/* =====================================================================
   NeurIPS 2026 Workshop — AI Agents for Biomedical Imaging and
   Multimodal Clinical Data. In collaboration with MELBA.
   Design language follows genai4health.github.io:
   fixed dark navbar, full-viewport dark hero, blue #2563eb primary,
   amber #f59e0b accent, Raleway + Open Sans.
   Plain CSS, no build system. Edit the variables below to re-theme.
   ===================================================================== */

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --accent: #f59e0b;
  --accent-dark: #d97706;
  --gray-50: #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --gray-900: #0f172a;
  --white: #ffffff;
  --max-width: 1080px;
  --font-heading: "Raleway", "Segoe UI", Arial, sans-serif;
  --font-body: "Open Sans", "Segoe UI", Arial, sans-serif;
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --radius: 0.75rem;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

section[id] { scroll-margin-top: 4.5rem; }

body {
  font-family: var(--font-body);
  color: var(--gray-700);
  background: var(--white);
  line-height: 1.7;
  font-size: 1rem;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.25rem;
}

h1, h2, h3 { font-family: var(--font-heading); line-height: 1.25; color: var(--gray-900); }

h3 { font-size: 1.15rem; font-weight: 700; margin: 1.5rem 0 0.5rem; }

p { margin-bottom: 1rem; }

a { color: var(--primary); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--primary-dark); text-decoration: underline; }

ul { margin: 0 0 1rem 1.4rem; }
li { margin-bottom: 0.4rem; }

.note { color: var(--gray-500); }

/* Section titles with gradient underline (genai4health style) */
.section-title {
  font-size: 2rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 0.75rem;
}

.section-title::after {
  content: "";
  display: block;
  width: 72px;
  height: 4px;
  margin: 0.75rem auto 0;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
}

.section-subtitle {
  text-align: center;
  color: var(--gray-500);
  max-width: 720px;
  margin: 0 auto 2rem;
}

/* ===================== Navigation ===================== */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1030;
  background: rgba(0, 0, 0, 0.9);
  -webkit-backdrop-filter: blur(15px);
  backdrop-filter: blur(15px);
  box-shadow: var(--shadow-md);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  padding-top: 0.55rem;
  padding-bottom: 0.55rem;
}

.brand { display: flex; align-items: center; text-decoration: none; transition: opacity 0.15s ease-in-out; }
.brand:hover { text-decoration: none; opacity: 0.8; }
.nav-logo-img { height: 55px; width: auto; object-fit: contain; display: block; }

.site-nav { display: flex; flex-wrap: wrap; gap: 0.1rem; }

.site-nav a {
  position: relative;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--white);
  text-decoration: none;
  padding: 0.5rem 0.8rem;
  border-radius: 0.25rem;
  transition: all 0.15s ease-in-out;
}

.site-nav a::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.15s ease-in-out;
}

.site-nav a:hover, .site-nav a:focus {
  color: var(--accent);
  background: rgba(255, 255, 255, 0.1);
  text-decoration: none;
  outline: none;
}

.site-nav a:hover::after { width: 80%; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 6px;
  cursor: pointer;
  padding: 0.45rem 0.5rem;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--white);
  margin: 5px 0;
  border-radius: 2px;
}

/* ===================== Hero (full-viewport, dark) ===================== */

.hero {
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding-top: 80px;
  padding-bottom: 3rem;
  text-align: center;
  color: var(--white);
  background: var(--gray-900);
}

/* Two background layers that slowly crossfade: the abstract network visual
   and the Atlanta skyline (workshop location). */
.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: 50% 50%;
  background-repeat: no-repeat;
}

.hero-bg-a {
  background-image:
    linear-gradient(135deg, rgba(2, 6, 17, 0.55), rgba(2, 6, 17, 0.55)),
    url("images/hero-bg.svg");
}

.hero-bg-b {
  background-image:
    linear-gradient(135deg, rgba(2, 6, 17, 0.5), rgba(8, 10, 22, 0.55)),
    url("images/atlanta.jpg");
  opacity: 0;
  animation: hero-crossfade 10s ease-in-out infinite;
}

@keyframes hero-crossfade {
  0%, 35%  { opacity: 0; }
  48%, 85% { opacity: 1; }
  98%, 100% { opacity: 0; }
}

#heroCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 860px;
  width: 100%;
  padding: 1rem 1.25rem 0;
  display: flex;
  flex-direction: column;
  min-height: calc(100vh - 80px);
}

/* title block: vertically centered in the free space */
.hero-center {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

/* tagline, date/venue, and buttons: pinned to the bottom of the hero */
.hero-bottom { padding-bottom: 2.25rem; }

