:root {
  --bg-primary: #090c12;
  --bg-secondary: #0f141f;
  --bg-card: rgba(18, 25, 38, 0.78);
  --bg-elevated: #161f30;
  --border-subtle: rgba(148, 163, 184, 0.14);
  --border-highlight: rgba(99, 102, 241, 0.45);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-primary: #6366f1;
  --accent-hover: #4f46e5;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  --accent-danger: #ef4444;
  --font-sans: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.45);
}

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

html {
  scroll-behavior: smooth;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-image:
    radial-gradient(circle at 15% 10%, rgba(99, 102, 241, 0.12), transparent 35%),
    radial-gradient(circle at 85% 20%, rgba(16, 185, 129, 0.08), transparent 35%);
  background-attachment: fixed;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease, opacity 0.2s ease;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(9, 12, 18, 0.85);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-subtle);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 20px;
}

.brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 1.125rem;
  letter-spacing: -0.02em;
}

.brand-logo svg {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
}

.brand-badge {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 2px 7px;
  border-radius: 999px;
  background: rgba(99, 102, 241, 0.16);
  color: #a5b4fc;
  border: 1px solid rgba(99, 102, 241, 0.3);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  font-weight: 500;
  padding: 6px 0;
  position: relative;
}

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

.nav-link.active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -20px;
  height: 2px;
  background: var(--accent-primary);
  border-radius: 2px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  padding: 5px 10px;
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.25);
  border-radius: 999px;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent-emerald);
  box-shadow: 0 0 8px var(--accent-emerald);
}

.mobile-menu-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 20px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.925rem;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s ease;
  font-family: inherit;
}

.btn-sm {
  padding: 8px 15px;
  font-size: 0.85rem;
}

.btn-primary {
  background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
  color: #fff;
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.35);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #4f46e5 0%, #4338ca 100%);
  transform: translateY(-1px);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-primary);
  border-color: var(--border-subtle);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(148, 163, 184, 0.35);
}

.btn:disabled {
  opacity: 0.65;
  cursor: not-allowed;
  transform: none;
}

/* Hero Section */
.hero {
  padding: 76px 0 60px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  color: #a5b4fc;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 20px;
}

.hero-title {
  font-size: clamp(2.1rem, 4vw, 3.25rem);
  line-height: 1.12;
  letter-spacing: -0.03em;
  font-weight: 800;
  margin-bottom: 20px;
}

.text-gradient {
  background: linear-gradient(95deg, #818cf8 0%, #34d399 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-lead {
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: 28px;
  max-width: 600px;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 32px;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Terminal / Interactive Demo Box */
.terminal-window {
  background: #0b0f19;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.terminal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: #111726;
  border-bottom: 1px solid var(--border-subtle);
}

.terminal-dots {
  display: flex;
  gap: 7px;
}

.terminal-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

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

.terminal-tabs {
  display: flex;
  gap: 6px;
}

.terminal-tab {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 4px 10px;
  border-radius: 6px;
  cursor: pointer;
}

.terminal-tab.active {
  background: rgba(99, 102, 241, 0.16);
  color: #c7d2fe;
  border-color: rgba(99, 102, 241, 0.35);
}

.terminal-body {
  padding: 20px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.65;
  color: #e2e8f0;
  min-height: 290px;
}

.terminal-pane {
  display: none;
}

.terminal-pane.active {
  display: block;
}

.code-comment { color: #64748b; }
.code-kw { color: #818cf8; }
.code-str { color: #34d399; }
.code-fn { color: #fbbf24; }

/* Sections & Cards */
.section {
  padding: 64px 0;
}

.section-alt {
  background: rgba(15, 20, 31, 0.6);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.section-header {
  max-width: 720px;
  margin-bottom: 40px;
}

.section-title {
  font-size: clamp(1.65rem, 2.8vw, 2.25rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-subtitle {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 32px;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px;
}

.stat-value {
  font-size: 2rem;
  font-weight: 800;
  font-family: var(--font-mono);
  color: var(--text-primary);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

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

.cards-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.card:hover {
  border-color: var(--border-highlight);
  transform: translateY(-2px);
}

.card-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: rgba(99, 102, 241, 0.14);
  border: 1px solid rgba(99, 102, 241, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #818cf8;
  margin-bottom: 18px;
}

.card-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.card-text {
  color: var(--text-secondary);
  font-size: 0.94rem;
  margin-bottom: 18px;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 4px 10px;
  border-radius: 6px;
  background: rgba(148, 163, 184, 0.1);
  color: #cbd5e1;
  border: 1px solid var(--border-subtle);
}

.tag-indigo {
  background: rgba(99, 102, 241, 0.15);
  color: #a5b4fc;
  border-color: rgba(99, 102, 241, 0.3);
}

.tag-emerald {
  background: rgba(16, 185, 129, 0.12);
  color: #6ee7b7;
  border-color: rgba(16, 185, 129, 0.3);
}

/* Filter Bar & Search */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 32px;
  padding: 16px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
}

.filter-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.filter-btn {
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  padding: 7px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: #fff;
}

.search-input {
  background: #0b0f19;
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  padding: 9px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  min-width: 260px;
}

