/* ============================================
   Review / Error Analysis Page
   ============================================ */
.review-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.error-group {
  margin-bottom: var(--space-6);
}
.error-group__header {
  display: flex; align-items: center; justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  background: var(--bg-surface-secondary);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-3);
}
.error-group__title {
  font-size: var(--text-sm); font-weight: var(--weight-semibold);
  display: flex; align-items: center; gap: var(--space-2);
}
.error-group__count {
  font-size: var(--text-xs); color: var(--text-tertiary);
}

.error-card {
  display: flex; gap: var(--space-4);
  padding: var(--space-4);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-surface);
  margin-bottom: var(--space-3);
  transition: all var(--transition-fast);
}
.error-card:hover {
  border-color: var(--color-primary-light);
  box-shadow: var(--shadow-sm);
}
.error-card__indicator {
  width: 4px; border-radius: var(--radius-full);
  flex-shrink: 0;
}
.error-card__indicator--wrong { background: var(--color-danger); }
.error-card__indicator--lucky { background: var(--color-warning); }
.error-card__indicator--slow { background: var(--color-info); }
.error-card__indicator--unstable { background: #8B5CF6; }

.error-card__content { flex: 1; min-width: 0; }
.error-card__question {
  font-size: var(--text-sm); color: var(--text-primary);
  margin-bottom: var(--space-2);
  line-height: var(--leading-normal);
}
.error-card__meta {
  display: flex; flex-wrap: wrap; gap: var(--space-2);
  margin-bottom: var(--space-3);
}
.error-card__actions {
  display: flex; gap: var(--space-2);
}

/* Resolved indicator */
.error-card.resolved {
  opacity: 0.6;
  border-left: 3px solid var(--color-accent);
}

@media (max-width: 767px) {
  .review-stats {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ============================================
   Knowledge Map Page
   ============================================ */
.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: var(--space-3);
  margin-bottom: var(--space-6);
}
.knowledge-cell {
  aspect-ratio: 1;
  border-radius: var(--radius-lg);
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  padding: var(--space-3);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 2px solid transparent;
}
.knowledge-cell:hover {
  transform: scale(1.05);
  border-color: rgba(255,255,255,0.3);
}
.knowledge-cell__unit {
  font-size: var(--text-xs); font-weight: var(--weight-semibold);
  opacity: 0.9; margin-bottom: var(--space-1);
}
.knowledge-cell__name {
  font-size: var(--text-xs);
  opacity: 0.8;
  line-height: 1.3;
}
.knowledge-cell__score {
  font-size: var(--text-xl); font-weight: var(--weight-bold);
  margin-top: var(--space-2);
}

/* Mastery levels → color mapping */
.knowledge-cell--mastered {
  background: linear-gradient(135deg, #059669, #10B981);
  color: #fff;
}
.knowledge-cell--proficient {
  background: linear-gradient(135deg, #0D9488, #14B8A6);
  color: #fff;
}
.knowledge-cell--developing {
  background: linear-gradient(135deg, #D97706, #F59E0B);
  color: #fff;
}
.knowledge-cell--weak {
  background: linear-gradient(135deg, #DC2626, #EF4444);
  color: #fff;
}
.knowledge-cell--untested {
  background: var(--bg-surface-secondary);
  color: var(--text-tertiary);
  border: 1px dashed var(--border-color);
}

/* Radar chart container */
.radar-container {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  display: flex; align-items: center; justify-content: center;
}
.radar-container canvas {
  max-width: 400px; max-height: 400px;
}

@media (max-width: 767px) {
  .knowledge-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}