/* ============================================
   Theme Variables
   ============================================ */
:root {
  --bg: #0a0a0f;
  --bg-alt: #12121c;
  --surface: #111118;
  --surface-hover: #16161f;
  --sidebar-bg: #0d0d14;
  --border: #1a1a25;
  --text: #e0e0e8;
  --text-secondary: #888;
  --accent: #6366f1;
  --accent-light: #8b5cf6;
  --radius: 12px;
  --sidebar-width: 240px;
}

/* ============================================
   Reset & Base
   ============================================ */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
}

/* ============================================
   Floating Sidebar Navigation
   ============================================ */
.sidebar {
  position: fixed;
  top: 20px;
  right: 20px;
  width: auto;
  background: var(--sidebar-bg);
  border: 1px solid var(--border);
  border-radius: 14px;
  display: flex;
  flex-direction: column;
  z-index: 100;
  padding: 16px 8px;
  backdrop-filter: blur(12px);
  background: rgba(13, 13, 20, 0.9);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.sidebar-header {
  padding: 0 8px 12px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}

.sidebar-logo {
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  white-space: nowrap;
}

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 7px 12px 7px 10px;
  border-radius: 8px;
  font-size: 12px;
  color: var(--text-secondary);
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s ease;
  border-left: 2px solid transparent;
  white-space: nowrap;
}

.nav-item:hover {
  color: var(--text);
  background: rgba(99, 102, 241, 0.08);
}

.nav-item.active {
  color: var(--accent);
  background: rgba(99, 102, 241, 0.12);
  border-left-color: var(--accent);
}

.nav-number {
  font-size: 10px;
  font-weight: 600;
  min-width: 14px;
  text-align: center;
}

/* ============================================
   Mobile Sidebar Toggle
   ============================================ */
.sidebar-toggle {
  display: none;
  position: fixed;
  top: 16px;
  left: 16px;
  z-index: 200;
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 20px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

/* ============================================
   Main Content
   ============================================ */
.main {
  margin-left: 0;
  min-height: 100vh;
  overflow: hidden;
}

.main-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 48px;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  text-align: center;
  padding: 60px 0 80px;
  margin-bottom: 0;
  position: relative;
}

.hero-bg-wrap {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100vw;
  height: 100%;
  overflow: hidden;
  z-index: 1;
  display: flex;
  flex-direction: row;
  gap: 0;
}

.hero-bg-video {
  flex: 1 1 50%;
  width: 50%;
  height: 100%;
  object-fit: cover;
  opacity: 0.15;
  pointer-events: none;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100vw;
  height: 100%;
  z-index: 0;
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100vw;
  height: 100%;
  z-index: 2;
  background: radial-gradient(ellipse 60% 50% at 50% 0%, rgba(99, 102, 241, 0.10) 0%, transparent 100%);
  pointer-events: none;
}

.hero > *:not(.hero-bg-wrap) {
  position: relative;
  z-index: 3;
}

.hero-title {
  font-size: 32px;
  font-weight: 700;
  color: #fff;
  line-height: 1.3;
  margin: 0 0 16px;
}

.hero-title-highlight {
  font-size: 38px;
  background: linear-gradient(135deg, #818cf8, #c084fc);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-authors {
  max-width: 900px;
  margin: 0 auto 32px;
  text-align: center;
}

.authors-list {
  font-size: 17px;
  color: #e7e7ef;
  line-height: 1.9;
  margin: 0 0 8px;
  font-weight: 500;
}

.authors-list .author {
  white-space: nowrap;
  margin: 0 2px;
}

.authors-list sup,
.authors-affiliations sup,
.authors-notes sup {
  background: linear-gradient(135deg, #818cf8, #c084fc);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-weight: 700;
  font-size: 0.72em;
}

.authors-affiliations {
  font-size: 14px;
  color: var(--text-secondary);
  margin: 0 0 6px;
  line-height: 1.6;
}

