/* ===== Reset & base ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "DM Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 18px;
  line-height: 1.65;
  color: #2d3748;
  background: #f7f8fc;
}

/* ===== Top bar (VILab header) ===== */
.top-bar {
  background: #1a3e6d;
  border-top: 1px solid #343a40;
  padding: 1.5rem 0;
}

.top-bar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.top-bar-brand {
  font-size: 1.25rem;
  font-weight: 600;
  color: #ffc107;
  text-decoration: none;
  transition: opacity 0.2s;
}

.top-bar-brand:hover {
  opacity: 0.9;
}

.top-bar-home {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.1rem;
  color: #e0e0e0;
  text-decoration: none;
  transition: opacity 0.2s;
}

.top-bar-home:hover {
  opacity: 0.9;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ===== Hero / header ===== */
.hero {
  background: linear-gradient(180deg, #fafbfc 0%, #f5f6f8 100%);
  padding: 3.5rem 0 3rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(ellipse 80% 50% at 50% -20%, rgba(255,255,255,0.6) 0%, transparent 50%);
  pointer-events: none;
}

.hero .container { position: relative; z-index: 1; }

.hero .title {
  font-family: "Fraunces", Georgia, serif;
  font-size: clamp(1.5rem, 3.2vw, 2.05rem);
  font-weight: 700;
  color: #1a202c;
  max-width: 900px;
  margin: 0 auto 1rem;
  line-height: 1.35;
  text-shadow: none;
}

.hero .authors {
  font-size: 1.05rem;
  color: #4a5568;
  margin: 0 0 0.25rem;
}

.hero .affiliations {
  font-size: 0.95rem;
  color: #718096;
  margin: 0 0 1.5rem;
}

.hero .notes {
  font-size: 0.8rem;
  color: #718096;
}

.hero .corresponding-icon {
  font-size: 0.65em;
  margin-left: 0.15rem;
  vertical-align: super;
  opacity: 0.9;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.65rem 1.35rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: all 0.25s ease;
  border: 2px solid transparent;
}

.btn-primary {
  background: #1e3a5f;
  color: #fff;
  border-color: #1e3a5f;
}

.btn-primary:hover {
  background: #2d4a6f;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

/* ===== Main content ===== */
.content {
  background: #fff;
  padding: 2.5rem 0 3.5rem;
  margin: 0 auto;
  box-shadow: 0 -4px 24px rgba(30,58,95,0.06);
}

/* ===== Teaser ===== */
.teaser-section {
  text-align: center;
  margin-bottom: 2.5rem;
}

.teaser-image {
  max-width: 100%;
  width: 100%;
  height: auto;
  display: block;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.08), 0 0 0 1px rgba(0,0,0,0.04);
}

/* ===== Examples ===== */
.examples-figure {
  margin: 1.5rem 0 0;
  text-align: center;
}

.examples-image {
  max-width: 100%;
  width: 100%;
  height: auto;
  display: block;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.08), 0 0 0 1px rgba(0,0,0,0.04);
}

.examples-figure figcaption {
  margin-top: 1rem;
  font-size: 1rem;
  color: #475569;
  font-style: italic;
  line-height: 1.55;
  max-width: 72ch;
  margin-left: auto;
  margin-right: auto;
}

/* ===== Section headings (yellow underline) ===== */
.section {
  margin-bottom: 2.5rem;
}

.section-heading {
  font-family: "Fraunces", Georgia, serif;
  font-size: 1.95rem;
  font-weight: 700;
  color: #1a202c;
  margin: 0 0 1rem;
  position: relative;
  display: inline-block;
  letter-spacing: -0.02em;
}

.section-heading::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -6px;
  width: 48px;
  height: 5px;
  background: linear-gradient(90deg, #e6b800 0%, #f0c933 100%);
  border-radius: 3px;
}

/* ===== Abstract ===== */
.abstract {
  font-size: 1.1rem;
  color: #4a5568;
  line-height: 1.75;
  margin: 0;
}

/* ===== Key Findings cards ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.25rem;
  margin-top: 0.5rem;
}

.stat-card {
  background: #fff;
  border: 1px solid #eee;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  padding: 1.5rem;
  text-align: center;
  transition: box-shadow 0.2s;
}

