/* STEM Flashcards Styles */
:root {
  /* Light Mode - Clean White/Black */
  --light-bg: #ffffff;
  --light-text: #000000;
  --light-card: #ffffff;
  --light-border: #e0e0e0;
  --light-accent: #333333;
  --light-highlight: #666666;
  --light-button: #f5f5f5;
  --light-button-hover: #e8e8e8;
  
  /* Dark Mode - Black/Green Neon */
  --dark-bg: #000000;
  --dark-text: #00ff00;
  --dark-card: #0a0a0a;
  --dark-border: #003300;
  --dark-accent: #00cc00;
  --dark-highlight: #00ff00;
  --dark-button: #001100;
  --dark-button-hover: #002200;
  --dark-glow: #00ff0050;
  
  /* Status Colors */
  --success: #00ff00;
  --warning: #ffff00;
  --error: #ff0000;
}

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

body {
  font-family: 'Work Sans', sans-serif;
  background: var(--light-bg);
  color: var(--light-text);
  min-height: 100vh;
  transition: all 0.3s ease;
}

/* Header */
.header {
  background: var(--light-bg);
  border-bottom: 2px solid var(--light-border);
  color: var(--light-text);
  padding: 1em 2em;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 1em;
  position: sticky;
  top: 0;
  z-index: 1000;
  transition: all 0.3s ease;
}

.logo-link {
  display: flex;
  align-items: center;
  text-decoration: none;
  color: inherit;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 0.4em;
}

.logo-area img {
  height: 50px;
  width: 50px;
}

.logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  margin-left: -4px;
}

.logo-text .title {
  font-size: 1.4em;
  font-weight: bold;
  color: var(--light-text);
}

.logo-text .tagline {
  font-size: 0.85em;
  color: var(--light-highlight);
}

.flashcards-title {
  justify-self: center;
  font-size: 1.3em;
  font-weight: bold;
  color: var(--light-accent);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 1em;
}

.toggle-theme {
  cursor: pointer;
  font-size: 1.5em;
  padding: 0.3em;
  border-radius: 50%;
  transition: all 0.3s ease;
  color: var(--light-text);
}

.toggle-theme:hover {
  background: var(--light-button-hover);
  transform: scale(1.1);
}

.nav-back {
  color: var(--light-highlight);
  text-decoration: none;
  padding: 0.5em 1em;
  border-radius: 25px;
  transition: all 0.3s ease;
}

.nav-back:hover {
  background: var(--light-button-hover);
  color: var(--light-text);
}

/* Learning Objectives */
.learning-objectives {
  background: var(--light-card);
  border: 2px solid var(--light-border);
  margin: 1em;
  border-radius: 15px;
  padding: 2em;
  color: var(--light-text);
  text-align: center;
  transition: all 0.3s ease;
}

.learning-objectives h2 {
  color: var(--light-accent);
  margin-bottom: 1.5em;
  font-size: 1.8em;
}

.objectives-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5em;
}

.objective {
  text-align: center;
  padding: 1em;
}

.objective-icon {
  font-size: 2.5em;
  margin-bottom: 0.5em;
  display: block;
}

/* Main App Layout */
.app-container {
  display: grid;
  grid-template-columns: 300px 1fr;
  min-height: calc(100vh - 200px);
  gap: 1em;
  padding: 1em;
}

/* Sidebar */
.sidebar {
  background: var(--light-card);
  border: 2px solid var(--light-border);
  border-radius: 15px;
  padding: 1.5em;
  height: fit-content;
  position: sticky;
  top: 120px;
  transition: all 0.3s ease;
}

.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5em;
  padding-bottom: 1em;
  border-bottom: 2px solid var(--highlight);
}

.sidebar-header h3 {
  color: var(--light-accent);
  font-size: 1.3em;
}

.sidebar-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5em;
  cursor: pointer;
  color: var(--light-accent);
}

