/* style.css - Premium Design System for NEESHANT Physics E-Book */

/* ==========================================================================
   1. CORE THEMES & CUSTOM VARIABLES
   ========================================================================== */

:root {
  /* Default Theme: Paper White Notebook */
  --bg-color: #fcfbf9;
  --panel-bg: rgba(255, 255, 255, 0.85);
  --text-color: #1a237e; /* Deep navy blue ballpoint pen */
  --text-muted: #5c6bc0;
  --border-color: rgba(26, 35, 126, 0.15);
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(26, 35, 126, 0.1);
  --shadow-color: rgba(26, 35, 126, 0.08);
  
  /* Accent Colors */
  --accent-red: #e53935; /* Warning/formulas */
  --accent-green: #43a047; /* Tips/tricks */
  --accent-orange: #fb8c00; /* Real-life connections */
  --accent-purple: #7b1fa2; /* Concept maps */
  --accent-blue: #0288d1; /* Notes/annotations */
  --highlighter-yellow: rgba(255, 241, 118, 0.5);
  
  /* Notebook Lines */
  --paper-line-color: rgba(2, 136, 209, 0.12); /* Light blue ruled lines */
  --margin-line-color: rgba(229, 57, 53, 0.35); /* Red vertical margin */
  
  /* Typography */
  --font-heading: 'Architects Daughter', cursive;
  --font-text: 'Caveat', cursive;
  --font-interface: 'Outfit', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  
  --transition-speed: 0.3s;
  --border-radius: 12px;
}

/* Theme: Darkboard Chalkboard */
.theme-darkboard-chalk {
  --bg-color: #12181b;
  --panel-bg: rgba(30, 39, 44, 0.85);
  --text-color: #eceff1; /* Chalk white */
  --text-muted: #90a4ae;
  --border-color: rgba(255, 255, 255, 0.12);
  --glass-bg: rgba(25, 34, 38, 0.7);
  --glass-border: rgba(255, 255, 255, 0.08);
  --shadow-color: rgba(0, 0, 0, 0.4);
  
  /* Chalk Accents */
  --accent-red: #ff5252;
  --accent-green: #69f0ae;
  --accent-orange: #ffd740;
  --accent-purple: #e040fb;
  --accent-blue: #40c4ff;
  --highlighter-yellow: rgba(255, 235, 59, 0.2);
  
  --paper-line-color: rgba(255, 255, 255, 0.04);
  --margin-line-color: rgba(255, 82, 82, 0.2);
}

/* Theme: Retro Parchment */
.theme-retro-parchment {
  --bg-color: #f2e3c6;
  --panel-bg: rgba(253, 246, 227, 0.9);
  --text-color: #3b2f2f; /* Dark brown ink */
  --text-muted: #6e5a5a;
  --border-color: rgba(139, 69, 19, 0.15);
  --glass-bg: rgba(253, 246, 227, 0.7);
  --glass-border: rgba(139, 69, 19, 0.1);
  --shadow-color: rgba(67, 40, 20, 0.15);
  
  /* Vintage Accents */
  --accent-red: #c0392b;
  --accent-green: #27ae60;
  --accent-orange: #d35400;
  --accent-purple: #8e44ad;
  --accent-blue: #2980b9;
  --highlighter-yellow: rgba(241, 196, 15, 0.4);
  
  --paper-line-color: rgba(139, 69, 19, 0.08);
  --margin-line-color: rgba(192, 57, 43, 0.25);
}

/* Font Toggle Layout Class override */
.font-sans-serif {
  --font-heading: 'Outfit', sans-serif;
  --font-text: 'Outfit', sans-serif;
}

/* ==========================================================================
   2. GLOBAL RESET & BASE LAYOUT
   ========================================================================== */

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

body {
  font-family: var(--font-interface);
  background-color: var(--bg-color);
  color: var(--text-color);
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color var(--transition-speed), color var(--transition-speed);
  position: relative;
}

/* Subtle background noise texture */
.paper-grain-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 100;
  opacity: 0.04;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
}

/* Diagonal Watermark */
.watermark {
  position: fixed;
  top: 40px;
  right: 40px;
  font-family: var(--font-heading);
  font-size: 5rem;
  font-weight: 800;
  color: var(--text-muted);
  opacity: 0.07;
  pointer-events: none;
  z-index: 1;
  transform: rotate(-15deg);
  user-select: none;
}

/* App Wrapper Grid */
.app-container {
  display: grid;
  grid-template-columns: 320px 1fr;
  height: 100vh;
  width: 100vw;
  overflow: hidden;
  transition: grid-template-columns var(--transition-speed) ease;
}

.app-container.sidebar-collapsed {
  grid-template-columns: 0 1fr;
}

.sidebar {
  width: 320px;
  transition: margin-left var(--transition-speed) ease, left var(--transition-speed) ease, opacity var(--transition-speed) ease, box-shadow var(--transition-speed) ease, visibility var(--transition-speed) ease;
}

.app-container.sidebar-collapsed .sidebar {
  margin-left: -320px;
  opacity: 0;
  visibility: hidden;
  box-shadow: none;
}

@media (max-width: 900px) {
  .app-container {
    grid-template-columns: 1fr;
  }
  .app-container.sidebar-collapsed {
    grid-template-columns: 1fr;
  }
  .sidebar {
    position: fixed;
    left: -320px;
    top: 0;
    width: 320px;
    max-width: 80vw;
    height: 100vh;
    z-index: 950 !important; /* Stack above backdrop (850) and top-bar (800) */
    margin-left: 0 !important;
    visibility: hidden;
    opacity: 0;
    box-shadow: none !important;
    transition: left var(--transition-speed) ease, opacity var(--transition-speed) ease, visibility var(--transition-speed) ease;
  }
  .sidebar.active {
    left: 0;
    visibility: visible !important;
    opacity: 1 !important;
    box-shadow: 4px 0 20px var(--shadow-color) !important;
  }
}

/* ==========================================================================
   3. SIDEBAR NAVIGATION
   ========================================================================== */

.sidebar {
  background: var(--glass-bg);
  backdrop-filter: blur(15px);
  border-right: 1px solid var(--glass-border);
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
  z-index: 10;
  box-shadow: 4px 0 20px var(--shadow-color);
}

.sidebar-header {
  padding: 24px;
  border-bottom: 1px solid var(--border-color);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-icon {
  font-size: 1.8rem;
  color: var(--accent-red);
  animation: pulse-atom 3s infinite linear;
}

@keyframes pulse-atom {
  0% { transform: rotate(0deg) scale(1); }
  50% { transform: rotate(180deg) scale(1.1); }
  100% { transform: rotate(360deg) scale(1); }
}

.brand-name {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.5rem;
  letter-spacing: -0.5px;
}

.sub-brand {
  color: var(--accent-blue);
  font-weight: 400;
}

.brand-tagline {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-top: 4px;
  color: var(--text-muted);
  font-weight: 600;
}

/* Search Area */
.search-box-container {
  margin: 16px 20px;
  position: relative;
}

.search-icon {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 0.9rem;
}

#chapter-search {
  width: 100%;
  padding: 10px 14px 10px 38px;
  border-radius: var(--border-radius);
  background: rgba(0, 0, 0, 0.03);
  border: 1px solid var(--glass-border);
  color: var(--text-color);
  font-family: var(--font-interface);
  font-size: 0.9rem;
  outline: none;
  transition: all var(--transition-speed);
}

#chapter-search:focus {
  background: rgba(255, 255, 255, 0.9);
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(2, 136, 209, 0.15);
}

/* Scrollable Chapter Navigation */
.chapters-nav {
  flex: 1;
  overflow-y: auto;
  padding: 0 16px 24px 16px;
  scrollbar-width: thin;
}

.chapters-nav::-webkit-scrollbar {
  width: 5px;
}

.chapters-nav::-webkit-scrollbar-thumb {
  background: var(--glass-border);
  border-radius: 10px;
}

.vol-group {
  margin-top: 18px;
}

.vol-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 1.5px;
  padding: 8px 12px;
}

.chapter-nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  margin: 2px 0;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 500;
  transition: all 0.2s;
  color: var(--text-muted);
}

.chapter-nav-item:hover {
  background: rgba(2, 136, 209, 0.08);
  color: var(--text-color);
}

.chapter-nav-item.active {
  background: var(--text-color);
  color: var(--bg-color);
  box-shadow: 0 4px 12px var(--shadow-color);
}

.ch-num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  opacity: 0.8;
}

/* ==========================================================================
   4. HEADER / ACTIONS BAR
   ========================================================================== */

.content-wrapper {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

.top-bar {
  position: relative;
  background: var(--glass-bg);
  backdrop-filter: blur(15px);
  border-bottom: 1px solid var(--glass-border);
  padding: 14px 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 800;
  box-shadow: 0 4px 12px var(--shadow-color);
}

.left-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.sidebar-toggle {
  display: inline-flex;
  background: var(--panel-bg);
  border: 1.5px solid var(--border-color);
  color: var(--text-color);
  width: 42px;
  height: 42px;
  border-radius: 10px;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  cursor: pointer;
  box-shadow: 0 2px 8px var(--shadow-color);
  transition: all 0.2s;
  padding: 0;
  box-sizing: border-box;
}
.sidebar-toggle:hover {
  background: var(--glass-bg);
  border-color: var(--accent-blue);
}

.mobile-sidebar-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.45);
  z-index: 850;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  backdrop-filter: blur(2px);
}
.mobile-sidebar-backdrop.active {
  opacity: 1;
  pointer-events: auto;
}

.current-chapter-title-wrap {
  display: flex;
  flex-direction: column;
}

.volume-badge {
  font-size: 0.7rem;
  font-weight: 800;
  text-transform: uppercase;
  color: var(--accent-blue);
  letter-spacing: 1.5px;
}

.current-chapter-head {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
  margin-top: 2px;
}

.right-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Buttons Styling */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--border-radius);
  font-family: var(--font-interface);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-color);
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  outline: none;
  user-select: none;
}

.btn-secondary {
  background: rgba(0, 0, 0, 0.04);
  border-color: var(--glass-border);
}

.theme-darkboard-chalk .btn-secondary {
  background: rgba(255, 255, 255, 0.04);
}

.btn-secondary:hover {
  background: rgba(0, 0, 0, 0.08);
}

.theme-darkboard-chalk .btn-secondary:hover {
  background: rgba(255, 255, 255, 0.08);
}

.btn-primary {
  background: var(--text-color);
  color: var(--bg-color);
  box-shadow: 0 4px 10px var(--shadow-color);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 14px var(--shadow-color);
}

.btn-danger {
  background: var(--accent-red);
  color: white;
}

.btn-danger:hover {
  background: #c62828;
}

.btn-icon-only {
  width: 38px;
  height: 38px;
  padding: 0;
  justify-content: center;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.04);
  border-color: var(--glass-border);
}

.btn-icon-only:hover {
  background: rgba(0, 0, 0, 0.08);
}

/* Theme Selector Dropdown */
.theme-selector-dropdown {
  position: relative;
  display: inline-block;
}

.dropdown-content {
  display: none;
  position: absolute;
  right: 0;
  top: 100%;
  margin-top: 6px;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  box-shadow: 0 10px 25px var(--shadow-color);
  min-width: 180px;
  z-index: 100;
  overflow: hidden;
}

.theme-selector-dropdown:hover .dropdown-content {
  display: block;
}

.theme-opt {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 10px 16px;
  border: none;
  background: transparent;
  color: var(--text-color);
  font-family: var(--font-interface);
  font-size: 0.88rem;
  text-align: left;
  cursor: pointer;
  transition: background 0.2s;
}

.theme-opt:hover {
  background: rgba(2, 136, 209, 0.08);
}

.theme-opt.active {
  font-weight: 700;
  color: var(--accent-blue);
  background: rgba(2, 136, 209, 0.04);
}

/* ==========================================================================
   5. FLOATING ACTIONS
   ========================================================================== */

.floating-quick-links {
  position: fixed;
  bottom: 140px;
  right: 40px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  z-index: 90;
}

.btn-floating {
  box-shadow: 0 8px 24px var(--shadow-color);
  border-radius: 30px;
  padding: 12px 22px;
  font-weight: 700;
  text-transform: uppercase;
  font-size: 0.8rem;
  letter-spacing: 1px;
}

.btn-simulation {
  background: var(--accent-orange);
  color: white;
  border-color: rgba(255, 255, 255, 0.2);
}

.btn-simulation:hover {
  background: #ef6c00;
  transform: scale(1.05);
}

.btn-cbt {
  background: var(--accent-purple);
  color: white;
  border-color: rgba(255, 255, 255, 0.2);
}

.btn-cbt:hover {
  background: #6a1b9a;
  transform: scale(1.05);
}

/* ==========================================================================
   6. NOTEBOOK CONTAINER & Ruled Pages
   ========================================================================== */

.notebook-container {
  flex: 1;
  overflow-y: auto;
  padding: 40px;
  display: flex;
  flex-direction: column;
  gap: 30px;
  background: linear-gradient(to bottom, transparent, rgba(0, 0, 0, 0.01));
}

.notebook-page {
  background: #ffffff !important;
  background-image: none !important;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  box-shadow: 0 8px 30px var(--shadow-color);
  padding: 50px 50px 50px 80px; /* Large left padding for binder margin */
  position: relative;
  min-height: 800px;
  line-height: 28px;
}

/* Red vertical margin line */
.notebook-page::before {
  display: none;
}

/* Handwriting text adjustments */
.font-handwriting .notebook-page {
  font-family: var(--font-text);
  font-size: 1.4rem;
  letter-spacing: 0.5px;
  word-spacing: 1px;
}

.font-handwriting .notebook-page h1,
.font-handwriting .notebook-page h2,
.font-handwriting .notebook-page h3,
.font-handwriting .notebook-page h4 {
  font-family: var(--font-heading);
}

