/* FlashCards - Design System Completo */

/* ============================================
   Componentes Base
   ============================================ */

/* Sidebar Components */
.sidebar-header {
  height: var(--header-height);
  display: flex;
  align-items: center;
  padding: 0 var(--spacing-lg);
  border-bottom: 1px solid var(--border);
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.sidebar-logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
}

.sidebar-logo-text {
  font-weight: 700;
  font-size: 1.2rem;
  transition: opacity var(--transition-base);
}

.sidebar.collapsed .sidebar-logo-text {
  opacity: 0;
  visibility: hidden;
}

.sidebar-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar-nav {
  flex: 1;
  padding: var(--spacing-sm);
  overflow-y: auto;
  overflow-x: hidden;
}

.sidebar-footer {
  padding: var(--spacing-sm);
  border-top: 1px solid var(--border);
}

.nav-item {
  display: flex;
  align-items: center;
  padding: var(--spacing-sm) var(--spacing-md);
  margin-bottom: var(--spacing-xs);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
  user-select: none;
}

.nav-item:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.nav-item.active {
  background: rgba(var(--primary-rgb), 0.15);
  color: var(--primary);
}

.nav-icon {
  width: 20px;
  height: 20px;
  margin-right: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.sidebar.collapsed .nav-icon {
  margin-right: 0;
}

.nav-text {
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
}

.sidebar.collapsed .nav-text {
  display: none;
}

.nav-badge {
  margin-left: auto;
  background: var(--bg-hover);
  color: var(--text-primary);
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 0.75rem;
  font-weight: 600;
}

.nav-badge.due {
  background: var(--primary);
  color: white;
}

.sidebar.collapsed .nav-badge {
  display: none;
}

/* Header */
.header-title {
  font-size: 1.5rem;
  font-weight: 600;
}

.header-actions {
  display: flex;
  gap: var(--spacing-sm);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  background: transparent;
  font-family: var(--font-sans);
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: white;
  box-shadow: 0 4px 14px rgba(var(--primary-rgb), 0.25);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(var(--primary-rgb), 0.35);
}

.btn-secondary {
  background: var(--bg-panel);
  color: var(--text-primary);
  border: 2px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  padding: var(--spacing-sm);
}

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

.icon-btn {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
}

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

/* Cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

/* Mobile Components */
.mobile-title {
  font-size: 1.125rem;
  font-weight: 600;
}

.mobile-nav-wrapper {
  display: flex;
  height: 100%;
  align-items: center;
  justify-content: space-around;
}

.mobile-nav-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.mobile-nav-item.active {
  color: var(--primary);
}

.mobile-nav-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: 40px;
  height: 3px;
  background: var(--primary);
  border-radius: 0 0 3px 3px;
  transition: transform var(--transition-fast);
}

.mobile-nav-item.active::before {
  transform: translateX(-50%) scaleX(1);
}

.mobile-nav-item span {
  font-size: 0.75rem;
  font-weight: 500;
}

.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 29;
  opacity: 0;
  transition: opacity var(--transition-base);
}

.sidebar-overlay.active {
  display: block;
  opacity: 1;
}

/* ============================================
   Dashboard Components
   ============================================ */

.view-section {
  animation: fadeIn var(--transition-base);
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  transition: all var(--transition-base);
}

.stat-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}

.stat-icon {
  width: 48px;
  height: 48px;
  background: rgba(var(--primary-rgb), 0.1);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
}

.stat-content h3 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text-primary);
}

.stat-content p {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.quick-actions {
  margin-bottom: var(--spacing-xl);
}

.quick-actions h2 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
}

.actions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--spacing-md);
}

.action-card {
  background: var(--bg-card);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-base);
}

.action-card:hover {
  border-color: var(--primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.action-card:hover svg {
  color: var(--primary);
  transform: scale(1.1);
}

.action-card svg {
  width: 32px;
  height: 32px;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-sm);
  transition: all var(--transition-base);
}

.action-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  color: var(--text-primary);
}

.action-card p {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.recent-activity {
  margin-top: var(--spacing-xl);
}

.recent-activity h2 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
}

.activity-list {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  min-height: 200px;
}

/* ============================================
   Decks View
   ============================================ */

