/* Modern Clean White Background Design System for The Low-Frequency Trap */
@import url('https://fonts.googleapis.com/css2?family=Fira+Code:wght@400;500;600&family=Inter:wght@300;400;500;600;700;800&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-card: #ffffff;
  --bg-card-subtle: #f1f5f9;
  
  --border-color: #e2e8f0;
  --border-hover: #cbd5e1;
  
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-dim: #64748b;
  
  --accent-blue: #2563eb;
  --accent-blue-hover: #1d4ed8;
  --accent-arxiv: #b31b1b;
  --accent-arxiv-hover: #8f1515;
  --accent-github: #24292e;
  --accent-github-hover: #1b1f23;
  --accent-hf: #fff7ed;
  --accent-hf-border: #fed7aa;
  
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 16px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 10px 30px rgba(15, 23, 42, 0.08);
  
  --radius-lg: 16px;
  --radius-md: 12px;
  --radius-sm: 8px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  padding-bottom: 60px;
}

.container {
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
  padding: 60px 0 40px;
  text-align: center;
}

.hero .container {
  max-width: 1280px;
}

.hero h1 {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: clamp(2.1rem, 3.5vw, 3.1rem);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.025em;
  color: #0f172a;
  max-width: 1250px;
  margin: 0 auto 20px;
}

.hero-subtitle {
  font-size: clamp(1.1rem, 2vw, 1.3rem);
  color: #475569;
  max-width: 820px;
  margin: 0 auto 32px;
  font-weight: 400;
  line-height: 1.55;
}

.authors {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 18px;
  max-width: 900px;
  margin: 0 auto 12px;
  font-size: 1.05rem;
}

.author {
  color: #1e293b;
  font-weight: 600;
  text-decoration: none;
  transition: color 0.2s ease;
}

.author:hover {
  color: var(--accent-blue);
}

.author sup {
  color: #ea580c;
  font-weight: 700;
  margin-left: 2px;
}

.affiliations {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 12px;
  color: var(--text-dim);
  font-size: 0.95rem;
  margin-bottom: 8px;
}

.affiliations i {
  display: inline-block;
  width: 4px;
  height: 4px;
  background: var(--text-dim);
  border-radius: 50%;
}

.equal-contrib {
  color: var(--text-dim);
  font-size: 0.85rem;
  margin-bottom: 32px;
}

/* Button Group */
.btn-group {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.92rem;
  text-decoration: none;
  transition: all 0.2s ease;
  border: 1px solid var(--border-color);
  background: #ffffff;
  color: var(--text-main);
  box-shadow: var(--shadow-sm);
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

/* arXiv Button Branding */
.btn-arxiv {
  background: var(--accent-arxiv);
  border-color: var(--accent-arxiv);
  color: #ffffff;
}

.btn-arxiv:hover {
  background: var(--accent-arxiv-hover);
  border-color: var(--accent-arxiv-hover);
  color: #ffffff;
}

/* GitHub Button Branding */
.btn-github {
  background: var(--accent-github);
  border-color: var(--accent-github);
  color: #ffffff;
}

.btn-github:hover {
  background: var(--accent-github-hover);
  border-color: var(--accent-github-hover);
  color: #ffffff;
}

.btn svg {
  flex-shrink: 0;
}

.badge-tag {
  font-size: 0.72rem;
  padding: 2px 6px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.2);
  color: #ffffff;
  font-family: 'Fira Code', monospace;
}

.btn-outline .badge-tag {
  background: #f1f5f9;
  color: var(--text-dim);
}

/* ==========================================================================
   Sticky Navigation Bar
   ========================================================================== */
.sticky-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  padding: 10px 0;
  margin-bottom: 40px;
  box-shadow: var(--shadow-sm);
}

.nav-container {
  display: flex;
  justify-content: center;
  gap: 20px;
  overflow-x: auto;
  white-space: nowrap;
  padding: 0 16px;
}

.nav-link {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  padding: 6px 14px;
  border-radius: 6px;
  transition: all 0.2s ease;
}

.nav-link:hover {
  color: var(--text-main);
  background: #f1f5f9;
}

.nav-link.active {
  color: var(--accent-blue);
  background: #eff6ff;
  font-weight: 600;
}

/* ==========================================================================
   Section & Card Layout
   ========================================================================== */
.section {
  margin-bottom: 48px;
}

.section-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1.7rem;
  font-weight: 700;
  margin-bottom: 18px;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 10px;
}

.section-title::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 22px;
  background: var(--accent-blue);
  border-radius: 4px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-md);
}

.figure-card {
  text-align: center;
  padding: 24px;
}

.figure-img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  margin-bottom: 16px;
  background: #ffffff;
}

.caption {
  text-align: left;
  font-size: 0.94rem;
  line-height: 1.6;
  color: var(--text-muted);
}

