:root {
  --primary-color: #4361ee;
  --secondary-color: #3a0ca3;
  --accent-color: #7209b7;
  --success-color: #28a745;
  --light-bg: #f8f9fa;
  --dark-bg: #212529;
  --text-color: #1a1a1a;
  --text-light: #4a5568;
  --border-color: #cbd5e0;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --transition: all 0.3s ease;
  --white-color: #ffffff;
  --orange-color: #fb8e2e;
  --orange-color-hover: #ff9f43;
  --gray-filter-btn: #a4a4a4;
  --text-dark: #1e1e1e;
  --toc-background: #f4f4f4;
  --chapter-active: #ffe7d2;
  --bg: #ffffff;
  --text: #333333;

  --primary-50: #fff8f0;
  --primary-100: #ffe7d2;
  --primary-500: #fb8e2e;
  --primary-600: #e07c27;
  --primary-700: #b8661f;

  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;

  --success-500: #10b981;
  --warning-500: #f59e0b;
  --danger-500: #ef4444;
  --info-500: #3b82f6;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 20px;
  --radius-full: 9999px;

  --font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background: var(--gray-50);
  color: var(--gray-900);
  line-height: 1.5;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== Accessibility ===== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

:focus {
  outline: 3px solid var(--primary-500);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

:focus-visible {
  outline: 3px solid var(--primary-500);
  outline-offset: 2px;
}

/* ===== App container ===== */
.app-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ===== Header ===== */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  gap: 1.5rem;
  background: var(--text-dark);
  box-shadow: var(--shadow);
  border-bottom: 3px solid var(--orange-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.logo {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-width: 0;
}

.logo i {
  font-size: 2rem;
  color: var(--orange-color);
}

.logo h1 {
  font-size: 1.5rem;
  color: var(--white-color);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.user-stats {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.user-authenticated {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.stat {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  color: var(--white-color);
}

.stat i {
  color: var(--orange-color);
}

/* ===== Menu toggle (mobile) ===== */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--white-color);
  cursor: pointer;
  padding: 0.5rem;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
}

.menu-toggle:hover {
  background: rgba(255, 255, 255, 0.08);
}

.header-menu {
  display: flex;
  transition: all 0.3s ease;
}

/* ===== User dropdown ===== */
.user-dropdown {
  position: relative;
  display: flex;
  align-items: center;
}

.user-dropdown-toggle {
  background: rgba(255, 255, 255, 0.08);
  color: var(--white-color);
  border: 1px solid rgba(251, 142, 46, 0.65);
  border-radius: 12px;
  padding: 0.55rem 0.9rem;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 0.95rem;
  text-decoration: none;
}

.user-dropdown-toggle:hover {
  border-color: var(--orange-color);
  background-color: rgba(255, 255, 255, 0.12);
  transform: translateY(-1px);
}

.user-dropdown-toggle:focus-visible {
  box-shadow: 0 0 0 3px rgba(251, 142, 46, 0.25);
}

.user-dropdown-toggle .dropdown-caret {
  font-size: 0.8rem;
  color: var(--orange-color);
  transition: transform var(--transition-fast);
}

.user-dropdown.open .dropdown-caret {
  transform: rotate(180deg);
}

.user-dropdown-menu {
  display: none;
  position: absolute;
  right: 0;
  top: calc(100% + 10px);
  min-width: 220px;
  background: var(--text-dark);
  border: 1px solid rgba(251, 142, 46, 0.35);
  border-radius: 14px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  overflow: hidden;
  z-index: 2000;
  flex-direction: column;
}

.user-dropdown.open .user-dropdown-menu {
  display: flex;
}

.user-dropdown-item {
  width: 100%;
  background: transparent;
  border: 0;
  color: var(--white-color);
  text-decoration: none;
  padding: 0.85rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  cursor: pointer;
  font-weight: 700;
  font-size: 0.95rem;
  transition: var(--transition);
}

.user-dropdown-item i {
  color: var(--orange-color);
  width: 18px;
  text-align: center;
}

