:root {
  --color-bg: #fbf9f4;
  --color-bg-alt: #f2ede1;
  --color-text: #201d18;
  --color-muted: #6f6a5e;
  --color-accent: #d98e4a;
  --color-accent-dark: #b6702e;
  --color-accent-light: #f3d19b;
  --color-ink: #16302f;
  --color-ink-deep: #0c1e1d;
  --color-border: #e2dbc9;
  --max-width: min(1160px, 92vw);
  --font-display: "Sora", -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-body: "Sora", -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: var(--font-display);
  line-height: 1.2;
  color: var(--color-text);
  font-weight: 600;
}

a {
  color: var(--color-accent-dark);
}

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

/* ---------- Hero ---------- */

.hero {
  position: relative;
  color: #f5f1e6;
  background:
    linear-gradient(165deg, rgba(9, 22, 32, 0.82), rgba(12, 34, 48, 0.78)),
    url("../assets/hero-bg.jpg");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  overflow: hidden;
}

.navbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.75rem 1.5rem;
  position: relative;
  z-index: 1;
}

.nav-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.4rem, 1vw + 1.1rem, 1.8rem);
  letter-spacing: 0.03em;
  color: #f5f1e6;
}

.nav-links {
  display: flex;
  gap: 1.75rem;
  list-style: none;
  margin: 0.6rem 0 0;
  padding: 0;
  flex-wrap: wrap;
}

.nav-links a {
  color: #f5f1e6;
  text-decoration: none;
  font-size: clamp(1rem, 0.3vw + 0.9rem, 1.1rem);
  opacity: 0.85;
  letter-spacing: 0.01em;
  transition: opacity 0.15s ease;
}

.nav-links a:hover {
  opacity: 1;
  color: #f5f1e6;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
  z-index: 2;
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: #f5f1e6;
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.hero-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: clamp(4rem, 9vw, 7rem) 1.5rem clamp(4.5rem, 10vw, 8rem);
  text-align: center;
  position: relative;
  z-index: 1;
}

.hero-content h1 {
  color: #fff;
  font-size: clamp(2.6rem, 4vw + 1.4rem, 4.6rem);
  letter-spacing: -0.01em;
  margin: 0 auto 1rem;
  max-width: 20ch;
}

.hero-subtitle {
  font-family: var(--font-display);
  font-style: italic;
  font-size: clamp(1.2rem, 0.6vw + 1rem, 1.5rem);
  color: var(--color-accent-light);
  margin: 0 0 0.75rem;
}

.hero-meta {
  opacity: 0.8;
  margin-bottom: 2rem;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.btn {
  display: inline-block;
  background: var(--color-accent);
  color: #fff;
  padding: 0.7rem 1.6rem;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  box-shadow: 0 4px 14px rgba(182, 112, 46, 0.28);
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

.btn:hover {
  background: var(--color-accent-dark);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(182, 112, 46, 0.34);
}

/* ---------- Sections ---------- */

.section {
  padding: clamp(3rem, 6vw, 6rem) 0;
}

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

.section > * {
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: clamp(1.5rem, 4vw, 2.5rem);
  padding-right: clamp(1.5rem, 4vw, 2.5rem);
}

.section h2 {
  position: relative;
  font-size: clamp(1.6rem, 1.2vw + 1.2rem, 2.3rem);
  padding-bottom: 1.15rem;
  margin-bottom: 2.5rem;
  text-align: center;
}

.section h2::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translateX(-50%);
  width: 72px;
  height: 4px;
  border-radius: 2px;
  background: var(--color-accent);
}

.section h3 {
  font-size: clamp(1.2rem, 0.6vw + 1rem, 1.5rem);
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  text-align: center;
}

.section-intro {
  color: var(--color-muted);
  font-style: italic;
}

/* ---------- People ---------- */

.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 210px));
  justify-content: center;
  gap: clamp(1rem, 2vw, 2rem);
}

.people-grid--fixed5 {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.person {
  text-align: center;
}

.person-photo {
  display: block;
  width: clamp(100px, 8vw, 132px);
  height: clamp(100px, 8vw, 132px);
  border-radius: 50%;
  background: linear-gradient(160deg, var(--color-border), #d8cfb8);
  object-fit: cover;
  margin: 0 auto 0.85rem;
  border: 3px solid #fff;
  box-shadow: 0 4px 14px rgba(22, 48, 47, 0.12);
}

.person h3 {
  margin: 0 0 0.2rem;
  font-size: 1.05rem;
}

.affiliation {
  color: var(--color-muted);
  font-size: 0.88rem;
  margin: 0;
}

.bio {
  font-size: 0.82rem;
  color: var(--color-muted);
  margin-top: 0.5rem;
  line-height: 1.5;
  text-align: left;
}

/* ---------- Speaker cards (keynotes/panelists) ---------- */

.speaker-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.speaker-card {
  display: flex;
  gap: 1.25rem;
  align-items: flex-start;
  background: #fff;
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-accent);
  border-radius: 12px;
  padding: 1.1rem 1.4rem;
  box-shadow: 0 2px 12px rgba(22, 48, 47, 0.07);
  transition: box-shadow 0.2s ease;
}