.caption strong {
  color: var(--text-main);
}

/* ==========================================================================
   Metrics Grid
   ========================================================================== */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.metric-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  text-align: left;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.metric-card:hover {
  transform: translateY(-2px);
  border-color: var(--border-hover);
}

.metric-val {
  font-family: 'Outfit', sans-serif;
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1;
  color: var(--accent-blue);
  margin-bottom: 6px;
}

.metric-card.alert .metric-val {
  color: #dc2626;
}

.metric-label {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 4px;
}

.metric-desc {
  font-size: 0.85rem;
  color: var(--text-dim);
  line-height: 1.45;
}

/* ==========================================================================
   BibTeX Section
   ========================================================================== */
.bibtex-wrapper {
  position: relative;
  background: #0f172a;
  border: 1px solid #1e293b;
  border-radius: var(--radius-md);
  padding: 20px;
  font-family: 'Fira Code', monospace;
  font-size: 0.88rem;
  color: #f1f5f9;
  overflow-x: auto;
  line-height: 1.65;
}

.copy-btn {
  position: absolute;
  top: 14px;
  right: 14px;
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #ffffff;
  padding: 6px 12px;
  border-radius: 6px;
  font-family: 'Inter', sans-serif;
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.copy-btn:hover {
  background: rgba(255, 255, 255, 0.25);
}

/* Footer */
footer {
  border-top: 1px solid var(--border-color);
  padding-top: 28px;
  margin-top: 50px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.88rem;
}

/* Model Heatmap Badges */
.heatmap-header {
  display: flex;
  align-items: center;
  margin-bottom: 8px;
  text-align: left;
}

.model-badge {
  font-size: 0.9rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 6px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: 'Inter', sans-serif;
}

.gemini-badge {
  background: #eff6ff;
  color: #1d4ed8;
  border: 1px solid #bfdbfe;
}

.qwen-badge {
  background: #f0fdf4;
  color: #15803d;
  border: 1px solid #bbf7d0;
}

/* Responsive */
@media (max-width: 768px) {
  .hero {
    padding: 40px 0 25px;
  }
  .hero h1 {
    font-size: 2rem;
  }
  .card {
    padding: 18px;
  }
  .metrics-grid {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   Qualitative Examples & Interactive Video Explorer (Reference Design)
   ========================================================================== */
.qual-viewer-card {
  padding: 28px !important;
  background: #ffffff !important;
  border: 1px solid var(--border-color) !important;
  border-radius: var(--radius-lg) !important;
  box-shadow: var(--shadow-md) !important;
  margin-top: 20px !important;
}

.qual-viewer-header {
  display: flex !important;
  flex-wrap: wrap !important;
  align-items: center !important;
  justify-content: space-between !important;
  gap: 16px !important;
  padding-bottom: 16px !important;
  border-bottom: 1px solid var(--border-color) !important;
  margin-bottom: 20px !important;
}

.qual-title-group {
  display: flex !important;
  align-items: center !important;
  gap: 12px !important;
}

.video-icon {
  font-size: 1.4rem !important;
}

.qual-category-title {
  font-size: 1.15rem !important;
  font-weight: 700 !important;
  color: var(--text-main) !important;
  margin: 0 !important;
}

.qual-domain-tag {
  font-size: 0.85rem !important;
  font-weight: 600 !important;
  background: #f1f5f9 !important;
  color: #475569 !important;
  padding: 4px 10px !important;
  border-radius: 6px !important;
  border: 1px solid #cbd5e1 !important;
}

.qual-nav-controls {
  display: flex !important;
  align-items: center !important;
  gap: 10px !important;
}

.qual-nav-btn {
  background: #ffffff !important;
  border: 1px solid var(--border-color) !important;
  color: var(--text-main) !important;
  padding: 6px 14px !important;
  border-radius: 20px !important;
  font-size: 0.88rem !important;
  font-weight: 600 !important;
  cursor: pointer !important;
  transition: all 0.2s ease !important;
  display: inline-block !important;
}

.qual-nav-btn:hover {
  background: var(--accent-blue) !important;
  color: #ffffff !important;
  border-color: var(--accent-blue) !important;
}

.qual-counter-badge {
  font-size: 0.88rem !important;
  font-weight: 600 !important;
  color: var(--text-muted) !important;
  padding: 4px 12px !important;
  background: var(--bg-card-subtle) !important;
  border-radius: 12px !important;
}

/* Category Filter Pills */
.qual-category-pills {
  display: flex !important;
  flex-wrap: wrap !important;
  gap: 8px !important;
  margin-bottom: 24px !important;
}

.qual-pill {
  background: var(--bg-card-subtle) !important;
  border: 1px solid var(--border-color) !important;
  color: var(--text-muted) !important;
  padding: 6px 14px !important;
  border-radius: 20px !important;
  font-size: 0.85rem !important;
  font-weight: 600 !important;
  cursor: pointer !important;
  transition: all 0.2s ease !important;
  display: inline-block !important;
}

