/* ===== CSS Custom Properties ===== */
:root {
  /* Colors - Tech Blue Palette */
  --color-bg-dark: #0a1628;
  --color-bg-darker: #060d18;
  --color-bg-card: #0f1f35;
  --color-bg-light: #f8fafc;

  /* Accent Colors */
  --color-cyan: #00d4ff;
  --color-cyan-glow: rgba(0, 212, 255, 0.3);
  --color-purple: #7c3aed;
  --color-purple-light: #a78bfa;
  --color-teal: #06b6d4;
  --color-orange: #f97316;
  --color-coral: #ff6f61;

  /* Character Colors */
  --color-pixel: #7c3aed;
  --color-echo: #06b6d4;
  --color-algo: #f97316;

  /* Text */
  --color-text-light: #ffffff;
  --color-text-muted: #94a3b8;
  --color-text-dark: #1e293b;
  --color-text-body: #475569;

  /* Typography */
  --font-heading: 'Quicksand', sans-serif;
  --font-body: 'Inter', sans-serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 300ms ease;
  --transition-slow: 500ms ease;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
  --shadow-glow-cyan: 0 0 30px var(--color-cyan-glow);

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 9999px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text-dark);
  background-color: var(--color-bg-light);
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  text-decoration: none;
  color: inherit;
}

ul {
  list-style: none;
}

/* ===== Utility Classes ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: var(--space-md);
}

.section-subtitle {
  text-align: center;
  color: var(--color-text-body);
  max-width: 600px;
  margin: 0 auto var(--space-3xl);
  font-size: 1.1rem;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.875rem 1.75rem;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1rem;
  border-radius: var(--radius-full);
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  text-align: center;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-cyan) 0%, var(--color-teal) 100%);
  color: var(--color-bg-dark);
  border-color: var(--color-cyan);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow-cyan);
}

.btn-secondary {
  background: transparent;
  color: var(--color-text-light);
  border-color: var(--color-text-light);
}

.btn-secondary:hover {
  background: var(--color-text-light);
  color: var(--color-bg-dark);
}

.btn-book {
  padding: 0.75rem 1.5rem;
  font-size: 0.9rem;
}

.btn-outline {
  background: transparent;
  color: var(--color-cyan);
  border-color: var(--color-cyan);
}

.btn-outline:hover {
  background: var(--color-cyan);
  color: var(--color-bg-dark);
}

/* ===== Header ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 22, 40, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.logo-text {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-light);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav-links a {
  color: var(--color-text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition-fast);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-cyan);
}

.nav-cta {
  padding: 0.5rem 1.25rem;
  background: var(--color-cyan);
  color: var(--color-bg-dark) !important;
  border-radius: var(--radius-full);
  font-weight: 600;
}

.nav-cta:hover {
  background: var(--color-text-light);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--color-text-light);
  transition: all var(--transition-base);
}

/* ===== Hero Section ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 120px 0 80px;
  background: var(--color-bg-dark);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(124, 58, 237, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 50%, rgba(6, 182, 212, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 100%, rgba(249, 115, 22, 0.1) 0%, transparent 40%);
  pointer-events: none;
}

/* Circuit pattern overlay */
.hero-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M30 0v10M30 50v10M0 30h10M50 30h10M30 20v20M20 30h20' stroke='%2300d4ff' stroke-width='0.5' fill='none' opacity='0.1'/%3E%3C/svg%3E");
  opacity: 0.3;
}

.hero-container {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.hero-content {
  max-width: 560px;
}

.hero-series {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-cyan);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-md);
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 700;
  color: var(--color-text-light);
  line-height: 1.2;
  margin-bottom: var(--space-lg);
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
  line-height: 1.7;
}

.hero-subtitle em {
  color: var(--color-cyan);
  font-style: normal;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.hero-image {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-book {
  max-width: 380px;
  border-radius: var(--radius-lg);
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.5), var(--shadow-glow-cyan);
  transform: perspective(1000px) rotateY(-5deg);
  transition: transform var(--transition-slow);
}

.hero-book:hover {
  transform: perspective(1000px) rotateY(0deg) scale(1.02);
}

.hero-characters {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  display: flex;
  justify-content: center;
  gap: var(--space-xl);
  pointer-events: none;
  z-index: 1;
}

.hero-char {
  width: 100px;
  height: auto;
  opacity: 0.15;
  transform: translateY(30%);
}

/* ===== Guides Section ===== */
.guides {
  padding: var(--space-4xl) 0;
  background: var(--color-bg-light);
}

