/* Quiz Header */
.quiz-header {
  background: #ffffff;
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
  padding-top: env(safe-area-inset-top);
}

.quiz-header-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
  margin: 0;
}

.progress-info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

#question-counter {
  font-weight: 600;
  color: var(--color-neutral-600);
  font-size: var(--text-sm);
}

/* Issue #12: Touch targets meet 44x44px minimum */
.menu-btn {
  background: none;
  border: 1px solid transparent;
  padding: 0.625rem 1rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 1.2rem;
  color: var(--color-neutral-600);
  transition: all 0.15s ease;
}

.menu-btn:hover {
  background: var(--color-neutral-50);
  border-color: var(--color-border);
  color: var(--color-neutral-800);
}

.progress-bar-container {
  height: 4px;
  background: var(--color-neutral-100);
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg,
    var(--color-primary-500),
    var(--color-primary-600)
  );
  transition: width 0.5s ease;
  box-shadow: 0 0 8px rgba(49, 130, 206, 0.3);
}

/* Question Menu */
.question-menu {
  position: fixed;
  top: 0;
  right: 0;
  width: 400px;
  max-width: 90vw;
  height: 100vh;
  background: white;
  box-shadow: -4px 0 24px rgba(0,0,0,0.15);
  z-index: 200;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
  padding-top: env(safe-area-inset-top);
  padding-bottom: env(safe-area-inset-bottom);
  padding-right: env(safe-area-inset-right);
}

/* Ensure hidden attribute works */
.question-menu[hidden] {
  display: none !important;
}

.question-menu-header {
  padding: 1.5rem;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.question-menu-header h2 {
  margin: 0;
  font-size: 1.25rem;
}

.close-btn {
  background: none;
  border: none;
  font-size: 2rem;
  cursor: pointer;
  color: var(--color-neutral-500);
  line-height: 1;
  padding: 0;
  transition: color 0.15s ease;
}

.close-btn:hover {
  color: var(--color-neutral-800);
}

.question-menu-stats {
  padding: 1rem 1.5rem;
  background: var(--color-neutral-50);
  display: flex;
  justify-content: space-between;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-neutral-600);
}

.question-grid {
  padding: 1.5rem;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
  gap: 0.75rem;
}

/* Issue #12: Touch targets meet 44x44px minimum */
.grid-question-btn {
  padding: 0.75rem;
  min-width: 44px;
  min-height: 44px;
  border: 2px solid var(--color-border);
  background: white;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 600;
  transition: all 0.15s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

.grid-question-btn:hover {
  background: var(--color-neutral-50);
  border-color: var(--color-border-dark);
}

.grid-question-btn.current {
  border-color: var(--color-primary-500);
  border-width: 3px;
  background: var(--color-primary-50);
}

.grid-question-btn.answered {
  background: var(--color-success-50);
  border-color: var(--color-success-500);
}

.grid-question-btn.correct {
  background: var(--color-success-500);
  color: white;
  border-color: var(--color-success-600);
}

.grid-question-btn.incorrect {
  background: var(--color-error-500);
  color: white;
  border-color: var(--color-error-600);
}

/* Quiz Container */
.quiz-container {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
  padding-bottom: max(2rem, env(safe-area-inset-bottom));
  min-height: calc(100vh - 150px);
}

.question-display {
  background: white;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: 2rem;
  margin-bottom: 2rem;
}

.question-content {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* Feedback Banner */
.feedback-banner {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1.25rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9375rem;
}

.feedback-banner.correct {
  background: var(--color-success-50);
  color: var(--color-success-700);
  border: 1px solid var(--color-success-200);
}

.feedback-banner.correct::before {
  content: '✓';
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: var(--color-success-500);
  color: #ffffff;
  border-radius: 50%;
  font-size: 0.875rem;
  font-weight: 700;
}

.feedback-banner.incorrect {
  background: var(--color-error-50);
  color: var(--color-error-700);
  border: 1px solid var(--color-error-200);
}

.feedback-banner.incorrect::before {
  content: '✗';
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: var(--color-error-500);
  color: #ffffff;
  border-radius: 50%;
  font-size: 0.875rem;
  font-weight: 700;
}

/* Question Metadata */
.question-meta {
  padding-bottom: 0.75rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.meta-text {
  margin: 0;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-neutral-600);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Question Stem */
.question-stem h2 {
  margin: 0 0 1rem 0;
  font-size: 1.25rem;
  color: var(--color-neutral-900);
}

/* Issue #5: Improved visual hierarchy for vignette */
.question-stem .vignette {
  margin: 0 0 1.5rem 0;
  font-family: var(--font-vignette);
  font-size: var(--text-lg);
  line-height: var(--leading-vignette);
  color: var(--color-text);
  max-width: 70ch;
  background: var(--color-neutral-50);
  padding: 1.25rem;
  border-left: 4px solid var(--color-primary-500);
  border-radius: var(--radius-sm);
}

/* Issue #5: Improved visual hierarchy for question text */
.question-stem .question-text {
  margin: 1.5rem 0;
  font-family: var(--font-body);
  font-size: 1.0625rem;
  font-weight: 600;
  line-height: 1.6;
  color: var(--color-neutral-900);
  padding: 0.75rem 0;
  border-top: 2px solid var(--color-border);
  border-bottom: 2px solid var(--color-border);
}

.question-stem .question-text strong {
  font-weight: 600;
  color: var(--color-neutral-900);
}

.question-stem p {
  margin: 0;
  line-height: 1.6;
  color: var(--color-text);
}

/* Answer Choices */
.answer-choices {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin: 1.5rem 0;
  /* Reset fieldset default styles */
  border: none;
  padding: 0;
  min-width: 0;
}

/* Issue #5: Improved visual hierarchy for answer choices */
.answer-choice {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.125rem 1.5rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.15s ease;
  background: #ffffff;
  min-height: 56px;
}

.answer-choice:hover:not(.answer-correct):not(.answer-incorrect) {
  border-color: var(--color-border-dark);
  background: var(--color-neutral-50);
}

.answer-choice input[type="radio"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

/* Issue #5: Improved visual hierarchy - larger answer letters */
.choice-letter {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 32px;
  width: 32px;
  height: 32px;
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--color-neutral-700);
  background: var(--color-neutral-50);
  border: 2px solid var(--color-border-dark);
  border-radius: 50%;
  transition: all 0.15s ease;
  margin-top: 2px;
}

.choice-text {
  flex: 1;
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  padding-top: 2px;
}

.answer-choice.answer-selected,
.answer-choice:has(input[type="radio"]:checked) {
  border-color: var(--color-primary-500);
  background: var(--color-primary-50);
}

.answer-choice.answer-selected .choice-letter,
.answer-choice:has(input[type="radio"]:checked) .choice-letter {
  background: var(--color-primary-500);
  border-color: var(--color-primary-500);
  color: #ffffff;
}

/* Strikethrough/elimination feature */
.answer-choice.eliminated {
  opacity: 0.5;
  position: relative;
}

.answer-choice.eliminated .choice-text {
  text-decoration: line-through;
  text-decoration-thickness: 2px;
  text-decoration-color: var(--color-error-500);
}

.answer-choice.eliminated .choice-letter {
  opacity: 0.6;
}

.answer-choice .eliminate-btn {
  position: absolute;
  right: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: 1px solid var(--color-border);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--text-xs);
  color: var(--color-neutral-600);
  opacity: 0;
  transition: all 0.15s ease;
}

.answer-choice:hover .eliminate-btn {
  opacity: 1;
}

.answer-choice.eliminated .eliminate-btn {
  opacity: 1;
  background: var(--color-error-50);
  border-color: var(--color-error-500);
  color: var(--color-error-700);
}

.answer-choice.eliminated .eliminate-btn:hover {
  background: var(--color-error-100);
}

/* Issue #29: Answer peek (temporary highlight when showing answer) */
.answer-choice.answer-peek {
  border-color: var(--color-primary-500);
  background: linear-gradient(135deg, #ebf8ff 0%, #dbeafe 100%);
  animation: peek-pulse 0.5s ease-in-out 3;
}

.answer-choice.answer-peek .choice-letter {
  background: var(--color-primary-500);
  border-color: var(--color-primary-500);
  color: white;
  animation: peek-pulse 0.5s ease-in-out 3;
}

@keyframes peek-pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.02); }
}

.answer-choice.answer-correct {
  border-color: var(--color-success-500);
  border-width: 2px;
  background: var(--color-success-50);
}

.answer-choice.answer-correct .choice-letter {
  background: var(--color-success-500);
  border-color: var(--color-success-500);
  color: #ffffff;
}

.answer-choice.answer-incorrect {
  border-color: var(--color-error-500);
  border-width: 2px;
  background: var(--color-error-50);
}

