/* ═══════════════════════════════════════════════════════════════
   DLOSafe — Project Page Stylesheet
   Premium dark theme with gradient accents, glassmorphism, 
   and micro-animations for academic research presentation
   ═══════════════════════════════════════════════════════════════ */

/* ── Custom Properties ── */
:root {
  /* Core palette */
  --bg-deep:       #06080f;
  --bg-surface:    #0c1020;
  --bg-card:       rgba(15, 22, 45, 0.65);
  --bg-card-hover: rgba(25, 35, 65, 0.75);
  --bg-glass:      rgba(255, 255, 255, 0.04);

  /* Accent gradient stops */
  --accent-1: #6366f1;   /* indigo */
  --accent-2: #8b5cf6;   /* violet */
  --accent-3: #a78bfa;   /* lavender */
  --accent-4: #c084fc;   /* orchid */
  --accent-5: #e879f9;   /* fuchsia */
  --accent-6: #f472b6;   /* pink */

  /* Text */
  --text-primary:   #e8eaf6;
  --text-secondary: #9ca3c4;
  --text-muted:     #5b6591;

  /* Borders */
  --border-subtle: rgba(139, 92, 246, 0.12);
  --border-glow:   rgba(139, 92, 246, 0.30);

  /* Sizes */
  --nav-height: 64px;
  --section-pad: 120px;
  --container-w: 1120px;

  /* Transitions */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

a {
  color: var(--accent-3);
  text-decoration: none;
  transition: color 0.25s;
}
a:hover {
  color: var(--accent-5);
}

img {
  max-width: 100%;
  display: block;
}

code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.88em;
  background: rgba(139, 92, 246, 0.12);
  padding: 2px 7px;
  border-radius: 4px;
}

.container {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px;
}

.accent {
  color: var(--accent-3);
}

/* ═══════════════════ NAVIGATION ═══════════════════ */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 1000;
  background: rgba(6, 8, 15, 0.6);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border-subtle);
  transition: background 0.4s, border-color 0.4s;
}

.nav.scrolled {
  background: rgba(6, 8, 15, 0.92);
  border-color: var(--border-glow);
}

.nav-inner {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.nav-logo-icon {
  font-size: 1.4rem;
  filter: drop-shadow(0 0 8px rgba(139, 92, 246, 0.5));
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.88rem;
  font-weight: 500;
  padding: 6px 14px;
  border-radius: 8px;
  transition: all 0.25s var(--ease-out-expo);
}

.nav-links a:hover {
  color: var(--text-primary);
  background: var(--bg-glass);
}

.nav-btn {
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2)) !important;
  color: #fff !important;
  padding: 8px 18px !important;
  border-radius: 8px !important;
  font-weight: 600 !important;
}

.nav-btn:hover {
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
  transform: translateY(-1px);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all 0.3s;
}

/* ═══════════════════ HERO ═══════════════════ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--nav-height) + 40px) 24px 60px;
  overflow: hidden;
}

#heroCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% 0%, rgba(99, 102, 241, 0.15), transparent),
    radial-gradient(ellipse 60% 40% at 80% 80%, rgba(192, 132, 252, 0.08), transparent),
    radial-gradient(ellipse 40% 30% at 20% 70%, rgba(244, 114, 182, 0.06), transparent);
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 820px;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-bottom: 28px;
}

.badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 5px 14px;
  border-radius: 20px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.badge-blue   { background: rgba(99, 102, 241, 0.18);  color: #818cf8; border: 1px solid rgba(99, 102, 241, 0.3); }
.badge-purple { background: rgba(139, 92, 246, 0.18);  color: #a78bfa; border: 1px solid rgba(139, 92, 246, 0.3); }
.badge-green  { background: rgba(52, 211, 153, 0.14);  color: #6ee7b7; border: 1px solid rgba(52, 211, 153, 0.25); }

.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
}

.hero-title-gradient {
  background: linear-gradient(135deg, var(--accent-3), var(--accent-4), var(--accent-6));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  font-weight: 400;
  margin-bottom: 18px;
}

.hero-author {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.hero-author strong {
  color: var(--text-primary);
}

.hero-cta {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.3s var(--ease-out-expo);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-1), var(--accent-4));
  color: #fff;
  box-shadow: 0 4px 24px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(99, 102, 241, 0.5);
  color: #fff;
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  transform: translateY(-2px);
  color: var(--text-primary);
}