.level-selection {
  margin-bottom: 2em;
}

.level-selection h4 {
  color: var(--light-accent);
  margin-bottom: 0.8em;
  font-size: 1.1em;
}

.level-select {
  width: 100%;
  padding: 0.8em;
  border: 2px solid var(--light-border);
  border-radius: 8px;
  background: var(--light-bg);
  color: var(--light-text);
  font-size: 0.9em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

.level-select:focus {
  outline: none;
  border-color: var(--light-accent);
  box-shadow: 0 0 10px var(--light-border);
}

/* Topic Categories */
.topic-categories {
  margin-bottom: 2em;
}

.topic-category {
  margin-bottom: 1em;
}

.category-header {
  background: var(--light-button);
  border: 2px solid var(--light-border);
  color: var(--light-text);
  padding: 0.8em 1em;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  transition: all 0.3s ease;
}

.category-header:hover {
  transform: translateY(-2px);
  background: var(--light-button-hover);
  box-shadow: 0 4px 15px var(--light-border);
}

.category-topics {
  background: var(--light-card);
  border: 1px solid var(--light-border);
  border-radius: 0 0 8px 8px;
  padding: 0.5em 0;
  display: none;
}

.category-topics.expanded {
  display: block;
}

.topic-item {
  padding: 0.6em 1em;
  cursor: pointer;
  transition: all 0.2s ease;
  border-left: 3px solid transparent;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.topic-item:hover {
  background: var(--light-button-hover);
  border-left-color: var(--light-accent);
  transform: translateX(5px);
}

.topic-item.active {
  background: var(--light-button-hover);
  border-left-color: var(--light-accent);
  color: var(--light-accent);
  font-weight: 600;
}

.topic-progress {
  font-size: 0.8em;
  color: #666;
}

/* Study Statistics */
.study-stats {
  margin-bottom: 2em;
  padding: 1em;
  background: rgba(0, 51, 160, 0.05);
  border-radius: 10px;
  border: 1px solid rgba(0, 51, 160, 0.1);
}

.study-stats h4 {
  color: var(--accent);
  margin-bottom: 1em;
  text-align: center;
}

.stat-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5em 0;
  border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.stat-item:last-child {
  border-bottom: none;
}

.stat-value {
  font-weight: bold;
  color: var(--highlight);
}

/* NotebookLM Integration */
.notebooklm-section {
  margin-bottom: 2em;
  padding: 1em;
  background: rgba(66, 133, 244, 0.1);
  border-radius: 10px;
  border: 1px solid rgba(66, 133, 244, 0.2);
  text-align: center;
}

.notebooklm-section h4 {
  color: #4285f4;
  margin-bottom: 1em;
  font-size: 1.1em;
}

.notebooklm-btn {
  width: 100%;
  padding: 1em;
  background: linear-gradient(45deg, #4285f4, #1a73e8);
  color: white;
  border: none;
  border-radius: 10px;
  font-weight: bold;
  cursor: pointer;
  margin-bottom: 0.8em;
  transition: all 0.3s ease;
  font-size: 1em;
}

.notebooklm-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(66, 133, 244, 0.4);
}

.notebooklm-description {
  font-size: 0.85em;
  color: #666;
  line-height: 1.4;
  margin: 0;
}

.notebooklm-study-btn {
  background: linear-gradient(45deg, #4285f4, #1a73e8);
  border-color: rgba(66, 133, 244, 0.3);
}

.notebooklm-study-btn:hover {
  background: linear-gradient(45deg, #1a73e8, #1557b0);
  box-shadow: 0 4px 15px rgba(66, 133, 244, 0.4);
}

/* Offline Section */
.offline-section {
  text-align: center;
}

.download-btn {
  width: 100%;
  padding: 1em;
  background: linear-gradient(45deg, var(--success), #45a049);
  color: white;
  border: none;
  border-radius: 10px;
  font-weight: bold;
  cursor: pointer;
  margin-bottom: 1em;
  transition: all 0.3s ease;
}