.authors-notes {
  font-size: 13px;
  color: #7a7a86;
  margin: 0 0 16px;
  line-height: 1.6;
}

.authors-notes a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.2s ease;
}

.authors-notes a:hover {
  color: #c084fc;
}

.hero-links {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin: 6px 0 30px;
  flex-wrap: wrap;
}

.hero-link-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-primary, #e8e8ea);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.3px;
  text-decoration: none;
  transition: all 0.2s ease;
  backdrop-filter: blur(8px);
}

.hero-link-btn:hover {
  background: rgba(192, 132, 252, 0.15);
  border-color: rgba(192, 132, 252, 0.5);
  color: #fff;
  transform: translateY(-1px);
}

.hero-link-btn svg {
  flex-shrink: 0;
}

.bibtex-wrap {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
}

.bibtex-block {
  background: rgba(12, 12, 16, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
  padding: 22px 26px;
  font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-secondary, #c9c9d0);
  overflow-x: auto;
  white-space: pre;
  margin: 0;
}

.bibtex-copy {
  position: absolute;
  top: 12px;
  right: 12px;
  padding: 6px 14px;
  font-size: 12px;
  font-weight: 500;
  border-radius: 6px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-secondary, #c9c9d0);
  cursor: pointer;
  transition: all 0.2s ease;
}

.bibtex-copy:hover {
  background: rgba(192, 132, 252, 0.2);
  color: #fff;
  border-color: rgba(192, 132, 252, 0.5);
}

.bibtex-copy.copied {
  background: rgba(74, 222, 128, 0.2);
  color: #86efac;
  border-color: rgba(74, 222, 128, 0.5);
}

.hero-abstract {
  max-width: 860px;
  margin: 0 auto;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.8;
  text-align: left;
}

.hero-abstract-label {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 14px;
  text-align: center;
}

/* ============================================
   Section Headings
   ============================================ */
.section {
  padding: 60px 0;
  margin-bottom: 0;
  position: relative;
}

.section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100vw;
  height: 100%;
  z-index: -1;
  border-bottom: 1px solid var(--border);
}

.section:nth-child(even)::before {
  background: var(--bg-alt);
}

.section:last-child::before {
  border-bottom: none;
}

.section-heading {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 32px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

.section-emoji {
  font-size: 22px;
  flex-shrink: 0;
  line-height: 1;
}

.section-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  color: #fff;
  font-size: 14px;
  font-weight: 700;
  flex-shrink: 0;
}

.section-title {
  font-size: 22px;
  font-weight: 600;
  color: #fff;
}

.subsection-title {
  font-size: 16px;
  font-weight: 500;
  color: var(--text-secondary);
  margin: 24px 0 16px;
}

/* ============================================
   Video Grid
   ============================================ */
.video-grid {
  display: grid;
  gap: 16px;
}

.video-grid.portrait {
  grid-template-columns: repeat(5, 1fr);
}

.video-grid.landscape-2col {
  grid-template-columns: repeat(2, 1fr);
}

/* Section 2.2 — portrait videos in a flex row with 5 per line. Flexbox
   (not grid) is used so the orphan videos in the last line stay centered. */
.styles-portrait-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  margin-bottom: 18px;
}

.styles-portrait-row .video-card {
  flex: 0 0 calc((100% - 56px) / 5);
  max-width: calc((100% - 56px) / 5);
}

/* Section 2.2 — near-square + landscape videos share one row at the same
   height. Each card's flex-grow equals its width/height ratio (set inline
   via --ratio), and aspect-ratio is set to the same number. Given width ∝
   ratio and width/height = ratio, every card ends up with identical height
   no matter how wide the container is, so no media-query tuning is needed. */
.styles-wide-row {
  display: flex;
  align-items: stretch;
  gap: 14px;
}

.styles-wide-row .video-card {
  flex: var(--ratio) 1 0;
  min-width: 0;
  aspect-ratio: var(--ratio);
}

