@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

:root {
  --bg: #060d1b;
  --surface: #0d1526;
  --surface-2: #141e33;
  --surface-3: #1c2a45;
  --primary: #3b82f6;
  --primary-light: #60a5fa;
  --accent: #10b981;
  --accent-light: #34d399;
  --warn: #f59e0b;
  --danger: #ef4444;
  --text: #f1f5f9;
  --text-secondary: #94a3b8;
  --muted: #64748b;
  --radius: 16px;
  --radius-lg: 24px;
  --shadow: 0 25px 60px rgba(0, 0, 0, 0.45);
  --glass-border: rgba(255, 255, 255, 0.06);
  --transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-size: 17px;
  line-height: 1.6;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 1200px 900px at 15% 5%, rgba(59, 130, 246, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse 800px 600px at 85% 90%, rgba(16, 185, 129, 0.05) 0%, transparent 50%),
    radial-gradient(ellipse 600px 400px at 50% 50%, rgba(59, 130, 246, 0.03) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}

/* ── Layout ── */
.landing {
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Nav ── */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0;
  border-bottom: 1px solid var(--glass-border);
}
.nav-brand {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.01em;
}
.nav-links {
  display: flex;
  gap: 24px;
  list-style: none;
}
.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: var(--transition);
}
.nav-links a:hover {
  color: var(--text);
}
.nav-cta {
  padding: 8px 20px;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.15), rgba(16, 185, 129, 0.1));
  border: 1px solid rgba(59, 130, 246, 0.25);
  border-radius: 10px;
  color: var(--primary-light) !important;
  font-weight: 600 !important;
  transition: var(--transition);
}
.nav-cta:hover {
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.25), rgba(16, 185, 129, 0.15)) !important;
  border-color: rgba(59, 130, 246, 0.4);
  transform: translateY(-1px);
}

/* ── Hero ── */
.hero {
  padding: 80px 0 60px;
  text-align: center;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 20px;
  border-radius: 99px;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.15), rgba(16, 185, 129, 0.1));
  border: 1px solid rgba(59, 130, 246, 0.2);
  color: var(--primary-light);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 28px;
}
.hero h1 {
  font-size: clamp(2.4rem, 5.5vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #f1f5f9 0%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-subtitle {
  color: var(--text-secondary);
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  max-width: 640px;
  margin: 0 auto 36px;
  line-height: 1.6;
}
.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 12px;
  font-family: 'Inter', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: var(--transition);
  cursor: pointer;
  border: none;
}
.btn-primary {
  background: linear-gradient(135deg, var(--primary), #2563eb);
  color: white;
  box-shadow: 0 4px 20px rgba(59, 130, 246, 0.25);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(59, 130, 246, 0.35);
}
.btn-secondary {
  background: rgba(20, 30, 51, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-secondary);
}
.btn-secondary:hover {
  border-color: var(--primary);
  color: var(--text);
  background: rgba(59, 130, 246, 0.08);
}

/* ── Stats ── */
.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  padding: 40px 0 60px;
}
.stat-card {
  text-align: center;
  padding: 28px 20px;
  background: rgba(20, 30, 51, 0.5);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  transition: var(--transition);
}
.stat-card:hover {
  border-color: rgba(59, 130, 246, 0.2);
  transform: translateY(-2px);
}
.stat-number {
  font-size: 2.4rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary-light), var(--accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 8px;
}
.stat-label {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
}

/* ── Section headers ── */
.section-header {
  text-align: center;
  margin-bottom: 48px;
}
.section-header h2 {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}
.section-header p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 560px;
  margin: 0 auto;
}

/* ── Roadmap ── */
.roadmap {
  padding: 60px 0 80px;
}
.roadmap-grid {
  display: grid;
  gap: 32px;
}

/* Module group */
.module-group {
  position: relative;
}
.module-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
  cursor: pointer;
  padding: 16px 20px;
  background: rgba(20, 30, 51, 0.5);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  transition: var(--transition);
}
.module-header:hover {
  border-color: rgba(59, 130, 246, 0.2);
  background: rgba(28, 42, 69, 0.5);
}
.module-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  flex-shrink: 0;
}
.module-icon.intro { background: rgba(59, 130, 246, 0.12); border: 1px solid rgba(59, 130, 246, 0.2); }
.module-icon.basics { background: rgba(16, 185, 129, 0.12); border: 1px solid rgba(16, 185, 129, 0.2); }
.module-icon.system { background: rgba(245, 158, 11, 0.12); border: 1px solid rgba(245, 158, 11, 0.2); }
.module-icon.infra { background: rgba(139, 92, 246, 0.12); border: 1px solid rgba(139, 92, 246, 0.2); }

