/* ===== FLASHCARDS TAB ===== */
.cards-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  flex-wrap: wrap;
  gap: 12px;
}

.cards-count {
  font-size: 1rem;
  color: var(--text-muted);
}

.cards-filters {
  display: flex;
  gap: 4px;
  background: var(--surface);
  border-radius: 50px;
  padding: 3px;
}

.filter-btn {
  padding: 6px 14px;
  border-radius: 50px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: all var(--transition);
}

.filter-btn:hover { color: var(--text); }
.filter-btn.active { background: var(--primary); color: #fff; }

.start-study-btn {
  padding: 12px 28px;
  background: linear-gradient(135deg, var(--primary), #6d28d9);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius);
  transition: all var(--transition);
}

.start-study-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 16px var(--primary-glow);
}

/* Card Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 32px;
}

/* Individual Card */
.flashcard {
  perspective: 1000px;
  height: 200px;
  cursor: pointer;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.4s ease;
  transform-style: preserve-3d;
}

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

.flashcard-front, .flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 20px;
  text-align: center;
  overflow: hidden;
}

.flashcard-front {
  background: linear-gradient(135deg, #7c3aed, #5b21b6);
  color: #fff;
}

.flashcard-back {
  background: linear-gradient(135deg, #06b6d4, #0891b2);
  color: #fff;
  transform: rotateY(180deg);
}

.flashcard-text {
  font-family: var(--font-content);
  font-size: 0.92rem;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.flashcard-meta {
  position: absolute;
  bottom: 10px;
  left: 12px;
  right: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.difficulty-badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 50px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.difficulty-badge.easy { background: rgba(34,197,94,0.2); color: var(--correct); }
.difficulty-badge.medium { background: rgba(251,191,36,0.2); color: var(--highlight); }
.difficulty-badge.hard { background: rgba(239,68,68,0.2); color: var(--wrong); }

.card-category {
  font-size: 0.7rem;
  color: rgba(255,255,255,0.6);
}

/* Deck Stats */
.deck-stats {
  background: var(--card);
  border-radius: var(--radius);
  padding: 20px;
  display: flex;
  gap: 24px;
  align-items: center;
  flex-wrap: wrap;
}

.deck-stat-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
}

.deck-stat-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.deck-stat-dot.mastered { background: var(--correct); }
.deck-stat-dot.reviewing { background: var(--highlight); }
.deck-stat-dot.unseen { background: var(--text-muted); }

.deck-progress-bar {
  flex: 1;
  min-width: 120px;
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.deck-progress-segments {
  display: flex;
  height: 100%;
}

.deck-progress-mastered { background: var(--correct); transition: width 0.3s ease; }
.deck-progress-reviewing { background: var(--highlight); transition: width 0.3s ease; }

/* ===== STUDY MODE ===== */
.study-mode-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--bg);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.study-mode-header {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
}

.study-mode-progress {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 1;
  max-width: 400px;
}

.study-progress-bar {
  flex: 1;
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.study-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  border-radius: 3px;
  transition: width 0.3s ease;
  width: 0%;
}

#study-progress-text {
  font-size: 0.85rem;
  color: var(--text-muted);
  white-space: nowrap;
}

/* Study Card */
.study-mode-card-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
}

.study-card {
  perspective: 1200px;
  width: 500px;
  height: 300px;
  cursor: pointer;
  animation: slideInRight 0.3s ease;
}

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(60px); }
  to { opacity: 1; transform: translateX(0); }
}

.study-card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.4s ease;
  transform-style: preserve-3d;
}

.study-card.flipped .study-card-inner {
  transform: rotateY(180deg);
}

.study-card-front, .study-card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 32px;
  text-align: center;
}

.study-card-front {
  background: linear-gradient(135deg, #7c3aed, #5b21b6);
  color: #fff;
}

.study-card-back {
  background: linear-gradient(135deg, #06b6d4, #0891b2);
  color: #fff;
  transform: rotateY(180deg);
}

.study-card-label {
  position: absolute;
  top: 14px;
  left: 20px;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  opacity: 0.6;
  font-weight: 600;
}

.study-card-front p, .study-card-back p {
  font-family: var(--font-content);
  font-size: 1.1rem;
  line-height: 1.6;
}

.study-flip-hint {
  margin-top: 16px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Study Actions */
.study-mode-actions {
  display: flex;
  gap: 16px;
  padding: 24px;
}

.study-btn {
  padding: 12px 32px;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  transition: all var(--transition);
}

.study-btn:hover { transform: translateY(-2px); }
.study-btn.again { background: rgba(239,68,68,0.15); color: var(--wrong); border: 1px solid rgba(239,68,68,0.3); }
.study-btn.again:hover { background: rgba(239,68,68,0.25); }
.study-btn.hard { background: rgba(251,191,36,0.15); color: var(--highlight); border: 1px solid rgba(251,191,36,0.3); }
.study-btn.hard:hover { background: rgba(251,191,36,0.25); }
.study-btn.got-it { background: rgba(34,197,94,0.15); color: var(--correct); border: 1px solid rgba(34,197,94,0.3); }
.study-btn.got-it:hover { background: rgba(34,197,94,0.25); }

.study-shortcuts-hint {
  padding-bottom: 16px;
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ===== DECK COMPLETE ===== */
.deck-complete-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(15,17,23,0.92);
  z-index: 1001;
  display: flex;
  align-items: center;
  justify-content: center;
}

.deck-complete-card {
  background: var(--card);
  border-radius: var(--radius-lg);
  padding: 40px;
  text-align: center;
  animation: fadeSlideUp 0.4s ease;
  max-width: 420px;
  width: 90%;
}

.deck-complete-card h2 {
  font-family: var(--font-display);
  font-size: 1.6rem;
  margin-bottom: 24px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.deck-complete-stats {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin-bottom: 28px;
}

.deck-stat { display: flex; flex-direction: column; align-items: center; gap: 4px; }
.deck-stat-value { font-size: 1.4rem; font-weight: 700; color: var(--text); }
.deck-stat-label { font-size: 0.78rem; color: var(--text-muted); }

.deck-complete-actions { display: flex; gap: 12px; justify-content: center; }

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
  .cards-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .cards-grid { grid-template-columns: 1fr; }
  .study-card { width: 90vw; max-width: 400px; height: 250px; }
  .cards-header { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 480px) {
  .flashcard { height: 180px; }
  .study-card { height: 220px; }
  .study-card-front p, .study-card-back p { font-size: 0.95rem; }
  .study-btn { padding: 10px 20px; font-size: 0.85rem; }
}