.styles-wide-row .video-card video {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
}

/* ============================================
   Video Card
   ============================================ */
.video-card {
  position: relative;
  background: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.video-card:hover {
  transform: scale(1.02);
  border-color: rgba(99, 102, 241, 0.3);
}

.video-card video {
  width: 100%;
  display: block;
  cursor: pointer;
}

.video-card .play-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.3);
  opacity: 0;
  transition: opacity 0.2s ease;
  cursor: pointer;
  pointer-events: none;
}

.video-card:hover .play-overlay,
.video-card .play-overlay.visible {
  opacity: 1;
}

.play-btn {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(99, 102, 241, 0.85);
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(4px);
}

.play-btn::after {
  content: '';
  width: 0;
  height: 0;
  border-left: 14px solid #fff;
  border-top: 9px solid transparent;
  border-bottom: 9px solid transparent;
  margin-left: 3px;
}

.video-card.playing .play-btn::after {
  border-left: 5px solid #fff;
  border-right: 5px solid #fff;
  border-top: none;
  border-bottom: none;
  width: 14px;
  height: 16px;
  margin-left: 0;
}

.video-caption {
  padding: 10px 12px;
  font-size: 12px;
  color: var(--text-secondary);
}

/* ============================================
   Featured Video (full-width)
   ============================================ */
.video-featured {
  margin-bottom: 20px;
}

.video-featured .video-card {
  max-width: 100%;
}

/* ============================================
   Single Large Video (Section 3)
   ============================================ */
.video-single {
  max-width: 800px;
  margin: 0 auto;
}

/* Two long-form videos displayed side-by-side (Section 3) */
.longform-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}

.section-description {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 20px;
  line-height: 1.7;
}

.duration-badge {
  position: absolute;
  bottom: 12px;
  right: 12px;
  background: rgba(0, 0, 0, 0.75);
  color: #fff;
  font-size: 11px;
  padding: 3px 8px;
  border-radius: 4px;
  backdrop-filter: blur(4px);
}

/* ============================================
   Placeholder Section (Sections 4 & 6)
   ============================================ */
.placeholder-box {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 60px 40px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 14px;
}

/* ============================================
   Comparison Row (Section 5)
   ============================================ */
.comparison-group {
  margin-bottom: 40px;
  text-align: center;
}

.comparison-group-label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 12px;
  text-align: center;
}

.sync-play-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  border: none;
  border-radius: 8px;
  color: #fff;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  margin-bottom: 16px;
  box-shadow: 0 2px 12px rgba(99, 102, 241, 0.4);
}

.sync-play-btn:hover {
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.6);
  transform: translateY(-1px);
}

.comparison-row {
  display: grid;
  gap: 12px;
}

.comparison-row.cols-3 {
  grid-template-columns: repeat(3, 1fr);
}

.comparison-row.cols-6 {
  grid-template-columns: repeat(6, 1fr);
}

/* Fluid comparison row — all cards in one row at equal video height, with
   widths proportional to each clip's native aspect ratio. Works because
   flex-grow ∝ ratio and aspect-ratio is the same ratio, so video height is
   constant across cards (= row_width / Σratio). Used by Section 4. */
.comparison-row.fluid {
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.comparison-row.fluid .comparison-card {
  flex: var(--ratio) 1 0;
  min-width: 0;
}

.comparison-row.fluid .comparison-card video {
  aspect-ratio: var(--ratio);
  height: auto;
  width: 100%;
  object-fit: cover;
}

.comparison-card {
  position: relative;
  background: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}

.comparison-card video {
  width: 100%;
  display: block;
  cursor: pointer;
}

.model-label {
  padding: 8px 12px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  text-align: center;
  border-top: 1px solid var(--border);
}