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-xl);
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.search-bar {
  flex: 1;
  max-width: 400px;
  position: relative;
}

.search-bar svg {
  position: absolute;
  left: var(--spacing-md);
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--text-muted);
}

.search-bar input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md) var(--spacing-sm) calc(var(--spacing-md) + 28px);
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.875rem;
}

.search-bar input:focus {
  outline: none;
  border-color: var(--primary);
}

.filter-buttons {
  display: flex;
  gap: var(--spacing-sm);
}

.filter-btn {
  padding: var(--spacing-xs) var(--spacing-md);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: 0.875rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.filter-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: white;
}

.decks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.deck-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.deck-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.deck-card:hover::before {
  transform: scaleX(1);
}

.deck-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}

.deck-header {
  display: flex;
  justify-content: space-between;
  align-items: start;
  margin-bottom: var(--spacing-md);
}

.deck-title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.deck-description {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.deck-stats {
  display: flex;
  gap: var(--spacing-lg);
  font-size: 0.875rem;
  color: var(--text-muted);
}

.deck-stat {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.deck-stat svg {
  width: 16px;
  height: 16px;
  color: var(--primary);
}

.deck-actions {
  display: flex;
  gap: var(--spacing-xs);
}

.deck-action {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-hover);
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.deck-action:hover {
  background: var(--primary);
  color: white;
}

/* ============================================
   Study View
   ============================================ */

.study-container {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--spacing-xl);
}

.study-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-xl);
  gap: var(--spacing-lg);
}

.study-progress {
  flex: 1;
  max-width: 400px;
}

.progress-bar {
  height: 8px;
  background: var(--bg-hover);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: var(--spacing-xs);
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  transition: width var(--transition-base);
}

.progress-text {
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-align: center;
  display: block;
}

.study-timer {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--primary);
  padding: var(--spacing-xs) var(--spacing-md);
  background: rgba(var(--primary-rgb), 0.1);
  border-radius: var(--radius-md);
}

.flashcard-container {
  perspective: 1000px;
  margin-bottom: var(--spacing-xl);
}

.flashcard {
  width: 100%;
  height: 400px;
  cursor: pointer;
  position: relative;
}

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

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

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  background: var(--bg-card);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-lg);
}

.flashcard-back {
  transform: rotateY(180deg);
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: white;
  border-color: var(--primary-dark);
}

.card-content {
  font-size: 1.25rem;
  text-align: center;
  line-height: 1.6;
  max-width: 100%;
  word-wrap: break-word;
}

.card-hint {
  position: absolute;
  bottom: var(--spacing-lg);
  font-size: 0.875rem;
  color: var(--text-muted);
}

.difficulty-buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-md);
  max-width: 600px;
  margin: 0 auto;
}

.diff-btn {
  padding: var(--spacing-md);
  border: none;
  border-radius: var(--radius-md);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
}

.diff-btn svg {
  width: 24px;
  height: 24px;
}

.diff-btn span {
  font-size: 0.875rem;
}

.diff-again {
  background: #ef4444;
  color: white;
}

.diff-hard {
  background: #f59e0b;
  color: white;
}

.diff-good {
  background: #10b981;
  color: white;
}

.diff-easy {
  background: #3b82f6;
  color: white;
}

.diff-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.study-complete {
  text-align: center;
  padding: var(--spacing-xl);
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 2px solid var(--primary);
}

.study-complete svg {
  width: 64px;
  height: 64px;
  color: var(--primary);
  margin-bottom: var(--spacing-lg);
}

.study-complete h2 {
  font-size: 1.75rem;
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
}

.session-stats {
  display: flex;
  justify-content: center;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

.session-stats .stat {
  text-align: center;
}

.stat-label {
  display: block;
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xs);
}

.stat-value {
  display: block;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
}

/* ============================================
   Import/Export View
   ============================================ */

.import-export-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
}

.import-section,
.export-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
}

.import-section h2,
.export-section h2 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
}

.import-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  text-align: center;
  transition: all var(--transition-base);
  cursor: pointer;
  margin-bottom: var(--spacing-lg);
}

.import-zone:hover {
  border-color: var(--primary);
  background: rgba(var(--primary-rgb), 0.05);
}

