/* ==========================================================================
   Quiz Review Stylesheet - FSRS-6 Smart Multiple-Choice Engine
   ========================================================================== */

.quiz-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: var(--bg-primary);
  display: none;
  flex-direction: column;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  box-sizing: border-box;
  opacity: 0;
  transform: translateY(12px) scale(0.98);
  transition: opacity 0.22s cubic-bezier(0.16, 1, 0.3, 1), transform 0.22s cubic-bezier(0.16, 1, 0.3, 1);
}

.quiz-overlay.active {
  display: flex;
  opacity: 1;
  transform: translateY(0) scale(1);
}

.quiz-layout-wrapper {
  display: flex;
  flex-direction: column;
  width: 100%;
  max-width: 560px;
  min-height: 100vh;
  margin: 0 auto;
  padding: 12px 16px 20px 16px;
  box-sizing: border-box;
}

/* ==========================================================================
   1. Quiz Header Bar & Progress
   ========================================================================== */
.quiz-header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  margin-bottom: 12px;
  flex-shrink: 0;
}

.btn-quiz-close,
.btn-quiz-icon {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.18s ease;
  touch-action: manipulation;
  flex-shrink: 0;
  padding: 0;
}

.btn-quiz-close:hover {
  background: rgba(239, 68, 68, 0.12);
  border-color: rgba(239, 68, 68, 0.3);
  color: #ef4444;
  transform: scale(1.05);
}

.btn-quiz-mode-switch:hover {
  background: rgba(99, 102, 241, 0.12);
  border-color: rgba(99, 102, 241, 0.3);
  color: var(--primary);
  transform: scale(1.05);
}

.quiz-progress-section {
  display: flex;
  flex-direction: column;
  gap: 4px;
  flex: 1;
  min-width: 0;
}

.quiz-progress-top-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-muted);
  gap: 8px;
}

.quiz-progress-left-meta {
  display: flex;
  align-items: center;
  gap: 8px;
}

.quiz-counter-text {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.quiz-combo-badge {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  font-size: 0.68rem;
  font-weight: 800;
  padding: 2px 7px;
  border-radius: 99px;
  background: rgba(245, 158, 11, 0.15);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: #f59e0b;
  opacity: 0;
  transform: scale(0.85);
  transition: all 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.quiz-combo-badge.active {
  opacity: 1;
  transform: scale(1);
}

/* Live Active Study Timer Badge */
.quiz-live-timer {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 2px 9px;
  border-radius: 99px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  color: var(--text-primary);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  transition: all 0.25s ease;
  user-select: none;
}

.quiz-live-timer .timer-icon {
  font-size: 0.78rem;
  line-height: 1;
}

.quiz-live-timer .timer-digits {
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.03em;
  color: var(--text-primary);
}

.quiz-live-timer .timer-status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  flex-shrink: 0;
  background: #10b981;
  box-shadow: 0 0 6px rgba(16, 185, 129, 0.6);
  animation: timerDotPulse 1.8s infinite ease-in-out;
}

.quiz-live-timer.is-idle {
  opacity: 0.68;
  border-color: rgba(245, 158, 11, 0.35);
  background: rgba(245, 158, 11, 0.07);
}

.quiz-live-timer.is-idle .timer-status-dot {
  background: #f59e0b;
  box-shadow: none;
  animation: none;
}

.quiz-live-timer.is-idle .timer-digits {
  color: var(--text-secondary);
}

@keyframes timerDotPulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.3);
    opacity: 0.75;
  }
}

.quiz-progress-track {
  width: 100%;
  height: 6px;
  background: var(--bg-tertiary);
  border-radius: 99px;
  overflow: hidden;
  border: 1px solid var(--border);
}

.quiz-progress-fill {
  height: 100%;
  border-radius: 99px;
  background: linear-gradient(90deg, var(--primary), #818cf8);
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   2. Main Question Card & Visual Reflex Bar
   ========================================================================== */
.quiz-main-stage {
  display: flex;
  flex-direction: column;
  gap: 14px;
  flex: 1;
  justify-content: center;
  width: 100%;
  margin: auto 0;
}

.quiz-question-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 22px 18px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-md);
  min-height: 190px;
  box-sizing: border-box;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

[data-theme="light"] .quiz-question-card {
  background: #ffffff;
  border-color: rgba(0, 0, 0, 0.08);
  box-shadow: 0 4px 16px rgba(15, 23, 42, 0.05);
}

