/* ============================================================
   Efficient and On-Device AI Agents — NeurIPS 2026 Workshop
   Custom Stylesheet
   ============================================================ */

/* ---- CSS Custom Properties ---- */
:root {
  /* Colors — derived from proposal's LaTeX color definitions */
  --primary:        #3465A4;   /* headerblue: RGB(52, 101, 164) */
  --primary-dark:   #1e3f6e;   /* darker shade for footer/hover */
  --primary-light:  #e8f0fb;   /* light blue tint for alt sections */
  --primary-hover:  #2a539e;   /* button/link hover */
  --confirmed:      #00823C;   /* darkgreen: RGB(0, 130, 60) */
  --pending:        #B48C00;   /* darkyellow: RGB(180, 140, 0) */
  --text:           #1a1a2e;   /* near-black body text */
  --text-muted:     #5a6a7e;   /* muted/secondary text */
  --bg-white:       #ffffff;
  --bg-gray:        #f4f6f9;
  --border-color:   #dee2e6;
  --card-shadow:    0 2px 8px rgba(52, 101, 164, 0.10);
  --card-shadow-hover: 0 6px 20px rgba(52, 101, 164, 0.18);

  /* Typography */
  --font-heading:   'Inter', system-ui, -apple-system, sans-serif;
  --font-body:      'Open Sans', system-ui, -apple-system, sans-serif;

  /* Spacing */
  --section-py:     3.5rem;
  --navbar-height:  64px;
}

/* ---- Base Reset & Typography ---- */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text);
  background-color: var(--bg-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.25;
  color: var(--text);
}

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

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

/* ---- Accessibility: Skip Link ---- */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  z-index: 9999;
  background: var(--primary);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 0 0 4px 4px;
  font-family: var(--font-heading);
  font-weight: 600;
  transition: top 0.2s;
}

.skip-link:focus {
  top: 0;
  color: #fff;
  text-decoration: none;
}

/* ---- Reduced Motion ---- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* ============================================================
   NAVBAR
   ============================================================ */
#navbar {
  background-color: var(--primary);
  padding-top: 1rem;
  padding-bottom: 1rem;
  transition: padding 0.3s ease, box-shadow 0.3s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

#navbar.navbar-shrunk {
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.25);
}

#navbar .navbar-brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: -0.01em;
  color: #fff;
  /* Allow brand to shrink on small screens so the toggler stays visible */
  flex-shrink: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Prevent toggler from being pushed off-screen */
#navbar .navbar-toggler {
  flex-shrink: 0;
  margin-left: 0.5rem;
}

#navbar .nav-link {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.88);
  padding-left: 0.85rem;
  padding-right: 0.85rem;
  transition: color 0.2s ease;
}

#navbar .nav-link:hover,
#navbar .nav-link:focus {
  color: #fff;
}

/* ============================================================
   HERO SECTION
   ============================================================ */
#hero {
  position: relative;
  min-height: 520px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: var(--navbar-height);
  background-image: url('../img/hero-bg.jpg');
  background-size: cover;
  background-position: center 30%;
  background-repeat: no-repeat;
  /* Fallback gradient if image fails to load */
  background-color: var(--primary-dark);
}

/* Dark overlay */
#hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  padding: 4rem 1.5rem;
  max-width: 900px;
  margin: 0 auto;
}

.hero-content h1 {
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 700;
  color: #fff;
  margin-bottom: 0.75rem;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
}

.hero-content .hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: rgba(255, 255, 255, 0.92);
  margin-bottom: 1rem;
  font-family: var(--font-heading);
  font-weight: 600;
}

.hero-content .hero-tagline {
  font-size: clamp(0.9rem, 1.5vw, 1.05rem);
  color: rgba(255, 255, 255, 0.82);
  font-style: italic;
  margin-bottom: 1.5rem;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
}

.hero-content .hero-date {
  display: inline-block;
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.4);
  color: #fff;
  padding: 0.35rem 1rem;
  border-radius: 2rem;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 2rem;
  backdrop-filter: blur(4px);
}

.hero-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
}

.hero-buttons .btn {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.55rem 1.4rem;
  border-radius: 4px;
  transition: all 0.2s ease;
  width: 200px;
  white-space: nowrap;
  justify-content: center;
  text-align: center;
}

.hero-buttons .btn-outline-light:hover {
  background-color: rgba(255, 255, 255, 0.2);
  transform: translateY(-1px);
}

.hero-contact {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.72);
  margin-top: 1.25rem;
  margin-bottom: 0;
}

.hero-contact a {
  color: rgba(255, 255, 255, 0.82);
  text-decoration: none;
  transition: color 0.2s ease;
}

.hero-contact a:hover {
  color: #fff;
  text-decoration: underline;
}

/* ============================================================
   SECTION BACKGROUNDS
   ============================================================ */
.section-white {
  background-color: var(--bg-white);
  padding: var(--section-py) 0;
}