.qual-pill:hover {
  background: #e2e8f0 !important;
  color: var(--text-main) !important;
}

.qual-pill.active {
  background: var(--text-main) !important;
  color: #ffffff !important;
  border-color: var(--text-main) !important;
}

/* Video Player Container */
.qual-video-container {
  position: relative !important;
  width: 100% !important;
  max-width: 820px !important;
  margin: 0 auto 24px !important;
  border-radius: var(--radius-md) !important;
  overflow: hidden !important;
  box-shadow: var(--shadow-sm) !important;
  border: 1px solid var(--border-color) !important;
  background: #0f172a !important;
}

.video-speed-badge {
  position: absolute !important;
  top: 12px !important;
  left: 12px !important;
  z-index: 10 !important;
  background: rgba(15, 23, 42, 0.75) !important;
  backdrop-filter: blur(4px) !important;
  color: #ffffff !important;
  font-size: 0.78rem !important;
  font-weight: 700 !important;
  padding: 3px 8px !important;
  border-radius: 4px !important;
}

.qual-video-element {
  width: 100% !important;
  aspect-ratio: 16 / 9 !important;
  display: block !important;
  object-fit: cover !important;
}

/* Cards / Boxes Styling */
.qual-info-box {
  border-radius: var(--radius-md) !important;
  padding: 18px 22px !important;
  margin-bottom: 18px !important;
  text-align: left !important;
}

.box-label {
  font-size: 0.75rem !important;
  font-weight: 800 !important;
  letter-spacing: 0.08em !important;
  text-transform: uppercase !important;
  margin-bottom: 8px !important;
}

.box-content {
  font-size: 0.95rem !important;
  color: var(--text-main) !important;
  line-height: 1.5 !important;
}

/* Prompt Box */
.prompt-box {
  background: #f0f9ff !important;
  border: 1px solid #bae6fd !important;
}
.prompt-box .box-label {
  color: #0369a1 !important;
}

/* Ground Truth Box */
.gt-box {
  background: #fffbeb !important;
  border: 1px solid #fde68a !important;
}
.gt-box .box-label {
  color: #b45309 !important;
}

.box-header {
  display: flex !important;
  flex-wrap: wrap !important;
  align-items: center !important;
  justify-content: space-between !important;
  gap: 12px !important;
  margin-bottom: 10px !important;
}

.gt-count-badge {
  font-size: 0.82rem !important;
  font-weight: 700 !important;
  background: #fef3c7 !important;
  color: #92400e !important;
  padding: 3px 10px !important;
  border-radius: 6px !important;
  border: 1px solid #fcd34d !important;
}

.gt-timestamps-bar {
  font-size: 0.88rem !important;
  color: #78350f !important;
  margin-bottom: 10px !important;
}
.gt-timestamps-bar code {
  font-family: 'Fira Code', monospace !important;
  background: #fef3c7 !important;
  padding: 2px 6px !important;
  border-radius: 4px !important;
}

.code-block {
  font-family: 'Fira Code', monospace !important;
  font-size: 0.86rem !important;
  background: rgba(255, 255, 255, 0.85) !important;
  padding: 14px !important;
  border-radius: 8px !important;
  border: 1px solid rgba(0,0,0,0.08) !important;
  white-space: pre-wrap !important;
  word-break: break-word !important;
  color: #1e293b !important;
}

/* Model Box */
.model-box {
  background: #f8fafc !important;
  border: 1px solid #cbd5e1 !important;
}
.model-box.status-correct {
  background: #f0fdf4 !important;
  border-color: #bbf7d0 !important;
}
.model-box.status-wrong {
  background: #fef2f2 !important;
  border-color: #fecaca !important;
}

.model-label {
  color: #334155 !important;
}

.model-metrics-row {
  display: flex !important;
  flex-wrap: wrap !important;
  gap: 8px !important;
}

.metric-chip {
  font-size: 0.8rem !important;
  font-weight: 700 !important;
  padding: 3px 10px !important;
  border-radius: 12px !important;
  background: #ffffff !important;
  border: 1px solid #cbd5e1 !important;
  color: #334155 !important;
}

.pred-answer-chip {
  font-size: 0.8rem !important;
  font-weight: 800 !important;
  padding: 3px 10px !important;
  border-radius: 12px !important;
  background: #0f172a !important;
  color: #ffffff !important;
}

.sub-label {
  font-size: 0.78rem !important;
  font-weight: 700 !important;
  color: var(--text-dim) !important;
  margin-bottom: 6px !important;
}

/* Justification Box */
.justification-box {
  background: #f1f5f9 !important;
  border: 1px solid #cbd5e1 !important;
}
.justification-label {
  color: #475569 !important;
}