/* ═══════════════════════════════════════════════════════
   U-3DGS Project Page — Stylesheet
   ═══════════════════════════════════════════════════════ */

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

:root {
  --accent:        #2563eb;
  --accent-dark:   #1d4ed8;
  --accent-light:  #eff6ff;
  --text-primary:  #111827;
  --text-secondary:#4b5563;
  --bg-white:      #ffffff;
  --bg-alt:        #f8fafc;
  --border:        #e5e7eb;
  --highlight:     #fef9c3;
  --gain:          #16a34a;
  --radius:        10px;
  --shadow:        0 2px 16px rgba(0,0,0,.08);
  --shadow-lg:     0 8px 40px rgba(0,0,0,.12);
  --font-sans:     'Inter', system-ui, sans-serif;
  --font-mono:     'Source Code Pro', monospace;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: var(--bg-white);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ─── Layout ────────────────────────────────────────────── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}
.container.narrow { max-width: 780px; }

.section {
  padding: 5rem 0;
}
.section-alt {
  background: var(--bg-alt);
}

/* ─── Hero ──────────────────────────────────────────────── */
.hero {
  background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 60%, #1d4ed8 100%);
  color: #fff;
  padding: 5rem 0 4rem;
  text-align: center;
}

.venue-badge {
  display: inline-block;
  background: rgba(255,255,255,.15);
  border: 1px solid rgba(255,255,255,.3);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  padding: .35em 1em;
  border-radius: 999px;
  margin-bottom: 1.5rem;
}

.hero .title {
  font-size: clamp(1.7rem, 4vw, 2.6rem);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 2rem;
  letter-spacing: -.02em;
}

.authors {
  font-size: 1.05rem;
  margin-bottom: 0.6rem;
  opacity: .9;
}
.author-block { margin: 0 .15rem; }

.affiliations {
  font-size: 0.9rem;
  opacity: .7;
  margin-bottom: 2.2rem;
}

/* ─── Buttons ───────────────────────────────────────────── */
.links { display: flex; flex-wrap: wrap; gap: .75rem; justify-content: center; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  padding: .55rem 1.25rem;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 500;
  transition: background .2s, transform .15s, box-shadow .2s;
  cursor: pointer;
  border: none;
}
.btn-dark {
  background: rgba(255,255,255,.12);
  color: #fff;
  border: 1px solid rgba(255,255,255,.25);
}
.btn-dark:hover {
  background: rgba(255,255,255,.22);
  text-decoration: none;
  transform: translateY(-1px);
}

/* ─── Section Typography ────────────────────────────────── */
.section-title {
  font-size: 1.85rem;
  font-weight: 700;
  letter-spacing: -.025em;
  margin-bottom: 1rem;
  text-align: center;
  color: var(--text-primary);
}
.section-title::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--accent);
  border-radius: 99px;
  margin: .6rem auto 0;
}

.subsection-title {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--text-primary);
  text-align: center;
}

.section-desc {
  color: var(--text-secondary);
  max-width: 700px;
  margin: 0 auto 2rem;
  text-align: center;
  font-size: 1rem;
}

/* ─── Abstract ──────────────────────────────────────────── */
.abstract-text {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  text-align: center;
}
.abstract-text:last-child { margin-bottom: 0; }

/* ─── Hero Figure ───────────────────────────────────────── */
.hero-figure {
  text-align: center;
}
.full-width-img {
  width: 100%;
  height: auto;
  display: block;
}
.rounded { border-radius: var(--radius); }
figure figcaption {
  font-size: .875rem;
  color: var(--text-secondary);
  margin-top: .75rem;
  text-align: center;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

/* ─── Highlights Grid ───────────────────────────────────── */
.highlights-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
}
.highlight-card {
  background: var(--bg-white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem 1.5rem;
  text-align: center;
  box-shadow: var(--shadow);
  transition: transform .2s, box-shadow .2s;
}
.highlight-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}
.highlight-icon {
  font-size: 2rem;
  color: var(--accent);
  margin-bottom: .75rem;
}
.highlight-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: .5rem;
}
.highlight-card p {
  font-size: .9rem;
  color: var(--text-secondary);
}

/* ─── Method Panels ─────────────────────────────────────── */
.method-panels {
  display: flex;
  align-items: flex-start;
  gap: .5rem;
  margin: 2rem 0;
  overflow-x: auto;
}
.method-step {
  flex: 1;
  min-width: 160px;
  background: var(--bg-white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1rem;
  box-shadow: var(--shadow);
  position: relative;
}
.step-number {
  position: absolute;
  top: -1px;
  left: -1px;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: .8rem;
  width: 28px;
  height: 28px;
  border-radius: var(--radius) 0 var(--radius) 0;
  display: flex;
  align-items: center;
  justify-content: center;
}
.method-step h4 {
  font-size: .95rem;
  font-weight: 600;
  margin-bottom: .5rem;
  padding-top: .25rem;
  text-align: center;
}
.method-step p {
  font-size: .85rem;
  color: var(--text-secondary);
  text-align: center;
}
.method-arrow {
  color: var(--accent);
  font-size: 1.3rem;
  align-self: center;
  flex-shrink: 0;
}