.answer-choice.answer-incorrect .choice-letter {
  background: var(--color-error-500);
  border-color: var(--color-error-500);
  color: #ffffff;
}

.answer-choice input[disabled] {
  cursor: not-allowed;
}

.choice-icon {
  font-size: 1.25rem;
  font-weight: 700;
  margin-left: auto;
  margin-top: 2px;
}

.answer-correct .choice-icon {
  color: var(--color-success-600);
}

.answer-incorrect .choice-icon {
  color: var(--color-error-600);
}

/* Explanation Section - Issue #1 and #4 enhancements */
.explanation-section {
  margin-top: 2rem;
  padding: 1.5rem;
  background: linear-gradient(to right, #ebf8ff 0%, #f0f9ff 100%);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-primary-500);
}

.explanation-section h3 {
  margin: 0 0 1.5rem 0;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-primary-700);
  letter-spacing: 0.025em;
}

/* Issue #4: TL;DR Section */
.tldr-section {
  background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
  border: 2px solid #f59e0b;
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
}

.tldr-header {
  font-size: 0.875rem;
  font-weight: 700;
  color: #92400e;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.tldr-content {
  font-size: 1rem;
  line-height: 1.6;
  color: #78350f;
  font-weight: 500;
}

/* Issue #1: Correct Answer Explanation Box */
.explanation-correct {
  background: linear-gradient(135deg, #d1fae5 0%, #a7f3d0 100%);
  border: 2px solid var(--color-success-500);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}

.explanation-heading {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.explanation-correct .explanation-heading {
  color: var(--color-success-700);
}

.explanation-content {
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--color-neutral-800);
}

/* Issue #1: Incorrect Answer Explanation Box */
.explanation-incorrect {
  background: linear-gradient(135deg, #fecaca 0%, #fca5a5 100%);
  border: 2px solid var(--color-error-500);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}

.explanation-incorrect .explanation-heading {
  color: var(--color-error-700);
}

/* Issue #4: Collapsible Detailed Explanation */
.detailed-explanation {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 2px dashed var(--color-border);
}

.toggle-details-btn {
  background: var(--color-neutral-100);
  border: 1px solid var(--color-border);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-neutral-700);
  cursor: pointer;
  transition: all 0.15s ease;
  width: 100%;
  text-align: left;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.toggle-details-btn:hover {
  background: var(--color-neutral-200);
  border-color: var(--color-neutral-400);
}

.details-content {
  margin-top: 1rem;
}

.explanation-text {
  margin-bottom: 1.25rem;
  line-height: 1.7;
  color: var(--color-text);
  font-size: var(--text-base);
}

.explanation-text:last-child {
  margin-bottom: 0;
}

.explanation-text strong {
  font-weight: 600;
  color: var(--color-neutral-800);
}

.explanation-text ul {
  margin: 0.75rem 0 0 1.5rem;
  padding: 0;
}

.explanation-text li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
}

.explanation-text li:last-child {
  margin-bottom: 0;
}

/* Issue #24, #28: Explanation Action Buttons */
.explanation-actions {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 2px dashed var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.report-error-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  min-height: 44px;
  background: var(--color-neutral-100);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-neutral-700);
  text-decoration: none;
  transition: all 0.15s ease;
}

.report-error-btn:hover {
  background: var(--color-neutral-200);
  border-color: var(--color-neutral-400);
  color: var(--color-neutral-900);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

/* Issue #28: Reset Question Button */
.reset-question-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  min-height: 44px;
  background: var(--color-neutral-100);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-neutral-700);
  cursor: pointer;
  transition: all 0.15s ease;
}

.reset-question-btn:hover {
  background: var(--color-primary-50);
  border-color: var(--color-primary-400);
  color: var(--color-primary-700);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

/* Navigation */
.quiz-navigation {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
  padding-bottom: max(1rem, env(safe-area-inset-bottom));
}

/* Issue #12: Touch targets meet 44x44px minimum */
.nav-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  min-height: 44px;
  background: #ffffff;
  border: 1px solid var(--color-border-dark);
  border-radius: var(--radius-sm);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-neutral-700);
  cursor: pointer;
  transition: all 0.15s ease;
}

.nav-btn:hover:not(:disabled) {
  background: var(--color-neutral-50);
  border-color: var(--color-neutral-400);
  color: var(--color-neutral-900);
}

.nav-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* Issue #12: Touch targets meet 44x44px minimum */
.submit-btn {
  padding: 0.75rem 2rem;
  min-height: 44px;
  background: var(--color-primary-500);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: all 0.15s ease;
}

.submit-btn:hover:not(:disabled) {
  background: var(--color-primary-600);
  box-shadow: var(--shadow-md);
}

.submit-btn:active:not(:disabled) {
  transform: translateY(1px);
}

.submit-btn:disabled {
  background: var(--color-neutral-300);
  cursor: not-allowed;
  box-shadow: none;
}

/* Skip Button (Issue #23) - Issue #12: Touch targets */
.skip-btn {
  padding: 0.75rem 1.5rem;
  min-height: 44px;
  background: var(--color-neutral-100);
  color: var(--color-neutral-700);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.skip-btn:hover {
  background: var(--color-neutral-200);
  border-color: var(--color-neutral-400);
  color: var(--color-neutral-900);
}

.skip-btn:active {
  transform: translateY(1px);
}

/* Error State */
.error {
  color: var(--color-error-600);
  text-align: center;
  padding: 2rem;
  font-size: 1.1rem;
}

/* Welcome Screen */
.welcome-screen {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  padding: 2rem;
}

.welcome-content {
  max-width: 600px;
  text-align: center;
  animation: fadeInUp 0.6s ease-out;
}

.welcome-content h1 {
  font-size: 2.5rem;
  color: var(--color-primary-700);
  margin: 0 0 0.5rem 0;
  font-weight: 700;
}

.welcome-subtitle {
  font-size: 1.25rem;
  color: var(--color-neutral-800); /* Darker for better contrast on Mac */
  margin: 0 0 2rem 0;
}

.welcome-stats {
  display: flex;
  justify-content: center;
  gap: 3rem;
  margin-bottom: 2rem;
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.stat-number {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary-500);
  margin-bottom: 0.25rem;
}

.stat-label {
  font-size: 0.9rem;
  color: var(--color-neutral-700); /* Darker for better contrast on Mac */
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.welcome-description {
  font-size: 1.1rem;
  line-height: 1.6;
  color: var(--color-neutral-800); /* Darker for better contrast on Mac */
  margin: 0 0 2.5rem 0;
}

.welcome-start-btn {
  padding: 1rem 3rem;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--color-primary-500);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-lg);
}

.welcome-start-btn:hover {
  background: var(--color-primary-600);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(43, 108, 176, 0.3);
}

.welcome-start-btn:active {
  transform: translateY(0);
}

.keyboard-shortcuts {
  margin-top: 2.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
  color: var(--color-neutral-600);
  font-size: var(--text-sm);
}

.keyboard-shortcuts p {
  margin: 0.25rem 0;
}

/* Mobile Gestures Hint */
.mobile-gestures {
  margin-top: 2.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
  color: var(--color-neutral-600);
  font-size: var(--text-sm);
  text-align: left;
}

.mobile-gestures p {
  margin: 0.35rem 0;
  line-height: 1.6;
}

.mobile-gestures p:first-child {
  margin-bottom: 0.75rem;
}

/* Keyboard Hint Toast */
.keyboard-hint-toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--color-neutral-900);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  opacity: 0;
  transition: all 0.3s ease;
  font-size: 0.95rem;
}

.keyboard-hint-toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Feedback Animation */
.feedback-animate {
  animation: feedbackPulse 0.5s ease-out;
}

@keyframes feedbackPulse {
  0% {
    transform: scale(0.95);
    opacity: 0;
  }
  50% {
    transform: scale(1.02);
  }
  100% {
    transform: scale(1);
    opacity: 1;
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Enhanced Feedback Banner */
.feedback-banner {
  padding: 1rem;
  border-radius: 6px;
  font-weight: 600;
  font-size: 1.1rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.feedback-banner::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  animation: shimmer 1.5s ease-in-out;
}

@keyframes shimmer {
  0% {
    left: -100%;
  }
  100% {
    left: 100%;
  }
}

.feedback-banner.correct {
  background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
  color: #2e7d32;
  border: 2px solid #4caf50;
}

.feedback-banner.incorrect {
  background: linear-gradient(135deg, #ffebee 0%, #ffcdd2 100%);
  color: #c62828;
  border: 2px solid #f44336;
}

/* Smooth Answer Choice Transitions */
.answer-choice {
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.answer-choice:hover {
  transform: translateX(4px);
}

.answer-choice.answer-correct,
.answer-choice.answer-incorrect {
  animation: answerReveal 0.4s ease-out;
}