.search-input:focus {
  outline: none;
  border-color: var(--accent-primary);
}

/* Accordion / FAQ / Curriculum Modules */
.accordion {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.accordion-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.accordion-trigger {
  width: 100%;
  background: transparent;
  border: none;
  color: var(--text-primary);
  padding: 18px 22px;
  text-align: left;
  font-size: 1rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-family: inherit;
}

.accordion-icon {
  font-family: var(--font-mono);
  color: var(--accent-primary);
  font-size: 1.2rem;
  transition: transform 0.2s ease;
}

.accordion-item.open .accordion-icon {
  transform: rotate(45deg);
}

.accordion-content {
  display: none;
  padding: 0 22px 20px;
  color: var(--text-secondary);
  font-size: 0.94rem;
  border-top: 1px solid rgba(148, 163, 184, 0.08);
  padding-top: 14px;
}

.accordion-item.open .accordion-content {
  display: block;
}

/* Article / Longread Layout */
.article-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 44px;
  align-items: start;
}

.toc-box {
  position: sticky;
  top: 96px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px;
}

.toc-title {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 12px;
  font-weight: 700;
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.toc-list a {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.toc-list a:hover {
  color: #a5b4fc;
}

.article-content {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 40px;
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.breadcrumbs a:hover {
  color: var(--text-primary);
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  font-size: 0.85rem;
  color: var(--text-secondary);
  padding-bottom: 24px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--border-subtle);
}

.prose h2 {
  font-size: 1.5rem;
  margin: 34px 0 14px;
  letter-spacing: -0.01em;
}

.prose h3 {
  font-size: 1.2rem;
  margin: 24px 0 10px;
}

.prose p {
  color: #cbd5e1;
  margin-bottom: 16px;
  font-size: 1.02rem;
}

.prose ul, .prose ol {
  margin: 0 0 18px 22px;
  color: #cbd5e1;
}

.prose li {
  margin-bottom: 8px;
}

.callout {
  background: rgba(99, 102, 241, 0.08);
  border-left: 3px solid var(--accent-primary);
  padding: 16px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 22px 0;
  color: #e2e8f0;
  font-size: 0.95rem;
}

.code-block-wrapper {
  position: relative;
  margin: 22px 0;
  background: #070a10;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.code-block-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 14px;
  background: #101624;
  border-bottom: 1px solid var(--border-subtle);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.copy-code-btn {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  padding: 3px 9px;
  border-radius: 5px;
  cursor: pointer;
}

.copy-code-btn:hover {
  background: rgba(99, 102, 241, 0.25);
}

.code-block-wrapper pre {
  padding: 16px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  line-height: 1.6;
  color: #e2e8f0;
}

/* Auth / LMS Portal Page */
.auth-wrapper {
  max-width: 540px;
  margin: 48px auto;
}

.auth-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 34px;
  box-shadow: var(--shadow-lg);
}

.auth-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  background: #090d16;
  padding: 5px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  margin-bottom: 26px;
}

.auth-tab {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 9px 8px;
  font-size: 0.82rem;
  font-weight: 600;
  border-radius: 6px;
  cursor: pointer;
  font-family: inherit;
}

.auth-tab.active {
  background: var(--bg-elevated);
  color: var(--text-primary);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.auth-pane {
  display: none;
}

.auth-pane.active {
  display: block;
}

.form-group {
  margin-bottom: 18px;
}

.form-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 7px;
  color: #cbd5e1;
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  background: #090d16;
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  padding: 11px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.94rem;
  font-family: inherit;
  transition: border-color 0.15s ease;
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--accent-primary);
}

.form-row-between {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.84rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

.alert-box {
  display: none;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  margin-bottom: 18px;
  line-height: 1.5;
}

.alert-box.show {
  display: block;
}

.alert-error {
  background: rgba(239, 68, 68, 0.12);
  border: 1px solid rgba(239, 68, 68, 0.38);
  color: #fca5a5;
}

.alert-warning {
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid rgba(245, 158, 11, 0.35);
  color: #fcd34d;
}

.alert-success {
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.35);
  color: #6ee7b7;
}

/* Modal */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(5, 8, 14, 0.78);
  backdrop-filter: blur(6px);
  z-index: 200;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-backdrop.open {
  display: flex;
}

.modal-dialog {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  max-width: 480px;
  width: 100%;
  padding: 30px;
  position: relative;
  box-shadow: var(--shadow-lg);
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 1.4rem;
  cursor: pointer;
}

/* Footer */
.site-footer {
  margin-top: auto;
  background: #06080d;
  border-top: 1px solid var(--border-subtle);
  padding: 56px 0 36px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
  gap: 36px;
  margin-bottom: 40px;
}

.footer-heading {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-primary);
  margin-bottom: 14px;
  font-weight: 700;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 9px;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 16px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Responsive */
@media (max-width: 960px) {
  .hero-grid,
  .article-layout,
  .cards-grid-3,
  .stats-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .toc-box {
    position: static;
  }
  .main-nav {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    flex-direction: column;
    padding: 20px;
    border-bottom: 1px solid var(--border-subtle);
  }
  .main-nav.open {
    display: flex;
  }
  .mobile-menu-btn {
    display: inline-flex;
  }
  .status-pill {
    display: none;
  }
}