;
  background-attachment: fixed;
  will-change: transform;
}

.countdown-content {
  position: relative;
  z-index: 2;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2rem;
}

.countdown-info {
  text-align: center;
  color: white;
}

.countdown-date {
  font-size: 2.25rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: white;
  font-family: var(--font-display);
}

.countdown-location {
  font-size: 1.1rem;
  opacity: 0.95;
  color: white;
}

/* Countdown Timer */
.countdown {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.countdown-item {
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(10px);
  padding: 1.5rem 2rem;
  border-radius: 12px;
  min-width: 100px;
  color: white;
}

.countdown-number {
  font-size: 2.5rem;
  font-weight: 700;
  display: block;
  color: white;
}

.countdown-label {
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  opacity: 0.9;
  color: white;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 1rem 2rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  text-align: center;
}

.btn-primary {
  background: #1f4952;
  color: var(--white);
}

.btn-primary:hover {
  background: #153840;
  color: var(--white);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
  background: var(--primary-light);
  transform: translateY(-2px);
}

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

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

.hero-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Sections */
.section {
  padding: 5rem 0;
}

.section-alt {
  background: var(--background-alt);
}

.cta-section {
  padding: 6rem 0;
  position: relative;
  background: linear-gradient(rgba(31, 41, 55, 0.65), rgba(17, 24, 39, 0.70)),
              url('../images/index/jeju2.jpg') center/cover no-repeat;
  background-attachment: fixed;
  color: white;
}

.cta-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.2);
  pointer-events: none;
}

.cta-section .container {
  position: relative;
  z-index: 1;
}

.section-header {
  text-align: center;
  margin-bottom: 3rem;
}

.section-header h2 {
  margin-bottom: 1rem;
}

.section-header p {
  max-width: 600px;
  margin: 0 auto;
}

/* Cards */
.card {
  background: var(--white);
  border-radius: 12px;
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: var(--transition);
}

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

.card-body {
  padding: 1.5rem;
}

/* Speaker Cards */
.speakers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
}

.speaker-card {
  background: var(--white);
  border-radius: 16px;
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: var(--transition);
}

.speaker-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.speaker-image {
  width: 100%;
  height: 280px;
  object-fit: cover;
  object-position: top;
}

.speaker-image-placeholder {
  width: 100%;
  height: 280px;
  background: linear-gradient(135deg, var(--primary-light) 0%, var(--primary) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-size: 4rem;
  font-weight: 700;
}

.speaker-info {
  padding: 1.5rem;
}

.speaker-name {
  font-size: 1.25rem;
  margin-bottom: 0.25rem;
  color: var(--text);
}

.speaker-title {
  font-size: 0.875rem;
  color: var(--secondary);
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.speaker-affiliation {
  font-size: 0.9rem;
  color: var(--text-light);
  margin-bottom: 1rem;
}

.speaker-bio {
  font-size: 0.875rem;
  color: var(--text-light);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.speaker-links {
  display: flex;
  gap: 0.75rem;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}

.speaker-link {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.8rem;
  color: var(--text-light);
}

.speaker-link:hover {
  color: var(--secondary);
}

/* Program/Agenda */
.agenda-day {
  margin-bottom: 3rem;
}

.agenda-day-header {
  background: var(--primary);
  color: var(--white);
  padding: 1rem 1.5rem;
  border-radius: 8px 8px 0 0;
}

.agenda-day-title {
  font-size: 1.25rem;
  margin: 0;
  color: var(--white);
}

.agenda-day-date {
  font-size: 0.9rem;
  opacity: 0.9;
  color: var(--white);
}

.agenda-items {
  background: var(--white);
  border-radius: 0 0 8px 8px;
  box-shadow: var(--shadow);
}

.agenda-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 1.5rem;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

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

.agenda-time {
  font-weight: 600;
  color: var(--primary);
  font-size: 0.9rem;
}

.agenda-content h4 {
  margin-bottom: 0.25rem;
  color: var(--text);
}

.agenda-content p {
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.agenda-speaker {
  font-size: 0.875rem;
  color: var(--primary);
  font-weight: 500;
  display: block;
  margin-top: 0.75rem;
}

.agenda-break {
  background: var(--background-alt);
}

.agenda-break .agenda-content h4 {
  color: var(--text-light);
}

/* Travel & Venue */
.travel-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2rem;
}

.travel-card {
  background: var(--white);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: var(--shadow);
}

.travel-card h3 {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
  color: var(--primary);
}

.travel-card-icon {
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, #2f616a 0%, #3d7d8a 100%) !important;
  color: var(--white);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: 0 4px 12px rgba(47, 97, 106, 0.25);
}

.travel-steps {
  list-style: none;
}

.travel-step {
  display: flex;
  gap: 1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
}

.travel-step:last-child {
  border-bottom: none;
}

.travel-step-number {
  width: 28px;
  height: 28px;
  background: var(--primary);
  color: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.875rem;
  font-weight: 600;
  flex-shrink: 0;
}

