:root {
  --bg: #0b1120;
  --surface: #111a2e;
  --surface-hover: #17243e;
  --surface-card: #152037;
  --border: #1e2d4a;
  --border-light: #2a3d62;
  --text: #f1f5f9;
  --muted: #94a3b8;
  --primary: #38bdf8;
  --primary-hover: #0ea5e9;
  --primary-glow: rgba(56, 189, 248, 0.25);
  --accent: #818cf8;
  --accent-glow: rgba(129, 140, 248, 0.2);
  --success: #34d399;
  --warning: #fbbf24;
  --danger: #f87171;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 12px 32px rgba(0, 0, 0, 0.35);
  --shadow-glow: 0 0 40px rgba(56, 189, 248, 0.15);
}

[data-theme="light"] {
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-hover: #f1f5f9;
  --surface-card: #ffffff;
  --border: #e2e8f0;
  --border-light: #cbd5e1;
  --text: #0f172a;
  --muted: #64748b;
  --primary: #0284c7;
  --primary-hover: #0369a1;
  --primary-glow: rgba(2, 132, 199, 0.15);
  --accent: #6366f1;
  --accent-glow: rgba(99, 102, 241, 0.15);
  --shadow-sm: 0 4px 12px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 12px 32px rgba(15, 23, 42, 0.08);
  --shadow-glow: 0 0 40px rgba(2, 132, 199, 0.08);
}

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

html {
  scroll-behavior: smooth;
  font-family: var(--font);
}

body {
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background 0.3s ease, color 0.3s ease;
}

/* BACKGROUND GLOWS */
.bg-glow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background: 
    radial-gradient(1000px 600px at 50% -10%, rgba(56, 189, 248, 0.12) 0%, transparent 70%),
    radial-gradient(800px 500px at 85% 20%, rgba(129, 140, 248, 0.08) 0%, transparent 65%),
    radial-gradient(900px 600px at 15% 70%, rgba(14, 165, 233, 0.06) 0%, transparent 70%);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* NAVBAR */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(11, 17, 32, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  transition: all 0.3s ease;
}

[data-theme="light"] .navbar {
  background: rgba(248, 250, 252, 0.85);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}

.brand-logo {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 0 12px var(--primary-glow);
}

.brand-name {
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, var(--text) 30%, var(--primary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-badge {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border-light);
  color: var(--primary);
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  list-style: none;
}

.nav-link {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-link:hover {
  color: var(--primary);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  border: 1px solid transparent;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), #0284c7);
  color: #020617;
  box-shadow: 0 4px 16px var(--primary-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--primary-glow);
  background: linear-gradient(135deg, #38bdf8, var(--primary));
}

.btn-secondary {
  background: var(--surface);
  border-color: var(--border-light);
  color: var(--text);
}

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

.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.theme-toggle:hover {
  background: var(--surface-hover);
  border-color: var(--border-light);
}

/* HERO SECTION */
.hero {
  padding: 80px 0 60px;
  text-align: center;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border-light);
  font-size: 13px;
  font-weight: 500;
  color: var(--primary);
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.hero-pill-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--success);
  box-shadow: 0 0 8px var(--success);
}

.hero-title {
  font-size: 52px;
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.15;
  margin-bottom: 20px;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.hero-title span {
  background: linear-gradient(135deg, #38bdf8 0%, #818cf8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-sub {
  font-size: 18px;
  color: var(--muted);
  max-width: 720px;
  margin: 0 auto 36px;
  line-height: 1.6;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 50px;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  max-width: 960px;
  margin: 0 auto;
}

.metric-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px 16px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s, border-color 0.2s;
}

.metric-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-light);
}

.metric-val {
  font-size: 32px;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--primary);
  line-height: 1;
}

.metric-label {
  font-size: 12px;
  color: var(--muted);
  margin-top: 6px;
  font-weight: 500;
}

/* SECTION TITLES */
.section {
  padding: 80px 0;
}

.section-head {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 50px;
}

.section-tag {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 10px;
}

.section-title {
  font-size: 36px;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 14px;
}

.section-desc {
  font-size: 16px;
  color: var(--muted);
}

/* FEATURE / ARCHITECTURE CARDS */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: all 0.25s ease;
  position: relative;
  overflow: hidden;
}

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

.card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--surface-hover);
  border: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  color: var(--primary);
  margin-bottom: 18px;
}

.card-title {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.card-text {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.65;
}

/* ML ACCURACY GRAPH SIMULATOR */
.demo-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  margin-top: 30px;
}

.graph-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 24px;
}

.toggle-group {
  display: flex;
  gap: 8px;
  background: var(--bg);
  padding: 4px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

.toggle-btn {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  color: var(--muted);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.toggle-btn.active {
  background: var(--primary);
  color: #020617;
}

.chart-svg {
  width: 100%;
  height: 240px;
  display: block;
}

/* INTERACTIVE LIVE SANDBOX DEMO */
.sandbox {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.sandbox-header {
  padding: 16px 24px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sandbox-dots {
  display: flex;
  gap: 6px;
}

.sandbox-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.sandbox-dot.red { background: #ef4444; }
.sandbox-dot.yellow { background: #f59e0b; }
.sandbox-dot.green { background: #10b981; }

.sandbox-title {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--muted);
  text-transform: uppercase;
}

