/* ============================================================
   DESIGN TOKENS — ELEGANT LIGHT ACADEMIC THEME
============================================================ */
:root {
  --bg:           #ffffff;
  --bg-dark:      #f8fafc;
  --bg-tint:      #f1f5f9;
  --surface:      #ffffff;
  --surface2:     #f8fafc;
  --surface3:     #e2e8f0;
  --border:       #e2e8f0;
  --border-bright:#cbd5e1;

  --accent:       #2563eb;
  --accent-2:     #7c3aed;
  --accent-grd:   linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
  --accent-subtle:rgba(37, 99, 235, 0.06);

  --text:         #0f172a;
  --text-muted:   #475569;
  --text-dim:     #64748b;

  --radius-sm:    8px;
  --radius-md:    14px;
  --radius-lg:    20px;

  --shadow-card:  0 10px 30px -5px rgba(0, 0, 0, 0.05), 0 4px 12px -2px rgba(0, 0, 0, 0.03);
  --shadow-hover: 0 20px 40px -10px rgba(37, 99, 235, 0.12), 0 8px 16px -4px rgba(0, 0, 0, 0.04);
  --shadow-glow:  0 0 40px rgba(37, 99, 235, 0.15);

  --font-sans:    'Inter', system-ui, -apple-system, sans-serif;
  --font-mono:    'JetBrains Mono', monospace;

  --transition:   0.22s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================================
   RESET & BASE
============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 19px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-2); }

/* ============================================================
   TOP NAVBAR WITH LOGOS
============================================================ */
.topnav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  transition: all var(--transition);
}
.topnav.scrolled {
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 4px 20px rgba(0,0,0,0.06);
}
.topnav-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.brand-logos {
  display: flex;
  align-items: center;
  gap: 16px;
}
.brand-logo {
  height: 32px;
  width: auto;
  object-fit: contain;
  transition: opacity var(--transition);
}
.brand-logo:hover { opacity: 0.85; }
.biu-logo { height: 34px; }
.nvidia-logo { height: 24px; }
.logo-divider {
  width: 1px;
  height: 22px;
  background: var(--border-bright);
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
}
.nav-links a {
  color: var(--text-muted);
  font-size: 16px;
  font-weight: 500;
}
.nav-links a:hover { color: var(--accent); }

/* ============================================================
   LAYOUT & CONTAINERS
============================================================ */
.container { max-width: 1180px; margin: 0 auto; padding: 0 24px; }
.section { padding: 92px 0; }
.section-dark  { background: var(--bg-dark); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section-tinted { background: var(--bg-tint); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }

/* ============================================================
   HERO SECTION
============================================================ */
.hero {
  position: relative;
  min-height: 85vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: 130px 0 80px;
  background: radial-gradient(ellipse 80% 50% at 50% -10%, rgba(37, 99, 235, 0.06) 0%, transparent 70%), var(--bg);
}
.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 22px;
}
/* HEADER TEASERS */
.header-teasers {
  display: grid;
  grid-template-columns: 1.45fr 1fr;
  align-items: flex-start;
  gap: 20px;
  width: 100%;
  max-width: 1140px;
  margin-bottom: 24px;
}
.teaser-item {
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
  width: 100%;
}
.teaser-label {
  font-size: 17.5px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent);
  text-align: center;
}
.teaser-explanation {
  font-size: 16.5px;
  color: var(--text-muted);
  line-height: 1.55;
  text-align: center;
  max-width: 100%;
  margin-top: 4px;
}
.hero-teaser-card {
  margin: 0;
  box-shadow: 0 12px 32px rgba(0,0,0,0.08);
  width: 100%;
}
.hero-teaser-card .card-header {
  min-height: 52px;
  align-items: center;
  width: 100%;
}
.hero-teaser-card .header-side {
  height: 100%;
  min-height: 52px;
  padding: 8px 14px;
  font-size: 15px;
  line-height: 1.3;
  text-align: center;
  box-sizing: border-box;
}
.hero-teaser-card.audio-card .video-wrapper {
  aspect-ratio: 1536 / 512;
}
.hero-teaser-card .video-wrapper {
  aspect-ratio: 1408 / 640;
  width: 100%;
  height: auto;
  background: transparent;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.hero-teaser-card .video-wrapper video {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
}
@media (max-width: 850px) {
  .header-teasers {
    grid-template-columns: 1fr;
  }
}

