:root {
  --bg-primary: #090d16;
  --bg-surface: #0f172a;
  --bg-card: #131e35;
  --bg-card-hover: #172544;
  --text-main: #f8fafc;
  --text-dim: #94a3b8;
  --text-muted: #64748b;
  --accent-cyan: #06b6d4;
  --accent-cyan-glow: rgba(6, 182, 212, 0.25);
  --accent-blue: #38bdf8;
  --accent-orange: #f97316;
  --border-subtle: #1e293b;
  --border-accent: rgba(6, 182, 212, 0.35);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-card: 0 4px 20px -2px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 25px rgba(6, 182, 212, 0.15);
}

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

body {
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

/* Header & Navigation */
.header-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(9, 13, 22, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  padding: 0.85rem 1.5rem;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text-main);
  letter-spacing: -0.02em;
}

.logo-badge {
  background: linear-gradient(135deg, var(--accent-cyan), #2563eb);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  font-weight: 800;
  letter-spacing: 0.05em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  font-size: 0.9rem;
  font-weight: 500;
}

.nav-links a {
  color: var(--text-dim);
}

.nav-links a:hover {
  color: var(--text-main);
}

/* Hero Section */
.hero-section {
  padding: 5rem 1.5rem 4rem;
  text-align: center;
  background: radial-gradient(circle at 50% 20%, rgba(6, 182, 212, 0.08) 0%, transparent 70%);
  border-bottom: 1px solid var(--border-subtle);
}

.hero-container {
  max-width: 900px;
  margin: 0 auto;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.85rem;
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid var(--border-accent);
  border-radius: 9999px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent-cyan);
  margin-bottom: 1.5rem;
}

.hero-tag .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-cyan);
  box-shadow: 0 0 8px var(--accent-cyan);
}

.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
  background: linear-gradient(180deg, #ffffff 0%, #cbd5e1 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.2rem);
  color: var(--text-dim);
  max-width: 720px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1.25rem;
  margin-top: 2rem;
  text-align: left;
}

.stat-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem;
}

.stat-value {
  font-family: var(--font-mono);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent-cyan);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* Main Content Layout */
.main-content {
  flex: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 4rem 1.5rem;
  width: 100%;
}

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

.section-title {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.section-desc {
  color: var(--text-dim);
  font-size: 1rem;
  max-width: 650px;
}

/* Network Grid */
.network-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.75rem;
  margin-bottom: 4rem;
}

.network-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  transition: all 0.25s ease;
  position: relative;
  overflow: hidden;
}

.network-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
  opacity: 0;
  transition: opacity 0.25s ease;
}

.network-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-card), var(--shadow-glow);
  background: var(--bg-card);
}

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

.card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.card-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid var(--border-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-cyan);
}

.card-badge {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.25rem 0.55rem;
  border-radius: 9999px;
  background: rgba(16, 185, 129, 0.12);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text-main);
}

.card-domain {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent-cyan);
  margin-bottom: 0.85rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.card-description {
  font-size: 0.92rem;
  color: var(--text-dim);
  margin-bottom: 1.25rem;
  flex: 1;
  line-height: 1.6;
}

.card-features {
  list-style: none;
  border-top: 1px solid var(--border-subtle);
  padding-top: 1rem;
  margin-bottom: 1.25rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.card-features li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.4rem;
}

.card-features li svg {
  color: var(--accent-cyan);
  flex-shrink: 0;
}

.card-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-main);
  font-size: 0.85rem;
  font-weight: 600;
  transition: all 0.2s ease;
}

.network-card:hover .card-btn {
  background: var(--accent-cyan);
  color: #090d16;
  border-color: var(--accent-cyan);
  box-shadow: 0 0 15px rgba(6, 182, 212, 0.4);
}

/* Engineering Philosophy / Architecture */
.philosophy-section {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 3rem 2.5rem;
  margin-bottom: 4rem;
}

.pillars-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.pillar-item {
  background: var(--bg-primary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.75rem;
}

.pillar-num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--accent-cyan);
  margin-bottom: 0.75rem;
}

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

.pillar-desc {
  font-size: 0.9rem;
  color: var(--text-dim);
  line-height: 1.6;
}

/* Footer */
.footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 1.5rem 2rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}

.footer-about p {
  color: var(--text-dim);
  margin-top: 0.5rem;
  max-width: 450px;
  line-height: 1.6;
}

.footer-links h4 {
  color: var(--text-main);
  font-size: 0.95rem;
  margin-bottom: 1rem;
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-links a {
  color: var(--text-dim);
}

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

.footer-bottom {
  max-width: 1200px;
  margin: 0 auto;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: gap;
  gap: 1rem;
}

@media (max-width: 768px) {
  .footer-container {
    grid-template-columns: 1fr;
  }
  .nav-links {
    display: none;
  }
}