.download-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(76, 175, 80, 0.4);
}

.offline-status {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  font-size: 0.9em;
  color: #666;
}

.status-indicator {
  font-size: 0.8em;
}

/* Study Area */
.study-area {
  background: var(--light-card);
  border: 2px solid var(--light-border);
  border-radius: 15px;
  padding: 2em;
  transition: all 0.3s ease;
}

/* Welcome Screen */
.welcome-screen {
  text-align: center;
  padding: 3em 2em;
}

.welcome-content h2 {
  color: var(--light-accent);
  margin-bottom: 1em;
  font-size: 2.2em;
}

.welcome-content p {
  font-size: 1.2em;
  color: var(--light-highlight);
  margin-bottom: 2em;
}

.quick-start h3 {
  color: var(--accent);
  margin-bottom: 1em;
}

.quick-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1em;
  max-width: 600px;
  margin: 0 auto;
}

.quick-btn {
  padding: 1em 1.5em;
  background: var(--light-button);
  border: 2px solid var(--light-border);
  color: var(--light-text);
  border-radius: 10px;
  font-size: 1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

.quick-btn:hover {
  transform: translateY(-3px);
  background: var(--light-button-hover);
  box-shadow: 0 6px 20px var(--light-border);
}

/* Progress Bar */
.progress-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2em;
}

.progress-bar {
  flex: 1;
  height: 8px;
  background: rgba(0, 51, 160, 0.2);
  border-radius: 4px;
  overflow: hidden;
  margin-right: 1em;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--highlight));
  border-radius: 4px;
  transition: width 0.3s ease;
  width: 0%;
}

.progress-text {
  font-weight: bold;
  color: var(--accent);
  min-width: 60px;
}

/* Flashcard */
.flashcard-container {
  perspective: 1000px;
  margin-bottom: 2em;
}

.flashcard {
  width: 100%;
  height: 400px;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.6s ease;
  cursor: pointer;
}

.flashcard.flipped {
  transform: rotateY(180deg);
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
}

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 15px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 2em;
}

.flashcard-front {
  background: linear-gradient(135deg, #ffffff 0%, #f8f9ff 100%);
  border: 2px solid rgba(0, 51, 160, 0.2);
}

.flashcard-back {
  background: linear-gradient(135deg, #f0f8ff 0%, #e6f3ff 100%);
  border: 2px solid rgba(255, 64, 129, 0.2);
  transform: rotateY(180deg);
}

.card-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  text-align: center;
}

.card-type {
  background: var(--accent);
  color: white;
  padding: 0.3em 1em;
  border-radius: 20px;
  font-size: 0.8em;
  font-weight: bold;
  align-self: center;
  margin-bottom: 1em;
}

.card-question {
  font-size: 1.4em;
  font-weight: 600;
  color: var(--accent);
  line-height: 1.4;
  margin-bottom: 1em;
}

.card-answer {
  font-size: 1.3em;
  font-weight: 600;
  color: var(--highlight);
  line-height: 1.4;
  margin-bottom: 1em;
}

.card-explanation {
  font-size: 1em;
  color: #555;
  line-height: 1.6;
  margin-bottom: 1em;
}

.card-formula {
  background: rgba(0, 51, 160, 0.1);
  padding: 1em;
  border-radius: 10px;
  font-family: 'Courier New', monospace;
  font-size: 1.1em;
  color: var(--accent);
  margin: 1em 0;
}

.card-image {
  max-width: 100%;
  max-height: 200px;
  margin: 1em auto;
  border-radius: 10px;
  overflow: hidden;
}

.card-image img {
  width: 100%;
  height: auto;
  object-fit: contain;
}

.card-hint {
  background: rgba(255, 193, 7, 0.1);
  border: 1px solid rgba(255, 193, 7, 0.3);
  border-radius: 10px;
  padding: 1em;
  margin-top: 1em;
  font-style: italic;
  color: #856404;
}

