:root {
  --bg-primary: #0a0f1a;
  --bg-secondary: #141c2e;
  --bg-card: #1a2540;
  --text-primary: #f0f4ff;
  --text-secondary: #8892a8;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
  --heart: #ef4444;
  --diamond: #3b82f6;
  --club: #22c55e;
  --spade: #8b5cf6;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
}

#app {
  max-width: 480px;
  margin: 0 auto;
  padding: 16px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0 24px;
}

.header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--accent-hover));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

.icon-btn {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  padding: 8px;
  border-radius: 50%;
  transition: background 0.2s;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
}

.icon-btn:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.icon-btn svg {
  width: 22px;
  height: 22px;
}

/* Screens */
.screen {
  display: none;
  flex-direction: column;
  flex: 1;
  animation: fadeIn 0.3s ease;
}

.screen.active {
  display: flex;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Playing Card */
.card-display {
  display: flex;
  justify-content: center;
  padding: 32px 0;
}

.playing-card {
  width: 140px;
  height: 196px;
  background: linear-gradient(145deg, #fff 0%, #f8f9fa 100%);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow), 0 0 0 2px rgba(255, 255, 255, 0.1);
  position: relative;
  transition: transform 0.3s ease;
}

.playing-card:hover {
  transform: scale(1.02);
}

.playing-card::before {
  content: '';
  position: absolute;
  inset: 6px;
  border: 2px solid #e5e7eb;
  border-radius: 8px;
}

.card-content {
  font-size: 3rem;
  font-weight: 700;
  color: #1f2937;
}

.playing-card.hearts .card-content,
.playing-card.diamonds .card-content {
  color: var(--heart);
}

.playing-card.clubs .card-content {
  color: #1f2937;
}

.playing-card.spades .card-content {
  color: #1f2937;
}

.playing-card.position .card-content {
  font-size: 2.5rem;
  color: var(--accent);
}

/* Question Text */
.question-text {
  text-align: center;
  font-size: 1.25rem;
  margin-bottom: 16px;
  color: var(--text-primary);
  min-height: 60px;
}

.hint-text {
  text-align: center;
  font-size: 1rem;
  color: var(--warning);
  margin-bottom: 16px;
  min-height: 24px;
}

/* Options Container */
.options-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 24px;
}

.option-btn {
  padding: 16px;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--bg-card);
  border: 2px solid transparent;
  border-radius: var(--radius);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s;
}

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

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

.option-btn.correct {
  background: var(--success);
  border-color: var(--success);
  color: white;
}

.option-btn.incorrect {
  background: var(--danger);
  border-color: var(--danger);
  color: white;
}

.option-btn.reveal {
  border-color: var(--success);
  opacity: 0.6;
}

/* Rating Container */
.rating-container {
  text-align: center;
  margin-bottom: 24px;
}

.rating-prompt {
  margin-bottom: 16px;
  color: var(--text-secondary);
}

.rating-buttons {
  display: flex;
  gap: 8px;
  justify-content: center;
}

.rating-btn {
  flex: 1;
  max-width: 80px;
  padding: 12px 8px;
  font-size: 0.85rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
}

.rating-btn.again { background: var(--danger); color: white; }
.rating-btn.hard { background: var(--warning); color: white; }
.rating-btn.good { background: var(--accent); color: white; }
.rating-btn.easy { background: var(--success); color: white; }

.rating-btn:hover {
  transform: translateY(-2px);
  filter: brightness(1.1);
}

/* Action Buttons */
.action-buttons {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-bottom: 24px;
}

.primary-btn {
  padding: 14px 32px;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
}

.primary-btn:hover {
  background: var(--accent-hover);
  transform: translateY(-2px);
}

.secondary-btn {
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 500;
  background: var(--bg-card);
  color: var(--text-primary);
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
}

.secondary-btn:hover {
  background: var(--bg-secondary);
}

.text-btn {
  background: none;
  border: none;
  color: var(--accent);
  font-size: 0.9rem;
  cursor: pointer;
  padding: 8px;
}

.text-btn:hover {
  text-decoration: underline;
}

.danger-btn {
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 500;
  background: transparent;
  color: var(--danger);
  border: 1px solid var(--danger);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
}

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

/* Feedback */
.feedback {
  text-align: center;
  padding: 16px;
  border-radius: var(--radius);
  margin-bottom: 16px;
  font-weight: 500;
}

.feedback.success {
  background: rgba(34, 197, 94, 0.15);
  color: var(--success);
}

.feedback.error {
  background: rgba(239, 68, 68, 0.15);
  color: var(--danger);
}

/* Stats Screen */
#statsScreen h2,
#settingsScreen h2 {
  text-align: center;
  margin-bottom: 24px;
}

.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 32px;
}

.stat-card {
  background: var(--bg-card);
  padding: 20px;
  border-radius: var(--radius);
  text-align: center;
}

.stat-value {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.deck-progress {
  margin-bottom: 32px;
}

.deck-progress h3 {
  font-size: 1rem;
  margin-bottom: 16px;
  color: var(--text-secondary);
}

.progress-bars {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

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

.progress-label {
  width: 60px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.progress-bar {
  flex: 1;
  height: 8px;
  background: var(--bg-secondary);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 4px;
  transition: width 0.3s ease;
}

/* Settings Screen */
.setting-group {
  background: var(--bg-card);
  padding: 20px;
  border-radius: var(--radius);
  margin-bottom: 16px;
}

.setting-group label {
  display: block;
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.toggle-group {
  display: flex;
  gap: 8px;
}

.toggle-btn {
  flex: 1;
  padding: 12px;
  font-size: 0.9rem;
  font-weight: 500;
  background: var(--bg-secondary);
  border: 2px solid transparent;
  border-radius: var(--radius);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.toggle-btn.active {
  background: var(--accent);
  color: white;
}

.toggle-btn:hover:not(.active) {
  border-color: var(--accent);
}

.range-selector {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.range-selector select {
  flex: 1;
  padding: 12px;
  font-size: 1rem;
  background: var(--bg-secondary);
  border: none;
  border-radius: var(--radius);
  color: var(--text-primary);
  cursor: pointer;
}

.range-selector span {
  color: var(--text-secondary);
}

.data-buttons {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

/* Utilities */
.hidden {
  display: none !important;
}

/* Mobile Adjustments */
@media (max-width: 400px) {
  .playing-card {
    width: 120px;
    height: 168px;
  }

  .card-content {
    font-size: 2.5rem;
  }

  .rating-buttons {
    flex-wrap: wrap;
  }

  .rating-btn {
    min-width: 70px;
  }
}