/* Elements inside Notebook */
.notebook-page h1 {
  font-size: 2.2rem;
  text-decoration: underline double var(--accent-blue);
  margin-bottom: 24px;
  line-height: 40px;
}

.notebook-page h2 {
  font-size: 1.6rem;
  color: var(--accent-purple);
  margin-top: 30px;
  margin-bottom: 12px;
  line-height: 36px;
  border-bottom: 1px dashed var(--accent-purple);
  display: inline-block;
}

.notebook-page h3 {
  font-size: 1.3rem;
  color: var(--accent-blue);
  margin-top: 20px;
  margin-bottom: 8px;
}

.notebook-page p {
  margin-bottom: 16px;
}

/* Margin Notes */
.margin-note {
  position: absolute;
  left: 5px;
  width: 55px;
  font-size: 0.8rem;
  color: var(--accent-blue);
  font-family: var(--font-heading);
  text-align: center;
  line-height: 14px;
  opacity: 0.85;
}

/* Highlighter effect */
.highlight-text {
  background-color: var(--highlighter-yellow);
  padding: 2px 6px;
  border-radius: 4px;
  box-shadow: 2px 2px 4px rgba(0,0,0,0.05);
}

/* Formula Intelligence Box */
.formula-box {
  background: rgba(255, 255, 255, 0.95);
  border: 2px solid var(--accent-red);
  border-radius: 8px;
  padding: 16px 20px;
  margin: 20px 0;
  box-shadow: 4px 4px 0 var(--accent-red);
  line-height: 24px;
  font-family: var(--font-interface);
  font-size: 0.95rem;
}

.theme-darkboard-chalk .formula-box {
  background: #1e272c;
  color: #fff;
}

.formula-title {
  color: var(--accent-red);
  font-weight: 800;
  text-transform: uppercase;
  font-size: 0.85rem;
  letter-spacing: 1px;
  margin-bottom: 6px;
}

.formula-math {
  font-family: var(--font-mono);
  font-size: 1.3rem;
  font-weight: 700;
  text-align: center;
  margin: 12px 0;
  color: var(--text-color);
  background: rgba(0,0,0,0.02);
  padding: 10px;
  border-radius: 4px;
}

.theme-darkboard-chalk .formula-math {
  background: rgba(255,255,255,0.05);
  color: #fff;
}

.formula-details {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-top: 10px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Gen-Z Box */
.genz-box {
  background: rgba(67, 160, 71, 0.08);
  border-left: 5px solid var(--accent-green);
  padding: 14px 18px;
  margin: 18px 0;
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
}

.genz-box-title {
  font-family: var(--font-heading);
  color: var(--accent-green);
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 4px;
}

/* Misconception Danger Box */
.misconception-box {
  background: rgba(229, 57, 53, 0.07);
  border: 1px dashed var(--accent-red);
  border-radius: var(--border-radius);
  padding: 16px 20px;
  margin: 18px 0;
  position: relative;
}

.misconception-box::before {
  content: '☠ WARNING';
  position: absolute;
  top: -10px;
  right: 15px;
  background: var(--accent-red);
  color: white;
  font-family: var(--font-heading);
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 10px;
}

/* Real-Life Application cards */
.real-life-app-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin: 20px 0;
}

@media (max-width: 768px) {
  .real-life-app-grid {
    grid-template-columns: 1fr;
  }
}

.real-life-card {
  background: rgba(251, 140, 0, 0.06);
  border: 1.5px solid rgba(251, 140, 0, 0.2);
  border-radius: var(--border-radius);
  padding: 18px;
  transition: transform 0.2s;
}

.real-life-card:hover {
  transform: translateY(-2px);
}

.real-life-card h5 {
  color: var(--accent-orange);
  font-family: var(--font-heading);
  font-size: 1.2rem;
  margin-bottom: 6px;
}

/* Doodles and sketches in margins */
.pencil-sketch-desc {
  border: 1px solid rgba(0, 0, 0, 0.08);
  background: rgba(0, 0, 0, 0.01);
  padding: 10px;
  margin: 10px 0;
  border-radius: 4px;
  font-style: italic;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.theme-darkboard-chalk .pencil-sketch-desc {
  border-color: rgba(255,255,255,0.08);
  background: rgba(255,255,255,0.02);
}

/* Interactive simulation link box styling */
.simulation-link-box {
  background: linear-gradient(135deg, rgba(2, 136, 209, 0.08) 0%, rgba(123, 31, 162, 0.08) 100%);
  border: 1px solid rgba(2, 136, 209, 0.2);
  border-radius: var(--border-radius);
  padding: 24px;
  margin: 24px 0;
  text-align: center;
}

.simulation-link-box h4 {
  font-family: var(--font-heading);
  color: var(--accent-blue);
  margin-bottom: 8px;
}

.simulation-link-box p {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

/* Dotted Horizontal Divider */
.hr-notebook {
  border: none;
  border-top: 2px dotted var(--paper-line-color);
  margin: 24px 0;
  height: 0;
}

/* Persistent Bottom Notes text area */
.bottom-notes-section {
  background: var(--panel-bg);
  border: 1.5px solid var(--accent-blue);
  border-radius: var(--border-radius);
  box-shadow: 0 4px 15px var(--shadow-color);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.notes-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.notes-header-left {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--accent-blue);
}

.handwritten-textarea {
  width: 100%;
  min-height: 120px;
  border: none;
  outline: none;
  background: transparent;
  font-family: var(--font-text);
  font-size: 1.4rem;
  line-height: 28px;
  color: var(--accent-blue);
  resize: vertical;
  background-image: repeating-linear-gradient(transparent, transparent 27px, rgba(2, 136, 209, 0.08) 27px, rgba(2, 136, 209, 0.08) 28px);
  background-size: 100% 28px;
}

/* ==========================================================================
   7. MODAL OVERLAY & POPUPS (Simulations)
   ========================================================================== */

.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0,0,0,0.5);
  backdrop-filter: blur(8px);
  display: none; /* Controlled by js */
  justify-content: center;
  align-items: center;
  z-index: 1000;
  padding: 20px;
}

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

.modal-card {
  background: var(--bg-color);
  border-radius: var(--border-radius);
  border: 1.5px solid var(--border-color);
  box-shadow: 0 20px 50px rgba(0,0,0,0.3);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  max-width: 1100px;
  width: 100%;
  max-height: 90vh;
  animation: modal-pop 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes modal-pop {
  from { transform: scale(0.9) translateY(20px); opacity: 0; }
  to { transform: scale(1) translateY(0); opacity: 1; }
}

.modal-header {
  padding: 16px 24px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(0,0,0,0.02);
}

.theme-darkboard-chalk .modal-header {
  background: rgba(255,255,255,0.02);
}

.modal-title {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 700;
}

.sim-subtitle {
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 1px;
}

.btn-close-modal {
  background: transparent;
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  color: var(--text-color);
}

.sim-body-grid {
  display: grid;
  grid-template-columns: 1fr 340px;
  height: 550px;
  overflow: hidden;
}

@media (max-width: 850px) {
  .sim-body-grid {
    grid-template-columns: 1fr;
    height: auto;
    overflow-y: auto;
  }
}

/* Simulation Canvas */
.canvas-container {
  position: relative;
  background: #000;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100%;
}

#physics-canvas {
  max-width: 100%;
  max-height: 100%;
  display: block;
}

.canvas-overlay-stats {
  position: absolute;
  top: 15px;
  left: 15px;
  background: rgba(0,0,0,0.7);
  color: #fff;
  border-radius: 6px;
  padding: 8px 14px;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  display: flex;
  gap: 16px;
  pointer-events: none;
  border: 1px solid rgba(255,255,255,0.1);
}

.canvas-overlay-stats strong {
  color: var(--accent-orange);
}

/* Controls Panel */
.controls-panel {
  border-left: 1px solid var(--border-color);
  background: rgba(0,0,0,0.01);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  overflow-y: auto;
}

.theme-darkboard-chalk .controls-panel {
  background: rgba(255,255,255,0.01);
}

.control-header {
  font-size: 1rem;
  border-bottom: 1px dashed var(--border-color);
  padding-bottom: 6px;
}

.controls-group {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.slider-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.slider-label-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
}

.slider-label-row span:last-child {
  font-family: var(--font-mono);
  color: var(--text-color);
}

.controls-panel input[type="range"] {
  width: 100%;
  accent-color: var(--accent-orange);
  cursor: pointer;
}

.controls-actions {
  display: flex;
  gap: 10px;
}

.controls-actions button {
  flex: 1;
}

.sim-explanation-box {
  background: rgba(0,0,0,0.03);
  padding: 14px;
  border-radius: var(--border-radius);
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 18px;
}

.theme-darkboard-chalk .sim-explanation-box {
  background: rgba(255,255,255,0.03);
}

.sim-explanation-box h5 {
  font-family: var(--font-heading);
  color: var(--text-color);
  margin-bottom: 4px;
  font-size: 1rem;
}

/* ==========================================================================
   8. NTA CBT FULLSCREEN SIMULATOR
   ========================================================================== */

.cbt-fullscreen-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: #f4f6f9;
  z-index: 2000;
  display: none; /* Controlled by JS */
  flex-direction: column;
  color: #333;
}

.cbt-fullscreen-overlay.active {
  display: flex;
}

.cbt-header {
  background: #1e3a8a; /* NTA Navy Blue */
  color: white;
  padding: 12px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.cbt-brand {
  display: flex;
  align-items: center;
  gap: 16px;
}

.cbt-logo {
  background: #fff;
  color: #1e3a8a;
  font-weight: 800;
  font-size: 1.4rem;
  padding: 4px 12px;
  border-radius: 4px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.cbt-title-group h1 {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.cbt-title-group p {
  font-size: 0.75rem;
  opacity: 0.8;
}

.cbt-meta {
  display: flex;
  gap: 24px;
}

.cbt-meta .meta-item {
  display: flex;
  flex-direction: column;
}

.cbt-meta .lbl {
  font-size: 0.7rem;
  opacity: 0.7;
}

.cbt-meta .val {
  font-size: 0.9rem;
  font-weight: 700;
}

.timer-item .val {
  color: #fca5a5;
  font-family: var(--font-mono);
  font-size: 1.1rem;
}

/* CBT Main Screen Grid */
.cbt-main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 300px;
  overflow: hidden;
}

.cbt-question-container {
  display: flex;
  flex-direction: column;
  background: white;
  border-right: 1px solid #d1d5db;
  height: 100%;
}

.question-header {
  padding: 14px 24px;
  border-bottom: 1px solid #e5e7eb;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #f9fafb;
}

.q-num-badge {
  font-weight: 700;
  font-size: 1.1rem;
  color: #1e3a8a;
}

.cbt-badge {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 12px;
  text-transform: uppercase;
}

.difficulty-badge {
  background: #fef3c7;
  color: #d97706;
}

.tag-badge {
  background: #e0f2fe;
  color: #0369a1;
  margin-left: 8px;
}

.cbt-scrollable-content {
  flex: 1;
  padding: 30px;
  overflow-y: auto;
}

.cbt-question-context {
  font-style: italic;
  color: #4b5563;
  margin-bottom: 20px;
  line-height: 1.6;
  font-size: 0.98rem;
  border-left: 3px solid #1e3a8a;
  padding-left: 14px;
}

.cbt-question-text {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 30px;
}

/* Options radio rows */
.cbt-options {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.cbt-option-row {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  border: 1px solid #d1d5db;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s;
}

.cbt-option-row:hover {
  background: #f3f4f6;
  border-color: #9ca3af;
}

.cbt-option-row.selected {
  background: #eff6ff;
  border-color: #3b82f6;
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.cbt-option-radio {
  width: 20px;
  height: 20px;
  cursor: pointer;
  accent-color: #1e3a8a;
}

.cbt-option-text {
  font-size: 1rem;
  font-weight: 500;
}

/* CBT Bottom Action Bar */
.cbt-actions-bar {
  padding: 16px 24px;
  border-top: 1px solid #e5e7eb;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #f9fafb;
}

.left-cbt-actions {
  display: flex;
  gap: 10px;
}

.btn-cbt-pri {
  background: #2563eb;
  color: white;
  font-weight: 700;
  border: 1px solid #1d4ed8;
  padding: 10px 24px;
}

.btn-cbt-pri:hover {
  background: #1d4ed8;
}

.btn-cbt-sec {
  background: #fff;
  border: 1px solid #d1d5db;
  color: #4b5563;
  padding: 10px 18px;
}

.btn-cbt-sec:hover {
  background: #f3f4f6;
}

/* CBT Right Navigation Sidebar */
.cbt-sidebar {
  background: #f3f4f6;
  display: flex;
  flex-direction: column;
  height: 100%;
}

.candidate-photo-box {
  padding: 20px;
  display: flex;
  align-items: center;
  gap: 14px;
  border-bottom: 1px solid #d1d5db;
}

.photo-placeholder {
  font-size: 2.2rem;
  color: #9ca3af;
  background: white;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  border: 1px solid #d1d5db;
}

.candidate-info {
  display: flex;
  flex-direction: column;
}

.candidate-info .name {
  font-weight: 700;
  font-size: 0.9rem;
}

.candidate-info .rank {
  font-size: 0.75rem;
  color: #10b981;
  font-weight: 600;
}

/* Palette Legend */
.palette-legend {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  padding: 16px;
  border-bottom: 1px solid #d1d5db;
  font-size: 0.72rem;
  font-weight: 600;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 8px;
}

.legend-box {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  width: 24px;
  height: 24px;
  border-radius: 4px;
  font-weight: bold;
  color: white;
}

.legend-answered { background-color: #22c55e; }
.legend-not-answered { background-color: #ef4444; }
.legend-not-visited { background-color: #e5e7eb; color: #4b5563; border: 1px solid #cbd5e1; }
.legend-review { background-color: #a855f7; }
.legend-review-answered { background-color: #a855f7; border: 2.5px solid #22c55e; }

