/* ==========================================================================
   ISSID 2027 — Durham | Shared design system
   Font pairing inspired by USYD Meta Lab (Playfair Display + Inter)
   Layout rhythm inspired by ECP22 Edinburgh / ISRE2026 (alternating photo
   sections, stat rows, card-based key dates)
   ========================================================================== */

:root {
  --color-bg: #faf6ef;
  --color-bg-alt: #ffffff;
  --color-ink: #211a12;
  --color-ink-soft: #63594a;
  --color-accent: #1c4f4c;       /* deep teal, from the river in the crest */
  --color-accent-soft: #e7efee;  /* pale teal tint for chips / backgrounds */
  --color-highlight: #b6472f;    /* warm red, from the crest stars — use sparingly */
  --color-line: rgba(33, 26, 18, 0.12);
  --radius-pill: 999px;
  --radius-card: 18px;
  --font-serif: "Playfair Display", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --max-width: 1120px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

a { color: inherit; }

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 32px;
}

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.15;
  margin: 0 0 0.5em;
  color: var(--color-ink);
}

h1 { font-size: clamp(2.6rem, 5vw, 4.4rem); font-weight: 600; }
h2 { font-size: clamp(1.8rem, 3vw, 2.6rem); }
h3 { font-size: 1.3rem; }

p { margin: 0 0 1.1em; color: var(--color-ink-soft); }

.eyebrow {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 14px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 13px 26px;
  border-radius: var(--radius-pill);
  border: 1.5px solid var(--color-ink);
  text-decoration: none;
  transition: all 0.15s ease;
  cursor: pointer;
}

.btn-primary {
  background: var(--color-ink);
  color: var(--color-bg);
  border-color: var(--color-ink);
}
.btn-primary:hover { background: var(--color-accent); border-color: var(--color-accent); }

.btn-secondary {
  background: transparent;
  color: var(--color-ink);
  border-color: var(--color-line);
}
.btn-secondary:hover { border-color: var(--color-ink); }

.btn-row { display: flex; gap: 14px; flex-wrap: wrap; }

/* ---------- Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(250, 246, 239, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-line);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 10px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--color-ink);
  white-space: nowrap;
}
.brand img { height: 54px; width: auto; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: wrap;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  display: inline-block;
  padding: 8px 14px;
  border-radius: var(--radius-pill);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-ink-soft);
  transition: all 0.15s ease;
}

.nav-links a:hover { background: var(--color-accent-soft); color: var(--color-accent); }
.nav-links a.active { background: var(--color-ink); color: var(--color-bg); }

/* Mobile nav toggle — hidden on desktop, shown in the responsive block */
.nav-toggle { display: none; }
.nav-toggle-label {
  display: none;
  cursor: pointer;
  padding: 8px;
  align-items: center;
  justify-content: center;
}
.nav-toggle-label span,
.nav-toggle-label span::before,
.nav-toggle-label span::after {
  content: '';
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-ink);
  border-radius: 2px;
  transition: transform 0.2s ease, background 0.2s ease, top 0.2s ease;
}
.nav-toggle-label span { position: relative; }
.nav-toggle-label span::before { position: absolute; top: -7px; }
.nav-toggle-label span::after { position: absolute; top: 7px; }
/* Animate burger to an X when open */
.nav-toggle:checked ~ .nav-toggle-label span { background: transparent; }
.nav-toggle:checked ~ .nav-toggle-label span::before { top: 0; transform: rotate(45deg); }
.nav-toggle:checked ~ .nav-toggle-label span::after { top: 0; transform: rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  text-align: center;
  padding: 64px 32px 56px;
  max-width: 880px;
  margin: 0 auto;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.hero-logo {
  max-width: 300px;
  margin: 0 auto 20px;
}