.user-dropdown-item:hover {
  background: rgba(255, 255, 255, 0.08);
}

/* ===== Main content ===== */
.main-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--spacing-xl);
  width: 100%;
}

/* ===== Back navigation ===== */
.back-nav {
  margin-bottom: var(--spacing-lg);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--gray-600);
  text-decoration: none;
  font-weight: var(--font-weight-semibold);
  font-size: 0.95rem;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-lg);
  transition: all var(--transition-fast);
}

.back-link:hover {
  color: var(--gray-900);
  background: var(--gray-100);
}

.back-link i {
  font-size: 0.85rem;
}


/* Banner mejorado */
.book-banner {
  position: relative;
  height: 300px;
  border-radius: var(--radius-xl);
  overflow: hidden;
  margin-bottom: var(--spacing-2xl);
  box-shadow: var(--shadow-lg);
}

.book-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, transparent 40%, rgba(0, 0, 0, 0.7));
  z-index: 1;
}

.banner-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 10s ease;
}

.book-banner:hover .banner-image {
  transform: scale(1.05);
}

/* ===== Banner Skeleton ===== */
.skeleton-banner {
  display: none;
  position: relative;
  height: 300px;
  border-radius: var(--radius-xl);
  overflow: hidden;
  margin-bottom: var(--spacing-2xl);
  box-shadow: var(--shadow-lg);
  background: white;
}

.skeleton-banner.is-loading {
  display: block;
}

.skeleton-banner-bg {
  width: 100%;
  height: 100%;
  border-radius: 0;
}

.skeleton-banner-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: var(--spacing-sm);
  padding: var(--spacing-xl);
  z-index: 2;
  background: linear-gradient(to bottom, transparent 40%, rgba(0, 0, 0, 0.65));
}

.skeleton-banner-title {
  height: 34px;
  width: 55%;
  border-radius: var(--radius-lg);
}

.skeleton-banner-author {
  height: 20px;
  width: 35%;
  border-radius: var(--radius-lg);
}

/* Banner overlay (real) */
.banner-overlay {
  position: absolute;
  inset: 0;
  z-index: 2;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  gap: 0.35rem;
  padding: var(--spacing-xl);
}

.banner-title {
  color: white;
  font-size: 2rem;
  font-weight: var(--font-weight-extrabold);
  line-height: 1.15;
  text-shadow: 0 6px 18px rgba(0, 0, 0, 0.45);
}

.banner-author {
  color: rgba(255, 255, 255, 0.9);
  font-size: 1.05rem;
  font-weight: var(--font-weight-semibold);
  text-shadow: 0 6px 18px rgba(0, 0, 0, 0.45);
}


/* ===== Loading State — Skeleton ===== */
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.loading-state {
  display: none;
}

.skeleton-details {
  display: none;
}

.skeleton-details.is-loading {
  display: block;
}

.skeleton-details .book-details-grid {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--spacing-2xl);
  align-items: start;
}

.skeleton-shimmer {
  background: linear-gradient(90deg, var(--gray-100) 25%, var(--gray-200) 50%, var(--gray-100) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
  border-radius: var(--radius-lg);
}

.skeleton-cover {
  aspect-ratio: 2 / 3;
  width: 100%;
  border-radius: var(--radius-xl);
}

.skeleton-title {
  height: 36px;
  width: 75%;
  margin-bottom: var(--spacing-sm);
}

.skeleton-author {
  height: 22px;
  width: 40%;
  margin-bottom: var(--spacing-lg);
}

.skeleton-badges {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.skeleton-badge {
  height: 32px;
  width: 90px;
  border-radius: var(--radius-full);
}

.skeleton-btn {
  height: 52px;
  width: 200px;
  margin-bottom: var(--spacing-lg);
  border-radius: var(--radius-lg);
}

.skeleton-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--gray-200);
}

.skeleton-stat {
  height: 48px;
  border-radius: var(--radius-md);
}

.skeleton-section {
  margin-top: var(--spacing-xl);
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
}

.skeleton-section-title {
  height: 28px;
  width: 200px;
  margin-bottom: var(--spacing-lg);
}

