/* ==========================================================================
   Tech-21 Freemium Web Reader SaaS Design System
   Modern, responsive, glassmorphic UI with Dark, Light, and Sepia themes
   ========================================================================== */

:root {
  /* Color Tokens - Dark Mode (Default) */
  --bg-primary: #0a0d14;
  --bg-secondary: #111622;
  --bg-tertiary: #182030;
  --bg-card: rgba(22, 30, 46, 0.7);
  --bg-card-hover: rgba(30, 41, 62, 0.85);
  --bg-glass: rgba(17, 22, 34, 0.8);
  --bg-modal: rgba(10, 13, 20, 0.85);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-accent: #818cf8;

  --border-subtle: rgba(148, 163, 184, 0.12);
  --border-card: rgba(148, 163, 184, 0.18);
  --border-hover: rgba(99, 102, 241, 0.4);
  --border-focus: #6366f1;

  --accent-primary: #6366f1;
  --accent-primary-hover: #4f46e5;
  --accent-secondary: #8b5cf6;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 50%, #ec4899 100%);
  --accent-glow: rgba(99, 102, 241, 0.35);

  --success: #10b981;
  --success-bg: rgba(16, 185, 129, 0.15);
  --warning: #f59e0b;
  --warning-bg: rgba(245, 158, 11, 0.15);
  --danger: #ef4444;
  --danger-bg: rgba(239, 68, 68, 0.15);
  --pro-color: #a855f7;
  --pro-bg: rgba(168, 85, 247, 0.15);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Outfit', var(--font-sans);
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  --font-serif: 'Merriweather', Georgia, serif;

  /* Sizing & Radius */
  --header-height: 68px;
  --sidebar-width: 340px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 25px var(--accent-glow);

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Light Mode Overrides */
[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: rgba(255, 255, 255, 0.98);
  --bg-glass: rgba(255, 255, 255, 0.85);
  --bg-modal: rgba(248, 250, 252, 0.9);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --text-accent: #4f46e5;

  --border-subtle: rgba(15, 23, 42, 0.08);
  --border-card: rgba(15, 23, 42, 0.12);
  --border-hover: rgba(99, 102, 241, 0.5);

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.2);
}

/* Sepia Mode Overrides */
[data-theme="sepia"] {
  --bg-primary: #fbf0d9;
  --bg-secondary: #f4e6c8;
  --bg-tertiary: #eeddbb;
  --bg-card: rgba(244, 230, 200, 0.85);
  --bg-card-hover: rgba(238, 221, 187, 0.95);
  --bg-glass: rgba(251, 240, 217, 0.85);
  --bg-modal: rgba(251, 240, 217, 0.9);

  --text-primary: #3b2c1e;
  --text-secondary: #6e5741;
  --text-muted: #9c8369;
  --text-accent: #92400e;

  --border-subtle: rgba(59, 44, 30, 0.1);
  --border-card: rgba(59, 44, 30, 0.15);
  --border-hover: rgba(146, 64, 14, 0.4);

  --accent-primary: #b45309;
  --accent-primary-hover: #92400e;
  --accent-secondary: #d97706;
  --accent-gradient: linear-gradient(135deg, #b45309 0%, #d97706 50%, #f59e0b 100%);
  --accent-glow: rgba(180, 83, 9, 0.25);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-primary-hover);
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  outline: none;
}

input, select, textarea {
  font-family: inherit;
  color: inherit;
  background: transparent;
  border: 1px solid var(--border-card);
  outline: none;
}

code, pre {
  font-family: var(--font-mono);
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--border-card);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--bg-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.brand-wrapper {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.logo-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-weight: 900;
  font-size: 1.1rem;
  box-shadow: var(--shadow-glow);
}

.brand-badge {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-full);
  background: var(--border-subtle);
  color: var(--accent-primary);
  border: 1px solid var(--border-card);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 0.85rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--border-subtle);
}

.nav-link.active {
  color: #ffffff;
  background: var(--accent-primary);
  box-shadow: 0 2px 8px var(--accent-glow);
}