.hero-tech-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.pill {
  font-size: 0.78rem;
  font-weight: 500;
  padding: 4px 12px;
  border-radius: 6px;
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.hero-scroll-hint {
  position: absolute;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.scroll-arrow {
  width: 20px;
  height: 32px;
  border: 2px solid var(--text-muted);
  border-radius: 12px;
  position: relative;
}

.scroll-arrow::after {
  content: '';
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 8px;
  border-radius: 2px;
  background: var(--accent-3);
  animation: scrollBounce 1.8s ease-in-out infinite;
}

@keyframes scrollBounce {
  0%, 100% { transform: translateX(-50%) translateY(0); opacity: 1; }
  50%      { transform: translateX(-50%) translateY(10px); opacity: 0.3; }
}

/* ═══════════════════ SECTIONS ═══════════════════ */
.section {
  padding: var(--section-pad) 0;
  position: relative;
}

.section-alt {
  background: var(--bg-surface);
}

.section-alt::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 50% 40% at 80% 20%, rgba(99, 102, 241, 0.04), transparent),
    radial-gradient(ellipse 40% 30% at 10% 80%, rgba(192, 132, 252, 0.03), transparent);
  pointer-events: none;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-label {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-3);
  margin-bottom: 12px;
  display: inline-block;
}

.section-title {
  font-size: clamp(1.8rem, 3.5vw, 2.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 16px;
}

.section-desc {
  max-width: 640px;
  margin: 0 auto;
  color: var(--text-secondary);
  font-size: 1.05rem;
}

/* ═══════════════════ DEMO ═══════════════════ */
.demo-video-wrapper {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
}

.demo-video-card {
  position: relative;
  border-radius: 20px;
  overflow: hidden;
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
}

.demo-video-glow {
  position: absolute;
  inset: -2px;
  border-radius: 22px;
  background: linear-gradient(135deg, var(--accent-1), var(--accent-4), var(--accent-6));
  opacity: 0.15;
  z-index: 0;
  filter: blur(1px);
}

.demo-video {
  position: relative;
  z-index: 1;
  width: 100%;
  border-radius: 19px;
}

.demo-phases {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.phase-item {
  display: flex;
  gap: 14px;
  padding: 20px;
  border-radius: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
  transition: all 0.3s var(--ease-out-expo);
}

.phase-item:hover {
  border-color: var(--border-glow);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.phase-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.phase-icon-pick     { background: rgba(99, 102, 241, 0.18); }
.phase-icon-handover { background: rgba(139, 92, 246, 0.18); }
.phase-icon-place    { background: rgba(52, 211, 153, 0.18); }

.phase-item h4 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.phase-item p {
  font-size: 0.82rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ═══════════════════ OVERVIEW ═══════════════════ */
.overview-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 60px;
  align-items: center;
}

.overview-lead {
  font-size: 1.15rem;
  line-height: 1.8;
  margin-bottom: 32px;
  color: var(--text-secondary);
}

.overview-lead strong {
  color: var(--text-primary);
}

.safety-cards {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.safety-card {
  padding: 22px 24px;
  border-radius: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
  transition: all 0.3s var(--ease-out-expo);
  position: relative;
  overflow: hidden;
}

.safety-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 3px;
  height: 100%;
  background: linear-gradient(to bottom, var(--accent-1), var(--accent-4));
  opacity: 0;
  transition: opacity 0.3s;
}

.safety-card:hover {
  border-color: var(--border-glow);
  transform: translateX(4px);
}

.safety-card:hover::before {
  opacity: 1;
}

.safety-num {
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--accent-3);
  letter-spacing: 0.08em;
  margin-bottom: 6px;
}

.safety-card h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.safety-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

/* Problem Diagram */
.overview-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.problem-diagram {
  position: relative;
  width: 300px;
  height: 300px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.diagram-ring {
  position: absolute;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  animation: ringPulse 4s ease-in-out infinite;
}

.diagram-ring span {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.diagram-ring-outer {
  width: 280px;
  height: 280px;
  border: 1.5px solid rgba(99, 102, 241, 0.2);
  background: rgba(99, 102, 241, 0.03);
}

