/* Book Reader Styles - v2.3 Enhanced Readability */

body.book-page {
  background: var(--bg-primary);
  padding-top: 0;
  font-size: 18px; /* Increased base font size for better readability */
  line-height: 1.8; /* Improved line height */
}

/* Book Navigation */
.book-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  background: rgba(13, 17, 23, 0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-primary);
  z-index: 1000;
  height: 70px; /* Increased for better touch targets */
}

.book-nav-inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-md);
}

.book-nav-home {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 1rem; /* Increased from 0.9rem */
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.book-nav-home:hover { color: var(--brand-primary); }

.book-nav-title {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-weight: 600;
  color: var(--text-primary);
  font-size: 1.1rem; /* Increased from 0.95rem */
}

.book-nav-icon { font-size: 1.4rem; /* Increased from 1.2rem */ }

.book-nav-version {
  background: var(--brand-gradient);
  color: white;
  padding: 4px 10px; /* Increased from 2px 8px */
  border-radius: 12px;
  font-size: 0.85rem; /* Increased from 0.75rem */
  font-weight: 600;
}

.book-nav-actions {
  display: flex;
  gap: var(--spacing-sm);
  align-items: center;
}

/* Layout */
.book-layout {
  display: flex;
  min-height: 100vh;
  padding-top: 70px;
}

/* Sidebar */
.book-sidebar {
  position: fixed;
  top: 70px;
  left: 0;
  width: 280px;
  height: calc(100vh - 70px);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-primary);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-normal);
  z-index: 100;
  flex-shrink: 0;
}

.sidebar-header {
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--border-primary);
}

.sidebar-book-cover {
  width: 100%;
  height: 120px;
  background: linear-gradient(135deg, #1a1a2e 0%, #0f3460 100%);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(245, 158, 11, 0.2);
}

.sidebar-cover-inner { text-align: center; }

.sidebar-nav {
  flex: 1;
  padding: var(--spacing-lg); /* Increased from md */
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm); /* Increased from xs */
}

.sidebar-section-label {
  color: var(--text-muted);
  font-size: 0.85rem; /* Increased from 0.75rem */
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: var(--spacing-sm) var(--spacing-md);
  margin-bottom: var(--spacing-sm); /* Increased from xs */
}

.sidebar-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-md); /* Increased from sm */
  padding: var(--spacing-md) var(--spacing-lg); /* Increased padding */
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 1rem; /* Increased from 0.9rem */
  transition: all var(--transition-fast);
  border: 1px solid transparent;
  min-height: 48px; /* Added minimum touch target */
}

.sidebar-link:hover {
  color: var(--text-primary);
  background: rgba(245, 158, 11, 0.08);
  border-color: rgba(245, 158, 11, 0.2);
}

.sidebar-link.active {
  color: var(--brand-primary);
  background: rgba(245, 158, 11, 0.12);
  border-color: rgba(245, 158, 11, 0.3);
}

.sidebar-num {
  background: var(--bg-tertiary);
  color: var(--text-muted);
  width: 28px; /* Increased from 24px */
  height: 28px; /* Increased from 24px */
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem; /* Increased from 0.7rem */
  font-weight: 700;
  flex-shrink: 0;
}

.sidebar-link.active .sidebar-num {
  background: var(--brand-gradient);
  color: white;
}

.sidebar-footer {
  padding: var(--spacing-lg);
  border-top: 1px solid var(--border-primary);
}

/* Main Content — fills all space to the right of the fixed sidebar */
.book-content {
  margin-left: 280px;
  flex: 1;
  min-width: 0;
  width: calc(100% - 280px);
  padding: 3rem 4rem;
  box-sizing: border-box;
}

/* Book Hero */
.book-hero {
  text-align: center;
  padding: var(--spacing-3xl) 0;
  margin-bottom: var(--spacing-3xl);
  border-bottom: 1px solid var(--border-primary);
}

.book-hero-badge {
  display: inline-block;
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: var(--brand-primary);
  padding: var(--spacing-md) var(--spacing-xl); /* Increased from sm/lg */
  border-radius: var(--radius-xl);
  font-size: 1rem; /* Increased from 0.85rem */
  font-weight: 600;
  margin-bottom: var(--spacing-xl);
}

.book-hero h1 {
  font-size: 3.5rem; /* Increased from 3rem */
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-lg);
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}

.book-hero-sub {
  font-size: 1.3rem; /* Increased from 1.15rem */
  color: var(--text-secondary);
  max-width: 700px; /* Increased from 600px */
  margin: 0 auto var(--spacing-lg);
  line-height: 1.8; /* Increased from 1.7 */
}