[data-theme="light"] .nav-link.active {
  color: #ffffff;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.search-trigger-btn {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.45rem 0.9rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: all var(--transition-fast);
}

.search-trigger-btn:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

.kbd-shortcut {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  background: var(--bg-primary);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  border: 1px solid var(--border-subtle);
}

/* Pro Status Pill */
.pro-status-pill {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
  background: var(--pro-bg);
  color: var(--pro-color);
  border: 1px solid rgba(168, 85, 247, 0.3);
  transition: all var(--transition-fast);
}

.pro-status-pill:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(168, 85, 247, 0.25);
}

.pro-status-pill.unlocked {
  background: var(--success-bg);
  color: var(--success);
  border-color: rgba(16, 185, 129, 0.4);
}

/* Theme Switcher */
.theme-switcher-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  transition: all var(--transition-fast);
}

.theme-switcher-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

/* Mobile Nav Toggle */
.mobile-nav-toggle {
  display: none;
  font-size: 1.25rem;
  padding: 0.5rem;
  color: var(--text-primary);
}

/* ==========================================================================
   Main Layout & Views Container
   ========================================================================== */
.app-container {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.view-section {
  display: none;
  animation: fadeIn 0.25s ease-out;
}

.view-section.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ==========================================================================
   Manoj Kumar Personal Brand Homepage Styles (themanojkumar.pro)
   ========================================================================== */
.home-hero {
  padding: 4.5rem 1.5rem 3rem;
  text-align: center;
  position: relative;
  overflow: hidden;
  background: radial-gradient(circle at 50% -20%, rgba(99, 102, 241, 0.25) 0%, rgba(168, 85, 247, 0.1) 40%, transparent 75%);
  border-bottom: 1px solid var(--border-subtle);
}

.author-monogram-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 72px;
  border-radius: var(--radius-xl);
  background: var(--accent-gradient);
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: 1.85rem;
  font-weight: 900;
  margin-bottom: 1.25rem;
  box-shadow: 0 0 30px var(--accent-glow);
  border: 2px solid rgba(255, 255, 255, 0.2);
}

.author-role-ribbon {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.35rem 1rem;
  border-radius: var(--radius-full);
  background: var(--bg-card);
  border: 1px solid var(--border-hover);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent-primary);
  margin-bottom: 1.25rem;
  box-shadow: var(--shadow-sm);
}

.home-headline {
  font-family: var(--font-heading);
  font-size: 3.25rem;
  font-weight: 900;
  letter-spacing: -0.03em;
  line-height: 1.15;
  max-width: 900px;
  margin: 0 auto 1.25rem;
}

.home-subhead {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 760px;
  margin: 0 auto 2.25rem;
  line-height: 1.6;
}

.home-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.btn-hero-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.75rem;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  color: #ffffff;
  font-size: 1rem;
  font-weight: 700;
  box-shadow: var(--shadow-glow);
  transition: all var(--transition-fast);
}

.btn-hero-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 30px var(--accent-glow);
  color: #ffffff;
}

.btn-hero-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.75rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  color: var(--text-primary);
  font-size: 1rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.btn-hero-secondary:hover {
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

/* 3 Pillars Section */
.pillars-section {
  max-width: 1280px;
  margin: 0 auto;
  padding: 4.5rem 1.5rem;
}

.section-label-center {
  text-align: center;
  margin-bottom: 3rem;
}

.section-tag {
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
  display: block;
}

.section-heading-lg {
  font-family: var(--font-heading);
  font-size: 2.4rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.pillars-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

.pillar-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 2.25rem 2rem;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
  backdrop-filter: blur(10px);
  position: relative;
}

.pillar-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-lg), 0 0 25px rgba(99, 102, 241, 0.15);
}

.pillar-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-lg);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 1.5rem;
}

.pillar-title {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.pillar-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 1.5rem;
  flex: 1;
}

.pillar-highlights-list {
  list-style: none;
  border-top: 1px solid var(--border-subtle);
  padding-top: 1rem;
}