.diagram-ring-outer span {
  position: absolute;
  top: 14px;
}

.diagram-ring-mid {
  width: 190px;
  height: 190px;
  border: 1.5px solid rgba(139, 92, 246, 0.3);
  background: rgba(139, 92, 246, 0.05);
  animation-delay: -1.3s;
}

.diagram-ring-mid span {
  position: absolute;
  top: 14px;
}

.diagram-ring-inner {
  width: 100px;
  height: 100px;
  border: 2px solid rgba(192, 132, 252, 0.5);
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.12), rgba(192, 132, 252, 0.12));
  animation-delay: -2.6s;
}

.diagram-ring-inner span {
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--accent-3);
}

@keyframes ringPulse {
  0%, 100% { transform: scale(1); }
  50%      { transform: scale(1.04); }
}

/* ═══════════════════ ARCHITECTURE ═══════════════════ */
.arch-diagram {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
  margin-bottom: 48px;
}

.arch-level {
  width: 100%;
  max-width: 580px;
  padding: 28px 32px;
  border-radius: 16px;
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  text-align: center;
  transition: all 0.3s var(--ease-out-expo);
  position: relative;
  overflow: hidden;
}

.arch-level::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
}

.arch-level-global::after { background: linear-gradient(90deg, transparent, var(--accent-1), var(--accent-2), transparent); }
.arch-level-local::after  { background: linear-gradient(90deg, transparent, var(--accent-2), var(--accent-4), transparent); }
.arch-level-sim::after    { background: linear-gradient(90deg, transparent, var(--accent-4), var(--accent-6), transparent); }

.arch-level:hover {
  border-color: var(--border-glow);
  transform: scale(1.02);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.arch-level-badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent-3);
  background: rgba(139, 92, 246, 0.1);
  padding: 3px 12px;
  border-radius: 6px;
  margin-bottom: 10px;
}

.arch-level h3 {
  font-size: 1.2rem;
  font-weight: 800;
  margin-bottom: 6px;
}

.arch-level p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 14px;
}

.arch-features {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.arch-features span {
  font-size: 0.74rem;
  font-weight: 500;
  padding: 4px 10px;
  border-radius: 6px;
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.arch-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 4px 0;
}

.arch-arrow-label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 2px;
}

/* Mode switching callout */
.mode-switch-card {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  max-width: 680px;
  margin: 0 auto;
  padding: 24px 28px;
  border-radius: 16px;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.08), rgba(192, 132, 252, 0.06));
  border: 1px solid rgba(139, 92, 246, 0.2);
}

.mode-switch-icon {
  font-size: 1.6rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.mode-switch-content h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.mode-switch-content p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ═══════════════════ TECH STACK ═══════════════════ */
.tech-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px;
}

.tech-card {
  width: calc(33.333% - 14px);
  padding: 28px 24px;
  border-radius: 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
  text-align: center;
  transition: all 0.35s var(--ease-out-expo);
  position: relative;
  overflow: hidden;
}

.tech-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.06), rgba(192, 132, 252, 0.04));
  opacity: 0;
  transition: opacity 0.35s;
}

.tech-card:hover {
  border-color: var(--border-glow);
  transform: translateY(-6px);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.35);
}

.tech-card:hover::before {
  opacity: 1;
}

.tech-card-icon {
  font-size: 2rem;
  margin-bottom: 14px;
  position: relative;
  z-index: 1;
}

.tech-card h4 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
  position: relative;
  z-index: 1;
}

.tech-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.55;
  position: relative;
  z-index: 1;
}

/* ═══════════════════ TIMELINE ═══════════════════ */
.timeline {
  position: relative;
  max-width: 640px;
  margin: 0 auto;
  padding-left: 48px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 18px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(
    to bottom,
    var(--accent-1),
    var(--accent-2),
    var(--accent-4),
    var(--accent-6),
    var(--text-muted)
  );
  border-radius: 2px;
}

.timeline-item {
  position: relative;
  margin-bottom: 28px;
}

.timeline-marker {
  position: absolute;
  left: -38px;
  top: 24px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2.5px solid var(--text-muted);
  background: var(--bg-deep);
  z-index: 1;
}