.venue-badge {
  display: inline-flex;
  align-items: center;
  background: var(--accent-grd);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 6px 20px;
  border-radius: 100px;
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.25);
}
.paper-title {
  font-size: clamp(30px, 4.4vw, 54px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.025em;
  color: var(--text);
  max-width: 880px;
}
.paper-title .highlight {
  background: var(--accent-grd);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.authors {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 24px;
}
.author { color: var(--text); font-size: 20px; font-weight: 500; }
.author sup { font-size: 13px; color: var(--accent); margin-left: 2px; }
.affiliations {
  color: var(--text-muted);
  font-size: 17px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}
.aff-sep { color: var(--border-bright); }
.equal-contribution-note {
  font-size: 14.5px;
  color: var(--text-dim);
  margin-top: -6px;
}
.hero-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  margin-top: 14px;
  margin-bottom: 28px;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 30px;
  border-radius: 100px;
  font-size: 16.5px;
  font-weight: 600;
  transition: all var(--transition);
  cursor: pointer;
  border: none;
}
.btn-primary {
  background: var(--accent-grd);
  color: #fff;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.3);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(37, 99, 235, 0.45); color: #fff; }
.btn-secondary {
  background: #fff;
  color: var(--text);
  border: 1px solid var(--border-bright);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
.btn-secondary:hover { background: var(--bg-dark); border-color: var(--accent); color: var(--accent); transform: translateY(-2px); }
.hero-scroll-hint {
  position: relative;
  margin-top: 24px;
  bottom: auto;
  left: auto;
  transform: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  color: var(--text-dim);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  z-index: 1;
}
.scroll-arrow {
  width: 16px;
  height: 16px;
  border-right: 2px solid var(--text-dim);
  border-bottom: 2px solid var(--text-dim);
  transform: rotate(45deg);
  animation: bounce 1.5s infinite;
}

/* ============================================================
   SECTION TITLES
============================================================ */
.section-title {
  font-size: clamp(28px, 3.6vw, 42px);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
  text-align: center;
  color: var(--text);
}
.section-subtitle {
  text-align: center;
  color: var(--text-muted);
  max-width: 820px;
  margin: 0 auto 48px;
  font-size: 20px;
  line-height: 1.7;
}

/* ============================================================
   FIGURE CARDS & TEASER (BLENDS WHITE FIGURES SEAMLESSLY)
============================================================ */
.figure-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  padding: 24px;
  text-align: center;
  transition: box-shadow var(--transition);
}
.figure-card:hover {
  box-shadow: var(--shadow-hover);
}
.figure-card img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  display: block;
  background: #ffffff;
}
.caption {
  font-size: 17.5px;
  color: var(--text-muted);
  margin-top: 18px;
  text-align: left;
  line-height: 1.7;
  background: var(--bg-dark);
  padding: 16px 20px;
  border-radius: var(--radius-md);
  border-left: 4px solid var(--accent);
}

/* METRICS BANNER */
.metrics-banner {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: 36px;
}
.metric-pill {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 22px 24px;
  text-align: center;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition), border-color var(--transition);
}
.metric-pill:hover { transform: translateY(-3px); border-color: var(--accent); }
.metric-val {
  display: block;
  font-size: 36px;
  font-weight: 800;
  background: var(--accent-grd);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.metric-label { display: block; font-size: 16px; font-weight: 700; color: var(--text); margin-top: 4px; }
.metric-sub { display: block; font-size: 13.5px; color: var(--text-muted); margin-top: 2px; }

/* ============================================================
   ABSTRACT & METHOD
============================================================ */
.abstract-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 44px 52px;
  max-width: 880px;
  margin: 0 auto;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.abstract-card p { color: var(--text-muted); font-size: 20px; line-height: 1.8; }
.abstract-card .reccar-name {
  background: var(--accent-grd);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 700;
}

.idea-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-bottom: 48px;
}
.idea-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  box-shadow: var(--shadow-card);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.idea-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--accent-grd);
  opacity: 0;
  transition: opacity var(--transition);
}
.idea-card:hover { border-color: var(--accent); transform: translateY(-3px); box-shadow: var(--shadow-hover); }
.idea-card:hover::before { opacity: 1; }
.idea-icon { font-size: 30px; margin-bottom: 12px; }
.idea-card h3 { font-size: 16.5px; font-weight: 700; color: var(--text); margin-bottom: 8px; }
.idea-card p { font-size: 14px; color: var(--text-muted); }