.flip-btn {
  padding: 1em 2em;
  background: linear-gradient(45deg, var(--accent), #0066cc);
  color: white;
  border: none;
  border-radius: 25px;
  font-size: 1.1em;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s ease;
  align-self: center;
}

.flip-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 51, 160, 0.4);
}

/* Difficulty Buttons */
.difficulty-buttons {
  display: flex;
  gap: 1em;
  justify-content: center;
  flex-wrap: wrap;
}

.diff-btn {
  padding: 0.8em 1.5em;
  border: none;
  border-radius: 25px;
  font-size: 1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  min-width: 120px;
}

.diff-btn.hard {
  background: linear-gradient(45deg, var(--error), #d32f2f);
  color: white;
}

.diff-btn.good {
  background: linear-gradient(45deg, var(--warning), #f57c00);
  color: white;
}

.diff-btn.easy {
  background: linear-gradient(45deg, var(--success), #388e3c);
  color: white;
}

.diff-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
}

/* Study Controls */
.study-controls {
  display: flex;
  justify-content: center;
  gap: 1em;
  flex-wrap: wrap;
}

.control-btn {
  padding: 0.8em 1.5em;
  background: rgba(0, 51, 160, 0.1);
  border: 2px solid rgba(0, 51, 160, 0.2);
  border-radius: 25px;
  color: var(--accent);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

.control-btn:hover {
  background: rgba(0, 51, 160, 0.2);
  transform: translateY(-2px);
}

/* Study Complete Screen */
.study-complete {
  text-align: center;
  padding: 3em 2em;
}

.complete-content h2 {
  color: var(--success);
  margin-bottom: 2em;
  font-size: 2.2em;
}

.session-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1.5em;
  margin-bottom: 2em;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

.stat-card {
  background: rgba(76, 175, 80, 0.1);
  border: 2px solid rgba(76, 175, 80, 0.2);
  border-radius: 15px;
  padding: 1.5em;
}

.stat-number {
  font-size: 2.5em;
  font-weight: bold;
  color: var(--success);
  margin-bottom: 0.5em;
}

.stat-label {
  color: #666;
  font-weight: 600;
}

.complete-actions {
  display: flex;
  gap: 1em;
  justify-content: center;
  flex-wrap: wrap;
}

.action-btn {
  padding: 1em 2em;
  border: none;
  border-radius: 25px;
  font-size: 1.1em;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s ease;
  min-width: 150px;
}

.action-btn.primary {
  background: linear-gradient(45deg, var(--accent), #0066cc);
  color: white;
}

.action-btn.secondary {
  background: rgba(0, 51, 160, 0.1);
  border: 2px solid var(--accent);
  color: var(--accent);
}

.action-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

/* Footer */
.footer {
  background-color: var(--light-bg);
  border-top: 2px solid var(--light-border);
  color: var(--light-text);
  padding: 2em 1em;
  margin-top: 3em;
  transition: all 0.3s ease;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  text-align: center;
  gap: 1em;
  max-width: 1200px;
  margin: 0 auto;
}

.footer-section {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5em;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1em;
  justify-content: center;
  font-size: 0.9em;
}

.footer-links a {
  color: #fff;
  text-decoration: none;
}

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

.social-links {
  display: flex;
  gap: 0.5em;
}

/* Dark Theme - Black/Green Neon */
body.dark {
  background: var(--dark-bg);
  color: var(--dark-text);
}

