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

:root {
  --color-bg: #06060f;
  --color-bg-elevated: #0d0d1a;
  --color-bg-card: #111125;
  --color-surface: #16162a;
  --color-text: #e8e8f0;
  --color-text-muted: #8888a8;
  --color-text-dim: #55556e;
  --color-primary: #6c5ce7;
  --color-primary-light: #a29bfe;
  --color-accent: #00cec9;
  --color-accent-light: #55efc4;
  --color-gradient-start: #6c5ce7;
  --color-gradient-end: #00cec9;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'Space Grotesk', 'Inter', sans-serif;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 24px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 48px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 60px rgba(108,92,231,0.15);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-main);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  overflow-x: hidden;
}

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

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

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

.container-narrow {
  max-width: 800px;
}

/* ========================================
   NAVBAR FLOTANTE
   ======================================== */
.navbar {
  position: fixed;
  top: 16px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 1000;
  width: calc(100% - 48px);
  max-width: 900px;
  transition: var(--transition);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  background: rgba(13, 13, 26, 0.7);
  backdrop-filter: blur(20px) saturate(1.4);
  -webkit-backdrop-filter: blur(20px) saturate(1.4);
  border-radius: var(--radius-full);
  box-shadow: 0 4px 30px rgba(0,0,0,0.4), inset 0 0 0 1px rgba(255,255,255,0.06);
}

.navbar.scrolled .navbar-inner {
  background: rgba(13, 13, 26, 0.92);
  box-shadow: 0 8px 40px rgba(0,0,0,0.5), inset 0 0 0 1px rgba(255,255,255,0.08);
}

.navbar-logo {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.1rem;
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
}

.navbar-links {
  display: flex;
  list-style: none;
  gap: 8px;
}

.navbar-links a {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  transition: var(--transition);
}

.navbar-links a:hover {
  color: var(--color-text);
  background: rgba(255,255,255,0.06);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-main);
  font-weight: 600;
  font-size: 0.85rem;
  padding: 10px 22px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition);
  border: none;
  white-space: nowrap;
}

.btn-nav {
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  color: #fff;
  font-size: 0.8rem;
  padding: 8px 18px;
}

.btn-nav:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  color: #fff;
  box-shadow: 0 4px 20px rgba(108,92,231,0.3);
}

.btn-primary:hover {
  box-shadow: 0 6px 30px rgba(108,92,231,0.45);
  transform: translateY(-2px);
}

.btn-ghost {
  background: rgba(255,255,255,0.06);
  color: var(--color-text);
}

.btn-ghost:hover {
  background: rgba(255,255,255,0.1);
  transform: translateY(-2px);
}

.btn-lg {
  font-size: 0.95rem;
  padding: 14px 32px;
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: var(--transition);
}

.mobile-menu {
  display: none;
  position: fixed;
  top: 80px;
  left: 50%;
  transform: translateX(-50%);
  width: calc(100% - 48px);
  max-width: 900px;
  background: rgba(13, 13, 26, 0.95);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-lg);
  z-index: 999;
  padding: 24px;
  box-shadow: var(--shadow-lg);
}

.mobile-menu.active {
  display: block;
}

.mobile-menu ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.mobile-menu a {
  display: block;
  padding: 12px 16px;
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.mobile-menu a:hover {
  color: var(--color-text);
  background: rgba(255,255,255,0.06);
}

/* ========================================
   HERO
   ======================================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 120px 24px 80px;
  overflow: hidden;
}

.hero-bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(108,92,231,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(108,92,231,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse at center, black 30%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse at center, black 30%, transparent 70%);
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
}

.hero-glow-1 {
  width: 600px;
  height: 600px;
  background: rgba(108, 92, 231, 0.12);
  top: -200px;
  right: -100px;
}

.hero-glow-2 {
  width: 500px;
  height: 500px;
  background: rgba(0, 206, 201, 0.08);
  bottom: -150px;
  left: -100px;
}

.hero-content {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: 80px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-accent);
  padding: 6px 16px;
  background: rgba(0, 206, 201, 0.1);
  border-radius: var(--radius-full);
  margin-bottom: 24px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
  color: #fff;
}

.gradient-text {
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--color-text-muted);
  line-height: 1.8;
  margin-bottom: 36px;
  max-width: 540px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

.hero-meta {
  display: flex;
  align-items: center;
  gap: 24px;
}

.hero-meta-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.hero-meta-value {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  color: #fff;
}

.hero-meta-label {
  font-size: 0.75rem;
  color: var(--color-text-dim);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.hero-meta-divider {
  width: 1px;
  height: 36px;
  background: rgba(255,255,255,0.08);
}

