/* ==========================================================================
   SaaS Architecture & Scale – Design System & Stylesheet
   Pure Vanilla CSS – Dark Modern Neon / Glassmorphism Aesthetic
   ========================================================================== */

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

:root {
  /* Color Palette */
  --bg-page: #060911;
  --bg-surface: #0c1220;
  --bg-card: rgba(16, 25, 44, 0.65);
  --bg-card-hover: rgba(24, 38, 66, 0.85);
  --bg-glass: rgba(14, 23, 42, 0.75);

  --border-subtle: rgba(255, 255, 255, 0.07);
  --border-card: rgba(56, 189, 248, 0.15);
  --border-accent: rgba(56, 189, 248, 0.4);

  --accent-cyan: #06b6d4;
  --accent-teal: #14b8a6;
  --accent-blue: #3b82f6;
  --accent-indigo: #6366f1;
  --accent-purple: #8b5cf6;

  --accent-gradient: linear-gradient(135deg, #22d3ee 0%, #38bdf8 40%, #6366f1 100%);
  --accent-glow: 0 0 35px rgba(6, 182, 212, 0.25);
  --accent-glow-strong: 0 0 50px rgba(56, 189, 248, 0.45);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-accent: #38bdf8;

  --success: #10b981;
  --success-glow: rgba(16, 185, 129, 0.25);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  /* Layout & Radii */
  --max-width: 1200px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 180ms ease;
  --transition-base: 280ms cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  color-scheme: dark;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-page);
  color: var(--text-primary);
  line-height: 1.6;
  background-image:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(6, 182, 212, 0.15), transparent),
    radial-gradient(ellipse 60% 40% at 80% 60%, rgba(99, 102, 241, 0.08), transparent);
  background-attachment: fixed;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Typography Helpers */
h1, h2, h3, h4 {
  font-family: var(--font-heading);
  color: var(--text-primary);
  line-height: 1.2;
  font-weight: 700;
}

.text-gradient {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

/* Navigation */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(6, 9, 17, 0.8);
  border-bottom: 1px solid var(--border-subtle);
  padding: 1rem 0;
}

.navbar .nav-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-primary);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.25rem;
}

.brand-icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--accent-glow);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav-links a:hover {
  color: var(--text-accent);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.85rem 1.8rem;
  border-radius: var(--radius-full);
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-base);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--accent-gradient);
  color: #060911;
  box-shadow: var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--accent-glow-strong);
  filter: brightness(1.1);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border-color: var(--border-subtle);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--border-accent);
  color: var(--text-accent);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 0.55rem 1.2rem;
  font-size: 0.88rem;
}

/* Hero Section */
.hero {
  padding: 5rem 0 4rem;
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 3.5rem;
}

.badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  border-radius: var(--radius-full);
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid rgba(6, 182, 212, 0.3);
  color: var(--accent-cyan);
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 1.5rem;
}

.badge-pulse {
  width: 8px;
  height: 8px;
  background-color: var(--accent-cyan);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--accent-cyan);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.3); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

.hero-title {
  font-size: clamp(2.3rem, 5vw, 3.6rem);
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
}

.hero-desc {
  font-size: 1.15rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 2rem;
  max-width: 580px;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 2.25rem;
}

.hero-guarantees {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.guarantee-item {
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

.guarantee-item svg {
  color: var(--success);
}

/* E-book Visual / 3D Mockup */
.book-visual-wrapper {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.book-glow {
  position: absolute;
  width: 320px;
  height: 420px;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.3) 0%, rgba(99, 102, 241, 0.15) 50%, transparent 80%);
  filter: blur(40px);
  z-index: 0;
  pointer-events: none;
}

.book-card {
  position: relative;
  z-index: 1;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow:
    0 25px 50px -12px rgba(0, 0, 0, 0.75),
    0 0 30px rgba(56, 189, 248, 0.2);
  border: 1px solid var(--border-accent);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  max-width: 360px;
}

.book-card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow:
    0 35px 60px -15px rgba(0, 0, 0, 0.85),
    0 0 45px rgba(56, 189, 248, 0.4);
}

.book-img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

/* Section Header */
.section {
  padding: 5.5rem 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 3.5rem;
}

.section-title {
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  margin-bottom: 1rem;
}

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

/* Value Props / Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.75rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 2.25rem;
  backdrop-filter: blur(12px);
  transition: all var(--transition-base);
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-accent);
  transform: translateY(-4px);
  box-shadow: 0 16px 32px rgba(0, 0, 0, 0.3);
}