.pillar-highlight-item {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.pillar-highlight-item strong {
  color: var(--text-primary);
}

/* Philosophy Callout */
.home-philosophy-banner {
  max-width: 1080px;
  margin: 1rem auto 4.5rem;
  padding: 0 1.5rem;
}

.philosophy-card-inner {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(168, 85, 247, 0.08) 100%);
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: var(--radius-xl);
  padding: 2.75rem 2.5rem;
  text-align: center;
  box-shadow: var(--shadow-glow);
  position: relative;
}

.quote-mark {
  font-size: 3rem;
  line-height: 1;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
}

.philosophy-quote-text {
  font-family: var(--font-heading);
  font-size: 1.45rem;
  font-weight: 700;
  line-height: 1.5;
  color: var(--text-primary);
  max-width: 860px;
  margin: 0 auto 1.5rem;
}

.philosophy-author {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--accent-primary);
}

.philosophy-author span {
  color: var(--text-muted);
  font-weight: 400;
}

/* Mentorship & Advisory Section */
.advisory-section {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  padding: 4.5rem 1.5rem;
}

.advisory-container {
  max-width: 1200px;
  margin: 0 auto;
}

.advisory-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.75rem;
  margin-top: 2.5rem;
}

.advisory-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: all var(--transition-normal);
}

.advisory-card:hover {
  border-color: var(--accent-primary);
  transform: translateY(-3px);
}

.advisory-card h4 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.advisory-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1.25rem;
}

/* Site Footer */
.app-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 1.5rem;
  margin-top: auto;
}

.footer-container {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.footer-domain {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--text-primary);
}

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.footer-link {
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-link:hover {
  color: var(--accent-primary);
}

/* ==========================================================================
   Catalog View (#/catalog)
   ========================================================================== */
.catalog-hero {
  padding: 3.5rem 1.5rem 2.5rem;
  text-align: center;
  background: radial-gradient(circle at 50% 0%, rgba(99, 102, 241, 0.12) 0%, transparent 70%);
  border-bottom: 1px solid var(--border-subtle);
}

.catalog-title {
  font-family: var(--font-heading);
  font-size: 2.75rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1rem;
  max-width: 860px;
  margin-left: auto;
  margin-right: auto;
}

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

.catalog-subtitle {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 1.8rem;
}

/* Stats Pill Bar */
.hero-stats-bar {
  display: inline-flex;
  align-items: center;
  gap: 1.5rem;
  padding: 0.65rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-full);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.stat-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.stat-item strong {
  color: var(--text-primary);
  font-weight: 700;
}

.stat-divider {
  width: 1px;
  height: 16px;
  background: var(--border-card);
}

/* Track Filter Pills */
.track-filter-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.6rem;
  padding: 1.5rem 1rem;
}

.track-pill {
  padding: 0.5rem 1.1rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-card);
  transition: all var(--transition-fast);
}

.track-pill:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

.track-pill.active {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  box-shadow: 0 2px 10px var(--accent-glow);
}

/* Books Grid */
.catalog-grid-container {
  max-width: 1380px;
  margin: 0 auto;
  padding: 1rem 1.5rem 4rem;
}

.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.75rem;
}

.book-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
  backdrop-filter: blur(8px);
  position: relative;
  overflow: hidden;
}

.book-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-lg), 0 0 20px rgba(99, 102, 241, 0.15);
}

.book-card-top {
  display: flex;
  gap: 1.1rem;
  margin-bottom: 1rem;
}

.book-cover-thumb {
  width: 90px;
  height: 140px;
  border-radius: var(--radius-sm);
  object-fit: cover;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-subtle);
  flex-shrink: 0;
  background: var(--bg-tertiary);
}

.book-card-info {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.book-vol-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-primary);
  margin-bottom: 0.25rem;
}

.book-card-title {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 0.35rem;
  color: var(--text-primary);
}

.book-card-track {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.book-meta-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: auto;
}

.meta-chip {
  font-size: 0.7rem;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}

