/* ── Variables ── */
:root {
  --bg: #0d1117;
  --bg-surface: #161b22;
  --bg-surface2: #1c2128;
  --fg: #e6edf3;
  --fg-muted: #7d8590;
  --fg-subtle: #484f58;
  --accent: #f59e0b;
  --accent-dim: rgba(245,158,11,0.12);
  --accent-border: rgba(245,158,11,0.3);
  --border: rgba(240,246,252,0.1);
  --font-sans: 'IBM Plex Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'IBM Plex Mono', 'Courier New', monospace;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── Header ── */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(13,17,23,0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--fg);
  letter-spacing: -0.02em;
}

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

.header-nav {
  display: flex;
  gap: 2rem;
}

.header-nav a {
  color: var(--fg-muted);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  transition: color 0.2s;
}

.header-nav a:hover {
  color: var(--fg);
}

/* ── Hero ── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 120px 2rem 80px;
  overflow: hidden;
}

.hero-bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(245,158,11,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245,158,11,0.04) 1px, transparent 1px);
  background-size: 64px 64px;
  pointer-events: none;
}

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

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.375rem 0.875rem;
  border: 1px solid var(--accent-border);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  background: var(--accent-dim);
  margin-bottom: 2rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

.hero-headline {
  font-size: clamp(2.75rem, 7vw, 5.5rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.03em;
  color: var(--fg);
  margin-bottom: 1.75rem;
}

.hero-sub {
  font-size: clamp(1rem, 1.5vw, 1.25rem);
  color: var(--fg-muted);
  max-width: 600px;
  line-height: 1.7;
  margin-bottom: 3rem;
}

.hero-meta {
  display: flex;
  align-items: center;
  gap: 2rem;
  flex-wrap: wrap;
  margin-bottom: 3rem;
}

.meta-stat {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.meta-number {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 600;
  color: var(--accent);
  line-height: 1;
}

.meta-label {
  font-size: 0.75rem;
  color: var(--fg-muted);
  max-width: 120px;
  line-height: 1.4;
}

.meta-divider {
  width: 1px;
  height: 48px;
  background: var(--border);
}

.hero-signal {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.signal-bar {
  display: block;
  width: 4px;
  height: 20px;
  background: var(--fg-subtle);
  border-radius: 2px;
}

.signal-bar:nth-child(1) { height: 8px; }
.signal-bar:nth-child(2) { height: 14px; }
.signal-bar:nth-child(3) { height: 18px; }
.signal-bar:nth-child(4) { height: 24px; }
.signal-bar.active {
  background: var(--accent);
}

.signal-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--fg-muted);
  margin-left: 0.5rem;
}

/* ── Section Shared ── */
.section-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 1rem;
}

.section-heading {
  font-size: clamp(1.75rem, 3.5vw, 2.75rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.025em;
  color: var(--fg);
  margin-bottom: 3.5rem;
}

/* ── Features ── */
.features {
  padding: 6rem 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.feature-card {
  background: var(--bg-surface);
  padding: 2.5rem 2rem;
  transition: background 0.2s;
}

.feature-card:hover {
  background: var(--bg-surface2);
}

.feature-icon {
  margin-bottom: 1.25rem;
}

.feature-card h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 0.75rem;
  letter-spacing: -0.01em;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--fg-muted);
  line-height: 1.65;
}

/* ── How It Works ── */
.how-it-works {
  padding: 6rem 2rem;
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.how-it-works .section-heading {
  max-width: 700px;
}

.steps-row {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
}

.step {
  padding: 2.5rem 3rem 2.5rem 0;
  position: relative;
}

.step:not(:last-child)::after {
  content: '';
  position: absolute;
  right: 0;
  top: 3rem;
  bottom: 3rem;
  width: 1px;
  background: var(--border);
}

.step-number {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.1em;
  margin-bottom: 1.25rem;
}

.step-content h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 0.75rem;
}

.step-content p {
  font-size: 0.9rem;
  color: var(--fg-muted);
  line-height: 1.65;
}

.proof-bar {
  max-width: 1200px;
  margin: 4rem auto 0;
  display: flex;
  align-items: center;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  background: var(--bg);
}

.proof-item {
  flex: 1;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  align-items: center;
  text-align: center;
}

.proof-sep {
  width: 1px;
  align-self: stretch;
  background: var(--border);
}

.proof-value {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 600;
  color: var(--accent);
  line-height: 1;
}