/* Header Dark Mode */
body.dark .header {
  background: var(--dark-bg);
  border-bottom: 2px solid var(--dark-border);
  box-shadow: 0 0 20px var(--dark-glow);
}

body.dark .logo-text .title {
  color: var(--dark-text);
  text-shadow: 0 0 10px var(--dark-glow);
}

body.dark .logo-text .tagline {
  color: var(--dark-accent);
}

body.dark .flashcards-title {
  color: var(--dark-text);
  text-shadow: 0 0 15px var(--dark-glow);
}

body.dark .toggle-theme {
  color: var(--dark-text);
}

body.dark .toggle-theme:hover {
  background: var(--dark-button-hover);
  box-shadow: 0 0 10px var(--dark-glow);
}

body.dark .nav-back {
  color: var(--dark-accent);
}

body.dark .nav-back:hover {
  background: var(--dark-button-hover);
  color: var(--dark-text);
  box-shadow: 0 0 10px var(--dark-glow);
}

/* Learning Objectives Dark Mode */
body.dark .learning-objectives {
  background: var(--dark-card);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
  box-shadow: 0 0 30px var(--dark-glow);
}

body.dark .learning-objectives h2 {
  color: var(--dark-text);
  text-shadow: 0 0 20px var(--dark-glow);
}

/* Sidebar Dark Mode */
body.dark .sidebar {
  background: var(--dark-card);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
  box-shadow: 0 0 25px var(--dark-glow);
}

body.dark .sidebar-header h3 {
  color: var(--dark-text);
  text-shadow: 0 0 10px var(--dark-glow);
}

body.dark .sidebar-toggle {
  color: var(--dark-text);
}

body.dark .level-selection h4 {
  color: var(--dark-text);
}

body.dark .level-select {
  background: var(--dark-button);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
}

body.dark .level-select:focus {
  border-color: var(--dark-accent);
  box-shadow: 0 0 15px var(--dark-glow);
}

/* Category Headers Dark Mode */
body.dark .category-header {
  background: var(--dark-button);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
}

body.dark .category-header:hover {
  box-shadow: 0 0 15px var(--dark-glow);
}

body.dark .category-topics {
  background: var(--dark-card);
  border: 1px solid var(--dark-border);
}

body.dark .topic-item {
  color: var(--dark-text);
  border-left-color: transparent;
}

body.dark .topic-item:hover {
  background: var(--dark-button-hover);
  border-left-color: var(--dark-accent);
  box-shadow: 0 0 10px var(--dark-glow);
}

body.dark .topic-item.active {
  background: var(--dark-button-hover);
  border-left-color: var(--dark-text);
  color: var(--dark-text);
  box-shadow: 0 0 15px var(--dark-glow);
}

/* Study Area Dark Mode */
body.dark .study-area {
  background: var(--dark-card);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
  box-shadow: 0 0 25px var(--dark-glow);
}

/* Flashcards Dark Mode */
body.dark .flashcard-front {
  background: var(--dark-card);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
  box-shadow: 0 0 20px var(--dark-glow);
}

body.dark .flashcard-back {
  background: var(--dark-card);
  border: 2px solid var(--dark-accent);
  color: var(--dark-text);
  box-shadow: 0 0 25px var(--dark-glow);
}

body.dark .card-type {
  background: var(--dark-accent);
  color: var(--dark-bg);
}

body.dark .card-question,
body.dark .card-answer {
  color: var(--dark-text);
  text-shadow: 0 0 10px var(--dark-glow);
}

body.dark .card-explanation {
  color: var(--dark-accent);
}

body.dark .card-formula {
  background: var(--dark-button);
  border: 1px solid var(--dark-border);
  color: var(--dark-text);
}

body.dark .flip-btn {
  background: var(--dark-button);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
}

body.dark .flip-btn:hover {
  box-shadow: 0 0 15px var(--dark-glow);
}

/* Buttons Dark Mode */
body.dark .control-btn {
  background: var(--dark-button);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
}

body.dark .control-btn:hover {
  background: var(--dark-button-hover);
  box-shadow: 0 0 10px var(--dark-glow);
}

body.dark .diff-btn.hard {
  background: var(--dark-button);
  border: 2px solid #ff0000;
  color: #ff0000;
}