.stat-card:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.stat-number {
  display: block;
  font-size: 2.5rem;
  font-weight: 700;
  color: #333;
  margin-bottom: 0.35rem;
}

.stat-label {
  font-size: 1rem;
  color: #777;
  line-height: 1.35;
}

.stat-note {
  font-size: 0.85em;
  color: #999;
}

/* ===== Example section (3 columns) ===== */
.example-section {
  margin-top: 2rem;
}

.clip-bar {
  background: #e9ecef;
  padding: 0.6rem 1rem;
  font-size: 1rem;
  color: #495057;
  margin-bottom: 1rem;
  border-radius: 4px;
}

.example-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 1.25rem;
  align-items: start;
}

@media (max-width: 900px) {
  .example-grid {
    grid-template-columns: 1fr;
  }
}

.col-label {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0 0 0.75rem;
}

.transcript-label { color: #c45c26; }
.vision-label { color: #2d6a4f; }

.transcript-block {
  background: #fafafa;
  border: 1px solid #eee;
  padding: 1rem;
  border-radius: 6px;
  margin-bottom: 0.5rem;
  font-size: 1rem;
  color: #444;
}

.example-col .meta {
  font-size: 0.8rem;
  color: #666;
  margin: 0 0 0.75rem;
}

.prediction {
  padding: 0.75rem;
  border-radius: 6px;
  font-size: 1rem;
  border-left: 3px solid;
}

.prediction-wrong {
  background: #fff5f5;
  border-left-color: #dc3545;
}

.prediction-correct {
  background: #f0f9f4;
  border-left-color: #28a745;
}

.badge {
  display: inline-block;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-left: 0.5rem;
}

.badge.incorrect { background: #f8d7da; color: #721c24; }
.badge.correct { background: #d4edda; color: #155724; }

.prediction p { margin: 0.5rem 0 0; color: #555; }

.video-placeholder {
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 0.75rem;
  border: 1px solid #eee;
}

.video-placeholder img {
  width: 100%;
  height: auto;
  display: block;
}

.observable-box {
  background: #f0f9f4;
  border: 1px solid #a3cfbb;
  border-radius: 6px;
  padding: 0.75rem;
  font-size: 0.95rem;
  color: #1a4d2e;
  margin-bottom: 0.75rem;
}

/* Bar chart */
.bar-chart {
  margin: 0.5rem 0;
}

.bar-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.6rem;
}

.bar-label {
  flex: 0 0 70px;
  font-size: 1rem;
}

.bar-track {
  flex: 1;
  display: flex;
  height: 24px;
  border-radius: 4px;
  overflow: hidden;
  background: #e9ecef;
}

.bar {
  height: 100%;
  min-width: 2px;
}

.transcript-bar { background: #74c0fc; }
.video-bar { background: #fd7e14; }

.bar-value {
  flex: 0 0 90px;
  font-size: 0.9rem;
  color: #555;
}

.legend {
  display: flex;
  gap: 1rem;
  font-size: 0.9rem;
  color: #666;
  margin-top: 0.5rem;
}

.legend-sq {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 2px;
  margin-right: 0.35rem;
  vertical-align: middle;
}

.transcript-sq { background: #74c0fc; }
.video-sq { background: #fd7e14; }

/* ===== Benchmark Overview ===== */
.overview-intro {
  color: #555;
  margin: 0 0 1rem;
  max-width: 75ch;
}

.cip-list {
  margin: 0;
  padding-left: 1.5rem;
  color: #555;
  line-height: 1.7;
}

.cip-list li { margin-bottom: 0.4rem; }

/* ===== Our contributions ===== */
.contributions-list {
  margin: 0;
  padding-left: 1.5rem;
  color: #555;
  line-height: 1.75;
  font-size: 1.05rem;
}

.contributions-list li {
  margin-bottom: 0.75rem;
  list-style: none;
  position: relative;
  padding-left: 1rem;
}

.contributions-list li::before {
  content: "◆";
  position: absolute;
  left: -1.25rem;
  color: #2d6a4f;
  font-size: 0.55em;
  top: 0.3em;
  opacity: 0.9;
}