.proof-label {
  font-size: 0.8rem;
  color: var(--fg-muted);
  line-height: 1.4;
}

/* ── Curriculum ── */
.curriculum {
  padding: 6rem 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

.curriculum-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}

.curriculum-card {
  background: var(--bg);
  padding: 2rem 1.75rem;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  transition: background 0.2s;
}

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

.curriculum-icon {
  font-size: 1.5rem;
  line-height: 1;
  flex-shrink: 0;
}

.curriculum-body h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 0.5rem;
}

.curriculum-body p {
  font-size: 0.825rem;
  color: var(--fg-muted);
  line-height: 1.55;
}

/* ── Closing ── */
.closing {
  padding: 8rem 2rem;
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
}

.closing-inner {
  max-width: 1200px;
  margin: 0 auto;
}

.closing-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 1.5rem;
}

.closing-headline {
  font-size: clamp(2rem, 4vw, 3.5rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--fg);
  margin-bottom: 2rem;
}

.closing-body {
  font-size: 1.1rem;
  color: var(--fg-muted);
  max-width: 640px;
  line-height: 1.7;
  margin-bottom: 3rem;
}

.closing-stats {
  display: flex;
  gap: 3rem;
  margin-bottom: 4rem;
  flex-wrap: wrap;
}

.closing-stat {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}

.cs-number {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--accent);
  line-height: 1;
}

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

.closing-signal {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.signal-row {
  display: flex;
  align-items: flex-end;
  gap: 6px;
}

.sr-bar {
  width: 6px;
  background: var(--fg-subtle);
  border-radius: 3px;
}

.sr-bar.a { height: 16px; }
.sr-bar.b { height: 28px; }
.sr-bar.c { height: 40px; }
.sr-bar.d { height: 32px; }
.sr-bar.e { height: 48px; }
.sr-bar.f { height: 36px; }
.sr-bar.g { height: 52px; background: var(--accent); }
.sr-bar.h { height: 44px; }

.signal-caption {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--fg-muted);
}

/* ── Footer ── */
.site-footer {
  padding: 4rem 2rem 2rem;
  background: var(--bg);
  border-top: 1px solid var(--border);
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 4rem;
  margin-bottom: 3rem;
}

.footer-brand .logo {
  display: block;
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.footer-tagline {
  font-size: 0.85rem;
  color: var(--fg-muted);
  max-width: 240px;
  line-height: 1.6;
}

.footer-links {
  display: flex;
  gap: 4rem;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-col h4 {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
  margin-bottom: 0.25rem;
}

.footer-col a,
.footer-col span {
  font-size: 0.85rem;
  color: var(--fg-subtle);
  text-decoration: none;
  transition: color 0.2s;
  cursor: default;
}

.footer-col a:hover {
  color: var(--fg-muted);
}

.footer-bottom {
  max-width: 1200px;
  margin: 0 auto;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.75rem;
  color: var(--fg-subtle);
}

/* ── CTA Buttons ── */
.btn-cta-primary {
  display: inline-block;
  background: var(--accent);
  color: #0d1117;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.75rem 1.75rem;
  border-radius: 8px;
  text-decoration: none;
  transition: background 0.2s;
}
.btn-cta-primary:hover {
  background: #d97706;
}

.btn-cta-ghost {
  display: inline-block;
  background: transparent;
  color: var(--fg-muted);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.75rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  text-decoration: none;
  transition: all 0.2s;
}
.btn-cta-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ── Responsive ── */
@media (max-width: 900px) {
  .features-grid,
  .curriculum-grid,
  .steps-row {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    flex-direction: column;
    gap: 2.5rem;
  }

  .footer-links {
    gap: 2rem;
    flex-wrap: wrap;
  }

  .proof-bar {
    flex-direction: column;
  }

  .proof-sep {
    width: 100%;
    height: 1px;
  }

  .closing-stats {
    gap: 2rem;
  }

  .meta-divider {
    display: none;
  }

  .hero-meta {
    gap: 1.5rem;
  }

  .step:not(:last-child)::after {
    display: none;
  }
}

@media (max-width: 600px) {
  .header-nav {
    display: none;
  }

  .hero-headline {
    font-size: 2.25rem;
  }

  .features,
  .how-it-works,
  .curriculum,
  .closing {
    padding: 4rem 1.25rem;
  }
}