.meta-chip.free-badge {
  background: var(--success-bg);
  color: var(--success);
  border-color: rgba(16, 185, 129, 0.3);
  font-weight: 600;
}

.book-card-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.45;
  margin-bottom: 1.25rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.book-card-actions {
  display: flex;
  gap: 0.6rem;
  margin-top: auto;
}

.btn-primary {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.6rem 1rem;
  border-radius: var(--radius-md);
  background: var(--accent-primary);
  color: #ffffff;
  font-size: 0.85rem;
  font-weight: 600;
  transition: all var(--transition-fast);
  box-shadow: 0 2px 6px var(--accent-glow);
}

.btn-primary:hover {
  background: var(--accent-primary-hover);
  color: #ffffff;
  transform: translateY(-1px);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 0.85rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-card);
  font-size: 0.85rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.btn-secondary:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

/* ==========================================================================
   Reader View (#/read/:book/:chapter)
   ========================================================================== */
.reader-layout {
  display: flex;
  height: calc(100vh - var(--header-height));
  position: relative;
  overflow: hidden;
}

/* Reader Left Sidebar */
.reader-sidebar {
  width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  transition: transform var(--transition-normal);
  z-index: 40;
}

.sidebar-book-picker {
  padding: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.book-select-dropdown {
  width: 100%;
  padding: 0.6rem 0.8rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
}

.sidebar-toc-filter {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.toc-search-input {
  width: 100%;
  padding: 0.45rem 0.75rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
}

.sidebar-toc-list {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem 0.75rem;
  list-style: none;
}

.toc-group-header {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  padding: 0.75rem 0.5rem 0.35rem;
}

.toc-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.55rem 0.65rem;
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 2px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.toc-item:hover {
  background: var(--border-subtle);
  color: var(--text-primary);
}

.toc-item.active {
  background: var(--accent-glow);
  color: var(--text-primary);
  font-weight: 600;
  border-left: 3px solid var(--accent-primary);
}

.toc-item-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.toc-badge {
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}

.toc-badge.free {
  background: var(--success-bg);
  color: var(--success);
}

.toc-badge.pro {
  background: var(--pro-bg);
  color: var(--pro-color);
}

.sidebar-footer-promo {
  padding: 1rem;
  background: var(--bg-tertiary);
  border-top: 1px solid var(--border-subtle);
  text-align: center;
}

.sidebar-promo-btn {
  width: 100%;
  padding: 0.55rem;
  background: var(--accent-gradient);
  color: #ffffff;
  border-radius: var(--radius-md);
  font-size: 0.8rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
}

/* Reader Main Content Viewport */
.reader-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  position: relative;
}

.reading-progress-track {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: transparent;
  z-index: 30;
}

.reading-progress-fill {
  height: 100%;
  width: 0%;
  background: var(--accent-gradient);
  transition: width 0.1s linear;
}

/* Reader Controls Toolbar */
.reader-toolbar {
  position: sticky;
  top: 3px;
  background: var(--bg-glass);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-subtle);
  padding: 0.6rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 20;
}

.reader-breadcrumbs {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.reader-breadcrumbs span {
  color: var(--text-primary);
  font-weight: 500;
}

.reader-settings-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.ctrl-btn {
  padding: 0.35rem 0.6rem;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  font-size: 0.8rem;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.ctrl-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

/* Reader Article Body */
.reader-article-container {
  max-width: 860px;
  margin: 0 auto;
  padding: 3rem 2rem 6rem;
  width: 100%;
  transition: max-width var(--transition-normal);
}

.reader-article-container.wide-mode {
  max-width: 1120px;
}

.reader-article-container.font-serif {
  font-family: var(--font-serif);
}

.reader-article-container.font-mono {
  font-family: var(--font-mono);
}

.reader-article-container.size-sm {
  font-size: 0.9rem;
}

.reader-article-container.size-lg {
  font-size: 1.15rem;
}

/* Chapter Heading */
.chapter-header-box {
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 1.5rem;
}

.chapter-number-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.25rem 0.6rem;
  border-radius: var(--radius-full);
  margin-bottom: 0.85rem;
}

