:root {
  --bg: #0a0a0f;
  --bg-surface: #12121a;
  --bg-card: #1a1a26;
  --fg: #e8e8ed;
  --fg-muted: #8888a0;
  --accent: #00e676;
  --accent-dim: #00c85320;
  --accent-glow: #00e67640;
  --grid-line: #1e1e2e;
  --border: #2a2a3a;
  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'DM Sans', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

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

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  line-height: 1.6;
  overflow-x: hidden;
}

/* Grid background pattern */
.grid-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 60px 60px;
  opacity: 0.4;
  pointer-events: none;
  z-index: 0;
}

.content-wrapper {
  position: relative;
  z-index: 1;
}

/* HERO */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 120px 24px 80px;
  max-width: 1100px;
  margin: 0 auto;
}

.hero-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.hero-label::before {
  content: '';
  width: 32px;
  height: 2px;
  background: var(--accent);
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 7vw, 5.5rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 32px;
  max-width: 900px;
}

.hero h1 .highlight {
  color: var(--accent);
}

.hero-sub {
  font-size: 1.25rem;
  color: var(--fg-muted);
  max-width: 560px;
  line-height: 1.7;
  margin-bottom: 56px;
}

/* Stats row */
.stats-row {
  display: flex;
  gap: 48px;
  flex-wrap: wrap;
}

.stat {
  border-left: 2px solid var(--accent);
  padding-left: 20px;
}

.stat-number {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--fg);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--fg-muted);
  margin-top: 4px;
}

/* SYSTEM SECTION */
.system-section {
  padding: 120px 24px;
  max-width: 1100px;
  margin: 0 auto;
}

.section-header {
  margin-bottom: 72px;
}

.section-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.section-header h2 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  max-width: 700px;
}

/* Grid cards */
.system-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2px;
  background: var(--border);
  border: 1px solid var(--border);
}

.system-card {
  background: var(--bg-surface);
  padding: 48px 40px;
  position: relative;
  transition: background 0.3s;
}

.system-card:hover {
  background: var(--bg-card);
}

.card-number {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  margin-bottom: 20px;
  opacity: 0.7;
}

.system-card h3 {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 600;
  margin-bottom: 14px;
  letter-spacing: -0.01em;
}

.system-card p {
  font-size: 0.95rem;
  color: var(--fg-muted);
  line-height: 1.65;
}

/* MATH SECTION */
.math-section {
  padding: 120px 24px;
  max-width: 1100px;
  margin: 0 auto;
}

.math-block {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: 64px 56px;
  margin-top: 56px;
}

.math-row {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 24px 0;
  border-bottom: 1px solid var(--grid-line);
}

.math-row:last-child {
  border-bottom: none;
  padding-top: 32px;
}

.math-row:last-child .math-value {
  color: var(--accent);
  font-size: 2.4rem;
}

.math-label {
  font-size: 1rem;
  color: var(--fg-muted);
  flex: 1;
}

.math-value {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  text-align: right;
  min-width: 140px;
}

.math-operator {
  font-family: var(--font-mono);
  color: var(--fg-muted);
  font-size: 1.2rem;
  width: 20px;
  text-align: center;
}

/* CLOSING */
.closing {
  padding: 160px 24px;
  text-align: center;
  position: relative;
}

.closing::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
}

.closing-content {
  position: relative;
  z-index: 1;
}

.closing h2 {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 5vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
}

.closing h2 .highlight {
  color: var(--accent);
}

.closing p {
  font-size: 1.15rem;
  color: var(--fg-muted);
  max-width: 500px;
  margin: 0 auto;
  line-height: 1.7;
}

/* FOOTER */
footer {
  padding: 48px 24px;
  border-top: 1px solid var(--border);
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.1rem;
}

.footer-note {
  font-size: 0.8rem;
  color: var(--fg-muted);
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .hero {
    padding: 100px 20px 60px;
  }

  .stats-row {
    gap: 32px;
  }

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

  .system-card {
    padding: 36px 28px;
  }

  .math-block {
    padding: 36px 28px;
  }

  .math-row {
    flex-direction: column;
    gap: 4px;
  }

  .math-value {
    text-align: left;
  }

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

@media (max-width: 480px) {
  .stats-row {
    flex-direction: column;
    gap: 28px;
  }

  .closing {
    padding: 100px 20px;
  }
}