.quiz-meta-pills-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 10px;
}

.quiz-mode-pill {
  font-size: 0.64rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 2px 8px;
  border-radius: 6px;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.25);
  color: var(--primary);
}

.quiz-badge-pos {
  font-size: 0.62rem;
  font-weight: 800;
  padding: 2px 6px;
  border-radius: 6px;
  background: var(--bg-tertiary);
  color: var(--text-muted);
  text-transform: uppercase;
}

.quiz-badge-cefr {
  font-size: 0.62rem;
  font-weight: 800;
  padding: 2px 6px;
  border-radius: 6px;
  background: rgba(16, 185, 129, 0.12);
  color: #10b981;
}

.quiz-word-prompt {
  font-size: 1.85rem;
  font-weight: 900;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 6px 0;
  word-break: break-word;
}

.quiz-ipa-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}

.quiz-ipa-text {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.btn-quiz-speaker {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.25);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.18s ease;
  touch-action: manipulation;
}

.btn-quiz-speaker:hover {
  background: var(--primary);
  color: #ffffff;
  transform: scale(1.06);
}

.btn-quiz-speaker.playing {
  background: var(--primary);
  color: #ffffff;
}

.quiz-prompt-hint {
  font-size: 0.74rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* ==========================================================================
   3. 4 Multiple-Choice Options Grid
   ========================================================================== */
.quiz-options-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 9px;
  width: 100%;
}

@media (min-width: 480px) {
  .quiz-options-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
}

.quiz-option-tile {
  background: var(--bg-card);
  border: 1.5px solid var(--border);
  border-radius: 14px;
  padding: 12px 14px;
  display: flex;
  align-items: center;
  gap: 10px;
  text-align: left;
  cursor: pointer;
  transition: all 0.18s cubic-bezier(0.34, 1.56, 0.64, 1);
  touch-action: manipulation;
  outline: none;
  min-height: 56px;
  box-sizing: border-box;
  position: relative;
  user-select: none;
}

[data-theme="light"] .quiz-option-tile {
  background: #ffffff;
  border-color: rgba(0, 0, 0, 0.08);
  box-shadow: 0 1px 4px rgba(15, 23, 42, 0.03);
}

.quiz-option-tile:hover:not(.locked) {
  transform: translateY(-2px);
  border-color: var(--primary);
  box-shadow: 0 6px 16px rgba(99, 102, 241, 0.15);
}

.quiz-option-tile:active:not(.locked) {
  transform: scale(0.97);
}

.quiz-option-key {
  width: 26px;
  height: 26px;
  border-radius: 8px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.76rem;
  font-weight: 800;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  flex-shrink: 0;
  transition: all 0.18s ease;
}

.quiz-option-text {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.35;
  flex: 1;
  word-break: break-word;
}

/* Answer Selected States */
.quiz-option-tile.state-correct {
  background: rgba(16, 185, 129, 0.15) !important;
  border-color: #10b981 !important;
  box-shadow: 0 0 0 1.5px #10b981, 0 6px 20px rgba(16, 185, 129, 0.25) !important;
  transform: scale(1.02);
}

.quiz-option-tile.state-correct .quiz-option-key {
  background: #10b981;
  border-color: #10b981;
  color: #ffffff;
}

.quiz-option-tile.state-correct .quiz-option-text {
  color: #10b981;
  font-weight: 700;
}

[data-theme="light"] .quiz-option-tile.state-correct {
  background: #ecfdf5 !important;
  border-color: #059669 !important;
}

[data-theme="light"] .quiz-option-tile.state-correct .quiz-option-text {
  color: #047857;
}

.quiz-option-tile.state-wrong {
  background: rgba(239, 68, 68, 0.15) !important;
  border-color: #ef4444 !important;
  box-shadow: 0 0 0 1.5px #ef4444, 0 6px 20px rgba(239, 68, 68, 0.2) !important;
  animation: shake-x 0.35s ease;
}

.quiz-option-tile.state-wrong .quiz-option-key {
  background: #ef4444;
  border-color: #ef4444;
  color: #ffffff;
}

.quiz-option-tile.state-wrong .quiz-option-text {
  color: #ef4444;
}

.quiz-option-tile.state-dimmed {
  opacity: 0.45;
  pointer-events: none;
}

/* Reflex Floating Toast Pill */
.quiz-reflex-toast {
  position: absolute;
  top: 10px;
  right: 12px;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.66rem;
  font-weight: 800;
  padding: 3px 8px;
  border-radius: 99px;
  opacity: 0;
  transform: translateY(-4px) scale(0.9);
  transition: all 0.22s cubic-bezier(0.34, 1.56, 0.64, 1);
  pointer-events: none;
}