.chapter-number-pill.free {
  background: var(--success-bg);
  color: var(--success);
}

.chapter-number-pill.pro {
  background: var(--pro-bg);
  color: var(--pro-color);
}

.chapter-title-main {
  font-family: var(--font-heading);
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--text-primary);
  margin-bottom: 0.8rem;
}

.chapter-meta-line {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Chapter Body HTML Typography */
.chapter-rendered-content {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.chapter-rendered-content h1 {
  display: none; /* Already rendered in chapter-header-box */
}

.chapter-rendered-content h2 {
  font-family: var(--font-heading);
  font-size: 1.55rem;
  font-weight: 700;
  margin: 2.5rem 0 1rem;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 0.4rem;
  letter-spacing: -0.01em;
}

.chapter-rendered-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 1.75rem 0 0.75rem;
  color: var(--text-accent);
}

.chapter-rendered-content p {
  margin-bottom: 1.35rem;
}

.chapter-rendered-content ul, .chapter-rendered-content ol {
  margin: 1rem 0 1.5rem 1.75rem;
}

.chapter-rendered-content li {
  margin-bottom: 0.5rem;
}

.chapter-rendered-content hr {
  border: none;
  height: 1px;
  background: var(--border-subtle);
  margin: 2.5rem 0;
}

/* Code Blocks */
.chapter-rendered-content pre {
  background: #0d1117 !important;
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 1.2rem;
  margin: 1.5rem 0;
  overflow-x: auto;
  position: relative;
}

.chapter-rendered-content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.1);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}

.chapter-rendered-content pre code {
  background: transparent;
  color: #e2e8f0;
  padding: 0;
}

.code-copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  font-size: 0.75rem;
  background: rgba(255, 255, 255, 0.1);
  color: #cbd5e1;
  padding: 0.25rem 0.55rem;
  border-radius: 4px;
  transition: all var(--transition-fast);
}

.code-copy-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  color: #ffffff;
}

/* Tables */
.chapter-rendered-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.92rem;
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.chapter-rendered-content th {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  font-weight: 700;
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 2px solid var(--border-card);
}

.chapter-rendered-content td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.chapter-rendered-content tr:last-child td {
  border-bottom: none;
}

.chapter-rendered-content tr:hover td {
  background: var(--border-subtle);
}

/* Blockquotes & Memory Anchors */
.chapter-rendered-content blockquote {
  background: var(--bg-tertiary);
  border-left: 4px solid var(--accent-primary);
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-style: normal;
  position: relative;
  box-shadow: var(--shadow-sm);
}

.memory-anchor-card {
  margin: 2.5rem 0;
  padding: 1.5rem;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(168, 85, 247, 0.1) 100%);
  border: 1px solid rgba(99, 102, 241, 0.3);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-glow);
}

.memory-anchor-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--accent-primary);
  margin-bottom: 0.6rem;
}

.memory-anchor-text {
  font-size: 1.15rem;
  font-weight: 600;
  line-height: 1.6;
  color: var(--text-primary);
}

/* Diagrams */
.diagram-wrapper {
  margin: 2rem 0;
  background: #ffffff;
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 1rem;
  text-align: center;
  cursor: zoom-in;
  transition: all var(--transition-normal);
}

.diagram-wrapper:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--accent-primary);
}

.diagram-wrapper img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 0 auto;
}

figcaption {
  font-size: 0.8rem;
  color: #475569;
  margin-top: 0.6rem;
  font-weight: 500;
}

/* Paywall Locked State Overlay */
.paywall-overlay-container {
  margin-top: 2rem;
  position: relative;
}

.paywall-teaser-blur {
  filter: blur(5px);
  opacity: 0.4;
  user-select: none;
  pointer-events: none;
  max-height: 250px;
  overflow: hidden;
}

.paywall-card {
  position: relative;
  margin-top: -120px;
  background: var(--bg-card);
  border: 1px solid var(--border-hover);
  border-radius: var(--radius-xl);
  padding: 2.5rem 2rem;
  text-align: center;
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  z-index: 10;
}