/* Palette Grid */
.palette-grid-title {
  font-weight: 700;
  font-size: 0.8rem;
  color: #4b5563;
  padding: 16px 16px 4px 16px;
}

.question-palette-grid {
  flex: 1;
  padding: 16px;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
  overflow-y: auto;
  align-content: start;
}

.palette-btn {
  height: 42px;
  border-radius: 4px;
  border: 1px solid #cbd5e1;
  background: #e5e7eb;
  color: #4b5563;
  font-weight: 700;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s;
}

.palette-btn:hover {
  transform: translateY(-1px);
}

.palette-btn.current {
  box-shadow: 0 0 0 2.5px #1e3a8a;
}

.palette-btn.not-visited {
  background-color: #e5e7eb;
  color: #4b5563;
  border: 1px solid #cbd5e1;
}

.palette-btn.not-answered {
  background-color: #ef4444;
  color: white;
  border-color: #dc2626;
}

.palette-btn.answered {
  background-color: #22c55e;
  color: white;
  border-color: #16a34a;
}

.palette-btn.review {
  background-color: #a855f7;
  color: white;
  border-color: #9333ea;
}

.palette-btn.review-answered {
  background-color: #a855f7;
  color: white;
  border: 2.5px solid #22c55e;
}

.cbt-sidebar-footer {
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  border-top: 1px solid #d1d5db;
}

.btn-cbt-submit {
  width: 100%;
  background: #10b981;
  color: white;
  font-weight: 700;
  padding: 12px;
  justify-content: center;
}

.btn-cbt-submit:hover {
  background: #059669;
}

.btn-cbt-quit {
  width: 100%;
  background: transparent;
  color: #ef4444;
  border: 1px solid #fca5a5;
  padding: 8px;
  justify-content: center;
}

.btn-cbt-quit:hover {
  background: rgba(239, 68, 68, 0.05);
}

/* CBT Results Sheet Styling */
.results-card {
  max-width: 950px;
}

.bg-gradient {
  background: linear-gradient(135deg, #1e3a8a 0%, #7b1fa2 100%);
}

.text-white {
  color: white !important;
}

.results-body {
  padding: 30px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 30px;
}

.score-summary-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

@media (max-width: 768px) {
  .score-summary-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.result-metric-card {
  border-radius: var(--border-radius);
  padding: 20px;
  color: white;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.score-card-badge { background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%); }
.accuracy-card-badge { background: linear-gradient(135deg, #10b981 0%, #047857 100%); }
.time-card-badge { background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%); }
.rank-card-badge { background: linear-gradient(135deg, #8b5cf6 0%, #6d28d9 100%); }

.result-metric-card .label {
  font-size: 0.8rem;
  opacity: 0.85;
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 1px;
}

.result-metric-card .value {
  font-size: 2.2rem;
  font-weight: 800;
  margin: 6px 0;
  font-family: var(--font-mono);
}

.result-metric-card .footer-lbl {
  font-size: 0.72rem;
  opacity: 0.8;
  font-style: italic;
}

.analytics-grid {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 24px;
}

@media (max-width: 800px) {
  .analytics-grid {
    grid-template-columns: 1fr;
  }
}

.glass-container {
  border: 1px solid var(--border-color);
  background: rgba(0,0,0,0.015);
  border-radius: var(--border-radius);
  padding: 20px;
}

.theme-darkboard-chalk .glass-container {
  background: rgba(255,255,255,0.015);
}

.glass-container h4 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  margin-bottom: 14px;
}

.table-scroll-wrap {
  overflow-x: auto;
}

.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.results-table th, .results-table td {
  padding: 10px 14px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

.results-table th {
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  font-size: 0.75rem;
  letter-spacing: 0.5px;
}

.btn-row-action {
  background: var(--accent-blue);
  color: white;
  border-radius: 4px;
  padding: 4px 8px;
  font-size: 0.75rem;
  border: none;
  cursor: pointer;
}

.btn-row-action:hover {
  background: #0277bd;
}

/* Feedback & Suggestions */
.feedback-box {
  background: rgba(2, 136, 209, 0.08);
  border-radius: 8px;
  padding: 16px;
  margin-bottom: 20px;
}

.genz-feedback-heading {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--accent-blue);
  margin-bottom: 6px;
}

.weak-topics-box h5 {
  font-size: 0.85rem;
  text-transform: uppercase;
  margin-bottom: 8px;
  color: var(--text-muted);
}

.priority-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.85rem;
}

.priority-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 500;
}

.badge {
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 4px;
  text-transform: uppercase;
}

.badge-low-acc { background: rgba(239, 68, 68, 0.1); color: #ef4444; }
.badge-high-time { background: rgba(245, 158, 11, 0.1); color: #d97706; }

/* ==========================================================================
   9. PRINT AND RESPONSIVE MEDIA STYLES
   ========================================================================== */

@media print {
  @page {
    margin: 15mm;
    size: A4;
  }
  body {
    background: white !important;
    color: black !important;
  }
  .sidebar, .top-bar, .floating-quick-links, .bottom-notes-section {
    display: none !important;
  }
  .app-container {
    display: block;
    height: auto;
  }
  .content-wrapper {
    height: auto;
    display: block;
  }
  .notebook-container {
    padding: 0;
  }
  .notebook-page {
    border: none;
    box-shadow: none;
    background: white;
    padding: 0;
    min-height: auto;
  }
  .notebook-page::before {
    display: none;
  }
  .watermark {
    display: none;
  }
}

/* Notebook Pagination Bar */
.notebook-pagination {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 12px 24px;
  box-shadow: 0 4px 15px var(--shadow-color);
  margin-top: 10px;
}
.page-number-display {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-size: 1.15rem;
}
.page-number-display input {
  width: 60px;
  padding: 4px 8px;
  border-radius: 6px;
  border: 1px dashed var(--border-color);
  background: transparent;
  color: var(--text-color);
  font-family: var(--font-heading);
  text-align: center;
  font-size: 1.15rem;
  outline: none;
}
.page-number-display input:focus {
  border-style: solid;
  border-color: var(--accent-blue);
  background: rgba(255, 255, 255, 0.9);
}
.theme-darkboard-chalk .page-number-display input:focus {
  background: rgba(30, 39, 44, 0.9);
}

/* Practice Worksheet Styles */
.worksheet-question-card {
  background: rgba(2, 136, 209, 0.03);
  border: 1px dashed var(--accent-blue);
  border-radius: var(--border-radius);
  padding: 24px;
  margin: 20px 0;
}
.worksheet-title {
  color: var(--accent-blue);
  font-family: var(--font-heading);
  font-size: 1.3rem;
  margin-bottom: 12px;
  border-bottom: 1px dotted var(--accent-blue);
  padding-bottom: 6px;
}
.worksheet-interactive-box {
  background: rgba(255, 255, 255, 0.95);
  border: 1.5px solid var(--border-color);
  border-radius: 8px;
  padding: 18px;
  margin: 18px 0;
  box-shadow: 3px 3px 0 var(--border-color);
}
.theme-darkboard-chalk .worksheet-interactive-box {
  background: #1e272c;
}
.worksheet-input-group {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}
.worksheet-input-group:last-child {
  margin-bottom: 0;
}
.worksheet-input-group label {
  font-family: var(--font-heading);
  min-width: 140px;
}
.worksheet-input-group input {
  padding: 6px 10px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background: transparent;
  color: var(--text-color);
  font-family: var(--font-mono);
  font-size: 0.95rem;
  width: 100px;
  outline: none;
}
.worksheet-input-group input:focus {
  border-color: var(--accent-blue);
}
.btn-worksheet-solve {
  background: var(--accent-blue);
  color: white;
  margin-top: 10px;
}
.btn-worksheet-solve:hover {
  background: #0277bd;
}
.worksheet-solution-pane {
  display: none;
  background: rgba(67, 160, 71, 0.03);
  border: 1px dashed var(--accent-green);
  border-radius: var(--border-radius);
  padding: 20px;
  margin-top: 20px;
}
.worksheet-solution-pane.active {
  display: block;
}

/* KaTeX & SVG Diagram Enhancements */
.katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  scrollbar-width: none;
  -ms-overflow-style: none;
  padding: 10px 0;
}
.katex-display::-webkit-scrollbar {
  display: none;
}
.katex {
  font-size: 1.15em !important;
  color: inherit;
}
.theme-darkboard-chalk .katex {
  color: #fff;
}

/* Notebook Responsive Diagrams */
.notebook-diagram {
  display: block;
  margin: 30px auto;
  max-width: 500px;
  width: 100%;
  height: auto;
  background: rgba(0, 0, 0, 0.01);
  border-radius: var(--border-radius);
  border: 1px dotted var(--border-color);
  padding: 15px;
  box-shadow: inset 0 0 10px rgba(0,0,0,0.02);
}
.theme-darkboard-chalk .notebook-diagram {
  background: rgba(255, 255, 255, 0.02);
  border-color: rgba(255, 255, 255, 0.1);
}
.notebook-diagram text {
  font-family: var(--font-heading);
  fill: var(--text-color);
  font-size: 13px;
  stroke: none;
}
.notebook-diagram line, 
.notebook-diagram path, 
.notebook-diagram circle, 
.notebook-diagram rect, 
.notebook-diagram polygon {
  stroke: var(--text-color);
  stroke-width: 2px;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.notebook-diagram .vector-arrow {
  fill: var(--text-color);
}
.notebook-diagram .dashed-line {
  stroke-dasharray: 4 4;
}
.notebook-diagram .thin-line {
  stroke-width: 1px;
}
.notebook-diagram .color-red {
  stroke: var(--accent-red);
}
.notebook-diagram .color-blue {
  stroke: var(--accent-blue);
}
.notebook-diagram .color-green {
  stroke: var(--accent-green);
}
.notebook-diagram .color-orange {
  stroke: var(--accent-orange);
}
.notebook-diagram .color-purple {
  stroke: var(--accent-purple);
}
.notebook-diagram .fill-red {
  fill: var(--accent-red);
}
.notebook-diagram .fill-blue {
  fill: var(--accent-blue);
}
.notebook-diagram .fill-green {
  fill: var(--accent-green);
}
.notebook-diagram .fill-text {
  fill: var(--text-color);
}

/* Smooth Scrolling/Sliding Page Transitions */
.page-slide-left-exit {
  animation: slideLeftExit 0.2s forwards cubic-bezier(0.4, 0, 0.2, 1);
}
.page-slide-left-enter {
  animation: slideLeftEnter 0.25s forwards cubic-bezier(0.4, 0, 0.2, 1);
}
.page-slide-right-exit {
  animation: slideRightExit 0.2s forwards cubic-bezier(0.4, 0, 0.2, 1);
}
.page-slide-right-enter {
  animation: slideRightEnter 0.25s forwards cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes slideLeftExit {
  0% { transform: translateX(0); opacity: 1; filter: blur(0); }
  100% { transform: translateX(-60px); opacity: 0; filter: blur(2px); }
}
@keyframes slideLeftEnter {
  0% { transform: translateX(60px); opacity: 0; filter: blur(2px); }
  100% { transform: translateX(0); opacity: 1; filter: blur(0); }
}

@keyframes slideRightExit {
  0% { transform: translateX(0); opacity: 1; filter: blur(0); }
  100% { transform: translateX(60px); opacity: 0; filter: blur(2px); }
}
@keyframes slideRightEnter {
  0% { transform: translateX(-60px); opacity: 0; filter: blur(2px); }
  100% { transform: translateX(0); opacity: 1; filter: blur(0); }
}

/* Continuous Scroll Mode Styles */
#pages-container {
  display: flex;
  flex-direction: column;
  gap: 35px;
  width: 100%;
}

.notebook-page.fade-in-up {
  animation: fadeInUp 0.4s cubic-bezier(0.25, 0.8, 0.25, 1) forwards;
}

@keyframes fadeInUp {
  0% {
    opacity: 0;
    transform: translateY(25px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Custom premium scrollbar for the notebook container */
.notebook-container::-webkit-scrollbar {
  width: 8px;
}
.notebook-container::-webkit-scrollbar-track {
  background: transparent;
}
.notebook-container::-webkit-scrollbar-thumb {
  background: var(--paper-line-color);
  border-radius: 4px;
  border: 2px solid transparent;
  background-clip: padding-box;
}
.notebook-container::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
  border-radius: 4px;
  border: 2px solid transparent;
  background-clip: padding-box;
}

/* ==========================================================================
   MODULE 1: SYLLABUS TAG BADGES
   ========================================================================== */
.syllabus-tag-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 12px;
  border-radius: 20px;
  font-size: 0.72rem;
  font-family: var(--font-interface);
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  line-height: 1.4;
  margin-bottom: 8px;
  transition: all var(--transition-speed) ease;
  box-shadow: 0 1px 4px rgba(0,0,0,0.1);
}
.syllabus-tag-badge.jee-important {
  background: linear-gradient(135deg, #10b981, #059669);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(16, 185, 129, 0.35);
}
.syllabus-tag-badge.nda-important {
  background: linear-gradient(135deg, #3b82f6, #2563eb);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.35);
}
.syllabus-tag-badge.both-important {
  background: linear-gradient(135deg, #f59e0b, #d97706);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(245, 158, 11, 0.35);
}
.syllabus-tag-badge.beyond-syllabus {
  background: linear-gradient(135deg, #8b5cf6, #7c3aed);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(139, 92, 246, 0.35);
}
.syllabus-note-text {
  font-size: 0.8rem;
  font-family: var(--font-interface);
  font-style: italic;
  color: var(--text-muted);
  margin-bottom: 12px;
  padding-left: 4px;
}