.section-light {
  background-color: var(--primary-light);
  padding: var(--section-py) 0;
}

.section-gray {
  background-color: var(--bg-gray);
  padding: var(--section-py) 0;
}

/* ============================================================
   SECTION TITLES
   ============================================================ */
.section-title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 0.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 3px solid var(--primary);
  display: inline-block;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
  margin-top: 0.5rem;
}

/* ============================================================
   CARDS (shared base)
   ============================================================ */
.workshop-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 1.5rem;
  height: 100%;
  box-shadow: var(--card-shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

/* ============================================================
   PERSON CARDS (speakers, organizers)
   ============================================================ */
.person-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 1.5rem 1rem;
  text-align: center;
  height: 100%;
  box-shadow: var(--card-shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  /* Flex column so the links row can be pinned to the bottom,
     keeping Scholar/Homepage buttons aligned across all cards. */
  display: flex;
  flex-direction: column;
}

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

/* Circular photo */
.person-photo {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--primary-light);
  margin: 0 auto 1rem;
  display: block;
}

/* CSS placeholder avatar (for organizers/speakers without photos) */
.person-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.6rem;
  color: #fff;
  border: 3px solid rgba(255, 255, 255, 0.4);
  flex-shrink: 0;
}

/* Avatar color palette */
.avatar-blue   { background-color: #3465A4; }
.avatar-teal   { background-color: #0d7377; }
.avatar-green  { background-color: #2d6a4f; }
.avatar-purple { background-color: #5e3a8c; }
.avatar-red    { background-color: #9b2335; }
.avatar-orange { background-color: #b5451b; }
.avatar-gray   { background-color: #6c757d; }

.person-name {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
  margin-bottom: 0.2rem;
}

.person-affil {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 0.2rem;
}

.person-role {
  font-size: 0.8rem;
  color: var(--primary);
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.person-bio {
  font-size: 0.875rem;
  color: var(--text);
  text-align: left;
  line-height: 1.6;
  /* Grow to fill remaining height so the links row is pushed to the
     bottom of the card, keeping buttons aligned across all cards. */
  flex: 1 0 auto;
}

.person-links {
  /* margin-top:auto pins this row to the bottom of the flex column,
     so Scholar/Homepage buttons align across cards of differing height. */
  margin-top: auto;
  padding-top: 0.75rem;
  display: flex;
  justify-content: center;
  gap: 0.75rem;
}

.person-links a {
  color: var(--text-muted);
  font-size: 1.1rem;
  transition: color 0.2s ease;
}

.person-links a:hover {
  color: var(--primary);
  text-decoration: none;
}

/* ============================================================
   TOPIC CARDS
   ============================================================ */
.topic-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 1.25rem 1.25rem 1.25rem 1rem;
  height: 100%;
  box-shadow: var(--card-shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  border-left: 4px solid var(--primary);
}

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

.topic-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.8rem;
  margin-bottom: 0.6rem;
  flex-shrink: 0;
}

.topic-title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text);
  margin-bottom: 0.4rem;
}

.topic-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 0;
}

/* ============================================================
   SCHEDULE TABLE
   ============================================================ */
.schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.schedule-table th {
  background-color: var(--primary);
  color: #fff;
  font-family: var(--font-heading);
  font-weight: 600;
  padding: 0.6rem 0.75rem;
  text-align: left;
}

.schedule-table td {
  padding: 0.55rem 0.75rem;
  vertical-align: top;
  border-bottom: 1px solid var(--border-color);
}

.schedule-table .time-col {
  white-space: nowrap;
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--primary);
  width: 110px;
}

/* Row type color coding */
.row-talk    { background-color: #eef3fb; }           /* blue  — invited talks & debate panel */
.row-poster  { background-color: #e8f4f8; }           /* teal  — poster sessions */
.row-special { background-color: #edf7f0; }           /* green — contributed spotlight */
.row-debate  { background-color: #fdf8e8; }           /* yellow — best paper award */
.row-neutral { background-color: #f8f9fa; color: var(--text-muted); }  /* gray — opening/closing/lunch (not in legend) */

/* ============================================================
   TIMELINE (Call for Papers dates)
   ============================================================ */
.timeline {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  position: relative;
  margin: 2rem 0 3rem;
  padding: 0 1rem;
}

.timeline::before {
  content: '';
  position: absolute;
  top: 20px;
  left: 2rem;
  right: 2rem;
  height: 3px;
  background: var(--primary-light);
  z-index: 0;
}

.timeline-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  flex: 1;
  position: relative;
  z-index: 1;
}

.timeline-dot {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.75rem;
  margin-bottom: 0.5rem;
  border: 3px solid var(--bg-white);
  box-shadow: 0 0 0 3px var(--primary);
}

.timeline-date {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--primary);
  margin-bottom: 0.2rem;
}

