/* AICE-26 Symposium Website
   Academic style: clean, readable, understated.
*/

:root {
  --primary:    #16395c;
  --accent:     #2e6da4;
  --accent-soft:#e8eef5;
  --ink:        #1c2733;
  --light-bg:   #f6f8fb;
  --border:     #dbe2ec;
  --border-2:   #c5d0de;
  --text-muted: #5a6675;
}

html { scroll-behavior: smooth; }

body {
  font-family: "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: #fff;
  font-size: 1.02rem;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

/* offset for sticky nav anchor jumps */
section[id] { scroll-margin-top: 70px; }

/* ---- Header ---- */
.site-header {
  background: #16395c;
  color: #fff;
  padding: 2.2rem 0 1.8rem;
  text-align: left;
  border-bottom: none;
}

.symposium-label {
  font-size: 0.82rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-weight: 600;
  color: rgba(255,255,255,0.75);
  margin-bottom: 0.5rem;
}

.symposium-title {
  font-size: 1.8rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 0.5rem;
  line-height: 1.25;
}

.symposium-subtitle {
  font-size: 0.95rem;
  color: rgba(255,255,255,0.85);
  margin: 0;
}

/* ---- Sticky nav ---- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 1020;
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(4px);
  border-bottom: 1px solid var(--border);
  margin-bottom: 3rem;
}

.site-nav .nav {
  padding: 0.5rem 0;
  gap: 0.2rem;
}

/* Plain text nav links — no pills */
.site-nav .nav-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 0.4rem 0.9rem;
  border-radius: 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.site-nav .nav-link:hover {
  color: var(--primary);
  background: none;
  border-bottom-color: var(--border-2);
}

.site-nav .nav-link.active {
  color: var(--primary);
  background: none;
  font-weight: 700;
  border-bottom-color: var(--accent);
}

/* ---- Section headings ---- */
.section-heading {
  font-size: 1.35rem;
  color: var(--ink);
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.4rem;
  margin-bottom: 1.4rem;
  font-weight: 600;
}

.subsection-heading {
  font-size: 1.05rem;
  color: var(--primary);
  font-weight: 600;
  margin-bottom: 0.6rem;
}

/* lead questions */
.lead-question {
  border-left: 3px solid var(--border-2);
  padding-left: 1.1rem;
  margin: 1.2rem 0;
  color: var(--primary);
  font-style: italic;
  font-weight: 500;
}

/* ---- Day headings ---- */
.day-heading {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 0.8rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--border);
}

/* ---- Topic lists ---- */
#topics ul {
  padding-left: 1.2rem;
  margin-bottom: 1.4rem;
}

#topics li {
  margin-bottom: 0.35rem;
}

/* ---- Programme table ---- */
.programme-table {
  font-size: 0.94rem;
  border: 1px solid var(--border);
}

.programme-table thead th {
  background: var(--light-bg);
  color: var(--primary);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  border-bottom: 1px solid var(--border-2);
  padding: 0.6rem 0.9rem;
}

.programme-table td {
  padding: 0.65rem 0.9rem;
  vertical-align: top;
  border-color: var(--border);
}

.programme-table td u {
  text-decoration: underline;
  font-weight: normal;
  color: var(--ink);
}

/* session band rows */
.programme-table .session-row td {
  background: var(--light-bg);
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.07em;
  border-top: 1px solid var(--border-2);
  padding: 0.5rem 0.9rem;
}

.programme-table .session-row td br { display: none; }

.roundtable td {
  background: var(--accent-soft);
}

/* ---- Committee list ---- */
.committee-list li {
  padding: 0.25rem 0;
  font-size: 0.97rem;
}

.committee-list strong {
  color: var(--accent);
}

/* ---- Footer ---- */
.site-footer {
  background: var(--light-bg);
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  padding: 1.4rem 0;
  font-size: 0.85rem;
}

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

.site-footer a:hover { color: var(--primary); }

/* ---- Links ---- */
a {
  color: var(--accent);
  text-underline-offset: 2px;
}

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

/* ---- Layout ---- */
.container { max-width: 820px; }

/* ---- Back to top ---- */
.back-to-top {
  position: fixed;
  right: 1.4rem;f
  bottom: 1.4rem;
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  text-decoration: none;
  box-shadow: 0 2px 8px rgba(22,57,92,0.25);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.back-to-top.show {
  opacity: 0.9;
  pointer-events: auto;
}

.back-to-top:hover { background: var(--accent); color: #fff; }

/* ---- Responsive ---- */
@media (max-width: 576px) {
  .symposium-title { font-size: 1.4rem; }
  .site-header { padding: 1.6rem 0 1.2rem; }
  .programme-table { font-size: 0.88rem; }
  .programme-table td, .programme-table thead th { padding: 0.5rem 0.6rem; }
}

/* ---- References ---- */
.references-list {
  font-size: 0.88rem;
  line-height: 1.75;
  padding-left: 1.5rem;
}

.references-list li {
  margin-bottom: 0.7rem;
}

sup a {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.75em;
}

sup a:hover {
  text-decoration: underline;
}

/* ---- Intro summary ---- */
.intro-summary {
  font-size: 1.05rem;
  color: var(--primary);
  line-height: 1.85;
   font-weight: 600;
}