/* ── Variables ─────────────────────────────────────────── */
:root {
  --color-bg: #fafaf8;
  --color-surface: #ffffff;
  --color-text: #2c2c2c;
  --color-text-muted: #5a5a5a;
  --color-accent: #1a5276;
  --color-accent-light: #2980b9;
  --color-border: #e0ddd8;
  --color-hero-bg: #1a5276;
  --color-hero-text: #ffffff;
  --color-nav-bg: #1a3c50;
  --font-body: 'Georgia', 'Times New Roman', serif;
  --font-heading: 'Helvetica Neue', 'Arial', sans-serif;
  --font-mono: 'Menlo', 'Consolas', monospace;
  --max-width: 900px;
  --nav-height: 52px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 16px);
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-size: 17px;
}

/* ── Nav ──────────────────────────────────────────────── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-nav-bg);
  border-bottom: 1px solid rgba(255,255,255,0.1);
  backdrop-filter: blur(8px);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 0 20px;
  height: var(--nav-height);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.nav-inner::-webkit-scrollbar { display: none; }

.nav a {
  color: rgba(255,255,255,0.8);
  text-decoration: none;
  font-family: var(--font-heading);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.02em;
  padding: 6px 10px;
  border-radius: 4px;
  white-space: nowrap;
  transition: color 0.2s, background 0.2s;
}

.nav a:hover,
.nav a:focus {
  color: #fff;
  background: rgba(255,255,255,0.12);
}

/* ── Hero ─────────────────────────────────────────────── */
.hero {
  background: var(--color-hero-bg);
  color: var(--color-hero-text);
  padding: 80px 20px 24px;
  text-align: center;
}

.hero h1 {
  font-family: var(--font-heading);
  font-size: clamp(1.8rem, 5vw, 2.8rem);
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.hero .subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  opacity: 0.9;
  margin-bottom: 8px;
}

.hero .dates {
  font-family: var(--font-heading);
  font-size: clamp(1rem, 2.5vw, 1.15rem);
  font-weight: 600;
  margin-bottom: 6px;
}

.hero .venue-line {
  font-size: 0.95rem;
  opacity: 0.75;
}

.hero .venue-line a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: rgba(255,255,255,0.4);
}

.hero .venue-line a:hover {
  text-decoration-color: rgba(255,255,255,0.8);
}

.hero-image {
  margin-top: 32px;
  max-width: 100%;
  width: 900px;
  border-radius: 8px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.3);
}

/* ── Sections ─────────────────────────────────────────── */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 56px 20px;
}

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

.section h2 {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: 24px;
  letter-spacing: -0.01em;
}

.section h3 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-text);
  margin-top: 28px;
  margin-bottom: 12px;
}

.section p {
  margin-bottom: 14px;
}

.section ul, .section ol {
  margin-bottom: 14px;
  padding-left: 24px;
}

.section li {
  margin-bottom: 6px;
}

.section a {
  color: var(--color-accent-light);
  text-decoration: underline;
  text-underline-offset: 2px;
}

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

/* ── Programme ────────────────────────────────────────── */
.day-tabs {
  display: flex;
  gap: 6px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.day-tab {
  font-family: var(--font-heading);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 8px 16px;
  border: 2px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-surface);
  color: var(--color-text-muted);
  cursor: pointer;
  transition: all 0.2s;
}

.day-tab:hover {
  border-color: var(--color-accent-light);
  color: var(--color-accent);
}

.day-tab.active {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}

.day-schedule {
  display: none;
}

.day-schedule.active {
  display: block;
}

.day-schedule h3 {
  margin-top: 0;
  margin-bottom: 16px;
  color: var(--color-accent);
}

.schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
  line-height: 1.5;
}

.schedule-table th {
  font-family: var(--font-heading);
  text-align: left;
  padding: 10px 12px;
  background: var(--color-accent);
  color: #fff;
  font-weight: 600;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.schedule-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.schedule-table tr:last-child td {
  border-bottom: none;
}

.schedule-table .time-col {
  white-space: nowrap;
  width: 130px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

.schedule-table .keynote {
  background: rgba(26, 82, 118, 0.06);
}

.schedule-table .break-row {
  color: var(--color-text-muted);
}

.schedule-table .break-row td:not(.time-col) {
  font-style: italic;
}

/* Week-at-a-glance summary */
.glance-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  margin-bottom: 32px;
}

.glance-table th,
.glance-table td {
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  text-align: left;
  vertical-align: top;
}

.glance-table th {
  background: var(--color-accent);
  color: #fff;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.glance-table td {
  background: var(--color-surface);
}

/* ── Keynote cards ────────────────────────────────────── */
.keynote-grid {
  display: grid;
  gap: 20px;
}

.keynote-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 24px;
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

.keynote-card .keynote-photo-placeholder {
  width: 72px;
  height: 72px;
  min-width: 72px;
  border-radius: 50%;
  background: var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: 0.7rem;
  color: var(--color-text-muted);
}

.keynote-card .keynote-info h3 {
  margin-top: 0;
  margin-bottom: 2px;
  font-size: 1.1rem;
}

.keynote-card .keynote-info .affiliation {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  margin-bottom: 6px;
}

.keynote-card .keynote-info .talk-title {
  font-style: italic;
  font-size: 0.92rem;
}

.keynote-card .keynote-info .talk-day {
  font-family: var(--font-heading);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-top: 6px;
}

/* ── Info cards (venue, excursion, etc.) ───────────────── */
.info-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-accent);
  border-radius: 4px;
  padding: 20px 24px;
  margin-bottom: 20px;
}

.info-box p {
  margin-bottom: 8px;
}

.info-box p:last-child {
  margin-bottom: 0;
}

/* ── Organisers ───────────────────────────────────────── */
.organizer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 20px;
}

.organizer-card {
  text-align: center;
  padding: 20px 12px;
}

.organizer-card .name {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1rem;
  margin-bottom: 4px;
}

.organizer-card .affil {
  font-size: 0.88rem;
  color: var(--color-text-muted);
}

/* ── Sponsors ─────────────────────────────────────────── */
.sponsor-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
  align-items: center;
}

.sponsor-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 20px 28px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--color-text-muted);
  text-align: center;
  text-decoration: none;
  transition: border-color 0.2s, color 0.2s;
}

.sponsor-item:hover {
  border-color: var(--color-accent-light);
  color: var(--color-accent);
}

/* ── Footer ───────────────────────────────────────────── */
.footer {
  background: var(--color-nav-bg);
  color: rgba(255,255,255,0.7);
  padding: 32px 20px;
  text-align: center;
  font-size: 0.85rem;
  font-family: var(--font-heading);
}

.footer a {
  color: rgba(255,255,255,0.9);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.footer a:hover {
  color: #fff;
}

.footer p {
  margin-bottom: 6px;
}

/* ── Responsive ───────────────────────────────────────── */
@media (max-width: 640px) {
  .hero {
    padding: 56px 16px 48px;
  }

  .section {
    padding: 40px 16px;
  }

  .schedule-table .time-col {
    width: auto;
  }

  .keynote-card {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .keynote-card .keynote-info h3 {
    margin-top: 8px;
  }

  .nav-inner {
    padding: 0 12px;
    gap: 2px;
  }

  .nav a {
    font-size: 12px;
    padding: 6px 8px;
  }

  .glance-table {
    font-size: 0.78rem;
  }

  .glance-table th,
  .glance-table td {
    padding: 6px 8px;
  }
}