/* ─── Method Strip ──────────────────────────────────────── */
.method-strip, .sparse-strip {
  display: flex;
  gap: 1rem;
  align-items: center;
  justify-content: center;
  margin: 2rem 0;
  flex-wrap: wrap;
}
.strip-item, .sparse-item {
  flex: 1;
  min-width: 140px;
  max-width: 220px;
  text-align: center;
}
.strip-img {
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.strip-label {
  font-size: .8rem;
  color: var(--text-secondary);
  margin-top: .4rem;
  font-weight: 500;
}
.strip-sep {
  color: var(--accent);
  font-size: 1.2rem;
  flex-shrink: 0;
}

/* ─── Info Box ──────────────────────────────────────────── */
.info-box {
  background: var(--accent-light);
  border-left: 4px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1.5rem 1.75rem;
  margin-top: 2.5rem;
}
.info-box h4 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--accent-dark);
  margin-bottom: .75rem;
  text-align: center;
}
.info-box p {
  font-size: .95rem;
  color: var(--text-secondary);
  margin-bottom: .75rem;
  text-align: center;
}
.info-box p:last-child { margin-bottom: 0; }
.math-display {
  text-align: center;
  margin: 1rem 0;
  font-size: .95rem;
}

/* ─── Tables ────────────────────────────────────────────── */
.table-wrapper { overflow-x: auto; margin-top: 1.5rem; }
.centered-table { display: flex; justify-content: center; margin-top: 1.5rem; }
.centered-table .results-table { max-width: 600px; }

.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .85rem;
  box-shadow: var(--shadow);
  border-radius: var(--radius);
  overflow: hidden;
}
.results-table th, .results-table td {
  padding: .55rem .75rem;
  text-align: center;
  border-bottom: 1px solid var(--border);
}
.results-table thead th {
  background: #1e3a5f;
  color: #fff;
  font-weight: 600;
  font-size: .8rem;
  letter-spacing: .03em;
  border-bottom: none;
}
.results-table td:first-child { text-align: left; font-weight: 500; }
.results-table tbody tr:hover { background: var(--accent-light); }
.results-table.compact { font-size: .9rem; }
.results-table.compact th,
.results-table.compact td { padding: .6rem .9rem; }

.best-row { background: var(--highlight) !important; }
.best-row td { font-weight: 600; }

.gain { color: var(--gain); font-weight: 600; }
.delta { color: var(--gain); font-size: .8rem; font-style: italic; }

.table-note {
  font-size: .825rem;
  color: var(--text-secondary);
  margin-top: .75rem;
  font-style: italic;
  text-align: center;
}

/* ─── Two-col layouts ───────────────────────────────────── */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: start;
  margin-top: 1.5rem;
}
.sparse-plots { display: flex; flex-direction: column; gap: 1rem; }
.three-col {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  align-items: center;
  margin-top: 1.5rem;
}
.two-col-asymm {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 2rem;
  align-items: center;
  margin-top: 1.5rem;
}
.small-table-wrap { align-self: center; }

/* ─── BibTeX ────────────────────────────────────────────── */
.bibtex {
  background: #0f172a;
  color: #e2e8f0;
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  font-family: var(--font-mono);
  font-size: .85rem;
  overflow-x: auto;
  margin-bottom: 1rem;
  line-height: 1.7;
}
.copy-btn {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: .5rem 1.1rem;
  border-radius: 6px;
  font-size: .9rem;
  font-weight: 500;
  cursor: pointer;
  transition: background .2s;
}
.copy-btn:hover { background: var(--accent-dark); }

/* ─── Footer ────────────────────────────────────────────── */
.footer {
  background: #0f172a;
  color: rgba(255,255,255,.6);
  text-align: center;
  padding: 2.5rem 1rem;
  font-size: .9rem;
}
.footer a { color: rgba(255,255,255,.8); }
.footer a:hover { color: #fff; }

/* ─── Responsive ─────────────────────────────────────────── */
@media (max-width: 768px) {
  .section { padding: 3rem 0; }
  .two-col, .two-col-asymm, .three-col { grid-template-columns: 1fr; }
  .method-panels { flex-direction: column; }
  .method-arrow { transform: rotate(90deg); align-self: center; }
  .results-table { font-size: .75rem; }
  .results-table th, .results-table td { padding: .4rem .5rem; }
  .method-strip, .sparse-strip { flex-wrap: wrap; }
  .strip-item, .sparse-item { min-width: 120px; }
}

@media (max-width: 480px) {
  .hero .title { font-size: 1.5rem; }
  .section-title { font-size: 1.5rem; }
  .highlights-grid { grid-template-columns: 1fr; }
}