/* ==========================================================================
   MODULE 2: SOLVED EXAMPLE BLOCKS
   ========================================================================== */
.solved-example-block {
  background: var(--glass-bg);
  border: 1.5px solid var(--border-color);
  border-left: 4px solid var(--accent-blue);
  border-radius: var(--border-radius);
  margin: 18px 0;
  overflow: hidden;
  transition: all var(--transition-speed) ease;
}
.solved-example-block:hover {
  box-shadow: 0 4px 16px var(--shadow-color);
}
.solved-example-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  cursor: pointer;
  user-select: none;
  transition: background 0.2s;
}
.solved-example-header:hover {
  background: rgba(2, 136, 209, 0.05);
}
.solved-example-header .ex-number {
  font-family: var(--font-interface);
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--accent-blue);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.solved-example-header .ex-question {
  flex: 1;
  margin-left: 12px;
  font-size: 1.1rem;
  line-height: 1.5;
  color: var(--text-color);
}
.solved-example-header .ex-toggle-icon {
  font-size: 1.2rem;
  color: var(--accent-blue);
  transition: transform 0.3s ease;
}
.solved-example-block.open .ex-toggle-icon {
  transform: rotate(180deg);
}
.solved-example-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  padding: 0 16px;
}
.solved-example-block.open .solved-example-body {
  max-height: 2000px;
  padding: 0 16px 16px 16px;
}
.solved-example-solution {
  font-size: 1.05rem;
  line-height: 1.7;
  color: var(--text-color);
  white-space: pre-line;
  padding: 12px 0;
  border-top: 1px dashed var(--border-color);
}
.solved-example-tip {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  background: rgba(251, 140, 0, 0.08);
  border: 1px solid rgba(251, 140, 0, 0.25);
  border-radius: 8px;
  padding: 10px 14px;
  margin-top: 10px;
  font-size: 0.95rem;
  color: var(--text-color);
}
.solved-example-tip .tip-icon {
  font-size: 1.2rem;
  flex-shrink: 0;
}
.solved-example-difficulty {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 0.7rem;
  font-family: var(--font-interface);
  font-weight: 600;
  margin-left: 8px;
}
.solved-example-difficulty.diff-1 { background: #d1fae5; color: #065f46; }
.solved-example-difficulty.diff-2 { background: #fef3c7; color: #92400e; }
.solved-example-difficulty.diff-3 { background: #fee2e2; color: #991b1b; }

/* ==========================================================================
   MODULE 4: CBT MODE SELECTION MODAL
   ========================================================================== */
.cbt-mode-selector-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 10000;
  animation: fadeInOverlay 0.3s ease;
}
.cbt-mode-selector-overlay.active {
  display: flex;
}
@keyframes fadeInOverlay {
  from { opacity: 0; }
  to { opacity: 1; }
}
.cbt-mode-selector-inner {
  background: var(--panel-bg);
  border-radius: 20px;
  padding: 40px;
  max-width: 850px;
  width: 90%;
  box-shadow: 0 20px 60px rgba(0,0,0,0.3);
  border: 1px solid var(--glass-border);
}
.cbt-mode-selector-title {
  text-align: center;
  font-family: var(--font-heading);
  font-size: 1.8rem;
  color: var(--text-color);
  margin-bottom: 8px;
}
.cbt-mode-selector-subtitle {
  text-align: center;
  font-family: var(--font-interface);
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 30px;
}
.cbt-mode-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
@media (max-width: 700px) {
  .cbt-mode-grid { grid-template-columns: 1fr; }
}
.cbt-mode-card {
  background: var(--glass-bg);
  border: 1.5px solid var(--glass-border);
  border-radius: 16px;
  padding: 30px 20px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  backdrop-filter: blur(4px);
}
.cbt-mode-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px var(--shadow-color);
  border-color: var(--accent-blue);
}
.cbt-mode-card .mode-icon {
  font-size: 2.8rem;
  margin-bottom: 12px;
  display: block;
}
.cbt-mode-card .mode-title {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  color: var(--text-color);
  margin-bottom: 8px;
}
.cbt-mode-card .mode-desc {
  font-family: var(--font-interface);
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.5;
}
.cbt-mode-card .mode-badge {
  display: inline-block;
  margin-top: 12px;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  font-family: var(--font-interface);
  background: var(--accent-blue);
  color: #fff;
}
.cbt-mode-close-btn {
  display: block;
  margin: 25px auto 0;
  padding: 8px 24px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background: transparent;
  color: var(--text-muted);
  font-family: var(--font-interface);
  cursor: pointer;
  transition: all 0.2s;
}
.cbt-mode-close-btn:hover {
  background: var(--glass-bg);
  color: var(--text-color);
}

/* ==========================================================================
   MODULE 4: SCRATCHPAD / ROUGH WORK OVERLAY
   ========================================================================== */
.scratchpad-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(6px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 10001;
  flex-direction: column;
}
.scratchpad-overlay.active {
  display: flex;
}
.scratchpad-container {
  background: #ffffff;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 20px 60px rgba(0,0,0,0.4);
  display: flex;
  flex-direction: column;
}
.scratchpad-container.size-standard {
  width: 90%;
  max-width: 800px;
  height: 80vh;
  max-height: 550px;
}
.scratchpad-container.size-large {
  width: 95%;
  max-width: 1100px;
  height: 85vh;
  max-height: 750px;
}
.scratchpad-container.size-fullscreen {
  width: 98vw;
  max-width: 100%;
  height: 96vh;
  max-height: 100%;
}
.scratchpad-header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}
.scratchpad-size-selector {
  display: flex;
  background: rgba(255, 255, 255, 0.12);
  border-radius: 8px;
  padding: 3px;
  border: 1px solid rgba(255, 255, 255, 0.1);
}
.scratchpad-size-selector .size-btn {
  background: transparent;
  border: none;
  color: rgba(255, 255, 255, 0.75);
  padding: 5px 12px;
  font-size: 0.75rem;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s ease;
  font-weight: 600;
  font-family: var(--font-interface);
}
.scratchpad-size-selector .size-btn:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.08);
}
.scratchpad-size-selector .size-btn.active {
  color: #1a237e;
  background: #ffffff;
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
}
.scratchpad-header-btn {
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: #ffffff;
  padding: 6px 14px;
  font-size: 0.8rem;
  border-radius: 8px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all 0.2s ease;
  font-weight: 600;
  font-family: var(--font-interface);
}
.scratchpad-header-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: rgba(255, 255, 255, 0.3);
  transform: translateY(-1px);
}
.scratchpad-header-btn:active {
  transform: translateY(0);
}
.scratchpad-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  background: linear-gradient(135deg, #1a237e, #0288d1);
  color: #fff;
}
.scratchpad-header h3 {
  font-family: var(--font-interface);
  font-size: 1.1rem;
  font-weight: 600;
}
.scratchpad-close-btn {
  background: rgba(255,255,255,0.2);
  border: none;
  color: #fff;
  width: 32px; height: 32px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}
.scratchpad-close-btn:hover {
  background: rgba(255,255,255,0.35);
}
.scratchpad-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  background: #f5f5f5;
  border-bottom: 1px solid #e0e0e0;
  flex-wrap: wrap;
}
.scratchpad-tool-btn {
  padding: 6px 14px;
  border: 1.5px solid #d0d0d0;
  border-radius: 8px;
  background: #fff;
  font-size: 0.85rem;
  font-family: var(--font-interface);
  cursor: pointer;
  transition: all 0.2s;
}
.scratchpad-tool-btn:hover {
  background: #e8f0fe;
  border-color: #90caf9;
}
.scratchpad-tool-btn.active {
  background: #0288d1;
  color: #fff;
  border-color: #0288d1;
}
.scratchpad-tool-btn.nc-danger {
  color: #e53935;
  border-color: #ffcdd2;
}
.scratchpad-tool-btn.nc-danger:hover {
  background: #ffebee;
}
.scratchpad-colors {
  display: flex;
  gap: 5px;
  margin: 0 6px;
}
.scratchpad-color-swatch {
  width: 24px; height: 24px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all 0.2s;
}
.scratchpad-color-swatch:hover {
  transform: scale(1.15);
}
.scratchpad-color-swatch.active {
  border-color: #0288d1;
  box-shadow: 0 0 0 2px rgba(2,136,209,0.3);
}
.scratchpad-canvas-wrap {
  flex: 1;
  padding: 10px;
  overflow: auto;
  background: #fafafa;
}
.scratchpad-canvas-wrap canvas {
  display: block;
  margin: 0 auto;
  border: 1px solid #e0e0e0;
  border-radius: 4px;
  cursor: crosshair;
  background: #fff;
}

/* ==========================================================================
   MODULE 6: DUAL-TAB NOTES SECTION
   ========================================================================== */
.notes-tabs {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--border-color);
  margin-bottom: 0;
}
.notes-tab-btn {
  flex: 1;
  padding: 10px 16px;
  border: none;
  border-bottom: 3px solid transparent;
  background: transparent;
  font-family: var(--font-interface);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}
.notes-tab-btn:hover {
  background: var(--glass-bg);
  color: var(--text-color);
}
.notes-tab-btn.active {
  color: var(--accent-blue);
  border-bottom-color: var(--accent-blue);
  background: var(--glass-bg);
}
.notes-tab-content {
  display: block;
}
.notes-tab-content.hidden {
  display: none;
}
.notes-canvas-container {
  position: relative;
  min-height: 400px;
  border: 1px dashed var(--border-color);
  border-radius: 0 0 var(--border-radius) var(--border-radius);
  overflow: hidden;
  background: #fff;
}
.theme-darkboard-chalk .notes-canvas-container {
  background: #1e272c;
}
.theme-retro-parchment .notes-canvas-container {
  background: #fdf6e3;
}
.notes-canvas-container canvas {
  display: block;
  width: 100%;
  cursor: crosshair;
}
/* Notes Canvas Toolbar */
.notes-canvas-toolbar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  background: var(--glass-bg);
  border-bottom: 1px solid var(--border-color);
  flex-wrap: wrap;
}
.nc-toolbar-group {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nc-toolbar-sep {
  width: 1px;
  height: 24px;
  background: var(--border-color);
  margin: 0 6px;
}
.nc-tool-btn, .nc-action-btn {
  padding: 5px 10px;
  border: 1.5px solid var(--border-color);
  border-radius: 8px;
  background: var(--panel-bg);
  font-size: 0.8rem;
  font-family: var(--font-interface);
  color: var(--text-color);
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  gap: 4px;
}
.nc-tool-btn:hover, .nc-action-btn:hover {
  background: var(--glass-bg);
  border-color: var(--accent-blue);
}
.nc-tool-btn.active {
  background: var(--accent-blue);
  color: #fff;
  border-color: var(--accent-blue);
}
.nc-action-btn.nc-danger { color: var(--accent-red); }
.nc-action-btn.nc-danger:hover { border-color: var(--accent-red); }
.nc-btn-icon { font-size: 1rem; }
.nc-btn-label { font-size: 0.75rem; }
.nc-size-btn {
  width: 32px; height: 32px;
  border: 1.5px solid var(--border-color);
  border-radius: 50%;
  background: var(--panel-bg);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}
.nc-size-btn:hover { border-color: var(--accent-blue); }
.nc-size-btn.active {
  background: var(--accent-blue);
  border-color: var(--accent-blue);
}
.nc-size-btn.active .nc-size-dot { background: #fff; }
.nc-size-dot {
  border-radius: 50%;
  background: var(--text-color);
  display: block;
}
.nc-color-swatch {
  width: 22px; height: 22px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all 0.2s;
}
.nc-color-swatch:hover { transform: scale(1.15); }
.nc-color-swatch.active {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 2px rgba(2,136,209,0.3);
}

/* ==========================================================================
   MODULE 5: SIMULATION PICKER GRID
   ========================================================================== */
.sim-picker-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
  padding: 20px;
  max-height: 450px;
  overflow-y: auto;
}
.sim-picker-card {
  background: var(--glass-bg);
  border: 1.5px solid var(--glass-border);
  border-radius: 14px;
  padding: 20px 16px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  backdrop-filter: blur(4px);
}
.sim-picker-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px var(--shadow-color);
  border-color: var(--accent-blue);
}
.sim-picker-card .sim-icon {
  font-size: 2.4rem;
  margin-bottom: 10px;
  display: block;
}
.sim-picker-card .sim-title {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  color: var(--text-color);
  margin-bottom: 6px;
}
.sim-picker-card .sim-desc {
  font-family: var(--font-interface);
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.4;
}
.sim-picker-back-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 20px;
  margin: 10px 20px;
  border: 1.5px solid var(--border-color);
  border-radius: 8px;
  background: var(--panel-bg);
  color: var(--text-color);
  font-family: var(--font-interface);
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s;
}
.sim-picker-back-btn:hover {
  background: var(--glass-bg);
  border-color: var(--accent-blue);
}

/* ==========================================================================
   MODULE 2: PDF/PRINT STYLES
   ========================================================================== */
@media print {
  /* ══════════════════════════════════════════════════════════
     PROFESSIONAL TEXTBOOK PRINT LAYOUT
     ══════════════════════════════════════════════════════════ */

  @page {
    size: A4;
    margin: 0 !important; /* Hides default browser header/footer (URL, date, IP, page title) */
  }

  /* ── HIDE ALL UI ELEMENTS ── */
  .sidebar,
  .top-bar,
  .floating-quick-links,
  .notebook-pagination,
  .bottom-notes-section,
  .watermark,
  .paper-grain-overlay,
  .cbt-fullscreen-overlay,
  .modal-overlay,
  .cbt-mode-selector-overlay,
  .scratchpad-overlay,
  .btn-download-pdf,
  #launch-sim-btn,
  #launch-cbt-btn,
  #launch-scratchpad-btn,
  .view-mode-toggle,
  .theme-dropdown,
  .font-dropdown,
  .sim-gallery-view,
  .chapter-navigation-badges,
  .chapter-actions-bar button {
    display: none !important;
  }