@keyframes answerReveal {
  0% {
    transform: scale(0.98);
    opacity: 0.8;
  }
  50% {
    transform: scale(1.01);
  }
  100% {
    transform: scale(1);
    opacity: 1;
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .quiz-header-content {
    padding: 0.75rem 1rem;
  }

  .logo {
    font-size: 1.25rem;
  }

  .progress-bar-container {
    height: 5px; /* More visible on mobile */
  }

  #question-counter {
    font-size: 0.9rem;
  }

  .quiz-container {
    padding: 1rem;
  }

  .question-display {
    padding: 1.5rem;
  }

  .quiz-navigation {
    flex-wrap: wrap;
    padding: 0 1rem;
  }

  .submit-btn {
    order: -1;
    width: 100%;
  }

  .question-menu {
    width: 100%;
  }

  .welcome-content h1 {
    font-size: 2rem;
  }

  .welcome-stats {
    gap: 2rem;
  }

  .stat-number {
    font-size: 1.5rem;
  }
}

/* Streak Toast */
.streak-toast {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0.8);
  background: linear-gradient(135deg, #ff6b6b 0%, #ff8e53 100%);
  color: white;
  padding: 1.5rem 2.5rem;
  border-radius: 12px;
  box-shadow: 0 8px 24px rgba(255, 107, 107, 0.4);
  z-index: 2000;
  opacity: 0;
  transition: all 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  font-size: 1.3rem;
  font-weight: 700;
  text-align: center;
}

.streak-toast.show {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1);
}

/* Milestone Overlay */
.milestone-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 3000;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.milestone-overlay.show {
  opacity: 1;
}

.milestone-card {
  background: white;
  padding: 3rem 2.5rem;
  border-radius: 16px;
  text-align: center;
  max-width: 500px;
  box-shadow: 0 12px 48px rgba(0, 0, 0, 0.3);
  animation: milestonePopIn 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

@keyframes milestonePopIn {
  0% {
    transform: scale(0.5) rotate(-5deg);
    opacity: 0;
  }
  50% {
    transform: scale(1.05) rotate(2deg);
  }
  100% {
    transform: scale(1) rotate(0);
    opacity: 1;
  }
}

.milestone-card h2 {
  font-size: 2rem;
  margin: 0 0 1rem 0;
  color: var(--color-primary-600);
  animation: celebrateText 0.6s ease-out;
}

@keyframes celebrateText {
  0%, 100% {
    transform: scale(1);
  }
  25% {
    transform: scale(1.1);
  }
  50% {
    transform: scale(0.95);
  }
  75% {
    transform: scale(1.05);
  }
}

.milestone-stats {
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--color-neutral-800);
  margin: 0 0 1rem 0;
}

.milestone-encouragement {
  font-size: 1.1rem;
  color: var(--color-neutral-600);
  margin: 0 0 2rem 0;
  line-height: 1.5;
}

.milestone-continue-btn {
  padding: 0.75rem 2.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--color-primary-500);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-lg);
}

.milestone-continue-btn:hover {
  background: var(--color-primary-600);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(43, 108, 176, 0.3);
}

.milestone-continue-btn:active {
  transform: translateY(0);
}

/* Enhanced Question Menu Stats */
.question-menu-stats {
  padding: 1rem 1.5rem;
  background: linear-gradient(135deg, var(--color-neutral-50) 0%, var(--color-neutral-100) 100%);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-neutral-800);
  border-bottom: 1px solid var(--color-border);
}

.question-menu-stats span {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Mobile Responsiveness for Phase 2 */
@media (max-width: 768px) {
  .streak-toast {
    font-size: 1.1rem;
    padding: 1.25rem 2rem;
  }

  .milestone-card {
    padding: 2rem 1.5rem;
    margin: 1rem;
  }

  .milestone-card h2 {
    font-size: 1.5rem;
  }

  .milestone-stats {
    font-size: 1.1rem;
  }

  .milestone-encouragement {
    font-size: 1rem;
  }
}

/* Phase 3: Teaching Intelligence - Filter Buttons */
.menu-filters {
  display: flex;
  gap: 0.5rem;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.filter-btn {
  flex: 1;
  padding: 0.5rem 1rem;
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-neutral-600);
  transition: all 0.15s ease;
}

.filter-btn:hover {
  background: var(--color-neutral-50);
  border-color: var(--color-border-dark);
}

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

/* Topic Mastery Section */
.topic-mastery {
  padding: 1.5rem;
  border-bottom: 1px solid var(--color-border);
  background: linear-gradient(135deg, var(--color-neutral-50) 0%, var(--color-neutral-100) 100%);
}

.topic-mastery h3 {
  margin: 0 0 1rem 0;
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-neutral-800);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

#topic-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.topic-item {
  background: white;
  border-radius: var(--radius-md);
  padding: 0.75rem;
  border: 1px solid var(--color-border);
  transition: all 0.15s ease;
}

.topic-item:hover {
  border-color: var(--color-primary-500);
  box-shadow: var(--shadow-sm);
  transform: translateX(2px);
}

.topic-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.topic-emoji {
  font-size: 1.2rem;
}

.topic-name {
  flex: 1;
  font-weight: 600;
  color: var(--color-neutral-800);
  font-size: 0.9rem;
}

.topic-stats {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
}

.topic-score {
  color: var(--color-neutral-600);
}

.topic-percentage {
  font-weight: 700;
  font-size: 0.9rem;
}

.topic-bar {
  height: 6px;
  background: var(--color-neutral-200);
  border-radius: 3px;
  overflow: hidden;
}

.topic-bar-fill {
  height: 100%;
  background: var(--color-primary-500);
  transition: width 0.4s ease;
  border-radius: 3px;
}

/* Topic Mastery Performance Levels */
.mastery-excellent .topic-percentage {
  color: var(--color-success-700);
}

.mastery-excellent .topic-bar-fill {
  background: linear-gradient(90deg, var(--color-success-500) 0%, var(--color-success-700) 100%);
}

.mastery-great .topic-percentage {
  color: var(--color-primary-700);
}

.mastery-great .topic-bar-fill {
  background: linear-gradient(90deg, var(--color-primary-500) 0%, var(--color-primary-700) 100%);
}

.mastery-good .topic-percentage {
  color: var(--color-primary-600);
}

.mastery-good .topic-bar-fill {
  background: linear-gradient(90deg, var(--color-primary-400) 0%, var(--color-primary-600) 100%);
}

.mastery-fair .topic-percentage {
  color: #f57c00;
}

.mastery-fair .topic-bar-fill {
  background: linear-gradient(90deg, #ffb74d 0%, #f57c00 100%);
}

.mastery-review .topic-percentage {
  color: var(--color-error-600);
}

.mastery-review .topic-bar-fill {
  background: linear-gradient(90deg, var(--color-error-200) 0%, var(--color-error-600) 100%);
}

/* Mobile Responsiveness for Phase 3 */
@media (max-width: 768px) {
  .menu-filters {
    flex-direction: column;
    gap: 0.5rem;
  }

  .filter-btn {
    width: 100%;
  }

  .topic-mastery {
    padding: 1rem;
  }

  .topic-item {
    padding: 0.6rem;
  }

  .topic-name {
    font-size: 0.85rem;
  }
}

/* ========================================
   PHASE 1, 2, 3 NEW FEATURES STYLING
   ======================================== */

/* Timer Display - Issue #8: Enhanced timer UX */
.timer-display {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background: var(--color-neutral-50);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-weight: 600;
  color: var(--color-neutral-700);
  transition: all 0.3s ease;
}

/* Issue #8: Intermediate warning state (30 seconds remaining) */
.timer-display.timer-caution {
  background: #fef3c7;
  border-color: #f59e0b;
  color: #92400e;
}

/* Issue #8: Critical warning state (10 seconds remaining) */
.timer-display.timer-warning {
  background: var(--color-error-50);
  border-color: var(--color-error-500);
  color: var(--color-error-700);
  animation: pulse 0.5s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.7; }
}

#timer-text {
  font-family: 'Courier New', monospace;
  font-size: 1.1rem;
  min-width: 4rem;
  text-align: center;
}

.timer-toggle-btn {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  padding: 0.25rem;
  color: var(--color-neutral-600);
  transition: color 0.15s ease;
}

.timer-toggle-btn:hover {
  color: var(--color-primary-600);
}

/* Settings Button - Issue #12: Touch targets */
.settings-btn {
  background: none;
  border: 1px solid transparent;
  padding: 0.5rem;
  min-width: 44px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 1.2rem;
  transition: all 0.15s ease;
}

.settings-btn:hover {
  background: var(--color-neutral-50);
  border-color: var(--color-border);
}

/* Flag Button - Issue #12: Touch targets */
.flag-btn {
  background: none;
  border: 1px solid var(--color-border);
  padding: 0.625rem 0.875rem;
  min-height: 44px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--text-sm);
  color: var(--color-neutral-600);
  transition: all 0.15s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
}