body.dark .diff-btn.good {
  background: var(--dark-button);
  border: 2px solid #ffff00;
  color: #ffff00;
}

body.dark .diff-btn.easy {
  background: var(--dark-button);
  border: 2px solid var(--dark-text);
  color: var(--dark-text);
}

body.dark .diff-btn:hover {
  box-shadow: 0 0 15px currentColor;
}

/* Progress Bar Dark Mode */
body.dark .progress-bar {
  background: var(--dark-button);
  border: 1px solid var(--dark-border);
}

body.dark .progress-fill {
  background: linear-gradient(90deg, var(--dark-accent), var(--dark-text));
  box-shadow: 0 0 10px var(--dark-glow);
}

body.dark .progress-text {
  color: var(--dark-text);
}

/* Stats Dark Mode */
body.dark .study-stats {
  background: var(--dark-button);
  border: 1px solid var(--dark-border);
}

body.dark .study-stats h4 {
  color: var(--dark-text);
}

body.dark .stat-item {
  border-bottom-color: var(--dark-border);
  color: var(--dark-text);
}

body.dark .stat-value {
  color: var(--dark-accent);
}

/* Welcome Screen Dark Mode */
body.dark .welcome-content h2 {
  color: var(--dark-text);
  text-shadow: 0 0 20px var(--dark-glow);
}

body.dark .welcome-content p {
  color: var(--dark-accent);
}

body.dark .quick-btn {
  background: var(--dark-button);
  border: 2px solid var(--dark-border);
  color: var(--dark-text);
}

body.dark .quick-btn:hover {
  box-shadow: 0 0 20px var(--dark-glow);
}

/* NotebookLM Dark Mode */
body.dark .notebooklm-section {
  background: rgba(66, 133, 244, 0.2);
  border-color: rgba(66, 133, 244, 0.4);
}

body.dark .notebooklm-section h4 {
  color: #8ab4f8;
}

body.dark .notebooklm-btn {
  background: linear-gradient(45deg, #1a73e8, #4285f4);
}

body.dark .notebooklm-btn:hover {
  box-shadow: 0 4px 15px rgba(66, 133, 244, 0.6);
}

body.dark .notebooklm-description {
  color: var(--dark-text);
}

body.dark .notebooklm-study-btn {
  background: linear-gradient(45deg, #1a73e8, #4285f4);
  border-color: rgba(66, 133, 244, 0.4);
  color: var(--dark-text);
}

/* Custom Flashcard Creation */
.custom-cards-section {
  margin-bottom: 2em;
  padding: 1em;
  background: rgba(255, 193, 7, 0.1);
  border-radius: 10px;
  border: 1px solid rgba(255, 193, 7, 0.2);
  text-align: center;
}

.custom-cards-section h4 {
  color: #ff6f00;
  margin-bottom: 1em;
  font-size: 1.1em;
}

.create-cards-btn,
.notebooklm-create-btn {
  width: 100%;
  padding: 0.8em;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
  margin-bottom: 0.5em;
  transition: all 0.3s ease;
  font-size: 0.9em;
}

.create-cards-btn {
  background: linear-gradient(45deg, #ff6f00, #ff8f00);
  color: white;
}

.notebooklm-create-btn {
  background: linear-gradient(45deg, #4285f4, #1a73e8);
  color: white;
}

.create-cards-btn:hover,
.notebooklm-create-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
}

.create-cards-description {
  font-size: 0.8em;
  color: #666;
  line-height: 1.4;
  margin: 0.5em 0 0 0;
}

.notebooklm-audio-btn {
  width: 100%;
  padding: 0.8em;
  background: linear-gradient(45deg, #34a853, #137333);
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
  margin-bottom: 0.5em;
  transition: all 0.3s ease;
  font-size: 0.9em;
}

.notebooklm-audio-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(52, 168, 83, 0.4);
}

