:root {
  --primary: #2563eb;
  --primary-dark: #1e40af;
  --accent: #0ea5e9;
  --text-muted: #64748b;
  --card-bg: #ffffff;
  --border-soft: #e2e8f0;
  --shadow-soft: 0 4px 14px rgba(15, 23, 42, 0.06);
  --shadow-hover: 0 12px 30px rgba(15, 23, 42, 0.12);
  --radius: 14px;
}

body {
  margin: 0;
  font-family: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  background: linear-gradient(to bottom, #f8fafc, #eef2f7);
  color: #0f172a;
  line-height: 1.6;
}
.container {
  max-width: 1100px;
  margin: auto;
  padding: 0 1rem;
}

.header {
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-soft);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.site-title {
  color: #2563eb;
  margin: 0;
}

.subtitle {
  color: #64748b;
  margin: 0;
}

.speakers-section {
  display: flex;
  flex-direction: column;
  gap: 3rem;
}

.lecture-title {
  font-size: 1.4rem;
  margin-bottom: 1rem;
  color: var(--primary);
  letter-spacing: 0.3px;
}

.group-title {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
  position: relative;
}

.group-title::after {
  content: "";
  display: block;
  width: 40px;
  height: 3px;
  background: var(--primary);
  margin-top: 6px;
  border-radius: 2px;
}

.speaker-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.speaker-list li {
  padding: 0.6rem 0;
  font-size: 1.05rem;
  border-bottom: 1px solid var(--border-soft);
  transition: color 0.2s ease;
  column-count: 2;
}

.speaker-list li:last-child {
  border-bottom: none;
}

.speaker-list li:hover {
  color: var(--primary);
}

.speaker-list.featured li {
  font-size: 1.2rem;
  font-weight: 600;
  color: #0f172a;
}
.speaker-entry {
  display: flex;
  flex-direction: column;
  margin-bottom: 0.6rem;
}

.speaker-name {
  font-weight: 600;
}

.speaker-affiliation {
  font-size: 0.9rem;
  opacity: 0.7;
}

.two-columns {
  columns: 2;
  column-gap: 3rem;
}

@media (max-width: 768px) {
  .two-columns {
    columns: 1;
  }
}

.nav-desktop button,
.nav-mobile button {
  background: none;
  border: none;
  padding: 0.6rem 1rem;
  cursor: pointer;
  border-radius: 8px;
  transition: all 0.2s ease;
  font-weight: 500;
}

.nav-desktop button:hover,
.nav-mobile button:hover {
  background: rgba(37,99,235,0.08);
}

.nav-desktop button.active,
.nav-mobile button.active {
  background: #2563eb;
  color: white;
  border-radius: 6px;
}

.nav-desktop {
  display: flex;
  gap: 0.5rem;
}

.mobile-toggle {
  display: none;
}

.nav-mobile {
  display: none;
  flex-direction: column;
  padding: 0.5rem 1rem;
}

.nav-mobile.open {
  display: flex;
}

.main-content {
  padding: 2rem 0;
}

.hero {
  background: radial-gradient(circle at top left, #3b82f6, #1e3a8a);
  color: white;
  padding: 3rem 2.5rem;
  border-radius: var(--radius);
  margin-bottom: 3rem;
  box-shadow: var(--shadow-soft);
}
.hero h2 {
  font-size: 2.4rem;
  margin-bottom: 1rem;
  letter-spacing: -0.5px;
}

.hero p {
  font-size: 1.1rem;
  opacity: 0.95;
}

.hero-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px,1fr));
  gap: 1rem;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px,1fr));
  gap: 1rem;
}
.card {
  background: var(--card-bg);
  padding: 1.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
  border: 1px solid var(--border-soft);
  transition: all 0.25s ease;
}
.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.venue-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px,1fr));
  gap: 1rem;
}

.map-container iframe {
  width: 100%;
  height: 320px;
  border-radius: var(--radius);
  filter: grayscale(20%) contrast(1.05);
}

.page {
  display: none;
}

.page.active {
  display: block;
  opacity: 0;
  animation: fadeIn 0.4s ease forwards;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

section {
  margin-bottom: 3.5rem;
}

h3 {
  font-size: 1.6rem;
  margin-bottom: 1.5rem;
  position: relative;
}

h3::after {
  content: "";
  display: block;
  width: 50px;
  height: 4px;
  background: var(--primary);
  margin-top: 8px;
  border-radius: 2px;
}