.travel-step-content h4 {
  font-size: 1rem;
  margin-bottom: 0.25rem;
}

.travel-step-content p {
  font-size: 0.875rem;
  margin: 0;
}

/* Map */
.map-container {
  margin-top: 3rem;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.map-container iframe {
  width: 100%;
  height: 400px;
  border: none;
}

/* Updates/Blog */
.updates-list {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.update-card {
  background: var(--white);
  border-radius: 12px;
  box-shadow: var(--shadow);
  overflow: hidden;
  display: grid;
  grid-template-columns: 200px 1fr;
}

.update-date {
  background: var(--primary);
  color: var(--white);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.update-date-day {
  font-size: 3rem;
  font-weight: 700;
  line-height: 1;
}

.update-date-month {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.update-content {
  padding: 2rem;
}

.update-content h3 {
  margin-bottom: 0.5rem;
}

.update-content p {
  margin-bottom: 1rem;
}

.update-tag {
  display: inline-block;
  background: var(--background-alt);
  color: var(--text-light);
  padding: 0.25rem 0.75rem;
  border-radius: 50px;
  font-size: 0.75rem;
  margin-right: 0.5rem;
}

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

.gallery-item {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  aspect-ratio: 4/3;
  cursor: pointer;
}

.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.gallery-item:hover img {
  transform: scale(1.05);
}

.gallery-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background: linear-gradient(transparent, rgba(0,0,0,0.7));
  color: var(--white);
  padding: 1.5rem;
  transform: translateY(100%);
  transition: var(--transition);
}

.gallery-item:hover .gallery-overlay {
  transform: translateY(0);
}

/* Footer */
.footer {
  background: var(--text);
  color: var(--white);
  padding: 4rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 3rem;
  margin-bottom: 3rem;
}

@media (max-width: 992px) {
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

.footer-section h4 {
  color: var(--white);
  margin-bottom: 1.5rem;
  font-size: 1.1rem;
}

.footer-section p,
.footer-section a {
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.9rem;
}

.footer-section a:hover {
  color: var(--white);
}

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

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

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.6);
}

/* Page Header */
.page-header {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: var(--white);
  padding: 5rem 0 3rem;
  text-align: center;
  margin-top: 90px;
  position: relative;
  overflow: hidden;
}

.page-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image:
    url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="300" height="300" viewBox="0 0 300 300"><text x="30" y="240" font-size="40" fill="rgba(255,255,255,0.12)" font-family="serif" font-weight="bold">∑</text><g><line x1="218" y1="150" x2="192" y2="132" stroke="rgba(255,255,255,0.12)" stroke-width="2.5"/><line x1="218" y1="150" x2="244" y2="132" stroke="rgba(255,255,255,0.12)" stroke-width="2.5"/><circle cx="218" cy="150" r="9" fill="rgba(255,255,255,0.12)"/><circle cx="192" cy="132" r="6" fill="rgba(255,255,255,0.12)"/><circle cx="244" cy="132" r="6" fill="rgba(255,255,255,0.12)"/></g><text x="120" y="70" font-size="26" fill="rgba(255,255,255,0.12)" font-family="monospace" font-weight="bold">&lt;/&gt;</text><path d="M40,60 L40,70 L32,94 Q32,98 36,98 L58,98 Q62,98 62,94 L54,70 L54,60 Q54,58 50,58 L44,58 Q40,58 40,60 Z" fill="none" stroke="rgba(255,255,255,0.12)" stroke-width="2.5"/></svg>');
  background-size: 300px 300px;
  background-position: 0 0;
  background-repeat: repeat;
  opacity: 0.45;
  pointer-events: none;
}

.page-header h1,
.page-header p {
  position: relative;
  z-index: 1;
}

.page-header h1 {
  color: var(--white);
  margin-bottom: 0.5rem;
}

.page-header p {
  color: rgba(255, 255, 255, 0.9);
  font-size: 1.1rem;
}

/* Utility Classes */
.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.text-secondary { color: var(--secondary); }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-4 { margin-top: 2rem; }

/* Responsive Design */
@media (max-width: 968px) {
  .nav-menu {
    position: fixed;
    top: 90px;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    padding: 2rem;
    gap: 1rem;
    box-shadow: var(--shadow);
    transform: translateY(-150%);
    transition: var(--transition);
  }

  .nav-menu.active {
    transform: translateY(0);
  }

  .nav-toggle {
    display: flex;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .countdown {
    flex-wrap: wrap;
  }

  .countdown-item {
    min-width: 80px;
    padding: 1rem;
  }

  .countdown-number {
    font-size: 2rem;
  }

  .agenda-item {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }

  .update-card {
    grid-template-columns: 1fr;
  }

  .update-date {
    flex-direction: row;
    gap: 0.5rem;
    padding: 1rem;
  }

  .update-date-day {
    font-size: 1.5rem;
  }
}

@media (max-width: 640px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }

  .section {
    padding: 3rem 0;
  }

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

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

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

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-fade-in-up {
  animation: fadeInUp 0.6s ease forwards;
}

/* Accessibility */
:focus-visible {
  outline: 3px solid var(--secondary);
  outline-offset: 2px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}