.skeleton-text-line {
  height: 16px;
  margin-bottom: var(--spacing-sm);
}

.skeleton-text-line:nth-child(2) { width: 95%; }
.skeleton-text-line:nth-child(3) { width: 88%; }
.skeleton-text-line:nth-child(4) { width: 60%; }

@media (max-width: 768px) {
  .skeleton-details .book-details-grid {
    grid-template-columns: 1fr;
  }
  .skeleton-cover {
    max-width: 220px;
    margin: 0 auto;
  }
}

/* ===== Error State ===== */
.error-state {
  display: none;
  background: white;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl);
  text-align: center;
  max-width: 500px;
  margin: var(--spacing-2xl) auto;
  box-shadow: var(--shadow-md);
}

.error-state.is-visible {
  display: block;
}

.error-state__icon {
  font-size: 3rem;
  color: var(--danger-500);
  margin-bottom: var(--spacing-md);
}

.error-state__title {
  font-size: 1.25rem;
  font-weight: var(--font-weight-bold);
  color: var(--gray-900);
  margin-bottom: var(--spacing-sm);
}

.error-state__desc {
  color: var(--gray-600);
  margin-bottom: var(--spacing-lg);
  line-height: 1.6;
}

.error-state__actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Book Details Grid ===== */
.book-details-grid {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--spacing-2xl);
  align-items: start;
}

/* ===== Book Cover ===== */
.book-cover-container {
  position: sticky;
  top: calc(80px + var(--spacing-lg));
  align-self: start;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.book-cover {
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  aspect-ratio: 2/3;
  position: relative;
  width: 100%;
  background: var(--gray-100);
}

.book-cover-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  border-radius: var(--radius-xl);
}

/* Color accent glow behind cover */
.book-cover-container[data-accent] .book-cover {
  box-shadow: var(--shadow-xl);
}

/* ===== Book Meta Card ===== */
.book-meta-card {
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-lg);
}

.book-title {
  font-size: 2rem;
  font-weight: var(--font-weight-extrabold);
  color: var(--gray-900);
  margin-bottom: var(--spacing-xs);
  line-height: 1.2;
}

.book-author {
  font-size: 1.125rem;
  color: var(--gray-600);
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-lg);
}

.book-buyer-summary {
  color: var(--gray-700);
  font-size: 1rem;
  line-height: 1.7;
  margin-bottom: var(--spacing-lg);
}

.book-author a {
  color: var(--primary-500);
  text-decoration: none;
}

.book-author a:hover {
  text-decoration: underline;
}

/* Badges */
.book-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 6px 12px;
  background: var(--gray-100);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: var(--font-weight-medium);
  color: var(--gray-700);
}

.badge i {
  color: var(--primary-500);
  font-size: 0.75rem;
}

.badge.rating {
  background: linear-gradient(135deg, #fff9db, #ffec99);
  border-color: #fcc419;
  color: #e67700;
}

/* ===== Action buttons ===== */
.book-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.btn {
  display: none;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: 14px 24px;
  border-radius: var(--radius-lg);
  font-weight: var(--font-weight-bold);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 2px solid transparent;
  font-size: 1rem;
  min-height: 52px;
  font-family: inherit;
}

.btn:focus-visible {
  outline: 3px solid var(--primary-500);
  outline-offset: 2px;
}

.btn.is-visible {
  display: inline-flex;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary-500), var(--primary-600));
  color: white;
  box-shadow: 0 4px 12px rgba(251, 142, 46, 0.3);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(251, 142, 46, 0.4);
  background: linear-gradient(135deg, var(--primary-600), var(--primary-700));
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
}

.btn-outline {
  background: transparent;
  border-color: var(--gray-300);
  color: var(--gray-700);
}

.btn-outline:hover:not(:disabled) {
  border-color: var(--primary-500);
  color: var(--primary-600);
  background: rgba(251, 142, 46, 0.06);
  transform: translateY(-2px);
}

.btn-secondary {
  background: var(--gray-100);
  border-color: var(--gray-200);
  color: var(--gray-700);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--gray-200);
  transform: translateY(-1px);
}