/* ===== Method ===== */
.method-intro {
  color: #555;
  margin: 0 0 1.25rem;
  line-height: 1.75;
}

.method-subheading {
  font-family: "Fraunces", Georgia, serif;
  font-size: 1.25rem;
  font-weight: 700;
  color: #1e293b;
  margin: 1.5rem 0 0.75rem;
  letter-spacing: -0.01em;
}

.method-subheading:first-of-type {
  margin-top: 0;
}

.method-outputs {
  margin: 0 0 1rem;
  padding-left: 1.5rem;
  color: #555;
  line-height: 1.75;
}

.method-outputs li {
  margin-bottom: 0.5rem;
}

.method-figure {
  margin: 1.5rem 0;
  text-align: center;
}

.method-figure-img {
  max-width: 100%;
  width: 100%;
  height: auto;
  display: block;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(0,0,0,0.08), 0 0 0 1px rgba(0,0,0,0.04);
}

.method-figure figcaption {
  margin-top: 0.75rem;
  font-size: 0.95rem;
  color: #666;
  font-style: italic;
  line-height: 1.5;
}

.method-modules {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin: 1rem 0 1.5rem;
}

.method-module {
  padding: 1.25rem;
  border-radius: 8px;
  border-left: 4px solid;
}

.method-module h4 {
  font-size: 1.05rem;
  margin: 0 0 0.75rem;
  color: #333;
}

.method-module ul {
  margin: 0;
  padding-left: 1.25rem;
  color: #555;
  font-size: 1rem;
  line-height: 1.6;
}

.method-module li {
  margin-bottom: 0.35rem;
}

.method-module-1 {
  background: linear-gradient(135deg, #fffbeb 0%, #fef3c7 100%);
  border-left-color: #d97706;
}

.method-module-2 {
  background: linear-gradient(135deg, #fdf2f8 0%, #fce7f3 100%);
  border-left-color: #be185d;
}

.method-module-3 {
  background: linear-gradient(135deg, #fff7ed 0%, #ffedd5 100%);
  border-left-color: #ea580c;
}

.method-challenges {
  margin: 0 0 1rem;
  padding-left: 1.5rem;
  color: #555;
  line-height: 1.75;
}

.method-challenges li {
  margin-bottom: 0.75rem;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.method-block h3 {
  font-size: 1.2rem;
  margin: 0 0 0.5rem;
  color: #333;
}

.method-block p {
  margin: 0.35rem 0;
  font-size: 1.05rem;
  color: #555;
}

/* ===== Results table ===== */
.table-wrapper {
  overflow-x: auto;
  margin: 1rem 0 0.5rem;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.06), 0 0 0 1px rgba(0,0,0,0.04);
  overflow: hidden;
}

.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 1.05rem;
}

.results-table thead {
  background: linear-gradient(180deg, #1e3a5f 0%, #2d4a6f 100%);
  color: #fff;
}

.results-table th {
  padding: 0.8rem 1.1rem;
  text-align: left;
  font-weight: 600;
  font-size: 0.98rem;
}

.results-table td {
  padding: 0.7rem 1.1rem;
  border-bottom: 1px solid #e2e8f0;
  color: #475569;
}

.results-table tbody tr:hover {
  background: #f8fafc;
}

.table-caption {
  font-size: 1rem;
  font-style: italic;
  color: #666;
  text-align: center;
  margin: 0 0 1rem;
}

.results-table-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: #333;
  margin: 1.5rem 0 0.5rem;
}

.results-table-title:first-of-type {
  margin-top: 1rem;
}

.results-subheading {
  font-size: 1.05rem;
  font-weight: 700;
  color: #333;
  margin: 1.5rem 0 0.5rem;
}

/* Expert evaluation instrument (Fig. 7) */
.evaluation-instrument {
  background: linear-gradient(180deg, #f8fafb 0%, #f1f5f9 100%);
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  padding: 1.5rem 1.75rem;
  margin: 1.25rem 0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.03);
}

.evaluation-instrument .results-table-title {
  margin-top: 0;
}

.instrument-desc {
  margin: 0 0 1rem;
  color: #555;
  font-size: 1rem;
  line-height: 1.6;
}