.speaker-card:hover {
  box-shadow: 0 6px 24px rgba(22, 48, 47, 0.13);
}

.speaker-photo {
  flex-shrink: 0;
  width: 68px;
  height: 68px;
  border-radius: 50%;
  object-fit: cover;
  object-position: top center;
  border: 2px solid var(--color-accent-light);
  box-shadow: 0 2px 8px rgba(22, 48, 47, 0.14);
}

.speaker-photo--placeholder {
  display: block;
  background: linear-gradient(160deg, var(--color-border), #d8cfb8);
}

.speaker-info {
  flex: 1;
  min-width: 0;
}

.speaker-info h3 {
  margin: 0 0 0.1rem;
  font-size: 1rem;
}

.speaker-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-accent-dark);
  background: var(--color-accent-light);
  border-radius: 20px;
  padding: 0.15em 0.65em;
  margin-bottom: 0.35rem;
}

.speaker-card--tba .speaker-info h3 {
  color: var(--color-muted);
}

.speaker-card--tba {
  border-left-color: var(--color-border);
  opacity: 0.75;
}

@media (max-width: 520px) {
  .speaker-card {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
  .speaker-info .bio {
    text-align: left;
  }
}

/* ---------- Agenda ---------- */

.table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.agenda-table {
  width: 100%;
  min-width: 480px;
  border-collapse: collapse;
  background: #fff;
  box-shadow: 0 2px 10px rgba(22, 48, 47, 0.06);
}

.agenda-table th,
.agenda-table td {
  text-align: left;
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.agenda-table th {
  background: var(--color-ink);
  color: #f5f1e6;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
}

.agenda-table tbody tr:hover {
  background: var(--color-bg-alt);
}

/* ---------- Call for papers ---------- */

.key-dates {
  list-style: none;
  margin-top: 0;
  margin-bottom: 1.75rem;
}

.key-dates li {
  padding: 0.5rem 0;
  border-bottom: 1px dashed var(--color-border);
}

.key-dates strong {
  color: var(--color-ink);
}

/* ---------- Split cards (Submission & Registration) ---------- */

.split-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(1.5rem, 3vw, 2.5rem);
}

.split-card {
  display: flex;
  flex-direction: column;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: clamp(1.75rem, 3vw, 2.5rem);
  box-shadow: 0 4px 14px rgba(22, 48, 47, 0.06);
}

.split-card h3 {
  margin-top: 0;
}

.split-card .key-dates {
  padding-left: 0;
}

.split-card .center {
  margin-top: auto;
  padding-top: 0.5rem;
}

.center {
  text-align: center;
}

@media (max-width: 800px) {
  .split-grid {
    grid-template-columns: 1fr;
  }
}

/* ---------- Venue ---------- */

.venue-content {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: clamp(2rem, 4vw, 3.25rem);
  align-items: start;
}

.venue-info .key-dates {
  margin-top: 1.25rem;
}

.venue-map {
  overflow: hidden;
  border-radius: 6px;
  border: 1px solid var(--color-border);
  box-shadow: 0 4px 14px rgba(22, 48, 47, 0.1);
  line-height: 0;
}

.venue-map iframe {
  display: block;
}

@media (max-width: 900px) {
  .people-grid {
    grid-template-columns: repeat(auto-fit, minmax(150px, 210px));
    justify-content: center;
  }
}

@media (max-width: 800px) {
  .venue-content {
    grid-template-columns: 1fr;
  }
}

/* ---------- Footer ---------- */

.footer {
  text-align: center;
  padding: 2.5rem 1.5rem;
  color: var(--color-muted);
  font-size: 0.9rem;
  background: var(--color-ink-deep);
}

.footer, .footer a {
  color: #cfc9b8;
}

.footer .credit {
  font-size: 0.78rem;
  opacity: 0.7;
  margin-top: 0.4rem;
}

.footer a:hover {
  color: var(--color-accent-light);
}

/* ---------- Scroll reveal ---------- */

.section {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.section.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Responsive ---------- */

@media (max-width: 640px) {
  .navbar {
    position: relative;
    align-items: center;
    z-index: 2;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin-top: 0.5rem;
    padding: 1.25rem 1.5rem;
    background: var(--color-ink-deep);
    border-radius: 12px;
    box-shadow: 0 12px 28px rgba(0, 0, 0, 0.25);
    z-index: 10;
  }

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

  .hero-content {
    padding-left: 1.25rem;
    padding-right: 1.25rem;
  }

  .hero-meta {
    font-size: 0.85rem;
  }

  .btn {
    padding: 0.7rem 1.4rem;
    font-size: 0.95rem;
  }

  .section h2 {
    margin-bottom: 1.5rem;
  }

  .people-grid {
    grid-template-columns: repeat(auto-fit, minmax(140px, 200px));
    justify-content: center;
    gap: 1.75rem;
  }

  .agenda-table th,
  .agenda-table td {
    padding: 0.65rem 0.85rem;
    font-size: 0.92rem;
  }
}