.hero-conference {
  display: inline-block;
  font-family: var(--font-heading);
  color: var(--accent);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-bottom: 1rem;
  text-decoration: none;
  animation: pop-in 0.6s ease-out 0.15s both;
}

@keyframes pop-in {
  0% { opacity: 0; transform: scale(0.8) translateY(10px); }
  70% { opacity: 1; transform: scale(1.04) translateY(0); }
  100% { opacity: 1; transform: scale(1) translateY(0); }
}

.hero-conference:hover { color: var(--white); text-decoration: none; }

.hero h1 {
  font-size: clamp(1.7rem, 4vw, 2.7rem);
  font-weight: 800;
  color: var(--white);
  line-height: 1.18;
  margin-bottom: 1.25rem;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

/* short acronym under the title; pops in after the typewriter finishes */
.hero-acronym {
  font-family: var(--font-heading);
  font-size: clamp(1.2rem, 2.5vw, 1.7rem);
  font-weight: 800;
  letter-spacing: 0.22em;
  margin: 0.75rem 0 0;
  background: linear-gradient(90deg, #60a5fa, var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: pop-in 0.6s ease-out 3.8s both;
}

/* Typewriter title: the hidden "ghost" copy reserves the final height so the
   layout never shifts while the visible copy types itself out. Without JS
   (or with reduced motion) the ghost stays visible as a normal title. */
.typewriter { position: relative; }
.typewriter .type-live { display: none; }
.typewriter.js-typing .type-ghost { visibility: hidden; }
.typewriter.js-typing .type-live { display: block; position: absolute; inset: 0; }

.type-caret {
  display: inline-block;
  width: 3px;
  height: 0.95em;
  margin-left: 4px;
  vertical-align: text-bottom;
  background: var(--accent);
  animation: caret-blink 0.8s steps(1) infinite;
  transition: opacity 0.6s ease;
}
.type-caret.done { opacity: 0; }

@keyframes caret-blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

.hero-tagline {
  font-size: 0.95rem;
  color: var(--gray-300);
  max-width: none;
  white-space: nowrap;
  margin: 0 auto 1rem;
}

@media (max-width: 700px) {
  .hero-tagline { white-space: normal; }
}

.hero-melba {
  display: inline-block;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 999px;
  padding: 0.5rem 1.4rem;
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
  color: var(--white);
  margin-bottom: 1.75rem;
}
.hero-melba a { color: var(--accent); text-decoration: none; }
.hero-melba a:hover { color: var(--white); }

.hero-meta { color: var(--gray-300); font-size: 1rem; margin-bottom: 1.5rem; }
.hero-meta span { margin: 0 0.5rem; }

.hero-actions {
  display: flex;
  gap: 1.25rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
}

.hero-deadline {
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--accent);
}

/* ===================== Buttons ===================== */

.btn {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  padding: 0.75rem 1.75rem;
  border-radius: 0.5rem;
  text-decoration: none;
  transition: all 0.2s ease-in-out;
}

.btn:hover { text-decoration: none; transform: translateY(-1px); }

.btn-primary { background: var(--primary); color: var(--white); box-shadow: var(--shadow-md); }
.btn-primary:hover { background: var(--primary-dark); color: var(--white); }

.btn-outline { border: 2px solid var(--white); color: var(--white); }
.btn-outline:hover { background: var(--white); color: var(--gray-900); }

.btn-disabled {
  background: var(--gray-500);
  color: var(--white);
  cursor: not-allowed;
  pointer-events: none;
  box-shadow: none;
}

/* ===================== MELBA banner ===================== */

.melba-banner { background: var(--gray-900); padding: 2.5rem 0; }

.melba-banner .container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
}

.melba-logo-box {
  background: var(--white);
  border-radius: var(--radius);
  padding: 1rem 1.5rem;
  flex-shrink: 0;
}
.melba-logo-box img { display: block; height: 56px; width: auto; }

.melba-text { max-width: 640px; color: var(--gray-300); }
.melba-text h3 { color: var(--white); margin: 0 0 0.4rem; font-size: 1.2rem; }
.melba-text p { margin: 0; font-size: 0.98rem; }
.melba-text a { color: var(--accent); font-weight: 600; }
.melba-text a:hover { color: var(--white); }

/* ===================== Sections ===================== */

.section { padding: 4rem 0; }
.section-alt { background: var(--gray-50); }

.topic-list { columns: 2; column-gap: 2.5rem; }
.topic-list li { break-inside: avoid; }

/* ===================== Important dates cards ===================== */

.dates-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0 1rem;
}

.date-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-left: 4px solid var(--primary);
  border-radius: 0.5rem;
  padding: 1rem 1.25rem;
  box-shadow: var(--shadow-md);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.date-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }

.date-card.date-accent { border-left-color: var(--accent); }
.date-card.date-tba { border-left-color: var(--gray-400); opacity: 0.85; }