.flag-btn:hover {
  background: var(--color-neutral-50);
  border-color: var(--color-neutral-400);
  color: var(--color-neutral-800);
}

.flag-btn.flagged {
  background: var(--color-error-50);
  border-color: var(--color-error-500);
  color: var(--color-error-700);
  font-weight: 600;
}

.flag-btn.flagged:hover {
  background: var(--color-error-100);
}

/* Issue #26: Previous Explanation Button */
.prev-explanation-btn {
  background: none;
  border: 1px solid var(--color-border);
  padding: 0.625rem 0.875rem;
  min-height: 44px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: var(--text-sm);
  color: var(--color-primary-600);
  transition: all 0.15s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
}

.prev-explanation-btn:hover {
  background: var(--color-primary-50);
  border-color: var(--color-primary-400);
  color: var(--color-primary-700);
}

.question-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  gap: 0.75rem;
}

/* Grid Flag Icon */
.grid-flag-icon {
  position: absolute;
  top: 2px;
  right: 2px;
  font-size: 0.7rem;
}

.grid-question-btn {
  position: relative;
}

/* Modals */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 300;
  animation: fadeIn 0.2s ease;
}

/* Ensure hidden attribute works even with modal styles */
.modal[hidden] {
  display: none !important;
}

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

.modal-content {
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
  max-width: 600px;
  width: 90%;
  max-height: 90vh;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
  animation: slideUp 0.3s ease;
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.modal-header {
  padding: 1.5rem;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-header h2 {
  margin: 0;
  font-size: 1.5rem;
  color: var(--color-neutral-800);
}

.modal-body {
  padding: 1.5rem;
}

.modal-footer {
  padding: 1.5rem;
  border-top: 1px solid var(--color-border);
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
}

/* Settings Modal */
.setting-group {
  margin-bottom: 1.5rem;
}

.setting-label {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 600;
  color: var(--color-neutral-800);
  cursor: pointer;
}

.setting-label input[type="checkbox"] {
  width: 1.5rem;
  height: 1.5rem;
  cursor: pointer;
  border: 2px solid var(--color-border-dark);
  border-radius: 4px;
  position: relative;
}

.setting-label input[type="checkbox"]:checked {
  background: var(--color-primary-500);
  border-color: var(--color-primary-500);
}

.setting-label input[type="checkbox"]:checked::after {
  content: '✓';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: white;
  font-size: 1.125rem;
  font-weight: bold;
}

.setting-label input[type="number"] {
  width: 100px;
  padding: 0.5rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 16px; /* Prevents iOS auto-zoom */
  -webkit-appearance: none;
  -moz-appearance: textfield;
  appearance: none;
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input[type="checkbox"] {
  -webkit-appearance: none;
  appearance: none;
}

.setting-description {
  margin: 0.5rem 0 0 0;
  font-size: var(--text-sm);
  color: var(--color-neutral-600);
}

/* Session Summary Modal */
.summary-modal {
  max-width: 700px;
}

.summary-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.summary-stat-card {
  background: var(--color-neutral-50);
  padding: 1.5rem;
  border-radius: var(--radius-md);
  text-align: center;
  border: 2px solid var(--color-border);
}

.summary-stat-card.stat-success {
  background: var(--color-success-50);
  border-color: var(--color-success-500);
}

.summary-stat-card.stat-error {
  background: var(--color-error-50);
  border-color: var(--color-error-500);
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-neutral-800);
  margin-bottom: 0.25rem;
}

.stat-success .stat-number {
  color: var(--color-success-700);
}

.stat-error .stat-number {
  color: var(--color-error-700);
}

.stat-label {
  font-size: var(--text-sm);
  color: var(--color-neutral-600);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
}

.summary-time {
  background: var(--color-neutral-50);
  padding: 1.5rem;
  border-radius: var(--radius-md);
  margin-bottom: 2rem;
}

.summary-time h3 {
  margin: 0 0 1rem 0;
  font-size: 1.125rem;
  color: var(--color-neutral-800);
}

.time-stats {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.time-warning {
  margin-top: 0.5rem;
  padding: 0.75rem;
  background: var(--color-error-50);
  border-left: 3px solid var(--color-error-500);
  color: var(--color-error-700);
  font-size: var(--text-sm);
  border-radius: var(--radius-sm);
}

.summary-topics {
  margin-bottom: 2rem;
}

.summary-topics h3 {
  margin: 0 0 1rem 0;
  font-size: 1.125rem;
  color: var(--color-neutral-800);
}

.summary-topic-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.summary-topic-item {
  background: var(--color-neutral-50);
  padding: 1rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.summary-topic-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.summary-topic-name {
  font-weight: 600;
  color: var(--color-neutral-800);
}

.summary-topic-score {
  font-weight: 600;
  color: var(--color-neutral-600);
  font-size: var(--text-sm);
}

.summary-topic-bar {
  height: 8px;
  background: var(--color-neutral-200);
  border-radius: 999px;
  overflow: hidden;
}

.summary-topic-bar-fill {
  height: 100%;
  transition: width 0.5s ease;
}

.fill-success {
  background: linear-gradient(90deg, var(--color-success-500) 0%, var(--color-success-700) 100%);
}

.fill-warning {
  background: linear-gradient(90deg, #ffb74d 0%, #f57c00 100%);
}

.fill-error {
  background: linear-gradient(90deg, var(--color-error-400) 0%, var(--color-error-600) 100%);
}

.summary-topic-suggestion {
  margin-top: 0.5rem;
  font-size: var(--text-sm);
  color: var(--color-error-700);
}

.summary-flagged,
.summary-incomplete,
.summary-complete {
  padding: 1.25rem;
  border-radius: var(--radius-md);
  text-align: center;
  margin-bottom: 1rem;
}

.summary-flagged {
  background: var(--color-error-50);
  border: 2px solid var(--color-error-500);
  color: var(--color-error-800);
}

.summary-incomplete {
  background: var(--color-primary-50);
  border: 2px solid var(--color-primary-500);
  color: var(--color-primary-800);
}

.summary-complete {
  background: var(--color-success-50);
  border: 2px solid var(--color-success-500);
  color: var(--color-success-800);
}

.summary-complete p {
  margin: 0.5rem 0;
  font-size: 1.125rem;
  font-weight: 600;
}

/* Menu Actions */
.menu-actions {
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.menu-action-btn {
  width: 100%;
  padding: 0.75rem 1rem;
  border: none;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: var(--text-sm);
  cursor: pointer;
  transition: all 0.15s ease;
  background: var(--color-primary-500);
  color: white;
}

.menu-action-btn:hover {
  background: var(--color-primary-600);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.menu-action-btn-secondary {
  background: var(--color-neutral-100);
  color: var(--color-neutral-700);
}

.menu-action-btn-secondary:hover {
  background: var(--color-neutral-200);
}

/* Toast Notifications */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--color-neutral-800);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  z-index: 400;
  opacity: 0;
  transform: translateY(10px);
  transition: all 0.3s ease;
  max-width: 400px;
  font-size: var(--text-sm);
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

.toast-success {
  background: var(--color-success-600);
}

.toast-warning {
  background: #f57c00;
}

.toast-error {
  background: var(--color-error-600);
}

/* Welcome Screen Features */
.welcome-features {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 1.5rem 0;
  padding: 1.25rem;
  background: var(--color-neutral-50);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.welcome-feature {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: var(--text-sm);
  color: var(--color-neutral-700);
  font-weight: 500;
}

/* Button Styles */
.button-primary {
  background: var(--color-primary-500);
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  font-size: var(--text-sm);
}

.button-primary:hover {
  background: var(--color-primary-600);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.button-secondary {
  background: var(--color-neutral-100);
  color: var(--color-neutral-700);
  border: 1px solid var(--color-border);
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  font-size: var(--text-sm);
}

.button-secondary:hover {
  background: var(--color-neutral-200);
  border-color: var(--color-neutral-400);
}

/* ========================================
   PHASE 3: MOBILE OPTIMIZATION
   ======================================== */

@media (max-width: 768px) {
  /* iOS-specific smooth interactions */
  * {
    -webkit-tap-highlight-color: rgba(43, 108, 176, 0.15);
    -webkit-touch-callout: none;
  }

  /* Enhanced momentum scrolling for iOS */
  .question-display,
  .question-menu,
  .quick-nav-menu {
    -webkit-overflow-scrolling: touch;
  }

  /* Smooth scroll snapping for iOS */
  html {
    scroll-behavior: smooth;
  }

  /* Disable text selection on interactive elements for better iOS UX */
  button,
  .answer-choice,
  .nav-btn,
  .submit-btn {
    -webkit-user-select: none;
    user-select: none;
    /* Prevent iOS zoom on double-tap */
    touch-action: manipulation;
  }