.book-hero-meta {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg); /* Increased from md */
  color: var(--text-muted);
  font-size: 1rem; /* Increased from 0.9rem */
  margin-bottom: var(--spacing-xl);
}

.book-hero-actions {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg); /* Increased from md */
  flex-wrap: wrap;
}

/* Chapters */
.chapter {
  margin-bottom: var(--spacing-3xl);
  padding-bottom: var(--spacing-3xl);
  border-bottom: 1px solid var(--border-primary);
}

.chapter-header {
  margin-bottom: var(--spacing-2xl);
}

.chapter-number {
  color: var(--brand-primary);
  font-size: 1rem; /* Increased from 0.85rem */
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: var(--spacing-md); /* Increased from sm */
}

.chapter-title {
  font-size: 2.5rem; /* Increased from 2rem */
  color: var(--text-primary);
  margin: 0;
  line-height: 1.3;
}

.chapter-body h3 {
  color: var(--text-primary);
  font-size: 1.6rem; /* Increased from 1.25rem */
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-lg); /* Increased from md */
  padding-bottom: var(--spacing-md); /* Increased from sm */
  border-bottom: 1px solid var(--border-primary);
  line-height: 1.4;
}

.chapter-body h4 {
  color: var(--text-primary);
  font-size: 1.3rem; /* Added for h4 */
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
  line-height: 1.4;
}

.chapter-body h5 {
  color: var(--text-primary);
  font-size: 1.1rem; /* Added for h5 */
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  line-height: 1.4;
}

.chapter-body p {
  color: var(--text-secondary);
  line-height: 1.9; /* Increased from 1.8 */
  margin-bottom: var(--spacing-lg); /* Increased from md */
  font-size: 1.1rem; /* Added explicit size */
}

.chapter-body ul, .chapter-body ol {
  color: var(--text-secondary);
  padding-left: var(--spacing-2xl); /* Increased from xl */
  margin-bottom: var(--spacing-lg); /* Increased from md */
  line-height: 1.9; /* Increased from 1.8 */
  font-size: 1.05rem; /* Added explicit size */
}

.chapter-body li { 
  margin-bottom: var(--spacing-md); /* Increased from sm */
}

.chapter-body strong { 
  color: var(--text-primary); 
  font-weight: 600;
}

.chapter-body code { 
  font-family: var(--font-mono); 
  color: var(--brand-primary); 
  font-size: 1rem; /* Increased from 0.9em */
  background: rgba(245,158,11,0.1); 
  padding: 3px 8px; /* Increased from 2px 6px */
  border-radius: 5px; /* Increased from 4px */
}

/* Code windows inside book chapters must not overflow */
.chapter-body .code-window {
  max-width: 100%;
  overflow: hidden;
}

.chapter-body .code-content {
  overflow-x: auto;
  max-width: 100%;
}

.chapter-body blockquote {
  border-left: 4px solid var(--brand-primary);
  padding: var(--spacing-lg) var(--spacing-xl);
  margin: var(--spacing-xl) 0;
  background: rgba(245, 158, 11, 0.05);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-style: italic;
  color: var(--text-secondary);
  font-size: 1.1rem;
  line-height: 1.8;
}

.code-example { margin: var(--spacing-xl) 0; }
.code-example-label { 
  color: var(--text-muted); 
  font-size: 0.9rem; /* Increased from 0.8rem */
  margin-bottom: var(--spacing-sm); 
  font-family: var(--font-mono); 
}

.chapter-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  gap: var(--spacing-md);
}

.chapter-nav .btn {
  min-height: 48px; /* Added for better touch targets */
  font-size: 1rem;
}

/* Install tabs in book */
.install-tabs { margin: var(--spacing-xl) 0; }
.install-tab-btns { 
  display: flex; 
  gap: var(--spacing-md); /* Increased from sm */ 
  margin-bottom: var(--spacing-lg); /* Increased from md */ 
  flex-wrap: wrap; 
}
.itab { 
  background: var(--bg-tertiary); 
  border: 1px solid var(--border-primary); 
  color: var(--text-secondary); 
  padding: var(--spacing-md) var(--spacing-lg); /* Increased from sm/md */
  border-radius: var(--radius-md); 
  cursor: pointer; 
  font-family: var(--font-family); 
  font-size: 1rem; /* Added explicit size */
  min-height: 44px; /* Added for touch targets */
  transition: all var(--transition-fast); 
}
.itab.active, .itab:hover { 
  background: rgba(245,158,11,0.15); 
  border-color: var(--brand-primary); 
  color: var(--brand-primary); 
}
.install-tab-content { display: none; }
.install-tab-content.active { display: block; }