.rubric-sections {
  display: grid;
  gap: 1rem;
}

.rubric-section {
  background: #fff;
  border-radius: 10px;
  padding: 1.1rem 1.35rem;
  border-left: 4px solid #2d6a4f;
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
}

.rubric-section h5 {
  font-size: 1rem;
  font-weight: 700;
  color: #333;
  margin: 0 0 0.5rem;
}

.response-type {
  font-weight: 400;
  font-style: italic;
  color: #666;
  font-size: 0.9em;
}

.rubric-section ul {
  margin: 0;
  padding-left: 1.25rem;
  color: #555;
  line-height: 1.65;
}

.rubric-section li {
  margin-bottom: 0.25rem;
}

.results-table td.table-subheader {
  background: #f1f3f5;
  font-weight: 600;
  color: #333;
  padding: 0.5rem 1rem;
  border-top: 1px solid #dee2e6;
}

/* Teacher perspectives cards (4.5) */
.perspective-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.35rem;
  margin-top: 1.75rem;
}

.perspective-card {
  background: #fff;
  border-radius: 14px;
  padding: 1.6rem;
  box-shadow: 0 4px 16px rgba(0,0,0,0.06), 0 0 0 1px rgba(0,0,0,0.03);
  border-left: 5px solid #1e3a5f;
  transition: box-shadow 0.3s ease, transform 0.25s ease;
}

.perspective-card:hover {
  box-shadow: 0 12px 32px rgba(0,0,0,0.08), 0 0 0 1px rgba(0,0,0,0.04);
  transform: translateY(-3px);
}

.perspective-card:nth-child(1) { border-left-color: #1e3a5f; }
.perspective-card:nth-child(2) { border-left-color: #2d6a4f; }
.perspective-card:nth-child(3) { border-left-color: #7c3aed; }
.perspective-card:nth-child(4) { border-left-color: #ea580c; }
.perspective-card:nth-child(5) { border-left-color: #0369a1; }

.perspective-card-title {
  font-family: "Fraunces", Georgia, serif;
  font-size: 1.08rem;
  font-weight: 700;
  color: #1e293b;
  margin: 0 0 0.85rem;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

.perspective-card p {
  margin: 0;
  font-size: 1rem;
  color: #475569;
  line-height: 1.72;
}

.perspective-card q {
  font-style: italic;
  color: #334155;
  quotes: """ """ "'" "'";
}

/* Key Observation box ===== */
.key-observation {
  background: linear-gradient(90deg, #fffbeb 0%, #fef9c3 100%);
  border-left: 4px solid #e6b800;
  padding: 1.15rem 1.35rem;
  margin-top: 1rem;
  border-radius: 0 10px 10px 0;
  color: #4a5568;
  font-size: 1.05rem;
  box-shadow: 0 2px 8px rgba(230,184,0,0.08);
}

.key-observation strong { color: #333; }

/* ===== BibTeX ===== */
.bibtex-block {
  position: relative;
  background: linear-gradient(180deg, #f1f5f9 0%, #e2e8f0 100%);
  border: 1px solid #cbd5e1;
  border-radius: 12px;
  padding: 1.15rem 1.4rem;
  padding-top: 2.75rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.copy-btn {
  position: absolute;
  top: 0.85rem;
  right: 0.85rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.9rem;
  background: linear-gradient(180deg, #1e3a5f 0%, #2d4a6f 100%);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: 0 2px 6px rgba(30,58,95,0.25);
}

.copy-btn:hover { background: linear-gradient(180deg, #2a4a7a 0%, #3d5a80 100%); transform: translateY(-1px); }
.copy-btn.copied { background: #16a34a; box-shadow: 0 2px 6px rgba(22,163,74,0.3); }

.bibtex-code {
  margin: 0;
  font-family: "Consolas", "Monaco", monospace;
  font-size: 0.95rem;
  color: #333;
  overflow-x: auto;
}

.bibtex-code code { white-space: pre; }

/* ===== Footer ===== */
.footer {
  background: linear-gradient(180deg, #1e3a5f 0%, #1a2f4a 100%);
  padding: 1.25rem;
  text-align: center;
  font-size: 0.95rem;
  color: rgba(255,255,255,0.8);
}

.footer .container { padding: 0 1rem; }

.footer p { margin: 0; }