  /* Header adjustments - iOS optimized */
  .quiz-header-content {
    padding: 0.75rem 1rem;
    flex-wrap: wrap;
  }

  .logo {
    font-size: 1.25rem;
  }

  .progress-info {
    gap: 0.5rem;
    flex-wrap: wrap;
  }

  .timer-display {
    padding: 0.5rem 0.875rem;
    font-size: 1.1rem;
  }

  #timer-text {
    font-size: 1.1rem;
    min-width: 3.5rem;
  }

  #question-counter {
    font-size: 0.9rem;
    font-weight: 600;
  }

  .settings-btn,
  .menu-btn {
    padding: 0.5rem 0.875rem;
    font-size: 1.1rem;
    min-width: 44px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .timer-toggle-btn {
    min-width: 44px;
    min-height: 44px;
    padding: 0.625rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  /* Question display - improved readability */
  .quiz-container {
    padding: 1rem 0.875rem;
  }

  .question-content {
    padding: 1.25rem 1rem;
  }

  .vignette {
    font-size: 1.0625rem;
    line-height: 1.7;
  }

  .question-text {
    font-size: 1.0625rem;
    margin-top: 1.25rem;
  }

  /* Question metadata */
  .question-meta {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .meta-text {
    font-size: 0.875rem;
  }

  /* Flag button - larger touch target */
  .flag-btn {
    padding: 0.5rem 0.875rem;
    font-size: 0.9rem;
    min-height: 44px;
  }

  /* Answer choices - iOS optimized */
  .answer-choice {
    padding: 1.125rem 1rem;
    min-height: 64px;
    margin-bottom: 0.75rem;
  }

  .choice-letter {
    min-width: 32px;
    width: 32px;
    height: 32px;
    font-size: 1rem;
    border-width: 2px;
  }

  .choice-text {
    font-size: 1rem;
    line-height: 1.5;
  }

  /* Eliminate button - hide on mobile (swipe gestures used instead) */
  .eliminate-btn {
    display: none;
  }

  /* Swipe gesture visual feedback */
  .answer-choice {
    position: relative;
    overflow: hidden;
    transition: transform 0.2s ease;
  }

  .answer-choice.swiping {
    transition: transform 0.05s ease;
  }

  .answer-choice::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.2s ease;
  }

  .answer-choice.swipe-left-hint::after {
    content: '✕ Cross out';
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding-right: 1.5rem;
    background: linear-gradient(to left, rgba(239, 68, 68, 0.15), transparent);
    color: var(--color-error-700);
    font-weight: 600;
    font-size: 0.9rem;
    opacity: 1;
  }

  .answer-choice.eliminated.swipe-right-hint::after {
    content: '↺ Undo';
    display: flex;
    align-items: center;
    justify-content: flex-start;
    padding-left: 1.5rem;
    background: linear-gradient(to right, rgba(59, 130, 246, 0.15), transparent);
    color: var(--color-primary-700);
    font-weight: 600;
    font-size: 0.9rem;
    opacity: 1;
  }

  /* Question navigation swipe hints */
  .question-content {
    position: relative;
    transition: transform 0.2s ease;
  }

  .question-content.swiping {
    transition: transform 0.05s ease;
  }

  .question-content::before {
    content: '';
    position: fixed;
    top: 50%;
    transform: translateY(-50%);
    font-size: 2.5rem;
    font-weight: 600;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease;
    z-index: 100;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
  }

  .question-content.swipe-left-hint::before {
    content: '→';
    right: 2rem;
    color: var(--color-primary-600);
    opacity: 0.8;
  }

  .question-content.swipe-right-hint::before {
    content: '←';
    left: 2rem;
    color: var(--color-primary-600);
    opacity: 0.8;
  }

  /* Explanation section */
  .explanation-section {
    padding: 1.25rem 1rem;
    margin-top: 1.5rem;
  }

  .explanation-section h3 {
    font-size: 0.9rem;
  }

  .explanation-text {
    font-size: 1rem;
    line-height: 1.6;
  }

  /* Navigation buttons - larger and more prominent */
  .quiz-navigation {
    flex-direction: column;
    gap: 0.875rem;
    padding: 1rem 0.875rem calc(1.5rem + env(safe-area-inset-bottom));
    /* Ensure navigation is above iOS home indicator */
    padding-bottom: max(1.5rem, calc(1.5rem + env(safe-area-inset-bottom)));
  }

  .nav-btn,
  .submit-btn {
    width: 100%;
    padding: 1rem 1.5rem;
    font-size: 1.0625rem;
    font-weight: 600;
    min-height: 52px;
  }

  .submit-btn {
    min-height: 56px;
    font-size: 1.125rem;
  }

  /* Modals mobile */
  .modal-content {
    width: 95%;
    max-height: calc(100vh - 100px);
    position: relative;
  }

  .modal-header,
  .modal-body,
  .modal-footer {
    padding: 1.125rem;
  }

  .modal-body {
    padding-bottom: max(1.125rem, env(safe-area-inset-bottom));
  }

  .modal-header h2 {
    font-size: 1.375rem;
  }

  .close-btn {
    font-size: 2.25rem;
    padding: 0.25rem 0.5rem;
  }

  .summary-stats {
    grid-template-columns: 1fr 1fr;
    gap: 0.875rem;
  }

  .summary-stat-card {
    padding: 1.125rem 1rem;
  }

  .stat-number {
    font-size: 2.25rem;
  }

  .stat-label {
    font-size: 0.8125rem;
  }

  .modal-footer {
    flex-direction: column-reverse;
    gap: 0.75rem;
  }

  .modal-footer button {
    width: 100%;
    min-height: 52px;
    font-size: 1.0625rem;
  }

  /* Toast mobile */
  .toast {
    bottom: 1.25rem;
    right: 1rem;
    left: 1rem;
    max-width: none;
    padding: 1rem 1.25rem;
    font-size: 0.9375rem;
  }

  /* Question menu mobile */
  .question-menu {
    width: 100%;
    max-width: 100%;
  }

  .question-menu-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.625rem;
    padding: 1rem 1.25rem;
    font-size: 0.875rem;
  }

  .question-menu-stats span {
    text-align: center;
    padding: 0.5rem;
    background: white;
    border-radius: var(--radius-sm);
  }

  .menu-filters {
    grid-template-columns: 1fr 1fr;
    gap: 0.625rem;
    padding: 1rem 1.25rem;
  }

  .filter-btn {
    font-size: 0.875rem;
    padding: 0.625rem 0.75rem;
    min-height: 44px;
  }

  .menu-actions {
    padding: 1rem 1.25rem;
  }

  .menu-action-btn {
    min-height: 48px;
    font-size: 0.9375rem;
  }

  /* Question grid */
  .question-grid {
    padding: 1rem 1.25rem;
    gap: 0.625rem;
    grid-template-columns: repeat(auto-fill, minmax(52px, 1fr));
  }

  .grid-question-btn {
    min-width: 44px;
    min-height: 44px;
    font-size: 1rem;
  }

  /* Topic mastery */
  .topic-mastery {
    padding: 1rem 1.25rem;
  }

  .topic-item {
    padding: 0.875rem;
  }

  .topic-name {
    font-size: 0.9375rem;
  }

  /* Feedback banner */
  .feedback-banner {
    font-size: 1rem;
    padding: 1rem 1.125rem;
  }

  /* Settings modal */
  .setting-label {
    font-size: 1rem;
  }

  .setting-label input[type="checkbox"] {
    width: 1.5rem;
    height: 1.5rem;
  }

  .setting-description {
    font-size: 0.875rem;
    line-height: 1.5;
  }

  #timer-duration {
    font-size: 16px; /* Prevents iOS auto-zoom */
    padding: 0.875rem;
    min-height: 52px;
    width: 100%;
  }

  /* Highlight toolbar - bottom positioned for mobile */
  .highlight-toolbar {
    bottom: max(140px, calc(env(safe-area-inset-bottom) + 140px));
    left: 50%;
    transform: translateX(-50%);
    top: auto !important;
    padding: 0.625rem;
    gap: 0.5rem;
  }

  .highlight-toolbar button {
    width: 36px;
    height: 36px;
    font-size: 0.875rem;
  }
}

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

  .menu-filters {
    grid-template-columns: 1fr 1fr;
  }

  /* Force max 5 columns on small phones */
  .question-grid {
    grid-template-columns: repeat(5, 1fr);
    gap: 0.5rem;
  }

  /* More conservative spacing for highlight toolbar on small screens */
  .highlight-toolbar {
    bottom: 160px;
  }
}

/* ========================================
   VERY SMALL SCREENS (iPhone SE, etc.)
   ======================================== */