.timeline-done .timeline-marker {
  border-color: var(--accent-1);
  background: var(--accent-1);
  box-shadow: 0 0 12px rgba(99, 102, 241, 0.5);
}

.timeline-card {
  padding: 22px 24px;
  border-radius: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
  transition: all 0.3s var(--ease-out-expo);
}

.timeline-card:hover {
  border-color: var(--border-glow);
  transform: translateX(4px);
}

.timeline-month {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--accent-3);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 4px;
}

.timeline-status {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 6px;
  margin-bottom: 8px;
}

.status-done    { background: rgba(52, 211, 153, 0.14); color: #6ee7b7; }
.status-planned { background: rgba(100, 116, 139, 0.14); color: #94a3b8; }

.timeline-card h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.timeline-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ═══════════════════ REFERENCES ═══════════════════ */
.ref-list {
  max-width: 760px;
  margin: 0 auto;
  padding-left: 22px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.ref-list li {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.65;
  padding: 14px 18px;
  border-radius: 10px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  list-style-position: inside;
  transition: border-color 0.3s;
}

.ref-list li:hover {
  border-color: var(--border-glow);
}

.ref-list li em {
  color: var(--accent-3);
  font-style: italic;
}

/* ═══════════════════ FOOTER ═══════════════════ */
.footer {
  padding: 60px 0 32px;
  background: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-info h3 {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 10px;
}

.footer-info p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links h4 {
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.footer-links a {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.footer-links a:hover {
  color: var(--accent-3);
}

.footer-bottom {
  border-top: 1px solid var(--border-subtle);
  padding-top: 20px;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ═══════════════════ ANIMATIONS ═══════════════════ */
.anim-fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s var(--ease-out-expo), transform 0.7s var(--ease-out-expo);
}

.anim-fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children */
.safety-cards .anim-fade-up:nth-child(2) { transition-delay: 0.1s; }
.safety-cards .anim-fade-up:nth-child(3) { transition-delay: 0.2s; }

.demo-phases .anim-fade-up:nth-child(2) { transition-delay: 0.1s; }
.demo-phases .anim-fade-up:nth-child(3) { transition-delay: 0.2s; }

.tech-grid .anim-fade-up:nth-child(2) { transition-delay: 0.06s; }
.tech-grid .anim-fade-up:nth-child(3) { transition-delay: 0.12s; }
.tech-grid .anim-fade-up:nth-child(4) { transition-delay: 0.18s; }
.tech-grid .anim-fade-up:nth-child(5) { transition-delay: 0.24s; }
.tech-grid .anim-fade-up:nth-child(6) { transition-delay: 0.30s; }

.timeline-item:nth-child(2) { transition-delay: 0.06s; }
.timeline-item:nth-child(3) { transition-delay: 0.12s; }
.timeline-item:nth-child(4) { transition-delay: 0.18s; }
.timeline-item:nth-child(5) { transition-delay: 0.24s; }
.timeline-item:nth-child(6) { transition-delay: 0.30s; }

/* ═══════════════════ RESPONSIVE ═══════════════════ */
@media (max-width: 900px) {
  :root {
    --section-pad: 80px;
  }

  .overview-grid {
    grid-template-columns: 1fr;
  }

  .overview-visual {
    order: -1;
  }

  .problem-diagram {
    width: 240px;
    height: 240px;
  }

  .diagram-ring-outer { width: 220px; height: 220px; }
  .diagram-ring-mid   { width: 150px; height: 150px; }
  .diagram-ring-inner { width: 80px;  height: 80px;  }

  .tech-card {
    width: calc(50% - 10px);
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }
}

@media (max-width: 640px) {
  :root {
    --section-pad: 60px;
  }

  /* Mobile nav */
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: rgba(6, 8, 15, 0.96);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 20px;
    gap: 4px;
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all 0.4s var(--ease-out-expo);
    border-bottom: 1px solid var(--border-subtle);
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav-links a {
    padding: 12px 16px;
    font-size: 1rem;
  }

  .demo-phases {
    grid-template-columns: 1fr;
  }

  .tech-card {
    width: 100%;
  }

  .timeline {
    padding-left: 36px;
  }

  .timeline::before {
    left: 10px;
  }

  .timeline-marker {
    left: -30px;
  }

  .mode-switch-card {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .hero-title {
    font-size: 1.8rem;
  }
}