/* ==========================================================================
   TriTrust-PBRL: Modern Academic Project Page Styles
   Theme: Precision Academic Dark/Light Mode with Sleek Glassmorphism
   ========================================================================== */

:root {
  /* Color Palette - Light Mode Default */
  --bg-body: #f8fafc;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #ffffff;
  --bg-surface-muted: #f1f5f9;
  --bg-code: #0f172a;
  --bg-overlay: rgba(15, 23, 42, 0.75);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-inverse: #f8fafc;
  --text-code: #e2e8f0;

  --accent-primary: #2563eb;
  --accent-primary-hover: #1d4ed8;
  --accent-primary-subtle: rgba(37, 99, 235, 0.08);
  --accent-secondary: #7c3aed;
  --accent-success: #059669;
  --accent-warning: #d97706;
  --accent-danger: #dc2626;

  --border-subtle: #e2e8f0;
  --border-medium: #cbd5e1;
  --border-focus: #3b82f6;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.04);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --nav-height: 64px;
  --container-max: 1160px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Outfit', var(--font-sans);
  --font-mono: 'JetBrains Mono', 'Fira Code', Menlo, monospace;

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

[data-theme="dark"] {
  --bg-body: #0b0f17;
  --bg-surface: #111827;
  --bg-surface-elevated: #1e293b;
  --bg-surface-muted: #1e293b;
  --bg-code: #030712;
  --bg-overlay: rgba(3, 7, 18, 0.85);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-inverse: #0f172a;
  --text-code: #f1f5f9;

  --accent-primary: #3b82f6;
  --accent-primary-hover: #60a5fa;
  --accent-primary-subtle: rgba(59, 130, 246, 0.15);
  --accent-secondary: #8b5cf6;
  --accent-success: #10b981;
  --accent-warning: #f59e0b;
  --accent-danger: #ef4444;

  --border-subtle: #1e293b;
  --border-medium: #334155;
  --border-focus: #60a5fa;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.6), 0 4px 6px -4px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.7), 0 8px 10px -6px rgba(0, 0, 0, 0.5);
}

/* ==========================================================================
   Base & Reset
   ========================================================================== */

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.65;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4 {
  font-family: var(--font-heading);
  color: var(--text-primary);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

p {
  margin-bottom: 1.15rem;
  color: var(--text-secondary);
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-primary-hover);
}

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

.container-narrow {
  max-width: 900px;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

[data-theme="dark"] .site-nav {
  background: rgba(11, 15, 23, 0.85);
}

.nav-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-badge {
  font-size: 0.75rem;
  padding: 0.15rem 0.55rem;
  background: var(--accent-primary-subtle);
  color: var(--accent-primary);
  border-radius: var(--radius-full);
  font-weight: 600;
  border: 1px solid rgba(37, 99, 235, 0.2);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav-links a:hover {
  color: var(--accent-primary);
}

.theme-toggle-btn {
  background: var(--bg-surface-muted);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-full);
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-primary);
  transition: background-color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
}

.theme-toggle-btn:hover {
  transform: scale(1.05);
  border-color: var(--accent-primary);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero {
  padding: 3.5rem 0 2.5rem 0;
  text-align: center;
  background: radial-gradient(circle at 50% -20%, rgba(37, 99, 235, 0.12) 0%, transparent 60%);
}

[data-theme="dark"] .hero {
  background: radial-gradient(circle at 50% -20%, rgba(59, 130, 246, 0.18) 0%, transparent 65%);
}

.hero-conference-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.9rem;
  border-radius: var(--radius-full);
  background: var(--accent-primary-subtle);
  color: var(--accent-primary);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
  border: 1px solid rgba(37, 99, 235, 0.25);
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  max-width: 950px;
  margin: 0 auto 1.5rem auto;
  line-height: 1.2;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 800px;
  margin: 0 auto 2rem auto;
  font-weight: 400;
}

/* Authors */
.authors-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem 1.75rem;
  margin-bottom: 1.25rem;
}

.author-item {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-primary);
}

.author-item a {
  color: var(--text-primary);
  font-weight: 600;
}

.author-item a:hover {
  color: var(--accent-primary);
  text-decoration: underline;
}

.author-item sup {
  color: var(--accent-primary);
  font-weight: 600;
  margin-left: 2px;
}

.affiliations-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem 2rem;
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
}

.affiliations-list span sup {
  color: var(--accent-primary);
  font-weight: 600;
}

.notes-list {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
}

.notes-list span {
  margin: 0 0.5rem;
}

/* Action Buttons */
.action-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.85rem;
  margin-bottom: 2.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.35rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
  cursor: pointer;
}