.guides-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.guide-card {
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
  opacity: 0;
  transform: translateY(20px);
}

.guide-card.animate-in {
  opacity: 1;
  transform: translateY(0);
}

.guide-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.pixel-card:hover { box-shadow: 0 20px 40px rgba(124, 58, 237, 0.2); }
.echo-card:hover { box-shadow: 0 20px 40px rgba(6, 182, 212, 0.2); }
.algo-card:hover { box-shadow: 0 20px 40px rgba(249, 115, 22, 0.2); }

.guide-image {
  width: 140px;
  height: 140px;
  margin: 0 auto var(--space-lg);
  border-radius: var(--radius-full);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.guide-image img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.guide-card h3 {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.pixel-card h3 { color: var(--color-pixel); }
.echo-card h3 { color: var(--color-echo); }
.algo-card h3 { color: var(--color-algo); }

.guide-role {
  font-weight: 600;
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.guide-desc {
  color: var(--color-text-body);
  font-size: 0.95rem;
}

/* ===== Series Section ===== */
.series {
  padding: var(--space-4xl) 0;
  background: var(--color-bg-dark);
  color: var(--color-text-light);
}

.series .section-title {
  color: var(--color-text-light);
}

.series .section-subtitle {
  color: var(--color-text-muted);
}

.series-label {
  text-align: center;
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-cyan);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: var(--space-sm);
}

.series-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.book-card {
  position: relative;
  background: var(--color-bg-card);
  border-radius: var(--radius-xl);
  overflow: hidden;
  transition: all var(--transition-base);
  opacity: 0;
  transform: translateY(20px);
}

.book-card.animate-in {
  opacity: 1;
  transform: translateY(0);
}

.book-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-glow-cyan);
}

.book-badge {
  position: absolute;
  top: var(--space-md);
  left: var(--space-md);
  padding: 0.25rem 0.75rem;
  background: var(--color-cyan);
  color: var(--color-bg-dark);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.75rem;
  border-radius: var(--radius-full);
  z-index: 2;
}

.book-cover {
  position: relative;
  padding: var(--space-xl);
  padding-bottom: 0;
}

.book-cover img {
  width: 100%;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
}

.book-cover.coming-soon img {
  filter: brightness(0.7);
}

.coming-tag {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 0.5rem 1rem;
  background: rgba(0, 0, 0, 0.8);
  color: var(--color-cyan);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.85rem;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-cyan);
}

.book-info {
  padding: var(--space-xl);
}

.book-info h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-light);
  margin-bottom: var(--space-xs);
}

.book-subtitle {
  color: var(--color-cyan);
  font-size: 0.9rem;
  margin-bottom: var(--space-md);
}

.book-desc {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: var(--space-lg);
}

/* ===== Features Section ===== */
.features {
  padding: var(--space-4xl) 0;
  background: white;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
}

.feature-card {
  text-align: center;
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  transition: all var(--transition-base);
  opacity: 0;
  transform: translateY(20px);
}

.feature-card.animate-in {
  opacity: 1;
  transform: translateY(0);
}

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

.feature-icon {
  width: 60px;
  height: 60px;
  margin: 0 auto var(--space-lg);
  padding: var(--space-md);
  background: linear-gradient(135deg, var(--color-cyan) 0%, var(--color-teal) 100%);
  border-radius: var(--radius-lg);
  color: white;
}

.feature-icon svg {
  width: 100%;
  height: 100%;
}

.feature-card h3 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
  color: var(--color-text-dark);
}

.feature-card p {
  color: var(--color-text-body);
  font-size: 0.9rem;
}

/* ===== Parents Section ===== */
.parents {
  padding: var(--space-4xl) 0;
  background: var(--color-bg-light);
}

.parents-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

.parents-text h2 {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  margin-bottom: var(--space-md);
  color: var(--color-text-dark);
}

.parents-lead {
  font-size: 1.25rem;
  color: var(--color-text-dark);
  margin-bottom: var(--space-lg);
}

.parents-lead em {
  color: var(--color-cyan);
  font-style: normal;
}

.parents-text p {
  color: var(--color-text-body);
  margin-bottom: var(--space-lg);
}

.parents-list {
  margin-bottom: var(--space-xl);
}

.parents-list li {
  position: relative;
  padding-left: var(--space-xl);
  margin-bottom: var(--space-sm);
  color: var(--color-text-body);
}

.parents-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.5em;
  width: 8px;
  height: 8px;
  background: var(--color-cyan);
  border-radius: var(--radius-full);
}