@media (max-width: 375px) {
  .welcome-stats {
    gap: 1.5rem;
    flex-direction: column;
    align-items: center;
  }

  .stat-item {
    width: 100%;
    flex-direction: row;
    justify-content: space-between;
    padding: 1rem;
    background: var(--color-neutral-50);
    border-radius: var(--radius-md);
  }

  .progress-info {
    width: 100%;
    justify-content: space-between;
  }

  .timer-display {
    order: -1;
    width: 100%;
    justify-content: center;
    margin-bottom: 0.5rem;
  }
}

/* ========================================
   SMALL SCREEN OPTIMIZATION (iPhone SE, etc.)
   ======================================== */

@media (max-width: 768px) and (max-height: 700px) {
  /* Optimize header for smaller screens like iPhone SE */
  .quiz-header-content {
    padding: 0.5rem 0.875rem;
  }

  .logo {
    font-size: 1.125rem;
  }

  .progress-info {
    font-size: 0.875rem;
  }

  .timer-display {
    padding: 0.375rem 0.75rem;
  }
}

/* ========================================
   LANDSCAPE ORIENTATION OPTIMIZATIONS
   ======================================== */

@media (max-width: 768px) and (orientation: landscape) {
  /* Compact header in landscape */
  .quiz-header-content {
    padding: 0.5rem 1rem;
  }

  .logo {
    font-size: 1.1rem;
  }

  .progress-bar-container {
    height: 3px;
  }

  #question-counter {
    font-size: 0.8125rem;
  }

  .timer-display {
    padding: 0.375rem 0.75rem;
  }

  #timer-text {
    font-size: 1rem;
  }

  /* Reduce vertical spacing in landscape */
  .quiz-container {
    padding: 0.75rem 1rem;
  }

  .question-display {
    padding: 1rem;
  }

  .question-content {
    gap: 1rem;
  }

  .answer-choice {
    padding: 0.875rem 1rem;
    min-height: 52px;
  }

  .explanation-section {
    padding: 1rem;
    margin-top: 1rem;
  }

  /* Make modals more efficient in landscape */
  .modal-content {
    max-height: 95vh;
    width: 98%;
  }

  .modal-header,
  .modal-body,
  .modal-footer {
    padding: 0.875rem;
  }

  /* Compact navigation in landscape */
  .quiz-navigation {
    padding: 0.5rem 1rem;
    gap: 0.75rem;
  }

  .nav-btn,
  .submit-btn {
    padding: 0.625rem 1rem;
    min-height: 44px;
    font-size: 0.9375rem;
  }
}

/* ========================================
   ACCESSIBILITY IMPROVEMENTS
   ======================================== */

/* Focus visible styles */
*:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

button:focus-visible,
a:focus-visible,
input:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
}

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

/* High contrast mode support */
@media (prefers-contrast: high) {
  .answer-choice {
    border-width: 2px;
  }

  .choice-letter {
    border-width: 3px;
  }

  .filter-btn.active {
    border-width: 3px;
  }
}

/* Skip to content link for screen readers */
.skip-to-content {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary-500);
  color: white;
  padding: 0.5rem 1rem;
  text-decoration: none;
  z-index: 1000;
}

.skip-to-content:focus {
  top: 0;
}

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

/* Improve contrast for better readability */
.question-meta .meta-text {
  color: var(--color-neutral-600);
  font-weight: 500;
}

/* Loading spinner */
.loading-spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--color-neutral-200);
  border-top-color: var(--color-primary-500);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto 1rem;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Prevent double-tap zoom on buttons */
button {
  touch-action: manipulation;
}

/* Better touch targets for mobile */
@media (hover: none) and (pointer: coarse) {
  button,
  a,
  .answer-choice {
    min-height: 44px;
    min-width: 44px;
  }

  /* Active touch states for immediate feedback */
  button:active,
  .answer-choice:active {
    transition: transform 0.05s ease, opacity 0.05s ease;
  }

  .nav-btn:active:not(:disabled),
  .submit-btn:active:not(:disabled),
  .filter-btn:active,
  .menu-action-btn:active {
    transform: scale(0.98);
    opacity: 0.9;
  }

  .answer-choice:active {
    transform: scale(0.995);
  }

  .grid-question-btn:active {
    transform: scale(0.95);
    opacity: 0.85;
  }
}

/* Text Highlighting Feature */
.vignette,
.question-text,
.choice-text,
.explanation-text {
  user-select: text;
  -webkit-user-select: text;
  -moz-user-select: text;
}

.highlight {
  background: linear-gradient(120deg, #fef3c7 0%, #fde68a 100%);
  padding: 0.125rem 0.25rem;
  border-radius: 2px;
  cursor: pointer;
  position: relative;
  transition: opacity 0.15s ease;
}

.highlight:hover {
  opacity: 0.85;
}

.highlight:active {
  opacity: 0.7;
}

/* Show remove hint on hover (desktop only) */
@media (hover: hover) {
  .highlight:hover::after {
    content: 'Click to remove';
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-neutral-800);
    color: white;
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    white-space: nowrap;
    margin-bottom: 4px;
    pointer-events: none;
    z-index: 10;
  }
}

/* Highlight colors */
.highlight-yellow {
  background: linear-gradient(120deg, #fef3c7 0%, #fde68a 100%);
}

.highlight-green {
  background: linear-gradient(120deg, #d1fae5 0%, #a7f3d0 100%);
}

.highlight-blue {
  background: linear-gradient(120deg, #dbeafe 0%, #bfdbfe 100%);
}

.highlight-pink {
  background: linear-gradient(120deg, #fce7f3 0%, #fbcfe8 100%);
}

/* Highlight toolbar */
.highlight-toolbar {
  position: fixed;
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: 0.5rem;
  display: none;
  gap: 0.25rem;
  z-index: 250;
}

.highlight-toolbar.show {
  display: flex;
}

.highlight-toolbar button {
  width: 28px;
  height: 28px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s ease;
  padding: 0;
  font-size: 0.75rem;
}

.highlight-toolbar button:hover {
  transform: scale(1.1);
  box-shadow: var(--shadow-sm);
}

.highlight-toolbar button.highlight-yellow-btn {
  background: linear-gradient(120deg, #fef3c7 0%, #fde68a 100%);
}

.highlight-toolbar button.highlight-green-btn {
  background: linear-gradient(120deg, #d1fae5 0%, #a7f3d0 100%);
}

.highlight-toolbar button.highlight-blue-btn {
  background: linear-gradient(120deg, #dbeafe 0%, #bfdbfe 100%);
}

.highlight-toolbar button.highlight-pink-btn {
  background: linear-gradient(120deg, #fce7f3 0%, #fbcfe8 100%);
}

.highlight-toolbar button.clear-btn {
  background: white;
  color: var(--color-error-600);
  font-weight: 700;
}

/* ========================================
   PWA INSTALL PROMPT
   ======================================== */

.install-prompt {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: white;
  box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.15);
  border-top: 2px solid var(--color-primary-600);
  transform: translateY(100%);
  transition: transform 0.3s ease;
  z-index: 1000;
  padding: 1.25rem;
  padding-bottom: max(1.25rem, env(safe-area-inset-bottom));
}

.install-prompt.show {
  transform: translateY(0);
}

.install-prompt-content {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.install-prompt-icon {
  font-size: 2.5rem;
  flex-shrink: 0;
}

.install-prompt-text {
  flex: 1;
}

.install-prompt-text strong {
  display: block;
  font-size: 1.0625rem;
  color: var(--color-neutral-800);
  margin-bottom: 0.25rem;
}

.install-prompt-text p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-neutral-600);
  line-height: 1.4;
}

.install-prompt-actions {
  display: flex;
  gap: 0.75rem;
  flex-shrink: 0;
}

.install-prompt-btn {
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9375rem;
  cursor: pointer;
  transition: all 0.15s ease;
  border: none;
  min-height: 44px;
  white-space: nowrap;
  touch-action: manipulation;
}

.install-btn-primary {
  background: var(--color-primary-600);
  color: white;
}

.install-btn-primary:hover {
  background: var(--color-primary-700);
  transform: translateY(-1px);
  box-shadow: 0 4px 8px rgba(43, 108, 176, 0.2);
}

.install-btn-primary:active {
  transform: translateY(0);
}

.install-btn-secondary {
  background: var(--color-neutral-100);
  color: var(--color-neutral-700);
}

.install-btn-secondary:hover {
  background: var(--color-neutral-200);
}

@media (max-width: 768px) {
  .install-prompt {
    padding: 1rem;
  }

  .install-prompt-content {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.875rem;
  }

  .install-prompt-icon {
    font-size: 2rem;
  }

  .install-prompt-text strong {
    font-size: 1rem;
  }

  .install-prompt-text p {
    font-size: 0.875rem;
  }

  .install-prompt-actions {
    width: 100%;
    flex-direction: column-reverse;
    gap: 0.5rem;
  }