/* Book 3D */
.hero-book {
  display: flex;
  justify-content: center;
  perspective: 1200px;
}

.book-3d {
  position: relative;
  transform-style: preserve-3d;
  transform: rotateY(-18deg) rotateX(4deg);
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.book-3d:hover {
  transform: rotateY(-8deg) rotateX(2deg);
}

.book-cover {
  width: 300px;
  height: 440px;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow:
    -20px 20px 60px rgba(0,0,0,0.5),
    0 0 80px rgba(108,92,231,0.1);
  position: relative;
}

.book-cover-placeholder {
  width: 100%;
  height: 100%;
  background: linear-gradient(160deg, #1a1a3e 0%, #0f0f2a 50%, #1a0a3e 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 40px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.book-cover-glow {
  position: absolute;
  top: -40%;
  left: -40%;
  width: 180%;
  height: 180%;
  background: conic-gradient(
    from 0deg,
    rgba(108,92,231,0.15),
    rgba(0,206,201,0.1),
    rgba(108,92,231,0.05),
    rgba(0,206,201,0.15),
    rgba(108,92,231,0.15)
  );
  animation: coverRotate 12s linear infinite;
}

@keyframes coverRotate {
  to { transform: rotate(360deg); }
}

.book-cover-label {
  font-size: 0.7rem;
  color: var(--color-text-dim);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  position: relative;
  z-index: 1;
}

.book-cover-title {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  color: #fff;
  line-height: 1.3;
  position: relative;
  z-index: 1;
}

.book-cover-author {
  font-size: 0.85rem;
  color: var(--color-accent);
  font-weight: 500;
  position: relative;
  z-index: 1;
}

.book-spine {
  position: absolute;
  top: 0;
  left: -24px;
  width: 24px;
  height: 100%;
  background: linear-gradient(to right, #0a0a20, #151535);
  transform: rotateY(90deg);
  transform-origin: right center;
  border-radius: 2px 0 0 2px;
}

/* ========================================
   MARQUEE
   ======================================== */
.marquee-section {
  padding: 32px 0;
  background: var(--color-bg-elevated);
  overflow: hidden;
}

.marquee {
  overflow: hidden;
  white-space: nowrap;
}

.marquee-track {
  display: inline-flex;
  align-items: center;
  gap: 32px;
  animation: marqueeScroll 30s linear infinite;
}

@keyframes marqueeScroll {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

.marquee-item {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text-muted);
  letter-spacing: -0.01em;
  flex-shrink: 0;
}

.marquee-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  flex-shrink: 0;
}

/* ========================================
   SECTIONS
   ======================================== */
.section {
  padding: 120px 0;
}

.section-dark {
  background: var(--color-bg-elevated);
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

.section-label {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 16px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3.5vw, 2.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
  color: #fff;
  margin-bottom: 20px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  line-height: 1.8;
}

/* ========================================
   FEATURES
   ======================================== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.feature-card {
  padding: 36px;
  background: var(--color-bg-elevated);
  border-radius: var(--radius-lg);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  padding: 1px;
  background: linear-gradient(135deg, rgba(108,92,231,0.2), rgba(0,206,201,0.1), transparent);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
  opacity: 0;
  transition: var(--transition);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-card:hover {
  background: var(--color-surface);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}

.feature-icon {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(108,92,231,0.1);
  border-radius: var(--radius-md);
  color: var(--color-primary-light);
  margin-bottom: 20px;
}

.feature-card h3 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: #fff;
}

.feature-card p {
  font-size: 0.92rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* ========================================
   QUOTE
   ======================================== */
.quote-section {
  padding: 100px 0;
  background: var(--color-bg);
  position: relative;
  overflow: hidden;
}

.quote-section::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(108,92,231,0.06), transparent);
  pointer-events: none;
}

.big-quote {
  text-align: center;
  position: relative;
}

.quote-icon {
  color: rgba(108,92,231,0.15);
  margin-bottom: 24px;
}

.big-quote p {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 2.5vw, 1.8rem);
  font-weight: 500;
  line-height: 1.6;
  color: #fff;
  max-width: 740px;
  margin: 0 auto 24px;
  font-style: italic;
}

.big-quote cite {
  font-style: normal;
  font-size: 0.95rem;
  color: var(--color-accent);
  font-weight: 600;
}

/* ========================================
   TOPICS
   ======================================== */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.topic-card {
  padding: 36px;
  background: var(--color-bg-card);
  border-radius: var(--radius-lg);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.topic-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-gradient-start), var(--color-gradient-end));
  opacity: 0;
  transition: var(--transition);
}