  /* ── BASE TYPOGRAPHY (Serif font, clean black on white) ── */
  * {
    -webkit-print-color-adjust: exact !important;
    print-color-adjust: exact !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  body {
    background: #fff !important;
    color: #000 !important;
    margin: 0 !important;
    padding: 0 !important;
    font-family: 'Georgia', 'Times New Roman', 'Cambria', serif !important;
    font-size: 13.5pt !important;
    line-height: 1.6 !important;
  }

  /* ── LAYOUT STRUCTURE ── */
  .app-container {
    display: block !important;
  }

  .content-wrapper {
    margin: 0 !important;
    padding: 0 !important;
    width: 100% !important;
  }

  .notebook-container {
    overflow: visible !important;
    height: auto !important;
    max-height: none !important;
    background: none !important;
  }

  .notebook-page {
    box-sizing: border-box !important;
    width: 210mm !important;
    height: 297mm !important;
    padding: 20mm 20mm 20mm 20mm !important;
    position: relative !important;
    page-break-after: always !important;
    page-break-inside: avoid !important;
    background: #fff !important;
    border: none !important;
    box-shadow: none !important;
    margin: 0 !important;
  }

  /* ── NEESHANT WATERMARK — subtle top-right on every A4 page ── */
  .notebook-page::after {
    content: 'neeshant' !important;
    position: absolute !important;
    top: 12mm !important;
    right: 20mm !important;
    font-family: 'Architects Daughter', 'Georgia', serif !important;
    font-size: 13pt !important;
    font-weight: 700 !important;
    color: rgba(0, 100, 180, 0.22) !important;
    letter-spacing: 3px !important;
    text-transform: lowercase !important;
    pointer-events: none !important;
    z-index: 99999 !important;
  }

  /* ── CENTRED PAGE NUMBER AT BOTTOM OF EACH PAGE ── */
  body {
    counter-reset: page;
  }
  .notebook-page {
    counter-increment: page;
  }
  .notebook-page::before {
    content: counter(page) !important;
    position: absolute !important;
    bottom: 12mm !important;
    left: 50% !important;
    transform: translateX(-50%) !important;
    font-family: 'Georgia', 'Times New Roman', serif !important;
    font-size: 10pt !important;
    color: #444 !important;
    font-weight: normal !important;
  }

  .notebook-page::before {
    display: none !important; /* Hide notebook vertical line decorations if any */
  }

  .page-content {
    max-width: 100% !important;
    width: 100% !important;
    padding: 0 !important;
    font-family: 'Georgia', 'Times New Roman', serif !important;
    font-size: 13.5pt !important;
    line-height: 1.6 !important;
    text-align: justify !important;
  }

  /* ── CHAPTER TITLE STYLE ──
     Centered, large serif, with horizontal rule below */
  .chapter-title-section {
    text-align: center !important;
    padding: 20pt 0 10pt 0 !important;
    margin-bottom: 25pt !important;
    border-bottom: 2.5pt solid #000 !important;
    page-break-after: avoid;
  }

  .chapter-title-section h1,
  .page-content h1 {
    font-family: 'Georgia', 'Times New Roman', serif !important;
    font-size: 30pt !important;
    font-weight: bold !important;
    text-align: center !important;
    text-transform: uppercase !important;
    letter-spacing: 2pt !important;
    margin: 0 0 8pt 0 !important;
    color: #000 !important;
  }

  /* Chapter subtitle / volume info */
  .chapter-title-section .chapter-meta,
  .chapter-title-section .chapter-subtitle {
    font-size: 13pt !important;
    font-style: italic !important;
    color: #333 !important;
    margin-bottom: 5pt !important;
  }

  /* ── SECTION HEADINGS (Bold, numbered like "1.1 REST AND MOTION") ── */
  .page-content h2 {
    font-family: 'Georgia', 'Times New Roman', serif !important;
    font-size: 18pt !important;
    font-weight: bold !important;
    text-transform: uppercase !important;
    margin: 24pt 0 10pt 0 !important;
    padding-bottom: 3pt !important;
    border-bottom: 1.2pt solid #000 !important;
    color: #000 !important;
    page-break-after: avoid;
    letter-spacing: 0.5pt !important;
  }

  .page-content h3 {
    font-family: 'Georgia', 'Times New Roman', serif !important;
    font-size: 15pt !important;
    font-weight: bold !important;
    margin: 16pt 0 8pt 0 !important;
    color: #000 !important;
    page-break-after: avoid;
  }

  .page-content h4 {
    font-family: 'Georgia', 'Times New Roman', serif !important;
    font-size: 13pt !important;
    font-weight: bold !important;
    font-style: italic !important;
    margin: 12pt 0 6pt 0 !important;
    color: #000 !important;
  }

  /* ── BODY TEXT ── */
  .page-content p,
  .page-content li,
  .page-content span:not(.katex-mathml span),
  .page-content div:not(.formula-box):not(.katex-html) {
    font-family: 'Georgia', 'Times New Roman', serif !important;
    font-size: 13.5pt !important;
    line-height: 1.6 !important;
    color: #000 !important;
  }

  /* ── FORMULAS & MATH (Centered, well-spaced) ── */
  .formula-box {
    font-size: 14pt !important;
    padding: 12pt 18pt !important;
    margin: 14pt 5% !important;
    text-align: center !important;
    border: 1.5pt solid #000 !important;
    border-radius: 0 !important;
    background: #fdfdfd !important;
    break-inside: avoid;
  }

  .formula-box .katex,
  .page-content .katex {
    font-size: 14.5pt !important;
  }

  /* ── SOLVED EXAMPLES ("Worked Out Examples" section) ── */
  .solved-example-block {
    break-inside: avoid;
    font-size: 13pt !important;
    margin: 14pt 0 !important;
    padding: 12pt 14pt !important;
    border: none !important;
    border-left: 3pt solid #000 !important;
    background: none !important;
  }

  .solved-example-header {
    background: none !important;
    border: none !important;
    padding: 0 0 5pt 0 !important;
  }

  .solved-example-block .example-title,
  .solved-example-header .example-title {
    font-family: 'Georgia', serif !important;
    font-size: 13pt !important;
    font-weight: bold !important;
    font-style: italic !important;
    color: #000 !important;
  }

  .solved-example-body {
    max-height: none !important;
    overflow: visible !important;
    padding: 5pt 0 0 0 !important;
    display: block !important;
    height: auto !important;
  }

  .solved-example-solution {
    font-size: 12.5pt !important;
  }

  /* ── INFO BOXES (Clean, bordered) ── */
  .genz-box, .misconception-box, .real-world-box, .jee-tip-box {
    font-size: 12pt !important;
    padding: 10pt 14pt !important;
    margin: 12pt 0 !important;
    border: 1pt solid #000 !important;
    border-radius: 0 !important;
    background: #fafafa !important;
    break-inside: avoid;
  }

  .genz-box h4, .misconception-box h4, .real-world-box h4, .jee-tip-box h4 {
    font-size: 13.5pt !important;
    font-weight: bold !important;
    color: #000 !important;
    border-bottom: 0.5pt solid #000 !important;
    padding-bottom: 4pt !important;
    margin-bottom: 6pt !important;
  }

  /* ── LISTS ── */
  .page-content ul, .page-content ol {
    font-size: 13.5pt !important;
    padding-left: 20pt !important;
    margin: 8pt 0 !important;
  }

  .page-content li {
    margin-bottom: 4pt !important;
  }

  /* ── SYLLABUS TAGS (small, clean) ── */
  .syllabus-tag-badge {
    font-size: 9pt !important;
    padding: 1pt 6pt !important;
    border-radius: 2pt !important;
    border: 0.5pt solid #000 !important;
    background: #fff !important;
    color: #000 !important;
  }

  /* ── TABLES (Clean lines, no color) ── */
  .page-content table {
    font-size: 12pt !important;
    width: 100% !important;
    border-collapse: collapse !important;
    margin: 12pt 0 !important;
    break-inside: avoid;
  }

  .page-content th {
    padding: 6pt 10pt !important;
    font-size: 12pt !important;
    font-weight: bold !important;
    border-top: 1.5pt solid #000 !important;
    border-bottom: 1pt solid #000 !important;
    background: #f5f5f5 !important;
    text-align: left !important;
  }

  .page-content td {
    padding: 5pt 10pt !important;
    font-size: 12pt !important;
    border-bottom: 0.5pt solid #000 !important;
  }

  /* ── QUESTIONS / WORKSHEETS ── */
  .worksheet-question-card {
    font-size: 13.5pt !important;
    break-inside: avoid;
    border: none !important;
    border-left: 2pt solid #000 !important;
    padding: 10pt 14pt !important;
    margin: 10pt 0 !important;
    background: none !important;
  }

  /* ── CODE / MONO TEXT ── */
  code, pre, .formula-derivation {
    font-size: 11pt !important;
    background: #fafafa !important;
    border: 0.5pt solid #ccc !important;
  }

  /* ── IMAGES & FIGURES ── */
  img {
    max-width: 100% !important;
    page-break-inside: avoid;
  }

  figure, .figure-container {
    text-align: center !important;
    margin: 12pt auto !important;
    break-inside: avoid;
  }

  figcaption, .figure-caption {
    font-size: 10.5pt !important;
    font-style: italic !important;
    text-align: center !important;
    margin-top: 5pt !important;
  }

  /* ── PAGE BREAK CONTROLS ── */
  h2, h3, h4 {
    page-break-after: avoid;
  }

  .formula-box, .genz-box, .misconception-box, .real-world-box {
    break-inside: avoid;
  }

  /* ── SINGLE COLUMN LAYOUT for theory text ── */

  /* Full-width elements break out of columns */
  .formula-box,
  .chapter-title-section,
  h2,
  .solved-example-block,
  .worksheet-question-card,
  table {
    column-span: all !important;
  }

  /* Remove any gradient backgrounds */
  .formula-box::before,
  .formula-box::after,
  .genz-box::before,
  .misconception-box::before {
    display: none !important;
  }

  /* ── SPECIAL: Weightage/prerequisite boxes hide in print ── */
  .chapter-weightage-bar,
  .chapter-prerequisite-box,
  .chapter-study-time,
  .chapter-motivation-box {
    display: none !important;
  }
}

/* ==========================================================================
   PDF DOWNLOAD BUTTON
   ========================================================================== */
.btn-download-pdf {
  background: linear-gradient(135deg, #e53935, #c62828);
  color: #fff;
  border: none;
  padding: 6px 14px;
  border-radius: 8px;
  font-family: var(--font-interface);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  gap: 6px;
}
.btn-download-pdf:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(229, 57, 53, 0.3);
}

/* ==========================================================================
   SIMULATION GALLERY
   ========================================================================== */
.sim-gallery-view {
  padding: 20px 24px;
  max-height: 70vh;
  overflow-y: auto;
}
.sim-gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}
.sim-gallery-card {
  background: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  padding: 20px 16px;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.sim-gallery-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
  opacity: 0;
  transition: opacity 0.3s;
}
.sim-gallery-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px var(--shadow-color);
  border-color: var(--accent-blue);
}
.sim-gallery-card:hover::before { opacity: 1; }
.sim-gallery-card .sim-card-icon {
  font-size: 2rem;
  color: var(--accent-blue);
  margin-bottom: 10px;
}
.sim-gallery-card .sim-card-title {
  font-family: var(--font-interface);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-color);
  margin-bottom: 6px;
  line-height: 1.3;
}
.sim-gallery-card .sim-card-desc {
  font-family: var(--font-interface);
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.4;
}
.sim-gallery-card .sim-card-badge {
  display: inline-block;
  margin-top: 8px;
  padding: 2px 10px;
  border-radius: 20px;
  font-size: 0.7rem;
  font-weight: 600;
  font-family: var(--font-interface);
  background: rgba(2,136,209,0.12);
  color: var(--accent-blue);
}
.btn-back-gallery {
  background: none;
  border: 2px solid var(--border-color);
  color: var(--text-color);
  width: 36px; height: 36px;
  border-radius: 10px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  transition: all 0.2s;
  flex-shrink: 0;
}
.btn-back-gallery:hover {
  background: var(--accent-blue);
  color: #fff;
  border-color: var(--accent-blue);
}

/* ==========================================================================
   MOBILE RESPONSIVENESS AND SMOOTH RUNNING OVERRIDES (Under 600px)
   ========================================================================== */
@media (max-width: 600px) {
  .app-container {
    height: 100vh;
    display: flex;
    flex-direction: column;
  }

  .top-bar {
    padding: 10px 14px !important;
    height: auto !important;
    flex-direction: column !important;
    align-items: flex-start !important;
    gap: 12px !important;
  }

  .top-bar .left-actions {
    width: 100% !important;
    justify-content: space-between !important;
  }

  .top-bar .right-actions {
    width: 100% !important;
    display: flex !important;
    justify-content: flex-start !important;
    flex-wrap: wrap !important;
    gap: 8px !important;
  }

  .top-bar .right-actions .btn,
  .top-bar .right-actions .btn-download-pdf {
    padding: 6px 10px !important;
    font-size: 0.78rem !important;
    gap: 4px !important;
  }

  .notebook-container {
    padding: 12px 10px !important;
    gap: 16px !important;
  }

  .notebook-page {
    padding: 30px 10px 20px 38px !important;
    min-height: 450px !important;
  }

  .notebook-page::before {
    left: 28px !important;
  }

  /* Form/Math scaling on mobile */
  .formula-box {
    margin: 10px 0 !important;
    padding: 10px !important;
    font-size: 0.95rem !important;
    overflow-x: auto !important;
  }

  .page-content .katex {
    font-size: 1.05rem !important;
  }

  .solved-example-block {
    padding: 10px !important;
    margin: 10px 0 !important;
  }

  /* Bottom tabs layout */
  .bottom-notes-section {
    margin-top: 15px !important;
  }

  .notes-canvas-container canvas {
    height: 300px !important;
  }

  /* CBT and Sim Modal Scaling */
  .modal-card {
    width: 95% !important;
    max-height: 90vh !important;
    margin: 10px auto !important;
  }

