/* ============================================================
   DANES ScHack 2026 — styles.css
   Colour palette extracted from OpenDANES (opendanes.org)
     Source: https://github.com/DigitalPasts/openDANES/_sass/_variables.scss
   Layout inspired by AI4AS 2026 (ai4asconference.github.io)
   ============================================================ */

/* 1. CSS custom properties (values from OpenDANES _variables.scss)
   ---------------------------------------------------------------- */
:root {
  /* Primary — deep purple (nav, footer, accents) */
  --primary:              #52053E;
  --primary-dark:         #330327;
  --primary-light:        #67074e;

  /* Secondary — neutral warm tones */
  --secondary:            #d7ccc8;
  --secondary-dark:       #b6af9d;
  --secondary-light:      #ece7e6;

  /* Fourth — teal (links, Track 1 accent) */
  --teal:                 #05878a;
  --teal-dark:            #074e67;

  /* Contrast — yellow (hover highlights) */
  --contrast:             #feda75;
  --contrast-secondary:   #e3ad5b;
  --contrast-dark:        #9a6b23;

  /* Background */
  --bg:                   #FEFBF1;

  /* Typography */
  --font-main:            'Taviraj', serif;
  --font-code:            'Source Code Pro', monospace;
  --font-size:            18px;
  --font-size-sm:         16px;
  --font-size-xs:         14px;

  /* Track accent colours */
  --track1:               #05878a;   /* teal  — Ancient Language Processing */
  --track2:               #c9543b;   /* terracotta — Computer Vision */
  --track3:               #9a6b23;   /* warm brown — Network Analysis */

  /* Layout */
  --card-radius:          10px;
  --max-content:          1100px;
}

/* 2. Reset & base
   ---------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg);
  font-family: var(--font-main);
  font-size: var(--font-size);
  color: #1a1a1a;
  overflow-x: hidden;
  line-height: 1.7;
}

::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-light); }

/* 3. Typography
   ---------------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-main);
  line-height: 1.3;
}

h1 { font-size: clamp(1.8rem, 4vw, 3rem); }
h2 { font-size: clamp(1.4rem, 2.8vw, 2.2rem); }
h3 { font-size: clamp(1.15rem, 2vw, 1.6rem); }
h4 { font-size: clamp(1rem, 1.7vw, 1.3rem); }

a {
  color: var(--teal);
  text-decoration: none;
  transition: color 0.25s ease;
}
a:hover { color: var(--contrast-dark); }

p { margin-bottom: 1rem; }

ul, ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

li { margin-bottom: 0.35rem; }

strong { font-weight: 700; }
em { font-style: italic; }

/* 4. Navigation
   ---------------------------------------------------------------- */
.site-header {
  background-color: var(--primary);
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  box-shadow: 0 2px 8px rgba(0,0,0,0.35);
}

.nav-inner {
  max-width: var(--max-content);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--bg);
  font-size: 1.15rem;
  font-weight: 700;
  transition: color 0.25s;
  flex-shrink: 0;
}
.nav-brand:hover { color: var(--contrast); }

.nav-brand-logo {
  height: 40px;
  width: auto;
  display: block;
  border-radius: 8px;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 0.25rem;
  margin: 0;
  padding: 0;
}

.nav-links li a {
  display: block;
  padding: 0.45rem 0.85rem;
  color: var(--bg);
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 4px;
  transition: background-color 0.25s, color 0.25s;
  text-decoration: none;
}
.nav-links li a:hover,
.nav-links li a.active {
  background-color: rgba(255,255,255,0.12);
  color: var(--contrast);
}
.nav-links li a.active {
  border-bottom: 2px solid var(--contrast);
}

.nav-toggle-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--bg);
  font-size: 1.8rem;
  line-height: 1;
  padding: 0.25rem;
  transition: color 0.25s;
}
.nav-toggle-btn:hover { color: var(--contrast); }

/* 5. Hero section
   ---------------------------------------------------------------- */
.hero {
  background: linear-gradient(rgba(51,3,39,0.72), rgba(26,3,16,0.82)),
              url('images/hero-bg.jpg') center/cover no-repeat;
  color: var(--bg);
  text-align: center;
  padding: 5rem 1.5rem 4rem;
  position: relative;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 6px;
  background: linear-gradient(90deg, var(--track1), var(--track2), var(--track3));
}

.hero h1 {
  color: var(--bg);
  margin-bottom: 0.6rem;
  text-shadow: 0 2px 8px rgba(0,0,0,0.4);
}

.hero .hero-sub {
  font-size: clamp(1rem, 2.2vw, 1.4rem);
  color: var(--contrast);
  margin-bottom: 1.8rem;
  font-style: italic;
}

.hero-facts {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem 1.5rem;
  margin-bottom: 2.2rem;
  font-size: 0.95rem;
  color: var(--secondary-light);
}