.method-concept-box {
  background: #ffffff;
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-md);
  padding: 22px 28px;
  margin-bottom: 32px;
  box-shadow: var(--shadow-card);
  font-size: 16.5px;
  color: var(--text);
  line-height: 1.7;
  text-align: center;
}

.method-figures-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-bottom: 40px;
}

.equation-block {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 44px;
  text-align: center;
  max-width: 880px;
  margin: 0 auto;
  box-shadow: var(--shadow-card);
}
.eq-label {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 20px;
}
.math-card {
  background: var(--bg-dark);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: inset 0 2px 6px rgba(0,0,0,0.02);
}
.math-equation {
  font-size: clamp(16px, 2.2vw, 21px);
  color: var(--text);
  overflow-x: auto;
  padding: 6px 0;
}
.math-equation.sub-eq {
  font-size: clamp(15px, 1.8vw, 18px);
  border-top: 1px dashed var(--border-bright);
  padding-top: 14px;
  margin-top: 4px;
}
.eq-note {
  font-size: 14.5px;
  color: var(--text-muted);
  margin-top: 18px;
  line-height: 1.65;
}

/* ============================================================
   FILTER BAR & VIDEO GALLERY
============================================================ */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 40px;
}
.filter-btn {
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 8px 22px;
  border-radius: 100px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  box-shadow: 0 2px 6px rgba(0,0,0,0.02);
}
.filter-btn:hover { border-color: var(--accent); color: var(--accent); }
.filter-btn.active {
  background: var(--accent-grd);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.3);
}

.video-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(520px, 1fr));
  gap: 32px;
  margin-bottom: 56px;
}
.video-cards-grid > .video-card:last-child:nth-child(odd) {
  grid-column: 1 / -1;
  justify-self: center;
  width: 100%;
  max-width: 550px;
}
.audio-cards-grid {
  grid-template-columns: repeat(auto-fill, minmax(540px, 1fr));
}

.video-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
}
.video-card:hover {
  border-color: var(--border-bright);
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.card-header {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-bottom: 1px solid var(--border);
  background: var(--bg-dark);
}
.card-header.header-3col {
  grid-template-columns: 1fr 1fr 1fr;
}
.header-side {
  padding: 10px 14px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  color: var(--text-muted);
}
.header-side.left { border-right: 1px solid var(--border); }
.header-side.right { color: var(--accent); background: rgba(37, 99, 235, 0.06); }
.header-side.center { color: var(--accent); background: rgba(37, 99, 235, 0.06); border-right: 1px solid var(--border); border-left: 1px solid var(--border); }

.badge-dot { width: 8px; height: 8px; border-radius: 50%; display: inline-block; }
.badge-dot.baseline { background: var(--text-dim); }
.badge-dot.ours { background: var(--accent); box-shadow: 0 0 6px rgba(37, 99, 235, 0.4); }
.badge-dot.ref { background: var(--accent-2); box-shadow: 0 0 6px rgba(124, 58, 237, 0.4); }

.video-wrapper {
  position: relative;
  background: #000000;
  aspect-ratio: 1408 / 640;
  cursor: pointer;
  overflow: hidden;
}
.audio-card .video-wrapper {
  aspect-ratio: 1536 / 512;
}
.video-wrapper video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.video-controls-overlay {
  position: absolute;
  bottom: 12px;
  left: 12px; right: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  opacity: 0;
  transition: opacity var(--transition);
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(8px);
  padding: 6px 14px;
  border-radius: 100px;
}
.video-wrapper:hover .video-controls-overlay { opacity: 1; }

.ctrl-btn {
  background: none;
  border: none;
  color: #fff;
  font-size: 14px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 6px;
  transition: background var(--transition);
}
.ctrl-btn:hover { background: rgba(255,255,255,0.2); }

.speed-selector {
  display: flex;
  gap: 6px;
  background: rgba(255,255,255,0.15);
  padding: 2px 6px;
  border-radius: 100px;
}
.speed-opt {
  font-size: 11px;
  font-weight: 600;
  color: rgba(255,255,255,0.7);
  cursor: pointer;
  padding: 2px 6px;
  border-radius: 100px;
}
.speed-opt.active { background: var(--accent); color: #fff; }

