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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 70px;
}

body {
  font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  color: #2d2d2d;
  background: #fdfdfd;
  line-height: 1.7;
}

a {
  color: #1a6fb5;
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: #0d4f8a;
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

/* ===== Navigation Bar ===== */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid #e5e5e5;
  z-index: 1000;
  padding: 0 2rem;
}

.navbar .nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.navbar .nav-brand {
  font-weight: 700;
  font-size: 1rem;
  color: #1a1a1a;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-logo {
  height: 36px;
  width: auto;
  border-radius: 4px;
}

.navbar .nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

.navbar .nav-links a {
  font-size: 0.88rem;
  font-weight: 500;
  color: #555;
  padding: 0.3rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}

.navbar .nav-links a:hover,
.navbar .nav-links a.active {
  color: #1a6fb5;
  border-bottom-color: #1a6fb5;
  text-decoration: none;
}

/* Hamburger menu (mobile) */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: #333;
}

/* ===== Hero Section ===== */
.hero {
  margin-top: 60px;
  background: linear-gradient(135deg, #0b3d6b 0%, #1a6fb5 50%, #2aa4d8 100%);
  color: #fff;
  text-align: center;
  padding: 5rem 2rem 4rem;
}

.hero-logo {
  max-width: 220px;
  height: auto;
  margin-bottom: 1.5rem;
  border-radius: 10px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.hero h1 {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1.3;
  max-width: 900px;
  margin: 0 auto 1rem;
}

.hero .subtitle {
  font-size: 1.2rem;
  font-weight: 400;
  opacity: 0.92;
  margin-bottom: 0.5rem;
}

.hero .meta {
  font-size: 1rem;
  opacity: 0.85;
  margin-bottom: 1.5rem;
}

.hero .meta span {
  display: inline-block;
  margin: 0 0.7rem;
}

.hero .btn-primary {
  display: inline-block;
  padding: 0.75rem 2rem;
  background: #fff;
  color: #0b3d6b;
  font-weight: 600;
  border-radius: 6px;
  font-size: 0.95rem;
  transition: transform 0.2s, box-shadow 0.2s;
}

.hero .btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
  text-decoration: none;
}

/* ===== Section Containers ===== */
.section {
  padding: 4rem 2rem;
  max-width: 1000px;
  margin: 0 auto;
}

.section:nth-child(even) {
  background: #f7f9fb;
}

.section:nth-child(even) .section-inner {
  max-width: 1000px;
  margin: 0 auto;
}

.section-title {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: #0b3d6b;
  text-align: center;
}

.section-title::after {
  content: '';
  display: block;
  width: 50px;
  height: 3px;
  background: #1a6fb5;
  margin: 0.6rem auto 0;
  border-radius: 2px;
}

/* ===== About ===== */
.about-text {
  max-width: 800px;
  margin: 0 auto;
  font-size: 1.02rem;
  text-align: justify;
}

.about-text p + p {
  margin-top: 1rem;
}

/* ===== Important Dates ===== */
.dates-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.2rem;
  margin-top: 1.5rem;
}

.date-card {
  background: #fff;
  border: 1px solid #e0e7ee;
  border-radius: 10px;
  padding: 1.5rem;
  text-align: center;
  transition: box-shadow 0.2s;
}

.date-card:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.07);
}

.date-card .date {
  font-size: 1.15rem;
  font-weight: 700;
  color: #1a6fb5;
}

.date-card .label {
  margin-top: 0.4rem;
  font-size: 0.92rem;
  color: #555;
}

/* ===== Call for Papers ===== */
.cfp-content {
  max-width: 800px;
  margin: 0 auto;
}

.cfp-content ul {
  margin: 1rem 0 1rem 1.5rem;
}

.cfp-content li {
  margin-bottom: 0.5rem;
}

/* ===== Schedule ===== */
.schedule-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
  font-size: 0.95rem;
}

.schedule-table thead {
  background: #0b3d6b;
  color: #fff;
}

.schedule-table th,
.schedule-table td {
  padding: 0.85rem 1rem;
  text-align: left;
  border-bottom: 1px solid #e5e5e5;
}

.schedule-table tbody tr:nth-child(even) {
  background: #f5f8fb;
}

.schedule-table tbody tr:hover {
  background: #eaf2fa;
}

.schedule-table .break-row {
  background: #fff8e6 !important;
  font-style: italic;
}

/* ===== Speakers / Organizers Grid ===== */
.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.person-card {
  text-align: center;
}

.person-card .avatar {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid #e0e7ee;
  margin-bottom: 0.8rem;
  transition: transform 0.2s;
}

.person-card:hover .avatar {
  transform: scale(1.05);
}

.person-card .name {
  font-weight: 600;
  font-size: 1rem;
  color: #1a1a1a;
}

.person-card .affiliation {
  font-size: 0.88rem;
  color: #666;
  margin-top: 0.2rem;
}

.person-card .talk-title {
  font-size: 0.85rem;
  color: #1a6fb5;
  font-style: italic;
  margin-top: 0.3rem;
}

/* ===== Speaker Bio Button Hover ===== */
.bio-btn:hover {
  background: #1a6fb5 !important;
  color: #fff !important;
}

/* ===== Papers ===== */
.paper-list {
  max-width: 800px;
  margin: 1.5rem auto 0;
}

.paper-item {
  background: #fff;
  border: 1px solid #e5e5e5;
  border-radius: 8px;
  padding: 1.2rem 1.5rem;
  margin-bottom: 1rem;
  transition: box-shadow 0.2s;
}

.paper-item:hover {
  box-shadow: 0 3px 12px rgba(0, 0, 0, 0.06);
}

.paper-item .paper-title {
  font-weight: 600;
  font-size: 1rem;
  margin-bottom: 0.3rem;
}

.paper-item .paper-authors {
  font-size: 0.9rem;
  color: #555;
}

.paper-item .paper-links {
  margin-top: 0.5rem;
}

.paper-item .paper-links a {
  font-size: 0.85rem;
  margin-right: 1rem;
  font-weight: 500;
}

/* ===== Sponsors ===== */
.sponsors-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  flex-wrap: wrap;
  margin-top: 1.5rem;
}

.sponsors-row img {
  max-height: 70px;
  opacity: 0.8;
  transition: opacity 0.2s;
}

.sponsors-row img:hover {
  opacity: 1;
}

/* ===== Footer ===== */
footer {
  background: #0b3d6b;
  color: #cbd5e1;
  text-align: center;
  padding: 2rem 1rem;
  font-size: 0.88rem;
}

footer a {
  color: #8dc7ec;
}

footer a:hover {
  color: #fff;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .navbar .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: #fff;
    border-bottom: 1px solid #e5e5e5;
    padding: 1rem 2rem;
    gap: 0.8rem;
  }

  .navbar .nav-links.open {
    display: flex;
  }

  .nav-toggle {
    display: block;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

  .hero .subtitle {
    font-size: 1rem;
  }

  .people-grid {
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 1.2rem;
  }

  .person-card .avatar {
    width: 110px;
    height: 110px;
  }

  .schedule-table {
    font-size: 0.85rem;
  }

  .schedule-table th,
  .schedule-table td {
    padding: 0.6rem 0.7rem;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 3rem 1.2rem 2.5rem;
  }

  .section {
    padding: 2.5rem 1.2rem;
  }

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