/* Flashcard Creator Modal */
.flashcard-creator {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(5px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2em;
  overflow-y: auto;
}

.creator-content {
  background: var(--light-card);
  border-radius: 20px;
  padding: 2em;
  max-width: 800px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
  border: 1px solid var(--light-border);
}

.creator-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2em;
  padding-bottom: 1em;
  border-bottom: 2px solid var(--light-border);
}

.creator-header h2 {
  color: var(--light-accent);
  margin: 0;
}

.close-creator {
  background: none;
  border: none;
  font-size: 1.5em;
  cursor: pointer;
  color: #666;
  padding: 0.5em;
  border-radius: 50%;
  transition: all 0.3s ease;
}

.close-creator:hover {
  background: rgba(255, 0, 0, 0.1);
  color: #ff0000;
}

.form-section {
  margin-bottom: 2em;
  padding: 1.5em;
  background: rgba(0, 0, 0, 0.02);
  border-radius: 10px;
  border: 1px solid var(--light-border);
}

.form-section h3 {
  color: var(--light-accent);
  margin-bottom: 1em;
  font-size: 1.2em;
}

.form-group {
  margin-bottom: 1.5em;
}

.form-group label {
  display: block;
  margin-bottom: 0.5em;
  font-weight: 600;
  color: #555;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.8em;
  border: 2px solid var(--light-border);
  border-radius: 8px;
  font-size: 1em;
  font-family: inherit;
  transition: all 0.3s ease;
}

.form-group textarea {
  min-height: 80px;
  resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--light-accent);
  box-shadow: 0 0 10px rgba(0, 51, 160, 0.2);
}

/* Media Options */
.media-options {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1em;
}

.media-option {
  padding: 1em;
  background: rgba(255, 255, 255, 0.5);
  border-radius: 8px;
  border: 1px solid var(--light-border);
}

.media-option label {
  font-size: 0.9em;
  font-weight: bold;
  color: var(--light-accent);
  margin-bottom: 0.5em;
}

.record-btn {
  width: 100%;
  padding: 0.6em;
  background: linear-gradient(45deg, #ea4335, #d33b2c);
  color: white;
  border: none;
  border-radius: 6px;
  font-size: 0.9em;
  cursor: pointer;
  margin-top: 0.5em;
  transition: all 0.3s ease;
}

.record-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 3px 10px rgba(234, 67, 53, 0.4);
}

.image-preview,
.audio-preview,
.video-preview {
  margin-top: 0.5em;
  padding: 0.5em;
  background: rgba(0, 0, 0, 0.05);
  border-radius: 4px;
  min-height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #666;
  font-size: 0.9em;
}

/* AI Options */
.ai-options {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 0.8em;
  margin-bottom: 1em;
}

.ai-btn {
  padding: 0.8em;
  background: linear-gradient(45deg, #4285f4, #1a73e8);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 0.9em;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s ease;
}

.ai-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(66, 133, 244, 0.4);
}

.ai-description {
  font-size: 0.85em;
  color: #666;
  line-height: 1.4;
  margin: 0;
}

/* Creator Actions */
.creator-actions {
  display: flex;
  gap: 1em;
  justify-content: center;
  margin-top: 2em;
  padding-top: 1em;
  border-top: 1px solid var(--light-border);
}

/* Download Button Dark Mode */
body.dark .download-btn {
  background: var(--dark-button);
  border: 2px solid var(--dark-accent);
  color: var(--dark-text);
}

body.dark .download-btn:hover {
  box-shadow: 0 0 20px var(--dark-glow);
}

/* Custom Cards Dark Mode */
body.dark .custom-cards-section {
  background: rgba(255, 193, 7, 0.2);
  border-color: rgba(255, 193, 7, 0.4);
}

body.dark .custom-cards-section h4 {
  color: #ffb300;
}

body.dark .create-cards-description {
  color: var(--dark-text);
}

body.dark .creator-content {
  background: var(--dark-card);
  border-color: var(--dark-border);
  color: var(--dark-text);
}