  .install-prompt-btn {
    width: 100%;
    padding: 0.875rem 1rem;
  }
}

/* ========================================
   QUICK NAVIGATION MENU (Long-press on flag button)
   ======================================== */

.quick-nav-menu {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  opacity: 0;
  transition: opacity 0.3s ease;
  padding: 1rem;
}

.quick-nav-menu.show {
  opacity: 1;
}

.quick-nav-menu > div {
  background: #ffffff;
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
  max-width: 400px;
  width: 100%;
  transform: scale(0.9);
  transition: transform 0.3s ease;
}

.quick-nav-menu.show > div {
  transform: scale(1);
}

.quick-nav-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--color-border);
}

.quick-nav-header span {
  font-weight: 600;
  font-size: var(--text-lg);
  color: var(--color-text);
}

.quick-nav-close {
  background: none;
  border: none;
  font-size: 1.75rem;
  color: var(--color-neutral-500);
  cursor: pointer;
  padding: 0;
  line-height: 1;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  transition: all 0.2s ease;
}

.quick-nav-close:hover {
  background: var(--color-neutral-100);
  color: var(--color-text);
}

.quick-nav-options {
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.quick-nav-option {
  background: var(--color-primary-50);
  border: 1px solid var(--color-primary-200);
  color: var(--color-primary-700);
  padding: 1rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: left;
  width: 100%;
}

.quick-nav-option:hover,
.quick-nav-option:focus {
  background: var(--color-primary-100);
  border-color: var(--color-primary-300);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(43, 108, 176, 0.15);
}

.quick-nav-option:active {
  transform: translateY(0);
}

@media (max-width: 480px) {
  .quick-nav-menu {
    padding: 0.5rem;
  }

  .quick-nav-header {
    padding: 0.875rem 1rem;
  }

  .quick-nav-header span {
    font-size: var(--text-base);
  }

  .quick-nav-option {
    padding: 0.875rem 1rem;
    font-size: var(--text-sm);
  }
}

/* ========================================
   PULL-TO-REFRESH INDICATOR
   ======================================== */

.pull-indicator {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 0;
  overflow: hidden;
  opacity: 0;
  transition: opacity 0.2s ease;
  background: linear-gradient(to bottom, var(--color-primary-50), transparent);
}

.pull-indicator.hiding {
  transition: height 0.3s ease, opacity 0.3s ease;
  height: 0 !important;
  opacity: 0 !important;
}

.pull-indicator.triggered {
  background: linear-gradient(to bottom, var(--color-success-100), transparent);
}

.pull-icon {
  font-size: 2rem;
  color: var(--color-primary-500);
  transition: transform 0.1s ease;
}

.pull-indicator.ready .pull-icon {
  color: var(--color-success-500);
}

.pull-indicator.triggered .pull-icon {
  animation: spin 0.5s linear infinite;
}

.pull-text {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-primary-600);
  margin-top: 0.25rem;
}

.pull-indicator.ready .pull-text {
  color: var(--color-success-600);
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

/* ========================================
   WELCOME SCREEN - TOUR BUTTON
   ======================================== */

.welcome-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  margin-top: 2rem;
  flex-wrap: wrap;
}

.welcome-tour-btn {
  background: var(--color-neutral-100);
  color: var(--color-neutral-700);
  border: 2px solid var(--color-neutral-300);
  padding: 1rem 2rem;
  border-radius: var(--radius-lg);
  font-size: var(--text-lg);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.welcome-tour-btn:hover {
  background: var(--color-neutral-200);
  border-color: var(--color-neutral-400);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.welcome-tour-btn:active {
  transform: translateY(0);
}

/* ========================================
   INTERACTIVE TOUR SYSTEM
   ======================================== */

.tour-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 3000;
  opacity: 0;
  transition: opacity 0.3s ease;
  padding: 1rem;
}

.tour-overlay.show {
  opacity: 1;
}

.tour-modal {
  background: #ffffff;
  border-radius: var(--radius-xl);
  box-shadow: 0 12px 48px rgba(0, 0, 0, 0.3);
  max-width: 500px;
  width: 100%;
  transform: scale(0.9);
  transition: transform 0.3s ease;
  overflow: hidden;
}

.tour-overlay.show .tour-modal {
  transform: scale(1);
}

.tour-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-primary-50);
}

.tour-step-indicator {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-primary-600);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.tour-close {
  background: none;
  border: none;
  font-size: 2rem;
  color: var(--color-neutral-500);
  cursor: pointer;
  padding: 0;
  line-height: 1;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  transition: all 0.2s ease;
}

.tour-close:hover {
  background: var(--color-neutral-100);
  color: var(--color-text);
}

.tour-content {
  padding: 2rem 1.5rem;
  text-align: center;
}

.tour-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  line-height: 1;
}

.tour-content h2 {
  font-size: var(--text-2xl);
  margin: 0 0 1rem 0;
  color: var(--color-text);
}

.tour-description {
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-neutral-600);
  text-align: left;
}

.tour-description strong {
  color: var(--color-text);
  font-weight: 600;
}

.tour-footer {
  padding: 1.25rem 1.5rem;
  border-top: 1px solid var(--color-border);
  background: var(--color-neutral-50);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.tour-nav-buttons {
  display: flex;
  gap: 0.5rem;
}

.tour-btn {
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  border: none;
}

.tour-btn-primary {
  background: var(--color-primary);
  color: white;
}

.tour-btn-primary:hover {
  background: var(--color-primary-600);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(43, 108, 176, 0.3);
}

.tour-btn-primary:active {
  transform: translateY(0);
}

.tour-btn-secondary {
  background: var(--color-neutral-100);
  color: var(--color-neutral-700);
}

.tour-btn-secondary:hover {
  background: var(--color-neutral-200);
}

.tour-highlight {
  position: relative;
  z-index: 3001;
  box-shadow: 0 0 0 4px var(--color-primary), 0 0 0 8px rgba(43, 108, 176, 0.3);
  border-radius: var(--radius-md);
  animation: tour-pulse 2s ease-in-out infinite;
}

@keyframes tour-pulse {
  0%, 100% {
    box-shadow: 0 0 0 4px var(--color-primary), 0 0 0 8px rgba(43, 108, 176, 0.3);
  }
  50% {
    box-shadow: 0 0 0 4px var(--color-primary), 0 0 0 12px rgba(43, 108, 176, 0.5);
  }
}

@media (max-width: 768px) {
  .welcome-actions {
    flex-direction: column;
    gap: 0.75rem;
  }

  .welcome-tour-btn,
  .welcome-start-btn {
    width: 100%;
  }

  .tour-modal {
    max-height: 90vh;
    overflow-y: auto;
  }

  .tour-content {
    padding: 1.5rem 1rem;
  }

  .tour-icon {
    font-size: 3rem;
  }

  .tour-content h2 {
    font-size: var(--text-xl);
  }

  .tour-footer {
    flex-direction: column;
    gap: 0.75rem;
  }

  .tour-nav-buttons {
    width: 100%;
    flex-direction: column;
  }

  .tour-btn {
    width: 100%;
    padding: 0.875rem 1rem;
  }
}

/* Issue #29: Show Answer Section */
.show-answer-section {
  margin-top: 1.5rem;
  padding: 1rem;
  background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
  border: 2px solid #f59e0b;
  border-radius: var(--radius-md);
  text-align: center;
}

.show-answer-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  min-height: 44px;
  background: #ffffff;
  border: 2px solid #f59e0b;
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  font-weight: 600;
  color: #92400e;
  cursor: pointer;
  transition: all 0.15s ease;
  box-shadow: var(--shadow-sm);
}

.show-answer-btn:hover {
  background: #fef3c7;
  border-color: #d97706;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.show-answer-hint {
  margin-top: 0.5rem;
  font-size: var(--text-sm);
  color: #78350f;
  font-weight: 500;
}

/* ============================================================================
   Issue #11: Keyboard Shortcuts Modal
   ============================================================================ */

.keyboard-shortcuts-modal {
  max-width: 600px;
}

.shortcuts-section {
  margin-bottom: 1.5rem;
}

.shortcuts-section:last-child {
  margin-bottom: 0;
}

.shortcuts-section h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-primary-700);
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-border);
}

.shortcut-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem;
  margin-bottom: 0.5rem;
  background: var(--color-neutral-50);
  border-radius: var(--radius-sm);
  transition: background 0.15s ease;
}

.shortcut-item:hover {
  background: var(--color-neutral-100);
}

.shortcut-item kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2rem;
  padding: 0.25rem 0.5rem;
  background: linear-gradient(180deg, #ffffff 0%, #f3f4f6 100%);
  border: 1px solid #d1d5db;
  border-bottom-width: 2px;
  border-radius: 0.25rem;
  font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Roboto Mono', 'Courier New', monospace;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-neutral-800);
  box-shadow: 0 2px 0 rgba(0, 0, 0, 0.1);
  line-height: 1;
}