.hero-facts span {
  background: rgba(255,255,255,0.1);
  padding: 0.3rem 0.9rem;
  border-radius: 20px;
  border: 1px solid rgba(255,255,255,0.2);
}

.hero-ctas {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}

/* 6. Buttons
   ---------------------------------------------------------------- */
.btn {
  display: inline-block;
  padding: 0.75rem 1.8rem;
  border-radius: 5px;
  font-family: var(--font-main);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 0.25s, color 0.25s, transform 0.15s;
  text-decoration: none;
  border: 2px solid transparent;
}
.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background-color: var(--teal);
  color: #fff;
  border-color: var(--teal);
}
.btn-primary:hover { background-color: var(--teal-dark); border-color: var(--teal-dark); color: #fff; }

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

.btn-outline {
  background-color: transparent;
  color: var(--teal);
  border-color: var(--teal);
}
.btn-outline:hover { background-color: var(--teal); color: #fff; }

.btn-gold {
  background-color: var(--contrast);
  color: var(--primary-dark);
  border-color: var(--contrast);
  font-weight: 700;
}
.btn-gold:hover {
  background-color: var(--contrast-secondary);
  border-color: var(--contrast-secondary);
  color: var(--primary-dark);
}

/* 7. Section / page layout
   ---------------------------------------------------------------- */
.page-main {
  max-width: var(--max-content);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

.section-block {
  margin-bottom: 3.5rem;
}

.section-block h2 {
  color: var(--primary);
  border-bottom: 2px solid var(--primary-dark);
  padding-bottom: 0.5rem;
  margin-bottom: 1.5rem;
}

.section-block h3 {
  color: var(--primary);
  margin-bottom: 0.75rem;
}

.page-title {
  color: var(--primary);
  text-align: center;
  padding: 2.5rem 1.5rem 0.5rem;
  max-width: var(--max-content);
  margin: 0 auto;
}

.page-title h1 {
  border-bottom: 3px solid var(--primary);
  display: inline-block;
  padding-bottom: 0.4rem;
}

/* 8. Track cards (index.html + tracks.html)
   ---------------------------------------------------------------- */
.tracks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
}

.track-card {
  background: #fff;
  border-radius: var(--card-radius);
  border-top: 5px solid var(--primary);
  padding: 1.5rem;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
  transition: box-shadow 0.25s, transform 0.2s;
}
.track-card:hover {
  box-shadow: 0 6px 24px rgba(0,0,0,0.13);
  transform: translateY(-3px);
}

.track-card.t1 { border-top-color: var(--track1); }
.track-card.t2 { border-top-color: var(--track2); }
.track-card.t3 { border-top-color: var(--track3); }

.track-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.25rem 0.7rem;
  border-radius: 3px;
  margin-bottom: 0.75rem;
  color: #fff;
}
.t1 .track-badge { background-color: var(--track1); }
.t2 .track-badge { background-color: var(--track2); }
.t3 .track-badge { background-color: var(--track3); }

.track-card h3 {
  font-size: 1.1rem;
  margin-bottom: 0.4rem;
}
.t1 .track-card-title, .t1 h3 { color: var(--track1) !important; }
.t2 .track-card-title, .t2 h3 { color: var(--track2) !important; }
.t3 .track-card-title, .t3 h3 { color: var(--track3) !important; }

.track-card .track-focus {
  font-style: italic;
  font-size: var(--font-size-sm);
  color: #555;
  margin-bottom: 0.75rem;
}

.track-card p {
  font-size: var(--font-size-sm);
  color: #333;
  margin-bottom: 1rem;
}

/* Full track sections on tracks.html */
.track-section {
  background: #fff;
  border-radius: var(--card-radius);
  border-left: 6px solid var(--primary);
  padding: 2rem 2rem 1.5rem;
  margin-bottom: 2.5rem;
  box-shadow: 0 2px 12px rgba(0,0,0,0.07);
}
.track-section.t1 { border-left-color: var(--track1); }
.track-section.t2 { border-left-color: var(--track2); }
.track-section.t3 { border-left-color: var(--track3); }

.track-section .track-number {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.3rem;
}
.t1 .track-number { color: var(--track1); }
.t2 .track-number { color: var(--track2); }
.t3 .track-number { color: var(--track3); }

.track-section h2 {
  border: none;
  margin-bottom: 0.3rem;
  padding-bottom: 0;
}
.t1 .track-section h2, .track-section.t1 h2 { color: var(--track1); }
.t2 .track-section h2, .track-section.t2 h2 { color: var(--track2); }
.t3 .track-section h2, .track-section.t3 h2 { color: var(--track3); }

.track-focus-line {
  font-style: italic;
  color: #555;
  margin-bottom: 1.2rem;
  font-size: var(--font-size-sm);
}