.timeline-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  max-width: 90px;
  line-height: 1.3;
}

/* Mobile: vertical timeline */
@media (max-width: 767px) {
  .timeline {
    flex-direction: column;
    align-items: flex-start;
    padding: 0 0 0 2rem;
  }
  .timeline::before {
    top: 0;
    bottom: 0;
    left: 20px;
    right: auto;
    width: 3px;
    height: auto;
  }
  .timeline-item {
    flex-direction: row;
    align-items: flex-start;
    text-align: left;
    margin-bottom: 1.5rem;
    gap: 1rem;
  }
  .timeline-dot {
    flex-shrink: 0;
    margin-bottom: 0;
  }
  .timeline-label {
    max-width: none;
  }
}

/* ============================================================
   NEWS SECTION
   ============================================================ */
.news-list {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0 0;
}

.news-item {
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--border-color);
}

.news-item:last-child {
  border-bottom: none;
}

.news-date {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.82rem;
  color: var(--primary);
  white-space: nowrap;
  min-width: 90px;
  flex-shrink: 0;
}

.news-text {
  font-size: 0.95rem;
  color: var(--text);
  line-height: 1.6;
}

.news-text a {
  color: var(--primary);
  font-weight: 600;
}

/* ============================================================
   PROGRAM COMMITTEE GRID
   ============================================================ */
.pc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.6rem;
  margin-top: 1.5rem;
}

.pc-pill {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.5rem 0.75rem;
  font-size: 0.9rem;
  transition: all 0.2s ease;
}

.pc-pill:hover {
  background: var(--primary-light);
  border-color: var(--primary);
  transform: translateY(-1px);
  box-shadow: 0 2px 6px rgba(52, 101, 164, 0.12);
}

.pc-pill .pc-name {
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--text);
  display: block;
  font-size: 0.9rem;
}

.pc-pill .pc-affil {
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* ============================================================
   CALLOUT BOXES
   ============================================================ */
.callout {
  border-left: 4px solid var(--primary);
  background: var(--primary-light);
  border-radius: 0 8px 8px 0;
  padding: 1rem 1.25rem;
  margin-bottom: 1rem;
}

.callout-green {
  border-left-color: var(--confirmed);
  background: #edf7f0;
}

.callout-yellow {
  border-left-color: var(--pending);
  background: #fdf8e8;
}

.callout-title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--primary);
  margin-bottom: 0.3rem;
}

.callout-green .callout-title { color: var(--confirmed); }
.callout-yellow .callout-title { color: var(--pending); }

/* ============================================================
   FOOTER
   ============================================================ */
#footer {
  background-color: var(--primary-dark);
  color: rgba(255, 255, 255, 0.85);
  padding: 2.5rem 0;
  font-size: 0.9rem;
}

#footer a {
  color: rgba(255, 255, 255, 0.75);
  transition: color 0.2s ease;
}

#footer a:hover {
  color: #fff;
  text-decoration: none;
}

#footer .footer-title {
  font-family: var(--font-heading);
  font-weight: 700;
  color: #fff;
  margin-bottom: 0.5rem;
  font-size: 0.95rem;
}

/* ============================================================
   UTILITY CLASSES
   ============================================================ */
.text-primary-custom { color: var(--primary) !important; }
.bg-primary-custom   { background-color: var(--primary) !important; }

.badge-confirmed {
  background-color: var(--confirmed);
  color: #fff;
  font-size: 0.75rem;
  padding: 0.25em 0.6em;
  border-radius: 4px;
  font-family: var(--font-heading);
  font-weight: 600;
}

.badge-pending {
  background-color: var(--pending);
  color: #fff;
  font-size: 0.75rem;
  padding: 0.25em 0.6em;
  border-radius: 4px;
  font-family: var(--font-heading);
  font-weight: 600;
}

/* Scroll margin for fixed navbar offset */
section[id] {
  scroll-margin-top: calc(var(--navbar-height) + 1rem);
}

/* ============================================================
   RESPONSIVE ADJUSTMENTS
   ============================================================ */
@media (max-width: 991px) {
  :root {
    --section-py: 2.5rem;
  }
  /* Drop the open menu below the fixed navbar as an absolute overlay */
  #navbar .navbar-collapse {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--primary-dark);
    padding: 0.75rem 1rem;
    border-radius: 0 0 8px 8px;
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.35);
    z-index: 1029;
  }
  #navbar .navbar-collapse .nav-link {
    padding: 0.55rem 0.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }
  #navbar .navbar-collapse .nav-link:last-child {
    border-bottom: none;
  }
}

@media (max-width: 767px) {
  :root {
    --section-py: 2rem;
  }
  #hero {
    min-height: 420px;
  }
  .hero-content {
    padding: 3rem 1rem;
  }
}

@media (max-width: 575px) {
  #navbar .navbar-brand {
    font-size: 0.82rem;
  }
}