.review-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  gap: var(--space-6);
  padding: var(--space-4);
}

.flashcard-wrapper {
  perspective: 1000px;
  width: 100%;
  max-width: 480px;
  height: 300px;
}

.flashcard {
  width: 100%;
  height: 100%;
  position: relative;
  transition: transform 0.6s;
  transform-style: preserve-3d;
  cursor: pointer;
}

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

.flashcard-face {
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-6);
  text-align: center;
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border);
}

.flashcard-face--front {
  background: var(--surface);
}

.flashcard-face--front .phrase-text {
  font-family: var(--font-display);
  font-size: 32px;
  font-weight: 700;
  color: var(--brand-dark);
}

.flashcard-face--front .click-hint {
  position: absolute;
  bottom: var(--space-4);
  font-size: 14px;
  color: var(--muted);
}

.flashcard-face--back {
  background: var(--surface-alt);
  transform: rotateY(180deg);
}

.flashcard-face--back .phrase-text {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: var(--space-4);
}

.flashcard-face--back .phrase-meaning {
  font-size: 18px;
  color: var(--text);
  line-height: 1.5;
}

.review-actions {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  width: 100%;
  max-width: 480px;
  opacity: 0;
  pointer-events: none;
  transform: translateY(10px);
  transition: all var(--transition-medium);
}

.review-actions.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.review-btn {
  flex: 1;
  padding: 12px 0;
  border-radius: var(--radius-md);
  font-size: 16px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform var(--transition-fast), filter var(--transition-fast), box-shadow var(--transition-fast);
}

.review-btn:hover {
  transform: translateY(-2px);
  filter: brightness(1.05);
  box-shadow: var(--shadow-sm);
}

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

.review-btn--forget {
  background: #FEF2F2;
  color: #DC2626;
  border: 1px solid #FECACA;
}

.review-btn--vague {
  background: #FFFBEB;
  color: #D97706;
  border: 1px solid #FDE68A;
}

.review-btn--know {
  background: #ECFDF5;
  color: #059669;
  border: 1px solid #A7F3D0;
}

.progress-text {
  font-size: 14px;
  color: var(--muted);
  font-weight: 600;
}

.empty-review {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-8);
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}

.empty-review h2 {
  font-size: 24px;
  color: var(--text-main);
}

.empty-review p {
  color: var(--muted);
}