.hero h1 { margin-bottom: 0.3em; }

.hero .lede {
  font-size: 1.15rem;
  max-width: 640px;
  margin: 0 auto 32px;
}

.hero .btn-row { justify-content: center; margin-bottom: 46px; }

.stat-row {
  display: flex;
  justify-content: center;
  gap: 0;
  flex-wrap: wrap;
  border-top: 1px solid var(--color-line);
  border-bottom: 1px solid var(--color-line);
  padding: 26px 0;
}

.stat {
  padding: 0 32px;
  text-align: center;
  border-right: 1px solid var(--color-line);
}
.stat:last-child { border-right: none; }

.stat .num {
  display: block;
  font-family: var(--font-serif);
  font-size: 1.6rem;
  color: var(--color-accent);
}
.stat .label {
  display: block;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-ink-soft);
  margin-top: 2px;
}

/* ---------- Alternating photo/text sections ---------- */
.feature {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
  padding: 64px 32px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.feature.reverse .feature-media { order: 2; }
.feature.reverse .feature-text { order: 1; }

.feature-media img {
  border-radius: var(--radius-card);
  width: 100%;
  height: 340px;
  object-fit: cover;
}

.feature-text .eyebrow { margin-bottom: 10px; }

.section-divider {
  max-width: var(--max-width);
  margin: 0 auto;
  border: none;
  border-top: 1px solid var(--color-line);
}

/* ---------- Gallery ---------- */
.gallery-block { padding: 64px 32px; background: var(--color-bg-alt); border-top: 1px solid var(--color-line); border-bottom: 1px solid var(--color-line); }
.gallery-inner { max-width: var(--max-width); margin: 0 auto; text-align: center; }
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 32px;
}
.gallery-grid img {
  border-radius: 12px;
  height: 220px;
  width: 100%;
  object-fit: cover;
}
.gallery-caption { max-width: 640px; margin: 24px auto 0; }

/* ---------- Speaker teaser / grid ---------- */
.section { padding: 72px 32px; max-width: var(--max-width); margin: 0 auto; }
.section-head { text-align: center; max-width: 640px; margin: 0 auto 44px; }

.speaker-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 28px;
}

.speaker-grid .speaker-card {
  flex: 1 1 260px;
  max-width: 320px;
}

.speaker-card {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  padding: 28px 24px;
  text-align: center;
}

.avatar {
  width: 104px;
  height: 104px;
  border-radius: 50%;
  margin: 0 auto 18px;
  overflow: hidden;
  border: 3px solid var(--color-bg-alt);
  box-shadow: 0 0 0 1px var(--color-line);
}
.avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 18%;
}

.speaker-card h3 { margin-bottom: 2px; }
.speaker-role { font-size: 0.85rem; color: var(--color-accent); font-weight: 600; margin-bottom: 14px; }
.speaker-bio { font-size: 0.9rem; text-align: left; }

/* Featured keynote (e.g. the Eysenck Lecture) */
.speaker-card.featured {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 1px var(--color-accent);
}
.keynote-badge {
  display: inline-block;
  background: var(--color-accent);
  color: #fff;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 5px 13px;
  border-radius: var(--radius-pill);
  margin-bottom: 12px;
}

/* ---------- Content pages (submission / registration) ---------- */
.page-hero {
  padding: 64px 32px 32px;
  text-align: center;
  border-bottom: 1px solid var(--color-line);
}

.content { max-width: 820px; margin: 0 auto; padding: 56px 32px; }
.content h2 { margin-top: 2.2em; }
.content h2:first-child { margin-top: 0; }
.content h3 { margin-top: 1.6em; }
.content ul { color: var(--color-ink-soft); padding-left: 1.2em; }
.content li { margin-bottom: 0.5em; }

/* Accommodation cards */
.stay {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 28px;
  align-items: center;
  margin: 28px 0;
  padding: 20px;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
}
.stay.no-img { grid-template-columns: 1fr; }
.stay img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: var(--radius-card);
}
.stay-body h3 { margin: 0 0 4px; }
.stay-body > p { margin: 0 0 14px; color: var(--color-ink-soft); }
.stay-meta { list-style: none; margin: 0; padding: 0; }
.stay-meta li {
  margin: 0 0 4px;
  padding-left: 0;
  color: var(--color-ink-soft);
  font-size: 0.92rem;
}
.stay-meta li strong { color: var(--color-ink); font-weight: 600; }