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

.btn .fa-spin {
  margin-right: 4px;
}

/* ===== Stats grid ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--gray-200);
}

.stat-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--gray-500);
  font-weight: var(--font-weight-medium);
  text-transform: uppercase;
  letter-spacing: 0.3px;
}

.stat-value {
  font-size: 1rem;
  font-weight: var(--font-weight-bold);
  color: var(--gray-900);
}

/* ===== Description ===== */
.description-section {
  margin-top: var(--spacing-xl);
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--gray-200);
}

.section-title {
  font-size: 1.25rem;
  font-weight: var(--font-weight-bold);
  color: var(--gray-900);
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.section-title i {
  color: var(--primary-500);
  font-size: 1rem;
}

.book-description {
  line-height: 1.7;
  color: var(--gray-700);
  font-size: 1rem;
}

.discovery-section,
.learning-section,
.sample-section,
.author-section,
.faq-section,
.related-section {
  margin-top: var(--spacing-xl);
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--gray-200);
}

.discovery-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--spacing-lg);
}

.discovery-card {
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  background: linear-gradient(180deg, #fff, #fff8f0);
}

.taxonomy-line {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-md);
  align-items: center;
  margin-bottom: var(--spacing-md);
  color: var(--gray-700);
}

.taxonomy-line strong {
  color: var(--gray-900);
}

.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  margin-bottom: 9px;
}

.chip-group--soft .chip {
  background: #eff6ff;
  border-color: #bfdbfe;
  color: #1d4ed8;
}

.chip {
  display: inline-flex;
  align-items: center;
  padding: 0.45rem 0.8rem;
  border-radius: var(--radius-full);
  border: 1px solid #fed7aa;
  background: #fff7ed;
  color: #9a3412;
  font-size: 0.9rem;
  font-weight: 700;
}

.chip.is-empty {
  border-style: dashed;
  color: var(--gray-500);
  background: var(--gray-50);
  border-color: var(--gray-300);
}

.discovery-copy {
  color: var(--gray-700);
  line-height: 1.7;
}

.mini-title {
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  color: var(--gray-900);
  font-size: 1rem;
}

.learning-list {
  list-style: none;
  display: grid;
  gap: 0.85rem;
  padding: 0;
}

.learning-list li {
  position: relative;
  padding-left: 1.6rem;
  color: var(--gray-700);
}

.learning-list li::before {
  content: "";
  position: absolute;
  left: 0.25rem;
  top: 0.65rem;
  width: 0.55rem;
  height: 0.55rem;
  border-radius: 999px;
  background: var(--primary-500);
}

#bookSampleAudio {
  width: 100%;
}

.author-card-public {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: var(--spacing-lg);
  align-items: start;
}

.author-photo-public {
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: 24px;
  box-shadow: var(--shadow-md);
}

.author-copy-public h3 {
  font-size: 1.4rem;
  margin-bottom: 0.3rem;
}

.author-headline-public {
  color: var(--primary-600);
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
}

.author-bio-public {
  color: var(--gray-700);
  line-height: 1.7;
}

.author-links-public {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: var(--spacing-md);
}

.author-links-public a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.55rem 0.85rem;
  border-radius: 999px;
  background: rgba(251, 146, 60, 0.08);
  border: 1px solid rgba(251, 146, 60, 0.2);
  color: var(--primary-600);
  font-weight: 700;
  text-decoration: none;
}

.author-links-public a:hover {
  text-decoration: underline;
}

.faq-list {
  display: grid;
  gap: var(--spacing-md);
}

.faq-item {
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  background: var(--gray-50);
}

.faq-item h3 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  color: var(--gray-900);
}

.faq-item p {
  color: var(--gray-700);
  line-height: 1.7;
}

.related-books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--spacing-lg);
}

.related-book-card {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: var(--spacing-md);
  text-decoration: none;
  color: inherit;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  background: var(--gray-50);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
}

.related-book-card:hover {
  transform: translateY(-3px);
  border-color: #fdba74;
  box-shadow: var(--shadow-md);
}