.module-info {
  flex: 1;
}
.module-info h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text);
}
.module-info p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.4;
}
.module-status {
  padding: 4px 12px;
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  white-space: nowrap;
}
.module-status.ready {
  background: rgba(16, 185, 129, 0.12);
  color: var(--accent-light);
  border: 1px solid rgba(16, 185, 129, 0.2);
}
.module-status.in-progress {
  background: rgba(245, 158, 11, 0.12);
  color: var(--warn);
  border: 1px solid rgba(245, 158, 11, 0.2);
}
.module-status.planned {
  background: rgba(100, 116, 139, 0.12);
  color: var(--muted);
  border: 1px solid rgba(100, 116, 139, 0.2);
}

.module-chevron {
  color: var(--muted);
  font-size: 1.2rem;
  transition: transform 0.3s ease;
  flex-shrink: 0;
}
.module-header.expanded .module-chevron {
  transform: rotate(90deg);
}

/* Lesson list */
.lesson-list {
  display: none;
  padding: 0 0 0 20px;
  margin: 0;
  list-style: none;
}
.lesson-list.expanded {
  display: grid;
  gap: 8px;
  animation: fadeInDown 0.3s ease;
}
@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

.lesson-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  background: rgba(13, 21, 38, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.04);
  border-radius: 12px;
  transition: var(--transition);
  text-decoration: none;
  color: inherit;
}
.lesson-item:hover {
  background: rgba(28, 42, 69, 0.5);
  border-color: rgba(59, 130, 246, 0.15);
}
.lesson-item.disabled {
  opacity: 0.45;
  pointer-events: none;
}
.lesson-number {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.15);
  color: var(--primary-light);
}
.lesson-item.disabled .lesson-number {
  background: rgba(100, 116, 139, 0.1);
  border-color: rgba(100, 116, 139, 0.15);
  color: var(--muted);
}
.lesson-info {
  flex: 1;
}
.lesson-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 2px;
}
.lesson-item.disabled .lesson-title {
  color: var(--muted);
}
.lesson-desc {
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.3;
}
.lesson-badge {
  padding: 3px 10px;
  border-radius: 99px;
  font-size: 0.7rem;
  font-weight: 600;
  white-space: nowrap;
}
.lesson-badge.available {
  background: rgba(16, 185, 129, 0.12);
  color: var(--accent-light);
  border: 1px solid rgba(16, 185, 129, 0.2);
}
.lesson-badge.coming {
  background: rgba(100, 116, 139, 0.12);
  color: var(--muted);
  border: 1px solid rgba(100, 116, 139, 0.15);
}

/* ── CTA Section ── */
.cta-section {
  padding: 60px 0 80px;
  text-align: center;
}
.cta-card {
  background: linear-gradient(160deg, rgba(20, 30, 51, 0.92), rgba(13, 21, 38, 0.96));
  border: 1px solid rgba(59, 130, 246, 0.15);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
  max-width: 700px;
  margin: 0 auto;
  position: relative;
  overflow: hidden;
}
.cta-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.4), rgba(16, 185, 129, 0.3), transparent);
}
.cta-card h2 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 12px;
}
.cta-card p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 500px;
  margin: 0 auto 28px;
  line-height: 1.6;
}
.cta-links {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ── Footer ── */
.landing-footer {
  border-top: 1px solid var(--glass-border);
  padding: 24px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.85rem;
}
.landing-footer a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition);
}
.landing-footer a:hover {
  color: var(--text);
}

/* ── Scroll animation ── */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .landing { padding: 0 16px; }
  .hero { padding: 48px 0 40px; }
  .hero h1 { font-size: 2rem; }
  .stats { grid-template-columns: 1fr; gap: 12px; }
  .stat-card { padding: 20px; }
  .stat-number { font-size: 1.8rem; }
  .nav-links { display: none; }
  .hero-actions { flex-direction: column; align-items: center; }
  .cta-card { padding: 32px 24px; }
  .cta-links { flex-direction: column; align-items: center; }
  .landing-footer { flex-direction: column; gap: 8px; text-align: center; }
  .module-header { flex-wrap: wrap; }
  .module-status { margin-top: 4px; }
}