.paywall-icon-badge {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  color: #ffffff;
  margin: 0 auto 1.25rem;
  box-shadow: var(--shadow-glow);
}

.paywall-title {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.paywall-subtext {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 540px;
  margin: 0 auto 1.75rem;
}

.paywall-pricing-row {
  display: flex;
  justify-content: center;
  gap: 1.25rem;
  margin-bottom: 1.75rem;
  flex-wrap: wrap;
}

.tier-mini-card {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  min-width: 170px;
  text-align: left;
}

.tier-mini-card.highlight {
  border-color: var(--accent-primary);
  background: var(--accent-glow);
}

.tier-mini-name {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
}

.tier-mini-price {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  margin: 0.2rem 0;
}

.tier-mini-desc {
  font-size: 0.7rem;
  color: var(--text-secondary);
}

.paywall-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn-demo-unlock {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.65rem 1.25rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px dashed var(--accent-primary);
  color: var(--accent-primary);
  font-size: 0.85rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.btn-demo-unlock:hover {
  background: var(--accent-glow);
  color: #ffffff;
}

/* Chapter Bottom Navigation */
.chapter-nav-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-subtle);
  gap: 1rem;
}

.nav-ch-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.nav-ch-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
  background: var(--bg-card);
}

/* ==========================================================================
   Quiz Mode View (#/quiz)
   ========================================================================== */
.quiz-container {
  max-width: 780px;
  margin: 2.5rem auto 4rem;
  padding: 0 1.5rem;
}

.quiz-header {
  text-align: center;
  margin-bottom: 2rem;
}

.quiz-header h2 {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.quiz-status-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  margin-bottom: 1.5rem;
}

.quiz-badge {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.quiz-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 2rem;
  box-shadow: var(--shadow-md);
}

.quiz-topic-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-primary);
  margin-bottom: 0.5rem;
}

.quiz-question-text {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.quiz-options-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  list-style: none;
}

.quiz-option-btn {
  width: 100%;
  text-align: left;
  padding: 1rem 1.25rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.5;
  transition: all var(--transition-fast);
}

.quiz-option-btn:hover:not(:disabled) {
  border-color: var(--accent-primary);
  color: var(--text-primary);
  transform: translateX(4px);
}

.quiz-option-btn.correct {
  background: var(--success-bg) !important;
  border-color: var(--success) !important;
  color: var(--success) !important;
  font-weight: 600;
}

.quiz-option-btn.incorrect {
  background: var(--danger-bg) !important;
  border-color: var(--danger) !important;
  color: var(--danger) !important;
}

.quiz-explanation-box {
  margin-top: 1.5rem;
  padding: 1.25rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border-left: 4px solid var(--accent-primary);
  animation: fadeIn 0.3s ease-out;
}

.quiz-explanation-title {
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--accent-primary);
  margin-bottom: 0.4rem;
}

.quiz-next-btn {
  margin-top: 1.5rem;
  width: 100%;
  padding: 0.85rem;
  background: var(--accent-primary);
  color: #ffffff;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 1rem;
}

/* ==========================================================================
   Interview Simulator View (#/interview)
   ========================================================================== */
.interview-container {
  max-width: 860px;
  margin: 2.5rem auto 4rem;
  padding: 0 1.5rem;
}

.interview-header {
  text-align: center;
  margin-bottom: 2rem;
}

.interview-header h2 {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.interview-config-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.config-item {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.config-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
}

.config-select {
  padding: 0.45rem 0.75rem;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  font-size: 0.85rem;
  font-weight: 600;
}

.interview-active-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 2.25rem;
  box-shadow: var(--shadow-md);
}

.interview-timer-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.timer-display {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--accent-primary);
}

.timer-controls {
  display: flex;
  gap: 0.5rem;
}

.interview-prompt-title {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.interview-scratchpad {
  width: 100%;
  height: 130px;
  padding: 1rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  font-size: 0.95rem;
  line-height: 1.5;
  margin-bottom: 1.5rem;
  resize: vertical;
}

