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

:root {
  --navy: #1b2a4a;
  --navy-light: #253a5e;
  --blue: #3a6ea5;
  --blue-bright: #4a90d9;
  --accent: #c8a951;
  --bg: #f5f6f8;
  --white: #ffffff;
  --text: #2c2c2c;
  --text-light: #5a5a5a;
  --border: #e0e3e8;
  --shadow: 0 2px 12px rgba(27,42,74,0.08);
  --radius: 8px;
  --max-width: 1100px;
  --font-heading: 'Montserrat', sans-serif;
  --font-body: 'Open Sans', sans-serif;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

a { color: var(--blue-bright); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--blue); text-decoration: underline; }

/* === Navbar === */
.navbar {
  background: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.navbar-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
}

.navbar-brand img {
  height: 48px;
  width: auto;
}

.navbar-brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.navbar-brand-text .title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--navy);
  letter-spacing: 0.5px;
}

.navbar-brand-text .subtitle {
  font-family: var(--font-heading);
  font-weight: 300;
  font-size: 0.78rem;
  color: var(--text-light);
  letter-spacing: 0.3px;
}

.navbar-nav {
  display: flex;
  list-style: none;
  gap: 4px;
}

.navbar-nav a {
  color: var(--text-light);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 8px 4px;
  transition: color 0.2s;
  text-decoration: none;
  letter-spacing: 0.3px;
  border-bottom: 3px solid transparent;
  margin: 0 14px;
}

.navbar-nav a:hover {
  color: var(--navy);
  text-decoration: none;
}

.navbar-nav a.active {
  color: var(--navy);
  font-weight: 700;
  border-bottom-color: var(--accent);
}

/* === Container === */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* === Hero Section === */
.hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 60%, var(--blue) 100%);
  color: var(--white);
  padding: 60px 0 50px;
  position: relative;
  overflow: hidden;
  text-align: center;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(200,169,81,0.08) 0%, transparent 70%);
  pointer-events: none;
}

.hero h1 {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.3px;
}

.hero-accent {
  width: 50px;
  height: 3px;
  background: var(--accent);
  margin: 0 auto;
  border-radius: 2px;
}

/* === Section === */
.section {
  padding: 50px 0;
}

.section + .section {
  border-top: 1px solid var(--border);
}

.section-title {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 28px;
  position: relative;
  padding-bottom: 10px;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 40px;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
}

/* === Intro Section === */
.intro {
  padding: 48px 0 28px;
}

.intro-text {
  border-left: 4px solid var(--accent);
  padding: 20px 28px;
  background: var(--white);
  border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: var(--shadow);
}

.intro-text p {
  font-size: 1.12rem;
  line-height: 1.85;
  color: var(--text);
  margin-bottom: 10px;
}

.intro-text p:last-child {
  margin-bottom: 0;
}

.intro-text strong {
  color: var(--accent);
  font-weight: 700;
}

/* === Dates Card === */
.dates-card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px 32px;
  margin-bottom: 16px;
  border-left: 4px solid var(--blue);
}

.dates-card h3 {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 10px;
}

.dates-card ul {
  list-style: none;
  padding: 0;
}

.dates-card li {
  padding: 6px 0;
  padding-left: 20px;
  position: relative;
  font-size: 0.95rem;
  color: var(--text);
}

.dates-card li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 14px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--blue);
}

.dates-card li strong {
  color: var(--navy);
}

/* === Registration === */
.registration-box {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px 32px;
  border-left: 4px solid var(--accent);
}

.registration-box p {
  font-size: 0.95rem;
  color: var(--text);
  margin-bottom: 8px;
}

.registration-box a {
  font-weight: 600;
}

/* === Speaker Grid === */
.speakers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.speaker-card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: transform 0.2s, box-shadow 0.2s;
}

.speaker-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(27,42,74,0.12);
}

.speaker-header {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 24px 24px 0;
}

.speaker-photo {
  width: 90px;
  height: 90px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--border);
  flex-shrink: 0;
}

.speaker-name {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 2px;
}

.speaker-affiliation {
  font-size: 0.88rem;
  color: var(--text-light);
}

.speaker-body {
  padding: 18px 24px 24px;
}

.speaker-title {
  font-family: var(--font-heading);
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--blue);
  margin-bottom: 10px;
  line-height: 1.4;
}

.speaker-abstract {
  font-size: 0.88rem;
  color: var(--text-light);
  line-height: 1.65;
  text-align: justify;
}

.speaker-abstract.tba {
  font-style: italic;
  color: var(--text-light);
}

/* === Organizers === */
.organizers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.org-card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 28px;
  text-align: center;
  transition: transform 0.2s, box-shadow 0.2s;
}

.org-card:last-child:nth-child(odd) {
  grid-column: 1 / -1;
  width: calc(50% - 14px);
  justify-self: center;
}

.org-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(27,42,74,0.12);
}

.org-card .org-name {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 6px;
}

.org-photo {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--border);
  margin: 0 auto 16px auto;
  display: block;
}

.org-card .org-uni {
  font-size: 0.92rem;
  color: var(--text-light);
}

/* === Footer === */
.footer {
  background: var(--navy);
  color: rgba(255,255,255,0.6);
  text-align: center;
  padding: 24px;
  font-size: 0.85rem;
}

.footer a {
  color: rgba(255,255,255,0.8);
}

/* === Responsive === */
@media (max-width: 768px) {
  .navbar-inner {
    flex-direction: column;
    height: auto;
    padding: 12px 16px;
    gap: 10px;
  }

  .navbar-brand {
    gap: 10px;
  }

  .navbar-brand img {
    height: 40px;
  }

  .navbar-nav {
    gap: 0;
  }

  .navbar-nav a {
    font-size: 0.85rem;
    padding: 6px 14px;
  }

  .hero h1 {
    font-size: 1.6rem;
  }

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

  .org-card:last-child:nth-child(odd) {
    grid-column: auto;
    width: auto;
    justify-self: auto;
  }

  .hero {
    padding: 40px 0 36px;
  }

  .section {
    padding: 36px 0;
  }

  .speaker-header {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .dates-card,
  .registration-box {
    padding: 20px;
  }
}