.feature-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid rgba(6, 182, 212, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
  color: var(--accent-cyan);
}

.feature-card h3 {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Curriculum / Chapters Grid */
.chapters-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 1.5rem;
}

.chapter-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  display: flex;
  gap: 1.25rem;
  transition: border-color var(--transition-fast);
}

.chapter-item:hover {
  border-color: rgba(56, 189, 248, 0.3);
}

.chapter-num {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--accent-cyan);
  opacity: 0.8;
  line-height: 1;
}

.chapter-content h4 {
  font-size: 1.1rem;
  margin-bottom: 0.4rem;
}

.chapter-content p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Pricing Card */
.pricing-wrapper {
  max-width: 560px;
  margin: 0 auto;
  position: relative;
}

.pricing-card {
  background: linear-gradient(180deg, rgba(16, 25, 46, 0.9) 0%, rgba(10, 16, 30, 0.95) 100%);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-lg);
  padding: 3rem 2.5rem;
  box-shadow:
    0 25px 50px -12px rgba(0, 0, 0, 0.8),
    var(--accent-glow);
  position: relative;
  overflow: hidden;
}

.pricing-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--accent-gradient);
}

.pricing-badge {
  display: inline-block;
  background: var(--accent-gradient);
  color: #060911;
  font-weight: 700;
  font-size: 0.78rem;
  text-transform: uppercase;
  padding: 0.3rem 0.85rem;
  border-radius: var(--radius-full);
  margin-bottom: 1.25rem;
}

.price-display {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  margin: 1.25rem 0 1.75rem;
}

.price-current {
  font-family: var(--font-heading);
  font-size: 3.2rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
}

.price-original {
  font-size: 1.3rem;
  color: var(--text-muted);
  text-decoration: line-through;
}

.price-tax-note {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.pricing-features {
  list-style: none;
  margin: 2rem 0 2.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.98rem;
  color: var(--text-primary);
}

.pricing-features svg {
  color: var(--success);
  flex-shrink: 0;
}

.stripe-badge-wrapper {
  margin-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.stripe-badge-wrapper svg {
  color: #6366f1;
}

/* FAQ Accordion */
.faq-list {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

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

.faq-item:hover {
  border-color: rgba(56, 189, 248, 0.25);
}

.faq-question {
  width: 100%;
  padding: 1.3rem 1.5rem;
  background: none;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 600;
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  gap: 1rem;
}

.faq-icon {
  width: 20px;
  height: 20px;
  transition: transform var(--transition-base);
  color: var(--accent-cyan);
  flex-shrink: 0;
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-base), padding var(--transition-base);
  padding: 0 1.5rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  padding: 0 1.5rem 1.4rem;
}

/* Thank You / Success Page */
.thanks-container {
  min-height: 80vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4rem 1.5rem;
}

.thanks-card {
  max-width: 600px;
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-lg);
  padding: 3.5rem 2.5rem;
  text-align: center;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.8), var(--accent-glow);
  backdrop-filter: blur(16px);
}

.success-icon-box {
  width: 76px;
  height: 76px;
  background: rgba(16, 185, 129, 0.15);
  border: 2px solid var(--success);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1.75rem;
  color: var(--success);
  box-shadow: 0 0 25px var(--success-glow);
}

.thanks-title {
  font-size: 2.2rem;
  margin-bottom: 0.75rem;
}

.thanks-subtitle {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 2rem;
}

.notice-box {
  background: rgba(6, 182, 212, 0.08);
  border: 1px solid rgba(6, 182, 212, 0.25);
  border-radius: var(--radius-md);
  padding: 1.4rem;
  text-align: left;
  margin-bottom: 2rem;
}

.notice-box h4 {
  font-size: 1rem;
  color: var(--accent-cyan);
  margin-bottom: 0.4rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.notice-box p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Footer */
.footer {
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 0;
  color: var(--text-muted);
  font-size: 0.88rem;
  text-align: center;
}

.footer p {
  margin-bottom: 0.5rem;
}

/* Responsive adjustments */
@media (max-width: 960px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 3rem;
  }

  .hero-desc {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta-group, .hero-guarantees {
    justify-content: center;
  }

  .book-card {
    max-width: 300px;
  }
}

@media (max-width: 640px) {
  .nav-links {
    display: none; /* simple mobile setup */
  }

  .pricing-card {
    padding: 2.25rem 1.5rem;
  }

  .hero {
    padding: 3rem 0;
  }
}