.sandbox-body {
  padding: 24px;
}

.prompt-chips {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.prompt-chip {
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--border-light);
  background: var(--bg);
  color: var(--text);
  font-size: 13px;
  cursor: pointer;
  transition: all 0.2s;
}

.prompt-chip:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.demo-input-row {
  display: flex;
  gap: 10px;
  margin-bottom: 24px;
}

.demo-input {
  flex: 1;
  padding: 12px 16px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-light);
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  outline: none;
}

.demo-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-glow);
}

.demo-result {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px;
}

.demo-card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 14px;
}

.demo-metric-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px;
  text-align: center;
}

.demo-metric-label {
  font-size: 10px;
  color: var(--muted);
  text-transform: uppercase;
  font-weight: 700;
}

.demo-metric-val {
  font-size: 18px;
  font-weight: 800;
  margin-top: 4px;
  color: var(--primary);
}

/* TECH STACK CHIPS */
.tech-grid {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 24px;
}

.tech-chip {
  padding: 8px 16px;
  border-radius: var(--radius-md);
  background: var(--surface);
  border: 1px solid var(--border);
  font-size: 13px;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

/* FOOTER */
.footer {
  border-top: 1px solid var(--border);
  padding: 50px 0;
  margin-top: 80px;
  background: var(--surface);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-copy {
  font-size: 13px;
  color: var(--muted);
}

/* RESPONSIVE DESIGN FOR MOBILE & TABLETS — UN-CONGESTED SPACIOUS SYSTEM */
.mobile-menu-btn {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border-light);
  color: var(--text);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.mobile-menu-btn:hover {
  background: var(--surface-hover);
  border-color: var(--primary);
}

@media (max-width: 900px) {
  .grid-4, .grid-3, .grid-2 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .brand-badge-desktop {
    display: none !important;
  }

  .container {
    padding: 0 20px;
  }

  .nav-container {
    height: 66px;
  }

  .brand-name {
    font-size: 17px;
  }

  .nav-actions {
    gap: 8px;
  }

  .theme-toggle {
    width: 38px;
    height: 38px;
    border-radius: var(--radius-sm);
  }

  .mobile-menu-btn {
    display: inline-flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 20px 24px;
    gap: 14px;
    box-shadow: var(--shadow-md);
  }

  .nav-links.mobile-open {
    display: flex;
  }

  /* HERO RESPONSIVE — SPACIOUS & AIRY */
  .hero {
    padding: 56px 0 44px;
  }

  .hero-pill {
    font-size: 11.5px;
    padding: 6px 14px;
    margin-bottom: 22px;
    max-width: 100%;
    white-space: normal;
    text-align: center;
    line-height: 1.45;
    box-shadow: var(--shadow-sm);
  }

  .hero-title {
    font-size: 26px;
    line-height: 1.35;
    margin-bottom: 18px;
    letter-spacing: -0.02em;
    word-break: break-word;
  }

  .hero-sub {
    font-size: 14px;
    line-height: 1.65;
    margin: 0 auto 28px;
    padding: 0 4px;
    color: var(--muted);
  }

  .hero-cta {
    flex-direction: column;
    width: 100%;
    gap: 12px;
    margin-bottom: 42px;
  }

  .hero-cta .btn {
    width: 100%;
    justify-content: center;
    padding: 13px 20px;
    font-size: 14px;
    border-radius: 12px;
    box-sizing: border-box;
  }

  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    max-width: 100%;
    margin-top: 8px;
  }

  .metric-card {
    padding: 16px 12px;
    border-radius: 14px;
    background: var(--surface);
    border: 1px solid var(--border);
  }

  .metric-val {
    font-size: 22px;
    margin-bottom: 2px;
  }

  .metric-label {
    font-size: 10.5px;
    margin-top: 4px;
    line-height: 1.4;
  }

  /* SECTIONS RESPONSIVE — BREATHING ROOM */
  .section {
    padding: 56px 0;
  }

  .section-head {
    margin-bottom: 32px;
    max-width: 100%;
  }

  .section-title {
    font-size: 24px;
    margin-bottom: 12px;
    line-height: 1.35;
  }

  .section-desc {
    font-size: 14px;
    line-height: 1.6;
  }

  .card {
    padding: 22px 18px;
    border-radius: 16px;
  }

  .card-title {
    font-size: 17px;
    margin-bottom: 10px;
  }

  .card-text {
    font-size: 13.5px;
    line-height: 1.6;
  }

  .card-icon {
    width: 44px;
    height: 44px;
    font-size: 20px;
    margin-bottom: 14px;
  }

  /* CHART SIMULATOR RESPONSIVE */
  .demo-box {
    padding: 20px 14px;
    border-radius: 16px;
    margin-top: 20px;
  }

  .graph-controls {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 20px;
  }

  .toggle-group {
    flex-wrap: wrap;
    width: 100%;
    gap: 6px;
  }

  .toggle-btn {
    flex: 1 1 calc(50% - 6px);
    text-align: center;
    font-size: 11px;
    padding: 8px 6px;
  }

  /* TECH STACK & FOOTER RESPONSIVE */
  .tech-grid {
    gap: 10px;
    margin-top: 20px;
  }

  .tech-chip {
    padding: 8px 14px;
    font-size: 12.5px;
  }

  .footer {
    padding: 40px 0;
    margin-top: 50px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 16px;
  }

  .footer-copy {
    align-items: center !important;
    text-align: center;
    font-size: 12.5px;
  }
}