/* Chapters grid */
.chapters-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-xl); /* Increased from lg */
  margin: var(--spacing-3xl) 0;
}

.chapter-card {
  background: var(--bg-card);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-2xl); /* Increased from xl */
  text-decoration: none;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.chapter-card:hover {
  border-color: var(--brand-primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.cc-num {
  font-size: 2.5rem; /* Increased from 2rem */
  font-weight: 700;
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-md); /* Increased from sm */
}

.chapter-card h3 { 
  color: var(--text-primary); 
  font-size: 1.2rem; /* Increased from 1rem */
  margin-bottom: var(--spacing-md); /* Increased from sm */
  line-height: 1.4;
}

.chapter-card p { 
  color: var(--text-secondary); 
  font-size: 1rem; /* Increased from 0.9rem */
  margin: 0; 
  flex: 1; 
  line-height: 1.7; /* Increased from 1.6 */
}

.cc-read { 
  color: var(--brand-primary); 
  font-size: 0.95rem; /* Increased from 0.85rem */
  font-weight: 500; 
  margin-top: var(--spacing-lg); /* Increased from md */
}

/* Download CTA */
.book-download-cta {
  text-align: center;
  padding: var(--spacing-3xl);
  background: var(--bg-card);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  margin-top: var(--spacing-3xl);
}

.book-download-icon { 
  font-size: 4.5rem; /* Increased from 4rem */ 
  margin-bottom: var(--spacing-xl); /* Increased from lg */ 
}

.book-download-cta h2 { 
  color: var(--text-primary); 
  margin-bottom: var(--spacing-lg); /* Increased from md */
  font-size: 2.2rem; /* Added explicit size */
}

.book-download-cta p { 
  color: var(--text-secondary); 
  margin-bottom: var(--spacing-xl); 
  font-size: 1.2rem; /* Added explicit size */
  line-height: 1.7;
}

.book-download-actions { 
  display: flex; 
  justify-content: center; 
  gap: var(--spacing-lg); /* Increased from md */ 
  flex-wrap: wrap; 
}

/* Responsive */
@media (max-width: 1024px) {
  .book-layout { display: block; }
  .book-sidebar { transform: translateX(-100%); }
  .book-sidebar.open { transform: translateX(0); }
  .book-content { 
    margin-left: 0; 
    width: 100%;
    padding: 2rem 1.5rem;
  }
  .chapters-grid { grid-template-columns: repeat(2, 1fr); }
  
  .book-hero h1 { font-size: 2.8rem; }
  .chapter-title { font-size: 2.2rem; }
  .chapter-body h3 { font-size: 1.4rem; }
}

@media (max-width: 768px) {
  body.book-page { font-size: 17px; } /* Slightly smaller but still readable */
  
  .book-nav { height: 60px; }
  .book-layout { padding-top: 60px; }
  .book-sidebar { top: 60px; height: calc(100vh - 60px); }
  
  .book-hero h1 { font-size: 2.2rem; }
  .book-hero-sub { font-size: 1.1rem; }
  .chapters-grid { grid-template-columns: 1fr; }
  .chapter-nav { flex-direction: column; gap: var(--spacing-md); }
  .chapter-nav .btn { width: 100%; justify-content: center; }
  .book-download-actions { flex-direction: column; align-items: stretch; }
  .book-download-actions .btn { width: 100%; }
  
  .chapter-title { font-size: 1.9rem; }
  .chapter-body h3 { font-size: 1.3rem; }
  .chapter-body p { font-size: 1.05rem; }
  .chapter-body ul, .chapter-body ol { font-size: 1rem; }
}

@media (max-width: 480px) {
  body.book-page { font-size: 16px; } /* Minimum readable size */
  
  .book-content { padding: var(--spacing-xl) var(--spacing-md); }
  .book-hero { padding: var(--spacing-2xl) 0; }
  .book-hero h1 { font-size: 1.9rem; }
  .book-hero-sub { font-size: 1rem; }
  
  .chapter-title { font-size: 1.7rem; }
  .chapter-body h3 { font-size: 1.2rem; }
  .chapter-body p { font-size: 1rem; line-height: 1.8; }
  .chapter-body ul, .chapter-body ol { font-size: 0.95rem; padding-left: var(--spacing-lg); }
  
  .sidebar-link { font-size: 0.95rem; padding: var(--spacing-sm) var(--spacing-md); }
  .book-nav-title { font-size: 1rem; }
  .book-nav-home { font-size: 0.9rem; }
}