.model-label.ours {
  color: var(--accent);
}

/* Highlight the Ours comparison card so visitors can spot our method instantly. */
.comparison-card.ours {
  border: 1px solid rgba(129, 140, 248, 0.55);
  box-shadow: 0 0 0 1px rgba(129, 140, 248, 0.35), 0 8px 28px rgba(99, 102, 241, 0.18);
}

.comparison-card.ours .model-label.ours {
  background: linear-gradient(180deg, rgba(99, 102, 241, 0.12), rgba(139, 92, 246, 0.12));
  border-top-color: rgba(129, 140, 248, 0.4);
}

/* Duration badge sits above the model label so they don't overlap. */
.comparison-card .duration-badge {
  bottom: 44px;
}

/* ============================================
   Dataset Pairs (Section 7)
   ============================================ */
.dataset-intro {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 24px;
  line-height: 1.7;
}

.pair-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.pair-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.pair-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
}

.pair-id {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}

.pair-play-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 5px 14px;
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  border: none;
  border-radius: 6px;
  color: #fff;
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: 0 2px 10px rgba(99, 102, 241, 0.4);
}

.pair-play-btn:hover {
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.6);
  transform: translateY(-1px);
}

.pair-videos {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
}

.pair-videos .pair-video-wrap {
  background: var(--bg);
  position: relative;
}

.pair-videos video {
  width: 100%;
  display: block;
  cursor: pointer;
}

.pair-person-label {
  position: absolute;
  top: 8px;
  left: 8px;
  background: rgba(0, 0, 0, 0.7);
  color: #fff;
  font-size: 10px;
  padding: 2px 8px;
  border-radius: 4px;
  backdrop-filter: blur(4px);
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 1024px) {
  .sidebar {
    opacity: 0;
    pointer-events: none;
    transform: translateX(20px);
  }

  .sidebar.open {
    opacity: 1;
    pointer-events: auto;
    transform: translateX(0);
  }

  .sidebar-toggle {
    display: flex;
  }

  .main-inner {
    padding: 40px 24px;
  }

  .video-grid.portrait {
    grid-template-columns: repeat(4, 1fr);
  }

  .styles-portrait-row .video-card {
    flex: 0 0 calc((100% - 42px) / 4);
    max-width: calc((100% - 42px) / 4);
  }

  .comparison-row.cols-6 {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 24px;
  }

  .authors-list {
    font-size: 14px;
    line-height: 1.8;
  }

  .authors-affiliations {
    font-size: 12px;
  }

  .authors-notes {
    font-size: 11px;
  }

  .main-inner {
    padding: 24px 16px;
  }

  .video-grid.portrait {
    grid-template-columns: repeat(2, 1fr);
  }

  .styles-portrait-row .video-card {
    flex: 0 0 calc((100% - 14px) / 2);
    max-width: calc((100% - 14px) / 2);
  }

  /* On narrow screens, wrap the wide row so near-square and landscape pairs
     stack as two rows — row heights still differ, but that's fine once we're
     below a phablet width where fitting 4 clips across is impractical. */
  .styles-wide-row {
    flex-wrap: wrap;
  }

  .styles-wide-row .video-card {
    flex: 1 1 calc(50% - 7px);
    max-width: calc(50% - 7px);
  }

  .longform-grid {
    grid-template-columns: 1fr;
  }

  .video-grid.landscape-2col {
    grid-template-columns: 1fr;
  }

  .comparison-row.cols-3 {
    grid-template-columns: repeat(2, 1fr);
  }

  .comparison-row.cols-6 {
    grid-template-columns: repeat(2, 1fr);
  }

  /* On narrow screens the fluid row wraps to 2 per line — equal-height
     property is lost, but six clips would be unreadable across a phone. */
  .comparison-row.fluid {
    flex-wrap: wrap;
  }

  .comparison-row.fluid .comparison-card {
    flex: 1 1 calc(50% - 6px);
    max-width: calc(50% - 6px);
  }

  .pair-grid {
    grid-template-columns: 1fr;
  }
}