.rubric-box {
  margin-top: 1.5rem;
  padding: 1.5rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-hover);
  animation: fadeIn 0.3s ease-out;
}

.rubric-heading {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--accent-primary);
}

.rubric-concept-text {
  font-size: 0.95rem;
  margin-bottom: 1rem;
  color: var(--text-secondary);
}

.rubric-pitfall-item {
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.self-rate-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.rate-btn {
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border-card);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.rate-btn:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

/* ==========================================================================
   Pricing View (#/pricing)
   ========================================================================== */
.pricing-hero {
  text-align: center;
  padding: 3.5rem 1.5rem 2rem;
}

.pricing-hero h2 {
  font-family: var(--font-heading);
  font-size: 2.75rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
  max-width: 1200px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-normal);
}

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

.pricing-card.featured {
  border-color: var(--accent-primary);
  background: linear-gradient(180deg, rgba(99, 102, 241, 0.12) 0%, var(--bg-card) 100%);
  box-shadow: var(--shadow-glow);
}

.featured-pill {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-gradient);
  color: #ffffff;
  font-size: 0.7rem;
  font-weight: 800;
  text-transform: uppercase;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
}

.plan-name {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.plan-price {
  font-size: 2.5rem;
  font-weight: 900;
  margin-bottom: 0.25rem;
}

.plan-price span {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
}

.plan-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.plan-features-list {
  list-style: none;
  margin-bottom: 2rem;
  flex: 1;
}

.plan-feature-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.6rem;
}

.plan-feature-item svg {
  color: var(--success);
  flex-shrink: 0;
}

.license-entry-box {
  max-width: 580px;
  margin: 3rem auto 4rem;
  padding: 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  text-align: center;
}

.license-entry-box h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.license-input-row {
  display: flex;
  gap: 0.5rem;
  margin-top: 1rem;
}

.license-input {
  flex: 1;
  padding: 0.65rem 1rem;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-card);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  text-transform: uppercase;
}

/* ==========================================================================
   Modals (Search & Diagram Lightbox)
   ========================================================================== */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: var(--bg-modal);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 1000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal-backdrop.active {
  display: flex;
}

.search-modal-box {
  width: 100%;
  max-width: 680px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  animation: fadeIn 0.2s ease-out;
}

.search-modal-header {
  padding: 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.search-modal-input {
  flex: 1;
  font-size: 1.1rem;
  border: none;
  color: var(--text-primary);
}

.search-results-list {
  max-height: 480px;
  overflow-y: auto;
  padding: 0.5rem;
  list-style: none;
}

.search-result-item {
  padding: 0.85rem 1rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.search-result-item:hover, .search-result-item.highlighted {
  background: var(--border-subtle);
}

.search-result-badge {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--accent-primary);
  margin-bottom: 0.2rem;
}

.search-result-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.search-result-snippet {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-top: 0.2rem;
}

/* Lightbox Diagram Modal */
.lightbox-modal-box {
  max-width: 90vw;
  max-height: 90vh;
  background: #ffffff;
  padding: 1.5rem;
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

.lightbox-img {
  max-width: 100%;
  max-height: 75vh;
  object-fit: contain;
}

.lightbox-close-btn {
  position: absolute;
  top: 10px;
  right: 12px;
  font-size: 1.5rem;
  color: #0f172a;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 992px) {
  .reader-sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    bottom: 0;
    transform: translateX(-100%);
    box-shadow: var(--shadow-lg);
  }

  .reader-sidebar.open {
    transform: translateX(0);
  }

  .reader-article-container {
    padding: 2rem 1.25rem 5rem;
  }
}

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

  .mobile-nav-toggle {
    display: block;
  }

  .catalog-title {
    font-size: 2rem;
  }

  .chapter-title-main {
    font-size: 1.75rem;
  }

  .hero-stats-bar {
    flex-direction: column;
    gap: 0.5rem;
    border-radius: var(--radius-lg);
  }

  .stat-divider {
    display: none;
  }
}