.quiz-reflex-toast.show {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.toast-easy { background: rgba(16, 185, 129, 0.2); border: 1px solid #10b981; color: #10b981; }
.toast-good { background: rgba(99, 102, 241, 0.2); border: 1px solid #6366f1; color: #818cf8; }
.toast-hard { background: rgba(245, 158, 11, 0.2); border: 1px solid #f59e0b; color: #f59e0b; }
.toast-again { background: rgba(239, 68, 68, 0.2); border: 1px solid #ef4444; color: #ef4444; }

/* ==========================================================================
   4. Manual Next Action Bar (Fixed Reserved Space, No Layout Shift)
   ========================================================================== */
.quiz-action-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 52px;
  margin-top: 12px;
  visibility: hidden;
  opacity: 0;
  pointer-events: none;
  transform: translateY(6px);
  transition: opacity 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), visibility 0.2s;
}

.quiz-action-bar.active {
  visibility: visible;
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.btn-quiz-next {
  width: 100%;
  min-height: 48px;
  padding: 12px 24px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--primary), #4338ca);
  color: #ffffff;
  border: none;
  font-size: 0.98rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  cursor: pointer;
  box-shadow: 0 4px 16px var(--primary-glow);
  transition: all 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
  touch-action: manipulation;
}

.btn-quiz-next:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 22px rgba(99, 102, 241, 0.4);
  background: linear-gradient(135deg, var(--primary-light), var(--primary));
}

.btn-quiz-next:active {
  transform: scale(0.98);
}

/* ==========================================================================
   5. Animations
   ========================================================================== */
@keyframes shake-x {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-5px); }
  40%, 80% { transform: translateX(5px); }
}



/* ==========================================================================
   6. Twin CTA Buttons in Tab Review
   ========================================================================== */
.hero-twin-cta-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  width: 100%;
}

.btn-hero-twin-quiz {
  width: 100%;
  min-height: 44px;
  padding: 10px 14px;
  border-radius: 10px;
  background: linear-gradient(135deg, #f59e0b, #d97706);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: #ffffff;
  font-size: 0.88rem;
  font-weight: 750;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  transition: all 0.18s ease;
  touch-action: manipulation;
  box-shadow: 0 3px 10px rgba(245, 158, 11, 0.25);
}

.btn-hero-twin-quiz:hover {
  background: linear-gradient(135deg, #fbbf24, #f59e0b);
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(245, 158, 11, 0.35);
}

.btn-hero-twin-quiz:active {
  transform: scale(0.98);
}

/* ==========================================================================
   🖥️ 7. Desktop PC Optimization (>= 768px & >= 860px)
   ========================================================================== */
@media (min-width: 768px) {
  .quiz-layout-wrapper {
    max-width: 860px;
    padding: 32px 36px 40px 36px;
  }

  .quiz-header-bar {
    margin-bottom: 20px;
  }

  .quiz-progress-top-row {
    font-size: 0.88rem;
  }

  .quiz-progress-track {
    height: 8px;
  }

  .quiz-question-card {
    padding: 36px 32px;
    border-radius: 26px;
    box-shadow: var(--shadow-lg);
    min-height: 230px;
  }

  .quiz-word-prompt {
    font-size: 2.85rem;
    margin: 4px 0 8px 0;
  }

  .quiz-ipa-text {
    font-size: 1.18rem;
  }

  .btn-quiz-speaker {
    width: 38px;
    height: 38px;
  }

  .quiz-badge-pos,
  .quiz-badge-cefr {
    font-size: 0.76rem;
    padding: 3px 10px;
    border-radius: 8px;
  }

  .quiz-prompt-hint {
    font-size: 0.95rem;
    margin-top: 6px;
  }

  .quiz-options-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    margin-top: 14px;
  }

  .quiz-option-tile {
    min-height: 74px;
    padding: 18px 22px;
    border-radius: 18px;
    gap: 14px;
  }

  .quiz-option-key {
    width: 36px;
    height: 36px;
    font-size: 0.95rem;
    border-radius: 10px;
  }

  .quiz-option-text {
    font-size: 1.05rem;
    line-height: 1.4;
  }

  .quiz-action-bar {
    min-height: 58px;
    margin-top: 16px;
  }

  .btn-quiz-next {
    min-height: 54px;
    font-size: 1.06rem;
    border-radius: 16px;
  }
}