.btn-primary {
  background: var(--accent-primary);
  color: #ffffff;
  box-shadow: 0 2px 10px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  background: var(--accent-primary-hover);
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-secondary {
  background: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-medium);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  background: var(--bg-surface-muted);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  transform: translateY(-2px);
}

/* ==========================================================================
   Teaser & TL;DR Section
   ========================================================================== */

.teaser-section {
  padding: 1.5rem 0 3.5rem 0;
}

.teaser-card {
  background: var(--bg-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  padding: 2rem;
  margin-bottom: 2rem;
  transition: border-color var(--transition-normal);
}

.teaser-card:hover {
  border-color: var(--border-medium);
}

.teaser-figure-container {
  text-align: center;
  cursor: zoom-in;
  margin-bottom: 1.5rem;
}

.teaser-img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-normal);
}

.teaser-figure-container:hover .teaser-img {
  transform: scale(1.008);
}

.teaser-caption {
  font-size: 0.92rem;
  color: var(--text-muted);
  text-align: center;
  max-width: 900px;
  margin: 0 auto;
}

/* Pillar Cards Grid */
.pillars-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.pillar-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.pillar-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
}

.pillar-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

.pillar-icon.blue { background: rgba(37, 99, 235, 0.12); color: var(--accent-primary); }
.pillar-icon.purple { background: rgba(124, 58, 237, 0.12); color: var(--accent-secondary); }
.pillar-icon.emerald { background: rgba(5, 150, 105, 0.12); color: var(--accent-success); }

.pillar-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.pillar-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 0;
}

/* ==========================================================================
   Content Sections
   ========================================================================== */

.content-section {
  padding: 3.5rem 0;
  border-top: 1px solid var(--border-subtle);
}

.section-header {
  text-align: center;
  margin-bottom: 2.5rem;
}

.section-tag {
  text-transform: uppercase;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  font-weight: 700;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
  display: block;
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 700px;
  margin: 0 auto;
}

/* Abstract Box */
.abstract-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2.25rem;
  box-shadow: var(--shadow-sm);
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-primary);
}

/* ==========================================================================
   Video Demonstration Section
   ========================================================================== */

.video-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}

.video-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.video-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-lg);
}

.video-player-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1; /* Fit 256x256 square video natively */
  background: #090d16;
  overflow: hidden;
  border-bottom: 1px solid var(--border-subtle);
}

.video-element {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  image-rendering: -webkit-optimize-contrast;
  image-rendering: crisp-edges;
}

.video-badge-overlay {
  position: absolute;
  top: 10px;
  left: 10px;
  padding: 0.25rem 0.6rem;
  background: rgba(15, 23, 42, 0.78);
  backdrop-filter: blur(8px);
  color: #fff;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  z-index: 2;
  border: 1px solid rgba(255, 255, 255, 0.12);
  pointer-events: none;
}

.video-badge-overlay .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-success);
}

.video-fps-tag {
  position: absolute;
  top: 10px;
  right: 10px;
  padding: 0.2rem 0.5rem;
  background: rgba(15, 23, 42, 0.78);
  backdrop-filter: blur(8px);
  color: #93c5fd;
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-family: var(--font-mono);
  font-weight: 600;
  z-index: 2;
  border: 1px solid rgba(147, 197, 253, 0.2);
  pointer-events: none;
}



.video-card-body {
  padding: 1.15rem;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.video-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.video-meta {
  font-size: 0.8rem;
  color: var(--accent-primary);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.video-desc {
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--text-secondary);
  margin-bottom: 0.85rem;
  flex-grow: 1;
}

.video-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.video-tag {
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  background: var(--bg-surface-muted);
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  font-weight: 500;
}

/* ==========================================================================
   Methodology & Mathematics Section
   ========================================================================== */

.method-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 2rem;
  align-items: start;
}

.method-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-sm);
}

.math-formula-box {
  background: var(--bg-surface-muted);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin: 1.25rem 0;
  overflow-x: auto;
  font-size: 1.05rem;
}

.algo-container {
  background: var(--bg-code);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-medium);
}

.algo-header {
  padding: 0.75rem 1.25rem;
  background: rgba(255, 255, 255, 0.05);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: #94a3b8;
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

.algo-body {
  padding: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-code);
  line-height: 1.7;
  overflow-x: auto;
}

.algo-line {
  display: flex;
  gap: 1rem;
}

.algo-num {
  color: #475569;
  user-select: none;
  min-width: 20px;
  text-align: right;
}

/* ==========================================================================
   Interactive Results Explorer
   ========================================================================== */

.tabs-nav {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 2rem;
  background: var(--bg-surface-muted);
  padding: 0.4rem;
  border-radius: var(--radius-full);
  max-width: fit-content;
  margin-left: auto;
  margin-right: auto;
}