.hackathon-callout {
  background: rgba(0,0,0,0.04);
  border-left: 4px solid var(--contrast-secondary);
  border-radius: 0 6px 6px 0;
  padding: 0.85rem 1.2rem;
  margin: 1.2rem 0;
  font-size: var(--font-size-sm);
}
.hackathon-callout strong { color: var(--primary); }

.teachers-mini {
  font-size: var(--font-size-sm);
  color: #444;
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--secondary);
}

.teachers-mini strong { color: var(--primary); }

/* 9. Teacher cards
   ---------------------------------------------------------------- */
.teachers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 1rem;
}

.teacher-card {
  background: #fff;
  border-radius: var(--card-radius);
  padding: 1.25rem 1.4rem;
  box-shadow: 0 2px 10px rgba(0,0,0,0.08);
  border-top: 4px solid var(--secondary);
}
.teacher-card.t1 { border-top-color: var(--track1); }
.teacher-card.t2 { border-top-color: var(--track2); }
.teacher-card.t3 { border-top-color: var(--track3); }

.teacher-card .teacher-name {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--primary);
  margin-bottom: 0.2rem;
}

.teacher-card .teacher-rank {
  font-style: italic;
  font-size: var(--font-size-sm);
  color: #555;
  margin-bottom: 0.2rem;
}

.teacher-card .teacher-affil {
  font-size: var(--font-size-sm);
  color: #333;
  margin-bottom: 0.4rem;
}

.teacher-card .teacher-expertise {
  font-size: var(--font-size-xs);
  color: #666;
  border-top: 1px solid var(--secondary);
  padding-top: 0.5rem;
  margin-top: 0.4rem;
}

/* 10. Schedule table
    ---------------------------------------------------------------- */
.schedule-day {
  margin-bottom: 3rem;
}

.schedule-day h2 {
  color: var(--primary);
  background: var(--bg);
  border-bottom: 2px solid var(--primary);
  padding-bottom: 0.4rem;
  margin-bottom: 1.2rem;
}

.schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
  box-shadow: 0 2px 10px rgba(0,0,0,0.06);
  border-radius: var(--card-radius);
  overflow: hidden;
}

.schedule-table thead th {
  background-color: var(--primary);
  color: var(--bg);
  padding: 0.75rem 1rem;
  text-align: left;
  font-weight: 700;
}
.schedule-table thead th.th-time { width: 130px; }
.schedule-table thead th.th-t1 { color: #a8e6e8; }
.schedule-table thead th.th-t2 { color: #f4b8ab; }
.schedule-table thead th.th-t3 { color: #d4b483; }

.schedule-table tbody tr:nth-child(even) { background-color: rgba(254,251,241,0.7); }
.schedule-table tbody tr:nth-child(odd) { background-color: #fff; }
.schedule-table tbody tr.lunch-row { background-color: var(--secondary-light); }

.schedule-table td {
  padding: 0.85rem 1rem;
  vertical-align: top;
  border-bottom: 1px solid var(--secondary);
}

.schedule-table td.time-cell {
  font-weight: 700;
  color: var(--primary);
  white-space: nowrap;
  font-size: var(--font-size-xs);
}

.schedule-table td.lunch-cell {
  text-align: center;
  font-style: italic;
  color: #666;
  font-size: var(--font-size-sm);
}

.schedule-table tbody tr.evening-row { background-color: rgba(82,5,62,0.06); }
.schedule-table td.evening-cell {
  text-align: center;
  font-style: italic;
  color: #444;
  font-size: var(--font-size-sm);
  font-weight: 500;
}

.session-label {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  margin-bottom: 0.35rem;
  color: #fff;
}
.label-t1 { background-color: var(--track1); }
.label-t2 { background-color: var(--track2); }
.label-t3 { background-color: var(--track3); }

.session-theme {
  font-weight: 700;
  margin-bottom: 0.25rem;
  font-size: 0.9rem;
}

.session-detail {
  font-size: var(--font-size-xs);
  color: #555;
}

.placeholder-cell {
  font-style: italic;
  color: #999;
  font-size: var(--font-size-xs);
}

/* 11. Practical info strip
    ---------------------------------------------------------------- */
.info-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  background: var(--primary);
  color: var(--bg);
  border-radius: var(--card-radius);
  padding: 1.5rem 2rem;
  margin: 2rem 0;
}

.info-strip-item {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.info-strip-item .info-label {
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--contrast);
  font-weight: 700;
}

.info-strip-item .info-value {
  font-size: 1rem;
  font-weight: 600;
}

/* 12. Organisers row
    ---------------------------------------------------------------- */
.organisers-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  padding: 1.5rem 1rem;
  border-top: 1px solid var(--secondary);
  margin-top: 2rem;
}