.related-book-card img {
  width: 80px;
  height: 112px;
  object-fit: cover;
  border-radius: 14px;
  background: var(--gray-100);
}

.related-book-card h3 {
  font-size: 1rem;
  margin-bottom: 0.35rem;
}

.related-book-card p {
  color: var(--gray-600);
  line-height: 1.5;
  font-size: 0.92rem;
}

/* ===== Chapters ===== */
.chapters-section {
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--gray-200);
  margin-top: var(--spacing-xl);
}

.chapters-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  list-style: none;
  padding: 0;
}

.chapter-item {
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md) var(--spacing-lg);
  transition: all var(--transition-fast);
  list-style-type: none;
}

.chapter-item[role="button"] {
  cursor: pointer;
}

.chapter-item[role="button"]:hover {
  background: var(--primary-50);
  border-color: var(--primary-500);
  transform: translateX(4px);
}

.chapter-item[role="button"]:focus-visible {
  outline: 3px solid var(--primary-500);
  outline-offset: 2px;
}

/* Play indicator for accessible chapters */
.chapter-item[role="button"] .chapter-header::after {
  content: "\f04b"; /* fa-play */
  font-family: "Font Awesome 6 Free";
  font-weight: 900;
  font-size: 0.75rem;
  color: var(--primary-500);
  opacity: 0;
  transition: opacity var(--transition-fast);
  margin-left: auto;
  flex-shrink: 0;
}

.chapter-item[role="button"]:hover .chapter-header::after {
  opacity: 1;
}

.chapter-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xs);
}

.chapter-title {
  font-weight: var(--font-weight-semibold);
  color: var(--gray-900);
  font-size: 1rem;
}

.chapter-meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--gray-500);
  font-size: 0.85rem;
  font-weight: var(--font-weight-medium);
  flex-shrink: 0;
}

.chapter-meta i {
  color: var(--primary-500);
  font-size: 0.75rem;
}

.chapter-summary {
  color: var(--gray-600);
  font-size: 0.9rem;
  line-height: 1.6;
}

.chapters-more {
  margin-top: var(--spacing-md);
  text-align: center;
}

.chapters-more .btn {
  display: inline-flex;
}

/* ===== Reviews Section ===== */
.reviews-section {
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--gray-200);
  margin-top: var(--spacing-xl);
}

.reviews-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.reviews-stats {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
  flex-wrap: wrap;
}

.rating-display {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.rating-value {
  font-size: 2.5rem;
  font-weight: var(--font-weight-extrabold);
  color: var(--gray-900);
  line-height: 1;
}

.rating-stars {
  display: flex;
  gap: 2px;
}

.rating-stars i {
  color: #ffb703;
  font-size: 1.125rem;
}

.rating-stars i.far {
  color: var(--gray-300);
}

.rating-count {
  color: var(--gray-500);
  font-size: 0.85rem;
  font-weight: var(--font-weight-medium);
}

/* Reviews filters */
.reviews-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-md);
  flex-wrap: wrap;
  margin-bottom: var(--spacing-lg);
}

.reviews-filters {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.filter-btn {
  padding: 8px 16px;
  background: var(--gray-100);
  border: 2px solid var(--gray-200);
  border-radius: var(--radius-full);
  font-weight: var(--font-weight-semibold);
  color: var(--gray-600);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 0.9rem;
  font-family: inherit;
}

.filter-btn:hover:not(.active) {
  background: rgba(251, 142, 46, 0.08);
  border-color: rgba(251, 142, 46, 0.4);
  color: var(--gray-700);
}

.filter-btn.active {
  background: var(--primary-500);
  border-color: var(--primary-500);
  color: white;
}

.filter-btn:focus-visible {
  outline: 3px solid var(--primary-500);
  outline-offset: 2px;
}

.filter-count {
  font-weight: var(--font-weight-bold);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  background: rgba(0, 0, 0, 0.06);
}

.filter-btn.active .filter-count {
  background: rgba(255, 255, 255, 0.25);
}

.reviews-hint {
  color: var(--gray-500);
  font-weight: var(--font-weight-medium);
  font-size: 0.9rem;
}