/* Organising chair card + committee lists */
.chair {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 28px;
  align-items: center;
  margin: 28px 0 8px;
}
.chair img {
  width: 180px;
  height: 180px;
  object-fit: cover;
  border-radius: 50%;
}
.chair h3 { margin: 0 0 2px; }
.chair .role { color: var(--color-accent); font-weight: 600; margin: 0 0 10px; }
.chair p { margin: 0 0 6px; color: var(--color-ink-soft); }

.people {
  list-style: none;
  padding: 0;
  margin: 18px 0 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 0 28px;
}
.people li {
  margin: 0;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-line);
  color: var(--color-ink);
}

.key-dates {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 16px;
  margin: 32px 0 40px;
}
.key-date-card {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-card);
  padding: 20px;
  text-align: center;
}
.key-date-card .label {
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-ink-soft);
  display: block;
  margin-bottom: 6px;
}
.key-date-card .value {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  color: var(--color-accent);
}

.callout {
  background: var(--color-accent-soft);
  border-radius: var(--radius-card);
  padding: 22px 26px;
  margin: 28px 0;
  font-size: 0.95rem;
}
.callout p:last-child { margin-bottom: 0; }
.callout strong { color: var(--color-accent); }

table.fee-table {
  width: 100%;
  border-collapse: collapse;
  margin: 28px 0 36px;
  font-size: 0.92rem;
}
table.fee-table th, table.fee-table td {
  padding: 13px 14px;
  text-align: left;
  border-bottom: 1px solid var(--color-line);
}
table.fee-table th {
  font-family: var(--font-sans);
  font-weight: 600;
  color: var(--color-ink-soft);
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
table.fee-table td:not(:first-child), table.fee-table th:not(:first-child) {
  text-align: right;
  font-variant-numeric: tabular-nums;
}
table.fee-table tr:last-child td { border-bottom: none; }

.placeholder-flag {
  color: var(--color-highlight);
  font-weight: 600;
}

/* ---------- Footer ---------- */
footer.site-footer {
  background: var(--color-ink);
  color: #efe9df;
  padding: 56px 32px 32px;
  margin-top: 40px;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 32px;
}
.footer-brand { font-family: var(--font-serif); font-size: 1.2rem; }
.footer-links { display: flex; gap: 40px; flex-wrap: wrap; }
.footer-links h4 { color: #efe9df; font-size: 0.8rem; letter-spacing: 0.06em; text-transform: uppercase; font-family: var(--font-sans); margin-bottom: 12px; }
.footer-links ul { list-style: none; padding: 0; margin: 0; }
.footer-links li { margin-bottom: 8px; }
.footer-links a { text-decoration: none; color: #cfc7b8; font-size: 0.9rem; }
.footer-links a:hover { color: #fff; }
.footer-bottom {
  max-width: var(--max-width);
  margin: 40px auto 0;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.12);
  font-size: 0.8rem;
  color: #9c927f;
}

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .feature { grid-template-columns: 1fr; gap: 28px; padding: 40px 24px; }
  .feature.reverse .feature-media,
  .feature.reverse .feature-text { order: initial; }
  .stay { grid-template-columns: 1fr; gap: 18px; }
  .chair { grid-template-columns: 1fr; gap: 16px; justify-items: center; text-align: center; }
  .gallery-grid { grid-template-columns: repeat(2, 1fr); }
  .nav-inner { flex-wrap: wrap; }
  .nav-toggle-label { display: flex; }
  .nav-links {
    display: none;
    flex-basis: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 8px 0 4px;
  }
  .nav-toggle:checked ~ .nav-links { display: flex; }
  .nav-links a { padding: 12px 14px; font-size: 1rem; }
  .stat { padding: 0 18px; }
}