.shortcut-item span {
  flex: 1;
  font-size: 0.9375rem;
  color: var(--color-text);
}

/* ============================================================================
   Issue #11: Improved Focus Indicators
   ============================================================================ */

/* Focus styles for all interactive elements */
button:focus-visible,
.nav-btn:focus-visible,
.submit-btn:focus-visible,
.skip-btn:focus-visible,
.flag-btn:focus-visible,
.settings-btn:focus-visible,
.menu-btn:focus-visible,
a:focus-visible {
  outline: 3px solid var(--color-primary-500);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Focus styles for radio buttons and answer choices */
.answer-choice:focus-within {
  outline: 3px solid var(--color-primary-500);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(49, 130, 206, 0.1);
}

input[type="radio"]:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
}

/* Focus styles for filter buttons */
.filter-btn:focus-visible {
  outline: 3px solid var(--color-primary-500);
  outline-offset: 2px;
}

/* Focus styles for grid question buttons */
.grid-question-btn:focus-visible {
  outline: 3px solid var(--color-primary-500);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(49, 130, 206, 0.15);
}

/* Focus styles for modal close buttons */
.close-btn:focus-visible {
  outline: 3px solid var(--color-error-500);
  outline-offset: 2px;
}

/* Ensure Tab navigation is visible */
*:focus {
  outline-width: 0;
}

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

/* ============================================================================
   Issue #10: Screen Reader Only (sr-only) Class
   ============================================================================ */

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

/* ============================================================================
   Issue #7: Search Functionality
   ============================================================================ */

.search-container {
  padding: 1rem;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-background);
}

.search-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.search-icon {
  position: absolute;
  left: 1rem;
  font-size: 1.125rem;
  color: var(--color-neutral-500);
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 0.75rem 3rem 0.75rem 3rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 0.9375rem;
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-background);
  transition: all 0.2s ease;
}

.search-input:focus {
  outline: none;
  border-color: var(--color-primary-500);
  box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.1);
}

.search-input::placeholder {
  color: var(--color-neutral-400);
}

.clear-search-btn {
  position: absolute;
  right: 0.75rem;
  padding: 0.25rem 0.5rem;
  background: transparent;
  border: none;
  font-size: 1.25rem;
  color: var(--color-neutral-500);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all 0.15s ease;
}

.clear-search-btn:hover {
  background: var(--color-neutral-100);
  color: var(--color-neutral-700);
}

.search-results-count {
  margin-top: 0.75rem;
  padding: 0.5rem 0.75rem;
  background: var(--color-primary-50);
  border-left: 3px solid var(--color-primary-500);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-primary-700);
}

.search-results-count.no-results {
  background: var(--color-error-50);
  border-left-color: var(--color-error-500);
  color: var(--color-error-700);
}

/* Highlight matching search terms in question text */
.search-highlight {
  background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
  padding: 0.125rem 0.25rem;
  border-radius: 0.125rem;
  font-weight: 600;
}

/* Issue #9: Enhanced session summary sections */

/* Performance comparison section */
.summary-comparison {
  margin: 1.5rem 0;
  padding: 1.25rem;
  background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
  border-left: 4px solid var(--color-primary-500);
  border-radius: var(--radius-md);
}

.summary-comparison h3 {
  margin: 0 0 1rem 0;
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-primary-700);
}

.comparison-stats {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.comparison-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem;
  background: white;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
}

.comparison-item.comparison-positive {
  border-left: 3px solid var(--color-success-500);
}

.comparison-item.comparison-negative {
  border-left: 3px solid var(--color-error-500);
}

.comparison-item.comparison-neutral {
  border-left: 3px solid var(--color-neutral-400);
}

.comparison-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}

.comparison-text {
  flex: 1;
  font-size: 0.9375rem;
  color: var(--color-neutral-800);
  font-weight: 500;
}

.comparison-detail {
  display: block;
  margin-top: 0.25rem;
  font-size: 0.8125rem;
  color: var(--color-neutral-600);
  font-weight: 400;
}

/* Recommendations section */
.summary-recommendations {
  margin: 1.5rem 0;
  padding: 1.25rem;
  background: linear-gradient(135deg, #fefce8 0%, #fef9c3 100%);
  border-left: 4px solid #eab308;
  border-radius: var(--radius-md);
}

.summary-recommendations h3 {
  margin: 0 0 1rem 0;
  font-size: 1.125rem;
  font-weight: 600;
  color: #854d0e;
}

.recommendations-list {
  margin: 0;
  padding-left: 1.5rem;
  list-style: none;
}

.recommendations-list li {
  position: relative;
  margin-bottom: 0.75rem;
  padding-left: 0.5rem;
  font-size: 0.9375rem;
  color: var(--color-neutral-800);
  line-height: 1.6;
}

.recommendations-list li:last-child {
  margin-bottom: 0;
}

.recommendations-list li::before {
  content: '▸';
  position: absolute;
  left: -1rem;
  color: #eab308;
  font-weight: 700;
}

/* Slow questions section */
.summary-slow-questions {
  margin: 1.5rem 0;
  padding: 1.25rem;
  background: linear-gradient(135deg, #fef2f2 0%, #fee2e2 100%);
  border-left: 4px solid var(--color-error-500);
  border-radius: var(--radius-md);
}

.summary-slow-questions h3 {
  margin: 0 0 0.75rem 0;
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-error-700);
}

.slow-questions-intro {
  margin: 0 0 1rem 0;
  font-size: 0.9375rem;
  color: var(--color-neutral-700);
  line-height: 1.6;
}

.slow-questions-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.slow-question-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.625rem 0.875rem;
  background: white;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
}

.slow-question-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.5rem;
  padding: 0.25rem 0.5rem;
  background: var(--color-error-100);
  color: var(--color-error-700);
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.8125rem;
}

.slow-question-topic {
  flex: 1;
  color: var(--color-neutral-700);
  font-weight: 500;
}

.slow-question-time {
  color: var(--color-error-600);
  font-weight: 600;
  font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Roboto Mono', monospace;
}

.slow-questions-more {
  padding: 0.5rem 0.875rem;
  text-align: center;
  color: var(--color-neutral-600);
  font-size: 0.8125rem;
  font-style: italic;
}

/* Issue #6: Notes feature styles */

/* Notes section in explanation */
.notes-section {
  margin-top: 2rem;
  padding: 1.5rem;
  background: linear-gradient(135deg, #fefce8 0%, #fef3c7 100%);
  border-left: 4px solid #eab308;
  border-radius: var(--radius-md);
}

.notes-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.notes-header h4 {
  margin: 0;
  font-size: 1.125rem;
  font-weight: 600;
  color: #78350f;
}

.note-date {
  font-size: 0.8125rem;
  color: #92400e;
  font-style: italic;
}

.notes-editor {
  margin-bottom: 0.75rem;
}

.note-textarea {
  width: 100%;
  min-height: 120px;
  padding: 0.875rem;
  border: 2px solid #fbbf24;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.9375rem;
  line-height: 1.6;
  color: var(--color-neutral-800);
  background: white;
  resize: vertical;
  transition: all 0.2s ease;
}

.note-textarea:focus {
  outline: none;
  border-color: #f59e0b;
  box-shadow: 0 0 0 3px rgba(251, 191, 36, 0.15);
}

.note-textarea::placeholder {
  color: #a16207;
  opacity: 0.6;
}

.notes-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.notes-char-count {
  font-size: 0.8125rem;
  color: #92400e;
  font-family: 'SF Mono', 'Monaco', 'Cascadia Code', 'Roboto Mono', monospace;
}

.notes-char-count span {
  font-weight: 600;
  color: #78350f;
}

.notes-actions {
  display: flex;
  gap: 0.5rem;
}

.note-action-btn {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.note-save-btn {
  background: #eab308;
  color: white;
}

.note-save-btn:hover {
  background: #f59e0b;
  transform: translateY(-1px);
  box-shadow: 0 2px 4px rgba(234, 179, 8, 0.3);
}

.note-delete-btn {
  background: var(--color-error-100);
  color: var(--color-error-700);
}

.note-delete-btn:hover {
  background: var(--color-error-200);
  transform: translateY(-1px);
}

.notes-formatting-hint {
  font-size: 0.8125rem;
  color: #92400e;
  line-height: 1.5;
}

.notes-formatting-hint strong {
  color: #78350f;
}

/* Note indicator in question grid */
.grid-note-icon {
  position: absolute;
  bottom: 2px;
  left: 2px;
  font-size: 0.625rem;
  line-height: 1;
  opacity: 0.9;
}