/* Reviews list */
.reviews-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  list-style: none;
  padding: 0;
}

.review-card {
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  transition: all var(--transition-fast);
}

.review-card:hover {
  background: white;
  border-color: var(--gray-300);
  box-shadow: var(--shadow-sm);
}

.review-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.review-user {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.user-avatar-small {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary-500);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-weight-bold);
  color: white;
  font-size: 0.875rem;
  flex-shrink: 0;
}

.user-name {
  font-weight: var(--font-weight-semibold);
  color: var(--gray-900);
  font-size: 0.95rem;
}

.review-date {
  color: var(--gray-500);
  font-size: 0.85rem;
}

.review-content {
  color: var(--gray-700);
  line-height: 1.6;
  margin-top: var(--spacing-sm);
  font-size: 0.95rem;
}

/* Reviews empty */
.reviews-empty {
  display: none;
  text-align: center;
  padding: var(--spacing-2xl);
  background: var(--gray-50);
  border-radius: var(--radius-lg);
  border: 1px dashed var(--gray-300);
}

.reviews-empty__icon {
  font-size: 2.5rem;
  color: var(--gray-300);
  margin-bottom: var(--spacing-md);
}

.reviews-empty__title {
  font-size: 1.05rem;
  font-weight: var(--font-weight-bold);
  color: var(--gray-700);
  margin-bottom: var(--spacing-xs);
}

.reviews-empty__desc {
  color: var(--gray-500);
  font-size: 0.9rem;
}

/* Reviews more */
.reviews-more {
  margin-top: var(--spacing-lg);
  text-align: center;
}

.reviews-more .btn {
  display: inline-flex;
}

/* ===== Notification Toast ===== */
@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

@keyframes slideOut {
  from { transform: translateX(0); opacity: 1; }
  to { transform: translateX(100%); opacity: 0; }
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .menu-toggle {
    display: block;
  }

  .header-menu {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--text-dark);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem;
    z-index: 1000;
    display: none;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
  }

  .header-menu.active {
    display: flex;
  }

  .user-stats {
    flex-direction: column;
    width: 100%;
    gap: 1rem;
  }

  .user-authenticated {
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .user-dropdown {
    width: 100%;
  }

  .user-dropdown-toggle {
    width: 100%;
    justify-content: space-between;
  }

  .user-dropdown-menu {
    position: static;
    width: 100%;
    margin-top: 0.75rem;
    box-shadow: none;
  }
}

@media (max-width: 768px) {
  .app-header {
    padding: var(--spacing-md);
  }

  .logo h1 {
    font-size: 1.2rem;
  }

  .main-content {
    padding: var(--spacing-md);
  }

  .book-details-grid {
    grid-template-columns: 1fr;
  }

  .book-cover-container {
    position: static;
    max-width: 260px;
    margin: 0 auto;
  }

  .book-title {
    font-size: 1.5rem;
  }

  .book-actions {
    flex-direction: column;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }

  .reviews-header {
    flex-direction: column;
    align-items: stretch;
  }

  .reviews-stats {
    justify-content: center;
  }

  .chapter-item[role="button"] .chapter-header::after {
    opacity: 1;
  }
}

@media (max-width: 480px) {
  .stats-grid {
    grid-template-columns: 1fr 1fr;
  }

  .rating-value {
    font-size: 2rem;
  }
}

/* ===== Accessibility: high contrast ===== */
@media (prefers-contrast: high) {
  .btn-primary {
    border: 3px solid currentColor;
  }

  .user-dropdown-toggle {
    border-width: 3px;
  }

  .chapter-item {
    border-width: 2px;
  }

  .review-card {
    border-width: 2px;
  }

  .badge {
    border-width: 2px;
  }
}

/* ===== Accessibility: reduced motion ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
}

@media (max-width: 768px) {
  .discovery-grid,
  .author-card-public {
    grid-template-columns: 1fr;
  }

  .author-photo-public {
    width: 96px;
    height: 96px;
  }
}