.tab-btn {
  padding: 0.6rem 1.25rem;
  border-radius: var(--radius-full);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.92rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.tab-btn:hover {
  color: var(--text-primary);
}

.tab-btn.active {
  background: var(--bg-surface);
  color: var(--accent-primary);
  box-shadow: var(--shadow-sm);
}

.tab-panel {
  display: none;
  animation: fadeIn 0.3s ease;
}

.tab-panel.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

.figures-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.figures-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.figures-grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.fig-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
  cursor: zoom-in;
  display: flex;
  flex-direction: column;
}

.fig-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-md);
}

.fig-card-img {
  width: 100%;
  height: auto;
  display: block;
  background: #ffffff; /* plots are white-backed */
}

.fig-card-caption {
  padding: 0.85rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  border-top: 1px solid var(--border-subtle);
  background: var(--bg-surface);
}

.fig-card-sub {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-muted);
  display: block;
  margin-top: 0.2rem;
}

/* Heatmap highlight card */
.heatmap-container {
  max-width: 750px;
  margin: 0 auto;
}

/* ==========================================================================
   Ablation Table
   ========================================================================== */

.table-wrapper {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  margin-bottom: 1.5rem;
}

.styled-table {
  width: 100%;
  border-collapse: collapse;
  text-align: center;
  font-size: 0.95rem;
}

.styled-table th {
  background: var(--bg-surface-muted);
  color: var(--text-primary);
  font-weight: 700;
  padding: 0.9rem 1rem;
  border-bottom: 1px solid var(--border-medium);
  font-family: var(--font-heading);
}

.styled-table td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.styled-table tr:last-child td {
  border-bottom: none;
}

.styled-table tr.highlight-row {
  background: var(--accent-primary-subtle);
  font-weight: 600;
}

.styled-table tr.highlight-row td {
  color: var(--accent-primary);
}

.badge-check {
  color: var(--accent-success);
  font-weight: 700;
}

/* ==========================================================================
   BibTeX Section
   ========================================================================== */

.bibtex-box {
  position: relative;
  background: var(--bg-code);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-medium);
  padding: 1.5rem;
  box-shadow: var(--shadow-md);
}

.bibtex-copy-btn {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-md);
  padding: 0.45rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: all var(--transition-fast);
}

.bibtex-copy-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: rgba(255, 255, 255, 0.4);
}

.bibtex-code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-code);
  line-height: 1.6;
  white-space: pre;
  overflow-x: auto;
  margin-bottom: 0;
}

/* ==========================================================================
   Modal Lightbox
   ========================================================================== */

.modal-lightbox {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: var(--bg-overlay);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
  padding: 2rem;
}

.modal-lightbox.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-content {
  position: relative;
  max-width: 92vw;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.modal-img {
  max-width: 100%;
  max-height: 82vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xl);
  background: #ffffff;
}

.modal-caption {
  color: #f8fafc;
  margin-top: 1rem;
  font-size: 1rem;
  font-weight: 500;
  text-align: center;
}

.modal-close-btn {
  position: absolute;
  top: -40px;
  right: 0;
  background: transparent;
  border: none;
  color: #fff;
  font-size: 1.75rem;
  cursor: pointer;
  line-height: 1;
}

/* Toast */
.toast-notification {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: #0f172a;
  color: #fff;
  border: 1px solid #334155;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 500;
  box-shadow: var(--shadow-xl);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  z-index: 1100;
  transform: translateY(100px);
  opacity: 0;
  transition: all var(--transition-normal);
}

.toast-notification.show {
  transform: translateY(0);
  opacity: 1;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  padding: 3rem 0;
  border-top: 1px solid var(--border-subtle);
  background: var(--bg-surface);
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.site-footer a {
  color: var(--text-secondary);
  font-weight: 500;
}

.site-footer a:hover {
  color: var(--accent-primary);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

@media (max-width: 1024px) {
  .hero-title { font-size: 2.1rem; }
  .pillars-grid { grid-template-columns: 1fr; }
  .method-grid { grid-template-columns: 1fr; }
  .figures-grid-3 { grid-template-columns: 1fr; }
  .figures-grid-4 { grid-template-columns: repeat(2, 1fr); }
  .video-grid { grid-template-columns: repeat(2, 1fr); gap: 1.25rem; }
}

@media (max-width: 768px) {
  .hero-title { font-size: 1.75rem; }
  .video-grid { grid-template-columns: 1fr; max-width: 320px; margin-left: auto; margin-right: auto; }
  .figures-grid-2 { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .action-buttons { flex-direction: column; width: 100%; max-width: 320px; margin-left: auto; margin-right: auto; }
  .btn { width: 100%; justify-content: center; }
  .tabs-nav { flex-wrap: wrap; border-radius: var(--radius-lg); }
  .tab-btn { flex: 1 1 45%; }
}