  .sim-body-grid {
    grid-template-columns: 1fr !important;
    height: auto !important;
  }

  .sim-gallery-grid {
    grid-template-columns: 1fr !important;
  }
}

/* ==========================================================================
   ANALYTICS & FORMULA SHEET GENERATOR MODALS
   ========================================================================== */
.formula-sheet-card {
  max-width: 650px;
  width: 90%;
}

.formula-sheet-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-height: 400px;
  overflow-y: auto;
  padding: 5px;
}

.formula-select-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px;
  background: rgba(0, 0, 0, 0.02);
  border: 1px solid var(--glass-border);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: all 0.2s;
}

.theme-darkboard-chalk .formula-select-item {
  background: rgba(255, 255, 255, 0.02);
}

.formula-select-item:hover {
  background: rgba(2, 136, 209, 0.05);
  border-color: var(--accent-blue);
}

.formula-select-item input[type="checkbox"] {
  margin-top: 4px;
  width: 18px;
  height: 18px;
  cursor: pointer;
}

.formula-select-item-content {
  flex: 1;
}

.formula-select-item-title {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-color);
  margin-bottom: 4px;
}

.formula-select-item-math {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--accent-blue);
  background: rgba(0, 0, 0, 0.03);
  padding: 4px 8px;
  border-radius: 4px;
  display: inline-block;
  margin-top: 4px;
}

.theme-darkboard-chalk .formula-select-item-math {
  background: rgba(255, 255, 255, 0.05);
}

/* Completion checklist item */
.chapter-checklist-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  background: rgba(0, 0, 0, 0.02);
  border: 1.5px solid var(--glass-border);
  border-radius: 8px;
  font-size: 0.88rem;
  transition: all 0.2s;
}

.theme-darkboard-chalk .chapter-checklist-item {
  background: rgba(255, 255, 255, 0.02);
}

.chapter-checklist-item.read {
  border-color: var(--accent-green);
  background: rgba(67, 160, 71, 0.04);
}

.chapter-checklist-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

.chapter-checklist-left input[type="checkbox"] {
  width: 16px;
  height: 16px;
  cursor: pointer;
}

.chapter-checklist-badge {
  font-size: 0.72rem;
  padding: 2px 6px;
  border-radius: 4px;
  font-weight: 700;
  text-transform: uppercase;
}

.chapter-checklist-badge.complete {
  background: var(--accent-green);
  color: white;
}

.chapter-checklist-badge.pending {
  background: var(--text-muted);
  color: white;
  opacity: 0.7;
}

/* Print container for Cheat Sheet */
#formula-print-container {
  display: none;
}

@media print {
  body.print-cheat-sheet-mode #formula-print-container {
    display: block !important;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 9999999;
    background: white;
    color: black;
    font-family: 'Georgia', 'Times New Roman', serif;
  }
  
  body.print-cheat-sheet-mode .app-container,
  body.print-cheat-sheet-mode .modal-overlay,
  body.print-cheat-sheet-mode .mobile-sidebar-backdrop {
    display: none !important;
  }

  .print-sheet-title {
    text-align: center;
    font-size: 20pt;
    font-weight: bold;
    margin-bottom: 5mm;
    border-bottom: 2px solid black;
    padding-bottom: 2mm;
  }

  .print-sheet-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
  }

  .print-sheet-item {
    border: 1px solid #ccc;
    padding: 10px;
    border-radius: 6px;
    break-inside: avoid;
  }

  .print-sheet-item-title {
    font-weight: bold;
    font-size: 11pt;
    margin-bottom: 4px;
    color: #111;
  }

  .print-sheet-item-math {
    font-family: monospace;
    font-size: 11pt;
    background: #f5f5f5;
    padding: 6px;
    margin: 6px 0;
    border-radius: 4px;
    text-align: center;
  }

  .print-sheet-item-details {
    font-size: 9pt;
    color: #555;
  }
}

/* Theory Diagram Aesthetics & Interactive Hover Effects */
.theory-diagram-container {
  transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.theory-diagram-container:hover {
  transform: translateY(-2px);
  border-color: var(--accent-blue) !important;
  box-shadow: 0 6px 20px rgba(0,0,0,0.05);
}

.theory-diagram {
  transition: transform 0.3s ease, filter 0.3s ease;
}

/* Dark mode compatibility for diagram container */
body.theme-darkboard-chalk .theory-diagram-container {
  background: rgba(255, 255, 255, 0.02) !important;
  border-color: rgba(255, 255, 255, 0.1) !important;
}

body.theme-darkboard-chalk .theory-diagram {
  background: #1c2022 !important;
  border-color: rgba(255, 255, 255, 0.1) !important;
  filter: invert(0.9) hue-rotate(180deg) brightness(0.95) contrast(1.05);
}

body.theme-retro-parchment .theory-diagram-container {
  background: rgba(139, 69, 19, 0.02) !important;
  border-color: rgba(139, 69, 19, 0.15) !important;
}

body.theme-retro-parchment .theory-diagram {
  background: #fdf5e6 !important;
  border-color: rgba(139, 69, 19, 0.15) !important;
  filter: sepia(0.25) contrast(1.02);
}

/* Premium Translucent Movable Floating Dock */
.floating-dock-container {
  position: fixed;
  bottom: 80px;
  right: 30px;
  z-index: 1500;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 15px;
  user-select: none;
  pointer-events: auto;
}

/* Translucent Main Floating Button */
.floating-dock-trigger {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--glass-bg);
  backdrop-filter: blur(15px);
  border: 1px solid var(--glass-border);
  box-shadow: var(--box-shadow);
  color: var(--text-color);
  cursor: grab;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  outline: none;
}

.floating-dock-trigger:active {
  cursor: grabbing;
  transform: scale(0.95);
}

.floating-dock-trigger:hover {
  background: rgba(255, 255, 255, 0.25);
  box-shadow: 0 8px 30px rgba(0,0,0,0.15);
  border-color: var(--accent-blue);
  color: var(--accent-blue);
}

/* Dark mode variations for trigger */
body.theme-darkboard-chalk .floating-dock-trigger {
  background: rgba(20, 20, 20, 0.6) !important;
  border-color: rgba(255, 255, 255, 0.1) !important;
  color: #fff !important;
}
body.theme-darkboard-chalk .floating-dock-trigger:hover {
  background: rgba(255, 255, 255, 0.1) !important;
  color: var(--accent-orange) !important;
  border-color: var(--accent-orange) !important;
}

/* Pulse ring animation */
.floating-dock-trigger .pulse-ring {
  content: '';
  position: absolute;
  top: -2px; left: -2px; right: -2px; bottom: -2px;
  border-radius: 50%;
  border: 1px solid var(--accent-blue);
  opacity: 0;
  animation: pulse-ring-anim 2.5s infinite;
  pointer-events: none;
}

body.theme-darkboard-chalk .floating-dock-trigger .pulse-ring {
  border-color: var(--accent-orange);
}

@keyframes pulse-ring-anim {
  0% { transform: scale(1); opacity: 0.5; }
  100% { transform: scale(1.3); opacity: 0; }
}

.floating-dock-trigger .trigger-icons {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.floating-dock-trigger .close-icon {
  position: absolute;
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
  transition: all 0.3s ease;
}

.floating-dock-trigger .main-icon {
  transition: all 0.3s ease;
}

.floating-dock-container.menu-active .main-icon {
  opacity: 0;
  transform: rotate(90deg) scale(0.5);
}

.floating-dock-container.menu-active .close-icon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
  color: var(--accent-red);
}

/* Floating Dock Menu */
.floating-dock-menu {
  display: flex;
  flex-direction: column;
  gap: 10px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px) scale(0.9);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  pointer-events: none;
  align-items: flex-end;
}

.floating-dock-container.menu-active .floating-dock-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

/* Dock menu items */
.dock-menu-item {
  height: 42px;
  border-radius: 21px;
  padding: 0 18px;
  background: var(--glass-bg);
  backdrop-filter: blur(15px);
  border: 1px solid var(--glass-border);
  box-shadow: 0 4px 15px rgba(0,0,0,0.08);
  color: var(--text-color);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s ease;
  outline: none;
}

.dock-menu-item i {
  font-size: 1.05rem;
}

.dock-menu-item:hover {
  transform: translateX(-4px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}

/* Premium gradient accents for dock menu items */
.dock-menu-item.btn-simulation:hover {
  background: linear-gradient(135deg, rgba(2,136,209,0.15), rgba(2,136,209,0.25));
  border-color: var(--accent-blue);
  color: var(--accent-blue);
}

.dock-menu-item.btn-cbt:hover {
  background: linear-gradient(135deg, rgba(224,64,251,0.15), rgba(224,64,251,0.25));
  border-color: var(--accent-red);
  color: var(--accent-red);
}

.dock-menu-item.btn-scratchpad:hover {
  background: linear-gradient(135deg, rgba(123,31,162,0.15), rgba(123,31,162,0.25));
  border-color: #e040fb;
  color: #e040fb;
}

body.theme-darkboard-chalk .dock-menu-item {
  background: rgba(20, 20, 20, 0.85) !important;
  border-color: rgba(255, 255, 255, 0.1) !important;
  color: #eee !important;
}

body.theme-darkboard-chalk .dock-menu-item:hover {
  border-color: var(--accent-orange) !important;
  color: var(--accent-orange) !important;
}

/* ==========================================================================
   8. COURSERA MODERN THEME VARIABLES & OVERRIDES
   ========================================================================== */
.theme-coursera {
  --bg-color: #f5f7fa;
  --panel-bg: #ffffff;
  --text-color: #1f1f1f;
  --text-muted: #5f6368;
  --border-color: #e2e8f0;
  --glass-bg: rgba(255, 255, 255, 0.95);
  --glass-border: #e2e8f0;
  --shadow-color: rgba(0, 86, 210, 0.05);
  
  /* Coursera Brand Colors */
  --accent-blue: #0056d2;
  --accent-red: #d93025;
  --accent-green: #1e7e34;
  --accent-orange: #f57c00;
  --accent-purple: #7b1fa2;
  
  --paper-line-color: transparent;
  --margin-line-color: transparent;
  
  /* Modern clean fonts */
  --font-heading: 'Outfit', sans-serif;
  --font-text: 'Outfit', sans-serif;
}

/* Notebook Page overrides for Coursera Theme */
body.theme-coursera .notebook-page {
  padding: 40px 45px;
  border-radius: var(--border-radius);
  box-shadow: 0 4px 25px var(--shadow-color);
  background: var(--panel-bg) !important;
  background-image: none !important;
  line-height: 1.65;
  font-size: 1.05rem;
}

body.theme-coursera .notebook-page::before {
  display: none !important;
}

body.theme-coursera .notebook-page h1 {
  font-size: 2.1rem;
  color: var(--text-color);
  text-decoration: none !important;
  border-bottom: 2px solid var(--accent-blue);
  padding-bottom: 12px;
  margin-bottom: 24px;
  line-height: 2.6rem;
}

body.theme-coursera .notebook-page h2 {
  font-size: 1.45rem;
  color: var(--accent-blue);
  border-bottom: none !important;
  margin-top: 30px;
  margin-bottom: 12px;
  padding-bottom: 0;
  display: block;
}

body.theme-coursera .notebook-page p {
  font-family: var(--font-text);
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text-color);
  text-indent: 0 !important;
  margin-bottom: 16px;
}

body.theme-coursera .formula-box {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-left: 4px solid var(--accent-red);
  box-shadow: 0 4px 12px rgba(0,0,0,0.02);
  border-radius: 6px;
}

body.theme-coursera .formula-math {
  background: #f8f9fa;
  color: #1f1f1f;
  border: 1px solid #edf2f7;
}

body.theme-coursera .genz-box {
  background: rgba(30, 126, 52, 0.05);
  border: 1px solid rgba(30, 126, 52, 0.1);
  border-left: 4px solid var(--accent-green);
  border-radius: 6px;
}

body.theme-coursera .misconception-box {
  background: rgba(217, 48, 37, 0.04);
  border: 1px solid rgba(217, 48, 37, 0.1);
  border-left: 4px solid var(--accent-red);
  border-radius: 6px;
}

body.theme-coursera .solved-example-block {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  background: #ffffff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.01);
}

body.theme-coursera .solved-example-header {
  background: #f8f9fa;
  padding: 12px 18px;
}

/* ==========================================================================
   9. TEXT-TO-SPEECH AUDIO PLAYER BAR
   ========================================================================== */
.audio-reader-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  background: var(--glass-bg);
  backdrop-filter: blur(15px);
  border: 1px solid var(--glass-border);
  border-radius: var(--border-radius);
  box-shadow: 0 4px 15px var(--shadow-color);
  margin-bottom: 20px;
  transition: all var(--transition-speed) ease;
  z-index: 10;
}

.audio-reader-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Audio wave animation when playing */
.audio-wave-anim {
  display: none;
  align-items: flex-end;
  gap: 3px;
  width: 24px;
  height: 20px;
}
.audio-wave-anim.active {
  display: flex;
}
.audio-wave-anim span {
  width: 3px;
  background-color: var(--accent-blue);
  animation: wavePulse 1.2s ease-in-out infinite;
  border-radius: 3px;
}
.audio-wave-anim span:nth-child(1) { height: 20%; animation-delay: 0.1s; }
.audio-wave-anim span:nth-child(2) { height: 40%; animation-delay: 0.3s; }
.audio-wave-anim span:nth-child(3) { height: 30%; animation-delay: 0.5s; }
.audio-wave-anim span:nth-child(4) { height: 10%; animation-delay: 0s; }

@keyframes wavePulse {
  0%, 100% { transform: scaleY(1); }
  50% { transform: scaleY(2.2); }
}

.audio-default-icon {
  font-size: 1.4rem;
  color: var(--text-muted);
}
.audio-wave-anim.active + .audio-default-icon {
  display: none;
}