.parents-image img {
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
}

/* ===== Testimonials Section ===== */
.testimonials {
  padding: var(--space-4xl) 0;
  background: var(--color-bg-dark);
  color: var(--color-text-light);
}

.testimonials .section-title {
  color: var(--color-text-light);
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.testimonial {
  background: var(--color-bg-card);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  opacity: 0;
  transform: translateY(20px);
}

.testimonial.animate-in {
  opacity: 1;
  transform: translateY(0);
}

.testimonial p {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
  font-style: italic;
  line-height: 1.7;
}

.testimonial cite {
  font-style: normal;
  display: block;
}

.testimonial cite strong {
  color: var(--color-text-light);
  display: block;
  margin-bottom: var(--space-xs);
}

.testimonial cite span {
  color: var(--color-cyan);
  font-size: 0.85rem;
}

/* ===== Newsletter Section ===== */
.newsletter {
  padding: var(--space-4xl) 0;
  background: linear-gradient(135deg, var(--color-bg-dark) 0%, var(--color-bg-darker) 100%);
  text-align: center;
}

.newsletter-content {
  max-width: 500px;
  margin: 0 auto;
}

.newsletter h2 {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  color: var(--color-text-light);
  margin-bottom: var(--space-md);
}

.newsletter p {
  color: var(--color-text-muted);
  margin-bottom: var(--space-xl);
}

.newsletter-form {
  display: flex;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.newsletter-form input {
  flex: 1;
  padding: 1rem 1.25rem;
  font-family: var(--font-body);
  font-size: 1rem;
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.05);
  color: var(--color-text-light);
  transition: all var(--transition-base);
}

.newsletter-form input::placeholder {
  color: var(--color-text-muted);
}

.newsletter-form input:focus {
  outline: none;
  border-color: var(--color-cyan);
  background: rgba(255, 255, 255, 0.1);
}

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

/* ===== Footer ===== */
.footer {
  padding: var(--space-3xl) 0 var(--space-xl);
  background: var(--color-bg-darker);
  color: var(--color-text-muted);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-3xl);
  margin-bottom: var(--space-3xl);
}

.footer-brand .logo-text {
  margin-bottom: var(--space-md);
  display: block;
}

.footer-brand p {
  font-size: 0.9rem;
  line-height: 1.6;
}

.footer-links h4,
.footer-social h4 {
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text-light);
  margin-bottom: var(--space-lg);
}

.footer-links ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer-links a {
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

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

.social-links {
  display: flex;
  gap: var(--space-md);
}

.social-links a {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
}

.social-links a:hover {
  background: var(--color-cyan);
  color: var(--color-bg-dark);
}

.social-links svg {
  width: 20px;
  height: 20px;
}

.footer-bottom {
  padding-top: var(--space-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: 0.85rem;
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
  .hero-container {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content {
    max-width: 100%;
  }

  .hero-cta {
    justify-content: center;
  }

  .hero-book {
    max-width: 300px;
    transform: none;
  }

  .guides-grid,
  .series-grid,
  .testimonials-grid {
    grid-template-columns: 1fr;
    max-width: 400px;
    margin: 0 auto;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .parents-content {
    grid-template-columns: 1fr;
  }

  .parents-image {
    order: -1;
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--color-bg-dark);
    padding: var(--space-xl);
    gap: var(--space-lg);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-base);
  }

  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .nav-toggle.active span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }

  .hero {
    padding-top: 100px;
  }

  .hero-characters {
    display: none;
  }

  .features-grid {
    grid-template-columns: 1fr;
    max-width: 400px;
    margin: 0 auto;
  }

  .newsletter-form {
    flex-direction: column;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .social-links {
    justify-content: center;
  }
}

/* ===== Animation Delays ===== */
.guide-card:nth-child(1) { transition-delay: 0ms; }
.guide-card:nth-child(2) { transition-delay: 100ms; }
.guide-card:nth-child(3) { transition-delay: 200ms; }

.book-card:nth-child(1) { transition-delay: 0ms; }
.book-card:nth-child(2) { transition-delay: 100ms; }
.book-card:nth-child(3) { transition-delay: 200ms; }

.feature-card:nth-child(1) { transition-delay: 0ms; }
.feature-card:nth-child(2) { transition-delay: 75ms; }
.feature-card:nth-child(3) { transition-delay: 150ms; }
.feature-card:nth-child(4) { transition-delay: 225ms; }

.testimonial:nth-child(1) { transition-delay: 0ms; }
.testimonial:nth-child(2) { transition-delay: 100ms; }
.testimonial:nth-child(3) { transition-delay: 200ms; }