body.dark .creator-header h2 {
  color: var(--dark-text);
}

body.dark .close-creator {
  color: var(--dark-text);
}

body.dark .form-section {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--dark-border);
}

body.dark .form-section h3 {
  color: var(--dark-text);
}

body.dark .form-group label {
  color: var(--dark-text);
}

body.dark .form-group input,
body.dark .form-group textarea,
body.dark .form-group select {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--dark-border);
  color: var(--dark-text);
}

body.dark .form-group input::placeholder,
body.dark .form-group textarea::placeholder {
  color: rgba(255, 255, 255, 0.5);
}

body.dark .media-option {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--dark-border);
}

body.dark .media-option label {
  color: var(--dark-text);
}

body.dark .image-preview,
body.dark .audio-preview,
body.dark .video-preview {
  background: rgba(255, 255, 255, 0.05);
  color: var(--dark-text);
}

body.dark .ai-description {
  color: var(--dark-text);
}

/* Footer Dark Mode */
body.dark .footer {
  background: var(--dark-bg);
  border-top: 2px solid var(--dark-border);
  color: var(--dark-text);
}

/* Responsive Design */
@media (max-width: 1024px) {
  .app-container {
    grid-template-columns: 250px 1fr;
  }
  
  .objectives-grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  }
}

@media (max-width: 768px) {
  .app-container {
    grid-template-columns: 1fr;
    gap: 0;
  }
  
  .sidebar {
    position: fixed;
    top: 0;
    left: -300px;
    width: 280px;
    height: 100vh;
    z-index: 2000;
    transition: left 0.3s ease;
    border-radius: 0;
    overflow-y: auto;
  }
  
  .sidebar.open {
    left: 0;
  }
  
  .sidebar-toggle {
    display: block;
  }
  
  .study-area {
    margin-top: 0;
    border-radius: 0;
    min-height: calc(100vh - 100px);
  }
  
  .flashcard {
    height: 350px;
  }
  
  .header {
    grid-template-columns: auto auto 1fr auto;
    gap: 0.5em;
  }
  
  .flashcards-title {
    font-size: 1.1em;
  }
  
  .objectives-grid {
    grid-template-columns: 1fr;
    gap: 1em;
  }
  
  .difficulty-buttons {
    flex-direction: column;
  }
  
  .diff-btn {
    min-width: auto;
  }
}

@media (max-width: 480px) {
  .header {
    padding: 0.8em 1em;
  }
  
  .learning-objectives {
    margin: 0.5em;
    padding: 1.5em;
  }
  
  .app-container {
    padding: 0.5em;
  }
  
  .study-area {
    padding: 1em;
  }
  
  .flashcard {
    height: 300px;
  }
  
  .card-question,
  .card-answer {
    font-size: 1.2em;
  }
  
  .flashcard-front,
  .flashcard-back {
    padding: 1.5em;
  }
}

/* Animations */
@keyframes slideInUp {
  from {
    transform: translateY(30px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.05); }
}

.flashcard-interface {
  animation: slideInUp 0.5s ease-out;
}

.study-complete {
  animation: fadeIn 0.5s ease-out;
}

.stat-card {
  animation: slideInUp 0.5s ease-out;
}

.stat-card:nth-child(2) {
  animation-delay: 0.1s;
}

.stat-card:nth-child(3) {
  animation-delay: 0.2s;
}

/* Print Styles */
@media print {
  .header,
  .sidebar,
  .study-controls,
  .difficulty-buttons,
  .newsletter-signup,
  .footer {
    display: none;
  }
  
  .app-container {
    grid-template-columns: 1fr;
  }
  
  .flashcard {
    height: auto;
    transform: none;
  }
  
  .flashcard-back {
    transform: none;
    margin-top: 2em;
  }
}