.date-event {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--gray-800);
  font-size: 0.98rem;
  margin-bottom: 0.2rem;
}

.date-value {
  color: var(--primary);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
.date-card.date-accent .date-value { color: var(--accent-dark); }
.date-card.date-tba .date-value { color: var(--gray-500); }

/* ===================== Agenda / program timeline ===================== */

.agenda-timeline { max-width: 820px; margin: 1.5rem auto 0; }

.agenda-event {
  display: flex;
  gap: 1.25rem;
  padding: 0.7rem 1rem;
  border-left: 3px solid var(--gray-200);
  margin-left: 0.5rem;
}

.agenda-event:nth-child(odd) { background: var(--gray-50); }

.agenda-event.agenda-highlight { border-left-color: var(--accent); }
.agenda-event.agenda-talk { border-left-color: var(--primary); }

.agenda-time {
  flex-shrink: 0;
  width: 120px;
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--gray-500);
  font-size: 0.92rem;
  font-variant-numeric: tabular-nums;
}

.agenda-title { color: var(--gray-700); }

/* ===================== People cards ===================== */

.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.person-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 1.5rem 1.1rem;
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.person-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }

.person-card h3 { margin: 0.9rem 0 0.15rem; font-size: 1.05rem; font-weight: 700; }

.person-photo {
  width: 128px;
  height: 128px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto;
  display: block;
  border: 3px solid var(--gray-100);
  box-shadow: var(--shadow-md);
}

.placeholder-photo {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--gray-100);
  color: var(--gray-400);
  font-family: var(--font-heading);
  font-weight: 700;
}

.person-affil { color: var(--gray-500); font-size: 0.9rem; margin-bottom: 0.3rem; }
.person-topic { font-style: italic; font-size: 0.9rem; color: var(--gray-600); margin: 0; }

.person-tag {
  display: inline-block;
  margin-top: 0.6rem;
  font-family: var(--font-heading);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-dark);
  background: rgba(245, 158, 11, 0.12);
  border-radius: 999px;
  padding: 0.15rem 0.7rem;
}

.people-subheading {
  text-align: center;
  font-size: 1.4rem;
  font-weight: 800;
  margin-top: 3rem;
  color: var(--gray-900);
}

.people-grid-narrow {
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* Program committee: compact boxes (scales to many members) */
.pc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 0.75rem;
  margin: 1.5rem 0 1.5rem;
}

.pc-card {
  background: var(--gray-50);
  border: 1px solid var(--gray-300);
  border-top: 3px solid var(--primary);
  border-radius: 0.5rem;
  padding: 0.65rem 0.75rem;
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.pc-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }

.pc-name {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--gray-800);
  line-height: 1.3;
}

.pc-affil { font-size: 0.78rem; color: var(--gray-500); }

.pc-tba { border-style: dashed; opacity: 0.75; }

/* ===================== Footer ===================== */

.site-footer {
  background: var(--gray-900);
  color: var(--gray-400);
  padding: 2.5rem 0 2rem;
  font-size: 0.92rem;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.footer-logo { display: inline-block; margin-bottom: 0.75rem; }
.footer-logo img { height: 48px; width: auto; display: block; }
.footer-logo:hover { opacity: 0.8; }

.footer-title {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--white);
  margin-bottom: 0.5rem;
}

.footer-section a { color: var(--gray-300); }
.footer-section a:hover { color: var(--accent); }

.footer-bottom {
  border-top: 1px solid var(--gray-800);
  padding-top: 1.25rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--gray-500);
}

.footer-bottom p { margin-bottom: 0.3rem; }
.footer-credit { font-size: 0.72rem; color: var(--gray-600); }

/* ===================== Mobile ===================== */

@media (max-width: 860px) {
  .nav-toggle { display: block; }

  .site-nav {
    display: none;
    flex-direction: column;
    width: 100%;
    padding: 0.5rem 0 0.75rem;
  }

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

  .site-nav a { padding: 0.8rem 0.75rem; width: 100%; border-bottom: 1px solid rgba(255, 255, 255, 0.05); }
  .site-nav a::after { display: none; }

  .topic-list { columns: 1; }
  .committee-list { columns: 2; }

  .hero { background-attachment: scroll; }

  .agenda-time { width: 96px; }
}

@media (max-width: 480px) {
  .committee-list { columns: 1; }
  .section { padding: 2.75rem 0; }
  .melba-banner .container { text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn:hover, .date-card:hover, .person-card:hover { transform: none; }
  .hero-bg-b { animation: none; opacity: 0.5; }
  .type-caret { animation: none; opacity: 0; }
  .hero-conference { animation: none; }
  .hero-acronym { animation: none; }
}