/* Learn Claude — Design System
   Matches theainhub.com visual identity
   Fonts: Fraunces (serif headings), Manrope (body)
   Colors: Navy #0e2439, Teal #22a095, White cards
*/

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

/* === Variables === */
:root {
  --navy: #0e2439;
  --navy-light: #142f4a;
  --navy-dark: #091a2a;
  --teal: #22a095;
  --teal-hover: #1b8a80;
  --teal-glow: rgba(34, 160, 149, 0.1);
  --teal-light: #e6f7f5;
  --white: #ffffff;
  --off-white: #f8fafb;
  --bg: #ffffff;
  --bg-alt: #f4f7f9;
  --text: #0e2439;
  --text-muted: #4a5568;
  --text-light: #718096;
  --border: #e2e8f0;
  --border-light: #edf2f7;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.1), 0 4px 10px rgba(0,0,0,0.05);
  --serif: 'Fraunces', Georgia, 'Times New Roman', serif;
  --sans: 'Manrope', system-ui, -apple-system, sans-serif;
  --mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  --radius: 8px;
  --radius-lg: 12px;
  --max-width: 1200px;
  --content-width: 800px;
  --nav-height: 64px;
}

/* === Reset === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--teal); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--teal-hover); }
img { max-width: 100%; display: block; }

/* === Navigation === */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--navy);
  z-index: 100;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  color: var(--white);
  font-family: var(--sans);
  font-weight: 700;
  font-size: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.nav-logo:hover { color: var(--white); }
.nav-logo .logo-icon {
  width: 28px;
  height: 28px;
  background: var(--teal);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}
.nav-links a {
  color: rgba(255,255,255,0.8);
  font-size: 14px;
  font-weight: 500;
  padding: 6px 14px;
  border-radius: 6px;
  transition: all 0.2s;
}
.nav-links a:hover { color: var(--white); background: rgba(255,255,255,0.08); }
.nav-links a.active { color: var(--white); background: rgba(255,255,255,0.1); }
.nav-links .nav-btn {
  background: var(--teal);
  color: var(--white);
  font-weight: 700;
  padding: 8px 16px;
}
.nav-links .nav-btn:hover { background: var(--teal-hover); }
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: var(--white);
  font-size: 24px;
  cursor: pointer;
  padding: 4px;
}

/* === Hero === */
.hero {
  padding: 120px 24px 80px;
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-light) 100%);
  color: var(--white);
  text-align: center;
}
.hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}
.hero-label {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--teal);
  margin-bottom: 16px;
}
.hero-title {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(32px, 5vw, 52px);
  line-height: 1.15;
  margin-bottom: 20px;
}
.hero-subtitle {
  font-size: 18px;
  color: rgba(255,255,255,0.75);
  max-width: 640px;
  margin: 0 auto 32px;
  line-height: 1.6;
}
.hero-cta {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-family: var(--sans);
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
  text-decoration: none;
}
.btn-primary {
  background: var(--teal);
  color: var(--white);
}
.btn-primary:hover { background: var(--teal-hover); color: var(--white); }
.btn-outline {
  background: transparent;
  color: var(--white);
  border: 1px solid rgba(255,255,255,0.25);
}
.btn-outline:hover { background: rgba(255,255,255,0.08); color: var(--white); border-color: rgba(255,255,255,0.4); }
.btn-teal-outline {
  background: transparent;
  color: var(--teal);
  border: 1px solid var(--teal);
}
.btn-teal-outline:hover { background: var(--teal-glow); }

/* === Sections === */
.section {
  padding: 80px 24px;
}
.section-alt {
  background: var(--bg-alt);
}
.section-dark {
  background: var(--navy);
  color: var(--white);
}
.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}
.section-label {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--teal);
  margin-bottom: 8px;
}
.section-title {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1.2;
  margin-bottom: 12px;
}
.section-subtitle {
  font-size: 17px;
  color: var(--text-muted);
  max-width: 640px;
  line-height: 1.6;
}
.section-header {
  text-align: center;
  margin-bottom: 48px;
}
.section-header .section-subtitle {
  margin: 0 auto;
}

/* === Card Grid === */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.card-grid-3 {
  grid-template-columns: repeat(3, 1fr);
}
.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: all 0.25s ease;
}
.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--teal);
}
.card-icon {
  width: 44px;
  height: 44px;
  background: var(--teal-glow);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  margin-bottom: 16px;
}
.card-title {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 17px;
  margin-bottom: 8px;
  color: var(--text);
}
.card-desc {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.6;
}
a.card { display: block; text-decoration: none; }
a.card .card-title { color: var(--text); }

/* === Badges / Pills === */
.badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: 4px 10px;
  border-radius: 99px;
}
.badge-beginner {
  background: var(--teal-glow);
  color: var(--teal);
}
.badge-intermediate {
  background: rgba(180, 83, 9, 0.1);
  color: #b45309;
}
.badge-advanced {
  background: rgba(126, 34, 206, 0.1);
  color: #7e22ce;
}
.badge-coming-soon {
  background: var(--bg-alt);
  color: var(--text-light);
}

/* === Module Card (for landing page) === */
.module-card {
  position: relative;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: all 0.25s ease;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.module-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--teal);
}
.module-card .module-number {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-light);
  text-transform: uppercase;
  letter-spacing: 1px;
}
.module-card .module-title {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 17px;
  color: var(--text);
}
.module-card .module-desc {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.6;
}
.module-card .module-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: auto;
}
a.module-card { text-decoration: none; }
.module-card.disabled { opacity: 0.5; pointer-events: none; }