.unmute-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(37, 99, 235, 0.4);
  border: 1px solid var(--accent);
  padding: 5px 14px;
  border-radius: 100px;
  font-size: 12px;
  font-weight: 600;
  color: #fff;
  transition: all var(--transition);
}
.unmute-btn:hover, .unmute-btn.active {
  background: var(--accent-grd);
  box-shadow: 0 0 14px rgba(37, 99, 235, 0.5);
}

.card-body {
  padding: 22px 24px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex-grow: 1;
}
.card-tag-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.card-tag {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  background: rgba(37, 99, 235, 0.08);
  padding: 3px 12px;
  border-radius: 100px;
}
.card-tag.audio-tag {
  color: var(--accent-2);
  background: rgba(124, 58, 237, 0.08);
}
.card-num { font-size: 12.5px; color: var(--text-dim); }
.card-title { font-size: 16.5px; font-weight: 700; color: var(--text); }
.card-caption { font-size: 14px; color: var(--text-muted); line-height: 1.55; }

/* ============================================================
   RESULTS TABLES
============================================================ */
.results-table-wrap { margin-top: 40px; }
.table-title { font-size: 16.5px; font-weight: 700; color: var(--text); margin-bottom: 16px; text-align: center; }
.table-scroll { overflow-x: auto; border-radius: var(--radius-md); border: 1px solid var(--border); box-shadow: var(--shadow-card); }
.results-table { width: 100%; border-collapse: collapse; font-size: 14px; background: #ffffff; }
.results-table thead { background: var(--bg-dark); }
.results-table th {
  padding: 14px 16px;
  text-align: center;
  font-weight: 700;
  color: var(--text);
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  white-space: nowrap;
  border-bottom: 1px solid var(--border);
}
.results-table th:first-child { text-align: left; }
.results-table td {
  padding: 13px 16px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
  white-space: nowrap;
}
.results-table td:first-child { text-align: left; color: var(--text); }
.results-table tbody tr:hover { background: var(--bg-dark); }
.ours-row { background: rgba(37, 99, 235, 0.06) !important; }
.ours-row td { color: var(--text) !important; font-weight: 600; }
.ours-row td:first-child { color: var(--accent) !important; font-weight: 700; }
.ours-row strong { color: var(--accent); }
.sub-ours-row { background: rgba(37, 99, 235, 0.03); }
.sub-ours-row td { color: var(--text); }

/* ============================================================
   CITATION / BIBTEX
============================================================ */
.bibtex-block {
  position: relative;
  max-width: 840px;
  margin: 24px auto 0;
  background: #0f172a;
  border: 1px solid #1e293b;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-card);
}
.bibtex-block pre {
  font-family: var(--font-mono);
  font-size: 13.5px;
  line-height: 1.7;
  color: #cbd5e1;
  padding: 28px 32px;
  overflow-x: auto;
  white-space: pre;
}
.copy-btn {
  position: absolute;
  top: 14px;
  right: 16px;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.2);
  color: #fff;
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 600;
  padding: 6px 16px;
  border-radius: 100px;
  cursor: pointer;
  transition: all var(--transition);
}
.copy-btn:hover { background: var(--accent); border-color: var(--accent); }
.copy-btn.copied { background: #10b981; border-color: #10b981; }

/* ============================================================
   FOOTER
============================================================ */
.footer { background: var(--bg-dark); border-top: 1px solid var(--border); padding: 44px 0; text-align: center; }
.footer p { color: var(--text-muted); font-size: 14.5px; }
.footer .footer-note { font-size: 12.5px; color: var(--text-dim); margin-top: 6px; }

/* ============================================================
   ANIMATIONS & RESPONSIVE
============================================================ */
@keyframes bounce {
  0%, 100% { transform: rotate(45deg) translateY(0); }
  50%       { transform: rotate(45deg) translateY(5px); }
}

@media (max-width: 900px) {
  .method-figures-grid { grid-template-columns: 1fr; }
  .video-cards-grid, .audio-cards-grid { grid-template-columns: 1fr; }
  .nav-links { display: none; }
}

@media (max-width: 600px) {
  .abstract-card { padding: 28px 22px; }
  .equation-block { padding: 22px 18px; }
  .bibtex-block pre { font-size: 11.5px; padding: 20px 18px; }
  .hero-links { flex-direction: column; width: 100%; }
  .btn { width: 100%; justify-content: center; }
}