.audio-reader-title {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-color);
  display: block;
}

.audio-reader-status {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.audio-reader-controls {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.audio-control-btn {
  background: rgba(0, 0, 0, 0.03);
  border: 1px solid var(--glass-border);
  color: var(--text-color);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  font-size: 0.9rem;
}

body.theme-darkboard-chalk .audio-control-btn {
  background: rgba(255, 255, 255, 0.04);
}

.audio-control-btn:hover {
  background: var(--accent-blue);
  color: #fff !important;
  border-color: var(--accent-blue);
  transform: translateY(-1px);
}

.audio-control-btn.play-btn {
  background: var(--accent-blue);
  color: white;
  border-color: var(--accent-blue);
  width: 40px;
  height: 40px;
  font-size: 1rem;
}
.audio-control-btn.play-btn:hover {
  background: #0043a4;
  transform: scale(1.05);
}

.audio-control-divider {
  width: 1px;
  height: 24px;
  background: var(--border-color);
  margin: 0 8px;
}

.audio-control-group {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(0, 0, 0, 0.03);
  border: 1px solid var(--glass-border);
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.8rem;
}

body.theme-darkboard-chalk .audio-control-group {
  background: rgba(255, 255, 255, 0.03);
}

.audio-control-group label {
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
}

.audio-control-group select {
  background: transparent;
  border: none;
  color: var(--text-color);
  outline: none;
  font-size: 0.8rem;
  font-family: var(--font-interface);
  cursor: pointer;
  max-width: 140px;
  text-overflow: ellipsis;
}
.audio-control-group select option {
  background: var(--bg-color);
  color: var(--text-color);
}

/* ==========================================================================
   10. TTS NARRATION HIGHLIGHTS & SIDEBAR CHECKS
   ========================================================================== */
.tts-readable {
  transition: background-color 0.25s ease, border-left 0.25s ease;
  position: relative;
}

.tts-speaker-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  margin-right: 8px;
  vertical-align: middle;
  border-radius: 50%;
  padding: 0;
  transition: all 0.2s ease-in-out;
}

.tts-speaker-btn:hover {
  color: var(--accent-blue);
  background: rgba(2, 136, 209, 0.1);
  transform: scale(1.15);
}

body.hide-speaker-icons .tts-speaker-btn {
  display: none !important;
}

.tts-active-highlight .tts-speaker-btn {
  color: var(--accent-orange);
}

@media print {
  .tts-speaker-btn {
    display: none !important;
  }
}

.tts-active-highlight {
  background-color: rgba(255, 235, 59, 0.35) !important;
  border-left: 4px solid var(--accent-orange) !important;
  padding-left: 10px !important;
  border-radius: 0 4px 4px 0 !important;
  box-shadow: 2px 2px 8px rgba(0, 0, 0, 0.03);
  animation: pulseHighlight 2.5s infinite ease-in-out;
}

body.theme-coursera .tts-active-highlight {
  background-color: rgba(0, 86, 210, 0.06) !important;
  border-left: 4px solid var(--accent-blue) !important;
  color: #000000 !important;
}

body.theme-darkboard-chalk .tts-active-highlight {
  background-color: rgba(64, 196, 255, 0.15) !important;
  border-left: 4px solid var(--accent-blue) !important;
  color: #ffffff !important;
}

body.theme-retro-parchment .tts-active-highlight {
  background-color: rgba(241, 196, 15, 0.25) !important;
  border-left: 4px solid var(--accent-orange) !important;
}

@keyframes pulseHighlight {
  0%, 100% { opacity: 1; }
  50% { background-color: rgba(255, 235, 59, 0.22); }
}

.tts-word {
  position: relative;
  transition: background-color 0.1s ease, color 0.1s ease;
  border-radius: 2px;
  display: inline-block;
}
.tts-word-highlight {
  background-color: var(--accent-orange) !important;
  color: white !important;
}
body.theme-coursera .tts-word-highlight {
  background-color: var(--accent-blue) !important;
  color: white !important;
}
body.theme-darkboard-chalk .tts-word-highlight {
  background-color: #00e5ff !important;
  color: #000000 !important;
}
body.theme-retro-parchment .tts-word-highlight {
  background-color: #d35400 !important;
  color: white !important;
}

/* Sidebar Completion Badges */
.chapter-nav-item {
  position: relative;
  padding-right: 32px !important;
}

.chapter-completion-badge {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--accent-green);
  font-size: 0.82rem;
  opacity: 0.85;
  transition: all 0.25s ease;
  animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.chapter-nav-item.active .chapter-completion-badge {
  color: var(--bg-color);
}

@keyframes popIn {
  0% { transform: translateY(-50%) scale(0); opacity: 0; }
  100% { transform: translateY(-50%) scale(1); opacity: 0.85; }
}

@media (max-width: 768px) {
  .audio-reader-bar {
    flex-direction: column;
    align-items: stretch;
    gap: 15px;
    padding: 16px;
  }
  .audio-reader-controls {
    justify-content: center;
  }
  .audio-control-group select {
    max-width: 90px;
  }
}

/* ==========================================================================
   11. AI CHAT PANEL WIDGET (RIGHT SLIDING DRAWER)
   ========================================================================== */
.ai-chat-panel {
  position: fixed;
  right: -390px;
  top: 0;
  width: 370px;
  height: 100vh;
  background: var(--panel-bg);
  backdrop-filter: blur(20px);
  border-left: 1px solid var(--border-color);
  box-shadow: -8px 0 30px var(--shadow-color);
  z-index: 1000;
  transition: right 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  flex-direction: column;
}

.ai-chat-panel.active {
  right: 0;
}

.ai-chat-header {
  padding: 20px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(2, 136, 209, 0.03);
}

.ai-chat-header-title {
  display: flex;
  align-items: center;
  gap: 12px;
}

.ai-chat-header-title i {
  font-size: 1.6rem;
  color: var(--accent-blue);
  animation: pulse-robot 2s infinite ease-in-out;
}

@keyframes pulse-robot {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.1); color: var(--accent-orange); }
}

.ai-chat-header-title h3 {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-color);
}

.ai-chat-header-title p {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.btn-close-chat {
  background: transparent;
  border: none;
  font-size: 1.2rem;
  color: var(--text-muted);
  cursor: pointer;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.btn-close-chat:hover {
  background: rgba(0,0,0,0.05);
  color: var(--text-color);
}

.ai-chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  scrollbar-width: thin;
}

.chat-message {
  max-width: 85%;
  padding: 12px 16px;
  border-radius: 14px;
  font-size: 0.88rem;
  line-height: 1.45;
  animation: messagePop 0.3s cubic-bezier(0.18, 0.89, 0.32, 1.28);
}

@keyframes messagePop {
  0% { transform: translateY(15px) scale(0.95); opacity: 0; }
  100% { transform: translateY(0) scale(1); opacity: 1; }
}

.chat-message.bot {
  align-self: flex-start;
  background: rgba(2, 136, 209, 0.05);
  border-left: 3px solid var(--accent-blue);
  color: var(--text-color);
  border-top-left-radius: 2px;
}

body.theme-darkboard-chalk .chat-message.bot {
  background: rgba(64, 196, 255, 0.1);
}

.chat-message.user {
  align-self: flex-end;
  background: var(--accent-blue);
  color: #ffffff !important;
  border-top-right-radius: 2px;
}

.ai-chat-suggestions {
  padding: 10px 20px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: none;
  border-top: 1px solid var(--border-color);
  background: rgba(0,0,0,0.005);
}

.ai-chat-suggestions::-webkit-scrollbar {
  display: none;
}

.suggestion-chip {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--text-color);
  padding: 6px 12px;
  border-radius: 20px;
  font-size: 0.78rem;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s;
  font-family: var(--font-interface);
  font-weight: 550;
}

.suggestion-chip:hover {
  border-color: var(--accent-blue);
  background: rgba(2, 136, 209, 0.04);
  transform: translateY(-1px);
}

.ai-chat-input-area {
  padding: 16px 20px;
  border-top: 1px solid var(--border-color);
  display: flex;
  gap: 10px;
}

#ai-chat-input {
  flex: 1;
  padding: 10px 16px;
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  background: rgba(0,0,0,0.02);
  color: var(--text-color);
  font-size: 0.88rem;
  outline: none;
  font-family: var(--font-interface);
}

#ai-chat-input:focus {
  border-color: var(--accent-blue);
  background: #ffffff;
}

body.theme-darkboard-chalk #ai-chat-input:focus {
  background: #1e272c;
}

/* ==========================================================================
   12. FLOATING SELECTION BUBBLE TOOLBAR
   ========================================================================== */
.selection-toolbar {
  position: absolute;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background: #212121;
  border-radius: 30px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.35);
  z-index: 999;
  transform: translate(-50%, -100%);
  margin-top: -10px;
  animation: toolbarBounce 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes toolbarBounce {
  0% { transform: translate(-50%, -80%) scale(0.8); opacity: 0; }
  100% { transform: translate(-50%, -100%) scale(1); opacity: 1; }
}

.hl-color-btn {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 1.5px solid rgba(255, 255, 255, 0.2);
  cursor: pointer;
  transition: transform 0.15s ease;
}

.hl-color-btn:hover {
  transform: scale(1.2);
}

.hl-yellow { background-color: #fff59d; }
.hl-green { background-color: #a5d6a7; }
.hl-blue { background-color: #90caf9; }

.toolbar-divider {
  width: 1px;
  height: 16px;
  background: rgba(255, 255, 255, 0.25);
  margin: 0 4px;
}

.toolbar-text-btn {
  background: transparent;
  border: none;
  color: #e0e0e0;
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 8px;
  border-radius: 4px;
  font-family: var(--font-interface);
  transition: all 0.2s;
}

.toolbar-text-btn:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.1);
}

.toolbar-text-btn.remove-hl:hover {
  color: var(--accent-red);
}

/* Inline Highlight Spans */
.hl-yellow-span { background-color: rgba(255, 241, 118, 0.6) !important; border-radius: 2px; }
.hl-green-span { background-color: rgba(105, 240, 174, 0.5) !important; border-radius: 2px; }
.hl-blue-span { background-color: rgba(64, 196, 255, 0.45) !important; border-radius: 2px; }

body.theme-darkboard-chalk .hl-yellow-span { background-color: rgba(255, 235, 59, 0.25) !important; }
body.theme-darkboard-chalk .hl-green-span { background-color: rgba(105, 240, 174, 0.25) !important; }
body.theme-darkboard-chalk .hl-blue-span { background-color: rgba(64, 196, 255, 0.25) !important; }

/* ==========================================================================
   13. INLINE PRACTICE QUIZZES (COURSERA STYLE)
   ========================================================================== */
.inline-quiz-card {
  background: var(--panel-bg);
  border: 1.5px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 24px;
  margin: 35px 0 20px 0;
  box-shadow: 0 4px 15px var(--shadow-color);
  font-family: var(--font-interface);
}

.quiz-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.72rem;
  font-weight: 800;
  text-transform: uppercase;
  color: var(--accent-blue);
  letter-spacing: 1px;
  margin-bottom: 12px;
  background: rgba(2, 136, 209, 0.05);
  padding: 4px 10px;
  border-radius: 12px;
}

.quiz-question-text {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-color);
  line-height: 1.5;
  margin-bottom: 18px;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.quiz-opt-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 12px 18px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background: var(--bg-color);
  color: var(--text-color);
  text-align: left;
  font-family: var(--font-interface);
  font-size: 0.9rem;
  font-weight: 550;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  outline: none;
}

.quiz-opt-btn:hover:not(.disabled) {
  border-color: var(--accent-blue);
  background: var(--panel-bg);
  transform: translateX(4px);
}

.quiz-opt-btn.correct {
  border-color: var(--accent-green) !important;
  background: rgba(30, 126, 52, 0.06) !important;
  color: var(--accent-green) !important;
}

.quiz-opt-btn.incorrect {
  border-color: var(--accent-red) !important;
  background: rgba(217, 48, 37, 0.06) !important;
  color: var(--accent-red) !important;
}

.quiz-opt-btn.disabled {
  cursor: not-allowed;
  opacity: 0.7;
}

.quiz-explanation-box {
  margin-top: 18px;
  padding: 16px;
  border-radius: 8px;
  background: rgba(2, 136, 209, 0.04);
  border: 1px solid rgba(2, 136, 209, 0.1);
  font-size: 0.88rem;
  line-height: 1.45;
  color: var(--text-color);
  display: none;
  animation: explanationSlide 0.3s ease-out;
}

@keyframes explanationSlide {
  from { opacity: 0; transform: translateY(-5px); }
  to { opacity: 1; transform: translateY(0); }
}

.quiz-explanation-box.correct-feedback {
  background: rgba(30, 126, 52, 0.04);
  border-color: rgba(30, 126, 52, 0.1);
}

/* ==========================================================================
   14. INTERACTIVE FORMULA CALCULATOR STYLES
   ========================================================================== */
.calc-btn-inline {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--accent-blue);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 0.78rem;
  font-weight: 700;
  cursor: pointer;
  margin-left: 10px;
  font-family: var(--font-interface);
  transition: all 0.2s;
}

.calc-btn-inline:hover {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
}

.calc-input-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.calc-input-group label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-color);
  font-family: var(--font-interface);
}

.calc-input-group input {
  padding: 8px 12px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background: var(--bg-color);
  color: var(--text-color);
  outline: none;
  font-family: var(--font-mono);
  font-size: 0.88rem;
}

.calc-input-group input:focus {
  border-color: var(--accent-blue);
  background: var(--panel-bg);
}

/* ==========================================================================
   15. ZEN FOCUS MODE & PAGE BOOKMARK RIBBONS
   ========================================================================== */
.focus-mode-active .sidebar,
.focus-mode-active .top-bar,
.focus-mode-active .floating-dock-container,
.focus-mode-active .bottom-notes-section,
.focus-mode-active .notebook-pagination {
  opacity: 0 !important;
  pointer-events: none !important;
  visibility: hidden !important;
  transition: all 0.5s ease;
}