.section-alt {
  padding: 2rem;
  background: white;
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.footer {
  background: #0f172a;
  color: #cbd5e1;
  text-align: center;
  padding: 3rem 0;
  margin-top: 4rem;
}

.footer p:first-child {
  font-weight: 600;
  color: white;
}

/* Responsive */
@media (max-width: 768px) {
  .nav-desktop {
    display: none;
  }

  .mobile-toggle {
    display: block;
    font-size: 1.5rem;
    background: none;
    border: none;
  }
}

.organizational-wrapper {
  display: flex;
  flex-direction: column;
  gap: 3.5rem;
}

.section-description {
  color: var(--text-muted);
  margin-top: 0.5rem;
}

.committee-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.8rem;
}

.committee-card {
  border: 1px solid #fde68a;
  background: linear-gradient(to bottom, #fffaf0, #ffffff);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
  transition: all 0.25s ease;
}

.committee-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.committee-card-header {
  display: flex;
  gap: 1rem;
  padding: 1.5rem;
  background: linear-gradient(to right, #fff7ed, #ffedd5);
  border-bottom: 1px solid #fde68a;
}

.avatar {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: #fb923c;
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 1.1rem;
}

.member-name {
  font-weight: 600;
  font-size: 1.05rem;
}

.committee-card-body {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

.member-affiliation {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.member-email a {
  color: var(--primary);
  font-size: 0.95rem;
}

.resp-title {
  font-weight: 600;
  margin-bottom: 0.4rem;
  font-size: 0.9rem;
}

.member-responsibilities ul {
  padding-left: 1rem;
  margin: 0;
}

.contact-card {
  background: linear-gradient(to right, #eff6ff, #dbeafe);
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.contact-title {
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.contact-email {
  color: var(--primary);
}

.volunteer-card {
  padding: 2rem;
  border-radius: var(--radius);
  background: white;
  box-shadow: var(--shadow-soft);
}

.volunteer-title {
  font-weight: 600;
  margin-bottom: 1rem;
}

.previous-editions {
  margin-top: 1.2rem;
  font-size: 0.95rem;
  opacity: 0.95;
}

.previous-editions a {
  color: #ffffff;
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid rgba(255,255,255,0.5);
  transition: all 0.2s ease;
}

.previous-editions a:hover {
  border-bottom: 1px solid white;
  opacity: 0.85;
}

.scientific-wrapper {
  display: flex;
  flex-direction: column;
  gap: 3rem;
}

/* Slightly cooler accent for distinction */
.scientific-card {
  border: 1px solid #c7d2fe;
  background: linear-gradient(to bottom, #f8fafc, #ffffff);
}

.scientific-header {
  background: linear-gradient(to right, #eef2ff, #e0e7ff);
  border-bottom: 1px solid #c7d2fe;
}

.scientific-avatar {
  background: #4f46e5;
}

.poster-wrapper {
  max-width: 1000px;
  margin: 0 auto;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.poster-description {
  opacity: 0.85;
}

.poster-container {
  display: flex;
  justify-content: center;
}

.poster-image {
  width: 100%;
  max-width: 1200px;   /* controls visual size */
  height: auto;
  border-radius: 12px;
  box-shadow: 0 20px 40px rgba(0,0,0,0.15);
}

.poster-image:hover {
  transform: scale(1.02);
}

.poster-button {
  display: inline-block;
  padding: 0.7rem 1.4rem;
  background: #4f46e5;
  color: white;
  text-decoration: none;
  border-radius: 8px;
  font-weight: 500;
  transition: all 0.2s ease;
}

.poster-button:hover {
  background: #4338ca;
}

.registration-wrapper {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.registration-text {
  opacity: 0.9;
}

.registration-button-container {
  margin-top: 1rem;
}

.registration-button {
  display: inline-block;
  padding: 0.9rem 2rem;
  background: #16a34a;
  color: white;
  text-decoration: none;
  font-size: 1.05rem;
  font-weight: 600;
  border-radius: 10px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.15);
  transition: all 0.2s ease;
}

.registration-button:hover {
  background: #15803d;
  transform: translateY(-2px);
}

.registration-note {
  font-size: 0.85rem;
  opacity: 0.7;
}