/* === Content Page Layout === */
.content-page {
  padding: 100px 24px 80px;
  max-width: var(--content-width);
  margin: 0 auto;
}
.content-page h1 {
  font-family: var(--serif);
  font-weight: 800;
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.2;
  margin-bottom: 16px;
}
.content-page h2 {
  font-family: var(--serif);
  font-weight: 700;
  font-size: clamp(22px, 3vw, 28px);
  margin-top: 48px;
  margin-bottom: 16px;
  padding-top: 24px;
  border-top: 1px solid var(--border-light);
}
.content-page h2:first-of-type {
  border-top: none;
  padding-top: 0;
}
.content-page h3 {
  font-weight: 700;
  font-size: 18px;
  margin-top: 32px;
  margin-bottom: 12px;
}
.content-page p {
  margin-bottom: 16px;
  color: var(--text-muted);
  font-size: 16px;
  line-height: 1.7;
}
.content-page ul, .content-page ol {
  margin-bottom: 16px;
  padding-left: 24px;
}
.content-page li {
  margin-bottom: 8px;
  color: var(--text-muted);
  line-height: 1.6;
}
.content-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}
.content-meta .badge { margin: 0; }
.content-meta .read-time {
  font-size: 14px;
  color: var(--text-light);
}

/* === Callout === */
.callout {
  background: var(--teal-glow);
  border-left: 3px solid var(--teal);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 20px 24px;
  margin: 24px 0;
  font-size: 15px;
  color: var(--text);
  line-height: 1.6;
}
.callout strong { color: var(--navy); }
.callout-warning {
  background: rgba(180, 83, 9, 0.06);
  border-left-color: #b45309;
}
.callout-info {
  background: rgba(59, 130, 246, 0.06);
  border-left-color: #3b82f6;
}

/* === Comparison (Before/After) === */
.comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 24px 0;
}
.comparison-side {
  border-radius: var(--radius);
  padding: 20px;
  font-size: 14px;
  line-height: 1.6;
}
.comparison-side.before {
  background: rgba(220, 38, 38, 0.04);
  border: 1px solid rgba(220, 38, 38, 0.15);
}
.comparison-side.after {
  background: rgba(34, 160, 149, 0.06);
  border: 1px solid rgba(34, 160, 149, 0.2);
}
.comparison-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 8px;
}
.comparison-side.before .comparison-label { color: #dc2626; }
.comparison-side.after .comparison-label { color: var(--teal); }

/* === Code Block === */
.code-block {
  position: relative;
  background: var(--navy);
  color: rgba(255,255,255,0.9);
  border-radius: var(--radius);
  padding: 20px 24px;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.6;
  overflow-x: auto;
  margin: 16px 0;
  white-space: pre-wrap;
  word-break: break-word;
}
.code-label {
  font-family: var(--sans);
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--teal);
  margin-bottom: 8px;
  display: block;
}
.copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.15);
  color: rgba(255,255,255,0.7);
  font-size: 12px;
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  font-family: var(--sans);
  transition: all 0.2s;
}
.copy-btn:hover { background: rgba(255,255,255,0.2); color: var(--white); }

/* === Module Navigation (bottom of content pages) === */
.module-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 64px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}
.module-nav a {
  display: block;
  padding: 20px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all 0.2s;
  text-decoration: none;
}
.module-nav a:hover { border-color: var(--teal); box-shadow: var(--shadow); }
.module-nav .nav-direction {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-light);
  margin-bottom: 4px;
}
.module-nav .nav-title {
  font-weight: 700;
  color: var(--text);
  font-size: 15px;
}
.module-nav .nav-next { text-align: right; }

/* === About Card === */
.about-card {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow);
}
.about-avatar {
  width: 64px;
  height: 64px;
  background: var(--navy);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-family: var(--serif);
  font-weight: 800;
  font-size: 24px;
  flex-shrink: 0;
}
.about-name {
  font-weight: 700;
  font-size: 17px;
  margin-bottom: 4px;
}
.about-role {
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 8px;
}
.about-text {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.6;
}

/* === Animations === */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* === Footer === */
.footer {
  background: var(--navy);
  color: rgba(255,255,255,0.6);
  padding: 40px 24px;
  text-align: center;
  font-size: 14px;
}
.footer a { color: var(--teal); }
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}
.footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.footer-links a { color: rgba(255,255,255,0.7); }
.footer-links a:hover { color: var(--white); }

/* === Mobile === */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--navy);
    padding: 16px 24px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    gap: 4px;
  }
  .nav-links.open a { padding: 12px 16px; font-size: 16px; }
  .mobile-menu-btn { display: block; }

  .hero { padding: 100px 20px 60px; }
  .hero-title { font-size: 28px; }
  .hero-subtitle { font-size: 16px; }

  .section { padding: 48px 20px; }

  .card-grid-3 { grid-template-columns: 1fr; }
  .card-grid { grid-template-columns: 1fr; }

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

  .module-nav { grid-template-columns: 1fr; }
  .module-nav .nav-next { text-align: left; }

  .about-card { flex-direction: column; }

  .content-page { padding: 84px 20px 60px; }
}