.focus-mode-active .app-container {
  grid-template-columns: 1fr !important;
  background: #12181b !important;
}

.focus-mode-active .notebook-container {
  max-width: 760px;
  margin: 0 auto;
  padding: 60px 20px;
  overflow-y: auto;
  scrollbar-width: none;
  background: transparent !important;
}

.focus-mode-active .notebook-page {
  background: #1e272c !important;
  color: #eceff1 !important;
  border: 1px solid rgba(255, 255, 255, 0.05) !important;
  box-shadow: 0 10px 40px rgba(0,0,0,0.5) !important;
}

.focus-mode-active .notebook-page::before {
  display: none !important;
}

.focus-mode-active .notebook-page p:not(.tts-active-highlight),
.focus-mode-active .notebook-page li:not(.tts-active-highlight),
.focus-mode-active .notebook-page h2:not(.tts-active-highlight) {
  opacity: 0.12 !important;
  filter: blur(0.5px);
  transition: opacity 0.5s ease, filter 0.5s ease;
}

/* Spotlight controls button */
.audio-control-btn#focus-mode-btn.active {
  background: var(--accent-orange) !important;
  border-color: var(--accent-orange) !important;
  color: white !important;
  animation: pulseHighlight 2s infinite linear;
}

/* Bookmark Page Ribbon */
.bookmark-ribbon-toggle {
  position: absolute;
  top: 0;
  right: 30px;
  width: 28px;
  height: 40px;
  cursor: pointer;
  z-index: 5;
  transition: transform 0.2s ease;
}

.bookmark-ribbon-toggle:hover {
  transform: translateY(2px);
}

.bookmark-ribbon-toggle svg {
  width: 100%;
  height: 100%;
  fill: rgba(0,0,0,0.1);
  stroke: var(--text-muted);
  stroke-width: 1.5;
  transition: fill 0.2s, stroke 0.2s;
}

.bookmark-ribbon-toggle.active svg {
  fill: var(--accent-orange);
  stroke: var(--accent-orange);
  filter: drop-shadow(0 2px 6px rgba(245, 124, 0, 0.4));
}

body.theme-darkboard-chalk .bookmark-ribbon-toggle svg {
  fill: rgba(255,255,255,0.05);
  stroke: rgba(255,255,255,0.2);
}

body.theme-darkboard-chalk .bookmark-ribbon-toggle.active svg {
  fill: var(--accent-orange);
  stroke: var(--accent-orange);
}

/* ==========================================================================
   MOBILE UX AND PERFORMANCE OVERRIDES (Deactivate backdrop-filter, optimize Top-Bar)
   ========================================================================== */
@media (max-width: 900px) {
  .top-bar,
  .sidebar,
  .ai-chat-panel,
  .modal-overlay,
  .audio-reader-bar {
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
  }
  .top-bar {
    background: var(--bg-color) !important;
  }
  .sidebar {
    background: var(--bg-color) !important;
  }
  .ai-chat-panel {
    background: var(--panel-bg) !important;
  }
  .audio-reader-bar {
    background: var(--panel-bg) !important;
  }
}

@media (max-width: 600px) {
  /* Prevent top bar from splitting into columns on mobile */
  .top-bar {
    flex-direction: row !important;
    align-items: center !important;
    justify-content: space-between !important;
    padding: 8px 12px !important;
    gap: 6px !important;
  }
  
  .current-chapter-title-wrap {
    max-width: 50vw !important;
  }

  .current-chapter-head {
    font-size: 0.95rem !important;
    white-space: nowrap !important;
    overflow: hidden !important;
    text-overflow: ellipsis !important;
    max-width: 100% !important;
  }

  .top-bar .right-actions {
    width: auto !important;
    justify-content: flex-end !important;
    flex-wrap: nowrap !important;
    gap: 6px !important;
  }

  /* Compact top-bar buttons (Icons only) */
  .top-bar .right-actions .btn,
  .top-bar .right-actions .btn-download-pdf,
  .top-bar .right-actions .theme-selector-dropdown .dropdown-btn {
    padding: 0 !important;
    width: 34px !important;
    height: 34px !important;
    min-width: 34px !important;
    border-radius: 50% !important;
    display: inline-flex !important;
    align-items: center !important;
    justify-content: center !important;
    font-size: 0.9rem !important;
    gap: 0 !important;
  }

  .top-bar .right-actions .btn span,
  .top-bar .right-actions .btn-download-pdf span,
  .top-bar .right-actions .theme-selector-dropdown .dropdown-btn span {
    display: none !important;
  }

  /* Analytics Modal Responsive Grid */
  .analytics-stats-grid {
    grid-template-columns: repeat(2, 1fr) !important;
    gap: 10px !important;
  }

  .analytics-dashboard-bottom-grid {
    grid-template-columns: 1fr !important;
    gap: 16px !important;
  }
}

/* ==========================================================================
   RESPONSIVE CBT SIMULATOR OVERRIDES (Sidebar Drawer on Mobile)
   ========================================================================== */
.cbt-toggle-sidebar-item {
  display: none !important;
}

@media (max-width: 768px) {
  .cbt-toggle-sidebar-item {
    display: inline-flex !important;
  }

  .cbt-header {
    flex-direction: column !important;
    align-items: stretch !important;
    padding: 8px 12px !important;
    gap: 8px !important;
  }

  .cbt-brand {
    justify-content: space-between !important;
    width: 100% !important;
  }

  .cbt-title-group h1 {
    font-size: 0.85rem !important;
  }

  .cbt-title-group p {
    font-size: 0.65rem !important;
  }

  .cbt-meta {
    width: 100% !important;
    justify-content: space-between !important;
    gap: 8px !important;
    flex-wrap: nowrap !important;
    align-items: center !important;
  }

  /* Hide Candidate name & Subject on mobile to save space */
  .cbt-meta .meta-item:nth-child(1),
  .cbt-meta .meta-item:nth-child(2) {
    display: none !important;
  }

  .cbt-meta .meta-item {
    font-size: 0.8rem !important;
  }

  .cbt-main {
    grid-template-columns: 1fr !important;
    position: relative !important;
  }

  /* CBT Sidebar Drawer positioning */
  .cbt-sidebar {
    position: absolute !important;
    top: 0 !important;
    right: -320px !important;
    width: 300px !important;
    max-width: 85vw !important;
    height: 100% !important;
    z-index: 1050 !important;
    box-shadow: -6px 0 20px rgba(0,0,0,0.3) !important;
    background: var(--panel-bg) !important;
    border-left: 1px solid var(--border-color) !important;
    transition: right 0.3s cubic-bezier(0.4, 0, 0.2, 1) !important;
    display: flex !important;
    padding: 16px !important;
  }

  .cbt-sidebar.active {
    right: 0 !important;
  }

  .cbt-sidebar-close-wrap {
    display: flex !important;
  }

  .candidate-photo-box {
    display: none !important; /* Hide candidate info inside mobile drawer */
  }

  /* CBT Sidebar Backdrop */
  .cbt-sidebar-backdrop {
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    width: 100% !important;
    height: 100% !important;
    background: rgba(0, 0, 0, 0.4) !important;
    z-index: 1040 !important;
    display: none;
  }

  .cbt-sidebar-backdrop.active {
    display: block !important;
  }
}

/* ==========================================================================
   Interactive Quiz & Inline 3D Visual Styles
   ========================================================================== */
.topic-quiz-card {
  margin-top: 30px;
  padding: 20px;
  border-radius: var(--border-radius);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.quiz-option-btn {
  padding: 12px;
  border-radius: 8px;
  border: 1.5px solid var(--border-color);
  text-align: left;
  background: var(--bg-card);
  color: var(--text-color);
  font-size: 1rem;
  transition: all 0.2s ease;
  cursor: pointer;
}

.quiz-option-btn:hover:not(:disabled) {
  background: var(--border-color) !important;
  border-color: var(--accent-blue) !important;
}

.quiz-option-btn.correct {
  background-color: #4CAF50 !important;
  color: white !important;
  border-color: #4CAF50 !important;
}

.quiz-option-btn.incorrect {
  background-color: #f44336 !important;
  color: white !important;
  border-color: #f44336 !important;
}

.quiz-solution-block {
  display: none;
  background: rgba(76, 175, 80, 0.1);
  border-left: 4px solid #4CAF50;
  padding: 15px;
  border-radius: 4px;
  margin-top: 15px;
}

.inline-3d-wrap {
  position: relative;
  width: 100%;
  border: 1.5px solid var(--border-color);
  border-radius: var(--border-radius);
  overflow: hidden;
  background: #0b0e14;
  margin: 20px 0;
  box-shadow: 0 4px 15px rgba(0,0,0,0.15);
}

#inline-3d-canvas {
  width: 100%;
  height: 350px;
  display: block;
}

#inline-3d-controls {
  background: rgba(11, 14, 20, 0.9);
  border-top: 1px solid var(--border-color);
  padding: 15px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 15px;
}

/* ==========================================================================
   10. STUDY PROGRESS VISUALIZATION & ANALYTICS
   ========================================================================== */
.sidebar-progress-container {
  margin-top: 15px;
  margin-bottom: 5px;
}

.sidebar-progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-color);
  margin-bottom: 6px;
}

.sidebar-progress-bar-wrap {
  width: 100%;
  height: 6px;
  background: var(--border-color);
  border-radius: 3px;
  overflow: hidden;
  position: relative;
}

.sidebar-progress-bar {
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
  border-radius: 3px;
  transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.volume-progress-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 25px;
  padding: 20px;
  background: var(--glass-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  backdrop-filter: blur(10px);
}

@media (max-width: 768px) {
  .volume-progress-container {
    grid-template-columns: 1fr;
    gap: 15px;
  }
}

.volume-progress-card {
  display: flex;
  flex-direction: column;
}

.vol-prog-label {
  display: flex;
  justify-content: space-between;
  font-weight: 700;
  font-size: 0.9rem;
  margin-bottom: 8px;
  color: var(--text-color);
}

.vol-prog-footer {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 5px;
  font-style: italic;
}

.cbt-trend-container h4 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  margin-bottom: 8px;
}

.chart-point-group circle {
  transition: r 0.2s ease, fill 0.2s ease;
}

.chart-point-group:hover circle:first-of-type {
  r: 8px;
  fill: var(--accent-purple);
}

.chart-point-group text {
  transition: font-size 0.2s ease, fill 0.2s ease;
}

.chart-point-group:hover text {
  fill: var(--accent-purple);
}

/* Disable tap highlight flash on mobile */
* {
  -webkit-tap-highlight-color: transparent;
}

/* Enable premium iOS-like momentum scrolling globally for scrollable containers */
.notebook-container,
.sidebar,
.ai-chat-messages,
.modal-body,
.cbt-results-modal,
.scratchpad-canvas-wrap {
  -webkit-overflow-scrolling: touch;
  scroll-behavior: smooth;
}

/* Premium Apple-like Active Click Feedback states */
.btn:active,
.dock-menu-item:active,
.theme-opt:active,
.audio-reader-bar button:active,
.tts-speaker-btn:active,
.close-btn:active,
.scratchpad-tool-btn:active,
.scratchpad-close-btn:active,
.floating-dock-trigger:active {
  transform: scale(0.94) !important;
  opacity: 0.8 !important;
  transition: transform 0.08s cubic-bezier(0.25, 0.46, 0.45, 0.94) !important;
}

/* Prevent body scrolling when modal is active */
body.body-scroll-locked {
  overflow: hidden !important;
  position: relative !important;
  height: 100vh !important;
}

/* ==========================================================================
   MOBILE OVERRIDES FOR FLOATING DOCK & ROUGH WORK MODAL
   ========================================================================== */
@media (max-width: 768px) {
  /* Draggable Floating Dock Mobile Enhancements */
  .floating-dock-container {
    bottom: 20px;
    right: 20px;
    gap: 10px !important;
    pointer-events: none !important;
  }

  .floating-dock-trigger {
    width: 46px !important;
    height: 46px !important;
    font-size: 1.1rem !important;
    cursor: default !important;
    opacity: 0.8 !important;
    pointer-events: auto !important;
  }

  .floating-dock-container.menu-active .floating-dock-trigger {
    opacity: 1 !important;
  }

  .floating-dock-menu {
    gap: 8px !important;
    pointer-events: none !important;
  }

  .floating-dock-container.menu-active .floating-dock-menu {
    pointer-events: auto !important;
  }

  .dock-menu-item {
    height: 36px !important;
    border-radius: 18px !important;
    padding: 0 14px !important;
    font-size: 0.8rem !important;
    gap: 6px !important;
  }

  .dock-menu-item i {
    font-size: 0.9rem !important;
  }

  /* Rough Work (Scratchpad) Mobile Layout Optimizations */
  .scratchpad-container.size-standard,
  .scratchpad-container.size-large,
  .scratchpad-container.size-fullscreen {
    width: 96% !important;
    height: 92vh !important;
    max-height: none !important;
    max-width: none !important;
  }

  .scratchpad-size-selector {
    display: none !important;
  }

  .scratchpad-header-btn span {
    display: none !important;
  }

  .scratchpad-header-btn {
    padding: 6px 10px !important;
  }

  .scratchpad-header h3 {
    font-size: 0.9rem !important;
  }

  .scratchpad-header {
    padding: 10px 12px !important;
  }

  .scratchpad-toolbar {
    padding: 6px 10px !important;
    gap: 6px !important;
  }

  .scratchpad-tool-btn {
    padding: 4px 8px !important;
    font-size: 0.75rem !important;
    border-radius: 6px !important;
  }

  .scratchpad-colors {
    gap: 4px !important;
  }

  .scratchpad-color-swatch {
    width: 16px !important;
    height: 16px !important;
  }
}