.topic-card:hover::after {
  opacity: 1;
}

.topic-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.3);
}

.topic-number {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, rgba(108,92,231,0.3), rgba(0,206,201,0.2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: block;
  margin-bottom: 16px;
  line-height: 1;
}

.topic-card h3 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}

.topic-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* ========================================
   STATS
   ======================================== */
.stats-section {
  padding: 80px 0;
  background: var(--color-bg);
}

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

.stat-item {
  text-align: center;
}

.stat-value {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 4vw, 3.5rem);
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: block;
  line-height: 1.1;
  margin-bottom: 8px;
}

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

/* ========================================
   AUTHOR
   ======================================== */
.author-grid {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 64px;
  align-items: start;
}

.author-image-placeholder {
  width: 100%;
  aspect-ratio: 3/4;
  background: linear-gradient(160deg, var(--color-surface), var(--color-bg-card));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.author-image-placeholder::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  padding: 1px;
  background: linear-gradient(160deg, rgba(108,92,231,0.3), transparent 50%);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
}

.author-image-placeholder span {
  font-size: 0.85rem;
  color: var(--color-text-dim);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.author-role {
  font-size: 1.05rem;
  color: var(--color-accent);
  font-weight: 500;
  margin-bottom: 28px;
}

.author-bio {
  margin-bottom: 32px;
}

.author-bio p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.8;
  margin-bottom: 16px;
}

.author-bio p:last-child {
  margin-bottom: 0;
}

.author-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 6px 16px;
  background: rgba(108,92,231,0.08);
  border-radius: var(--radius-full);
  transition: var(--transition);
}

.tag:hover {
  background: rgba(108,92,231,0.15);
  color: var(--color-primary-light);
}

/* ========================================
   CTA
   ======================================== */
.cta-section {
  padding: 120px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-glow {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 800px;
  height: 400px;
  background: radial-gradient(ellipse, rgba(108,92,231,0.1), transparent);
  pointer-events: none;
}

.cta-content {
  position: relative;
  z-index: 1;
}

.cta-content h2 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  color: #fff;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  line-height: 1.2;
}

.cta-content p {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 520px;
  margin: 0 auto 36px;
  line-height: 1.8;
}

.cta-actions {
  display: flex;
  justify-content: center;
}

/* ========================================
   FAQ
   ======================================== */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

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

.faq-item.active {
  box-shadow: 0 4px 24px rgba(108,92,231,0.08);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  background: none;
  border: none;
  cursor: pointer;
  font-family: var(--font-main);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text);
  text-align: left;
  transition: var(--transition);
  gap: 16px;
}

.faq-question:hover {
  color: #fff;
}

.faq-chevron {
  color: var(--color-text-dim);
  flex-shrink: 0;
  transition: transform 0.3s ease;
}

.faq-item.active .faq-chevron {
  transform: rotate(180deg);
  color: var(--color-accent);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.faq-item.active .faq-answer {
  max-height: 300px;
}

.faq-answer p {
  padding: 0 24px 20px;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.8;
}

/* ========================================
   FOOTER
   ======================================== */
.footer {
  padding: 64px 0 40px;
  background: var(--color-bg);
}

.footer-content {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  margin-bottom: 32px;
}

.footer-logo {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.3rem;
  background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: inline-block;
  margin-bottom: 12px;
}

.footer-brand p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

.footer-copy {
  margin-top: 12px;
  font-size: 0.8rem !important;
  color: var(--color-text-dim) !important;
}

.footer-links h4 {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.footer-links ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  transition: var(--transition);
}

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

/* ========================================
   ANIMATIONS
   ======================================== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========================================
   RESPONSIVE
   ======================================== */
@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    gap: 60px;
    text-align: center;
  }

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

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

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

  .hero-book {
    order: -1;
  }

  .book-cover {
    width: 240px;
    height: 352px;
  }

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

  .author-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .author-image-placeholder {
    max-width: 340px;
    margin: 0 auto;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
  }
}

@media (max-width: 768px) {
  .navbar-links,
  .btn-nav {
    display: none;
  }

  .menu-toggle {
    display: flex;
  }

  .hero {
    padding: 100px 20px 60px;
  }

  .section {
    padding: 80px 0;
  }

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

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

  .footer-content {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .book-cover {
    width: 200px;
    height: 293px;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2rem;
  }

  .hero-meta {
    flex-direction: column;
    gap: 16px;
  }

  .hero-meta-divider {
    width: 40px;
    height: 1px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn-lg {
    justify-content: center;
  }

  .stats-grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }
}