.org-logo img {
  height: 120px;
  width: auto;
  max-width: min(240px, 80vw);
  object-fit: contain;
  opacity: 0.9;
  transition: opacity 0.2s;
}
.org-logo img:hover { opacity: 1; }
.org-logo-placeholder {
  font-size: var(--font-size-sm);
  color: #888;
  font-style: italic;
}

/* 13. Registration page
    ---------------------------------------------------------------- */
.reg-info {
  background: #fff;
  border-radius: var(--card-radius);
  padding: 1.75rem 2rem;
  margin-bottom: 2rem;
  box-shadow: 0 2px 10px rgba(0,0,0,0.07);
}

.reg-info h2 {
  color: var(--primary);
  border-bottom: 2px solid var(--primary-dark);
  padding-bottom: 0.4rem;
  margin-bottom: 1rem;
}

.reg-info ul { margin-left: 1.5rem; }
.reg-info ul li { margin-bottom: 0.4rem; font-size: var(--font-size-sm); }

.contact-list {
  list-style: none;
  padding: 0;
  margin: 0.75rem 0 0;
}
.contact-list li {
  padding: 0.25rem 0;
  font-size: var(--font-size-sm);
}

.form-wrapper {
  background: #fff;
  border-radius: var(--card-radius);
  padding: 1.5rem;
  box-shadow: 0 2px 10px rgba(0,0,0,0.07);
  overflow: hidden;
}

.form-wrapper iframe {
  display: block;
  width: 100%;
  border: none;
}

/* 14. Footer
    ---------------------------------------------------------------- */
.site-footer {
  background-color: var(--primary);
  color: var(--bg);
  padding: 2rem 1.5rem;
  margin-top: 3rem;
  font-family: var(--font-main);
  font-size: var(--font-size-sm);
}

.footer-inner {
  max-width: var(--max-content);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: space-between;
}

.footer-col h4 {
  color: var(--contrast);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.6rem;
}

.footer-col p, .footer-col address {
  font-style: normal;
  line-height: 1.7;
  color: rgba(254,251,241,0.85);
  font-size: var(--font-size-sm);
  margin-bottom: 0.4rem;
}

.footer-col a {
  color: var(--contrast);
  text-decoration: none;
  transition: color 0.2s;
}
.footer-col a:hover { color: var(--bg); }

.footer-bottom {
  max-width: var(--max-content);
  margin: 1.5rem auto 0;
  padding-top: 1rem;
  border-top: 1px solid rgba(255,255,255,0.15);
  text-align: center;
  font-size: var(--font-size-xs);
  color: rgba(254,251,241,0.6);
}

/* 15. Utilities
    ---------------------------------------------------------------- */
.text-center { text-align: center; }
.text-muted { color: #666; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

.warning-note {
  background: rgba(239,156,3,0.12);
  border-left: 4px solid #ef9c03;
  padding: 0.75rem 1rem;
  border-radius: 0 6px 6px 0;
  font-size: var(--font-size-sm);
  margin: 1rem 0;
}

/* 16. Responsive (≤768px)
    ---------------------------------------------------------------- */
@media (max-width: 768px) {
  .nav-toggle-btn { display: block; }

  .nav-links {
    display: none;
    flex-direction: column;
    width: 100%;
    position: absolute;
    top: 64px;
    left: 0;
    background-color: var(--primary-dark);
    box-shadow: 0 6px 16px rgba(0,0,0,0.4);
    padding: 0.5rem 0 1rem;
  }

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

  .nav-links li a {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    border-radius: 0;
    border-bottom: none;
  }
  .nav-links li a.active {
    border-bottom: none;
    border-left: 4px solid var(--contrast);
  }

  .hero { padding: 3.5rem 1rem 3rem; }

  .info-strip { padding: 1.25rem 1rem; }

  .schedule-table { font-size: var(--font-size-xs); }
  .schedule-table td, .schedule-table th { padding: 0.6rem 0.5rem; }
  .schedule-table thead th.th-time { width: 80px; }

  .track-section { padding: 1.25rem 1.25rem 1rem; }

  .footer-inner { flex-direction: column; gap: 1.5rem; }

  .form-wrapper { padding: 0.75rem; }
}

@media (max-width: 480px) {
  .schedule-table, .schedule-table thead, .schedule-table tbody,
  .schedule-table th, .schedule-table td, .schedule-table tr {
    display: block;
  }
  .schedule-table thead { display: none; }
  .schedule-table tr { margin-bottom: 1rem; border: 1px solid var(--secondary); border-radius: 6px; overflow: hidden; }
  .schedule-table td { border-bottom: 1px solid var(--secondary-light); }
  .schedule-table td.time-cell::before { content: 'Time: '; }

  .teachers-grid { grid-template-columns: 1fr; }
  .tracks-grid { grid-template-columns: 1fr; }

  .org-logo img { height: 80px; }
  .organisers-row { gap: 1rem; }
}