/* ============================================================
   Karteikarten (Leitner-System) — physisches Kartei-Metapher
   ============================================================ */

.flashcard-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
}

.flashcard-progress {
  display: flex;
  gap: var(--space-1);
  align-items: center;
  font-size: var(--text-sm);
  color: var(--ink-soft);
}

.flashcard-scene {
  perspective: 1200px;
  width: 100%;
  max-width: 520px;
  height: 320px;
}

.flashcard {
  position: relative;
  width: 100%;
  height: 100%;
  cursor: pointer;
  transform-style: preserve-3d;
  transition: transform 400ms cubic-bezier(0.4, 0.0, 0.2, 1);
}

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

@media (prefers-reduced-motion: reduce) {
  .flashcard, .flashcard.flipped { transition: none; }
}

.flashcard-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: var(--radius-lg);
  border: 1px solid var(--paper-line);
  background: var(--paper);
  box-shadow: var(--shadow-raised);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-5);
  text-align: center;
  gap: var(--space-2);
}

.flashcard-face .face-label {
  position: absolute;
  top: var(--space-3); left: var(--space-3);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
  font-weight: 700;
}

.flashcard-face .face-content {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 500;
  line-height: 1.4;
}

.flashcard-back {
  transform: rotateY(180deg);
  background: var(--pen-blue-light);
}

.flashcard-hint {
  font-size: var(--text-sm);
  color: var(--ink-soft);
}

.flashcard-actions {
  display: flex;
  gap: var(--space-3);
  width: 100%;
  max-width: 520px;
}

.flashcard-actions .btn {
  flex: 1;
  justify-content: center;
  padding: var(--space-3);
  font-size: var(--text-base);
}

.btn-correct {
  background: var(--sage);
  color: white;
}
.btn-incorrect {
  background: var(--brick);
  color: white;
}

/* --- Leitner-Kasten: 5 sichtbare Boxen als Fortschrittsanzeige --- */
.leitner-box-row {
  display: flex;
  gap: var(--space-2);
  justify-content: center;
}

.leitner-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: var(--space-2);
  border-radius: var(--radius-sm);
  min-width: 52px;
}

.leitner-box .box-num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--ink-soft);
}

.leitner-box .box-icon {
  width: 28px; height: 22px;
  border-radius: 2px;
  background: var(--paper-line);
  transition: background var(--transition-base), transform var(--transition-base);
}

.leitner-box.box-current .box-icon {
  background: var(--gold);
  transform: scale(1.15);
}