.import-zone.dragging {
  border-color: var(--primary);
  background: rgba(var(--primary-rgb), 0.1);
}

.import-zone svg {
  width: 48px;
  height: 48px;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
}

.import-zone p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
}

.import-text h3 {
  font-size: 1rem;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.import-text textarea {
  width: 100%;
  min-height: 120px;
  padding: var(--spacing-md);
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: monospace;
  font-size: 0.875rem;
  resize: vertical;
  margin-bottom: var(--spacing-md);
}

.import-text textarea:focus {
  outline: none;
  border-color: var(--primary);
}

.export-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.export-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md);
  background: var(--bg-panel);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.export-item:hover {
  background: var(--bg-hover);
}

.export-item-info h4 {
  font-size: 1rem;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.export-item-info p {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* ============================================
   Empty States
   ============================================ */

.empty-state {
  text-align: center;
  padding: var(--spacing-3xl) var(--spacing-xl);
}

.empty-state svg {
  width: 64px;
  height: 64px;
  color: var(--text-muted);
  margin-bottom: var(--spacing-lg);
}

.empty-state h3 {
  font-size: 1.25rem;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.empty-state p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
}

/* ============================================
   Modals
   ============================================ */

.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: var(--spacing-lg);
  animation: fadeIn var(--transition-fast);
}

.modal-content {
  background: var(--bg-panel);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 500px;
  max-height: 90vh;
  overflow-y: auto;
  animation: slideIn var(--transition-base);
}

@keyframes slideIn {
  from {
    transform: translateY(-20px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--border);
}

.modal-header h3 {
  font-size: 1.125rem;
  color: var(--text-primary);
}

.modal-close {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.modal-body {
  padding: var(--spacing-lg);
}

.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-dark);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.875rem;
  font-family: var(--font-sans);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.1);
}

.form-textarea {
  min-height: 100px;
  resize: vertical;
}

.card-editor {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  max-height: 300px;
  overflow-y: auto;
}

.card-item {
  display: grid;
  grid-template-columns: 1fr 1fr auto;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  background: var(--bg-dark);
  border-radius: var(--radius-md);
  align-items: center;
}

.card-input {
  padding: var(--spacing-sm);
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.875rem;
}

.delete-card {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.delete-card:hover {
  background: rgba(var(--primary-rgb), 0.1);
  color: var(--error);
}

/* ============================================
   Toast Notifications
   ============================================ */

.toast-container {
  position: fixed;
  bottom: var(--spacing-lg);
  right: var(--spacing-lg);
  z-index: 150;
  pointer-events: none;
}

.toast {
  background: var(--bg-card);
  border-left: 4px solid var(--primary);
  border-radius: var(--radius-md);
  padding: var(--spacing-md) var(--spacing-lg);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  box-shadow: var(--shadow-lg);
  transform: translateX(400px);
  opacity: 0;
  transition: all var(--transition-base);
  pointer-events: all;
}

.toast.show {
  transform: translateX(0);
  opacity: 1;
}

.toast.success {
  border-left-color: var(--success);
}

.toast.error {
  border-left-color: var(--error);
}

.toast.warning {
  border-left-color: var(--warning);
}

.toast svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 768px) {
  .stats-grid {
    grid-template-columns: 1fr 1fr;
  }
  
  .actions-grid {
    grid-template-columns: 1fr 1fr;
  }
  
  .decks-grid {
    grid-template-columns: 1fr;
  }
  
  .import-export-container {
    grid-template-columns: 1fr;
  }
  
  .difficulty-buttons {
    grid-template-columns: 1fr 1fr;
  }
  
  .flashcard {
    height: 300px;
  }
  
  .toast-container {
    left: var(--spacing-md);
    right: var(--spacing-md);
    bottom: calc(var(--mobile-nav) + var(--spacing-md));
  }
  
  .session-stats {
    flex-direction: column;
    gap: var(--spacing-md);
  }
}

@media (max-width: 480px) {
  .stats-grid {
    grid-template-columns: 1fr;
  }
  
  .section-header {
    flex-direction: column;
    align-items: stretch;
  }
  
  .search-bar {
    max-width: 100%;
  }
  
  .filter-buttons {
    width: 100%;
  }
  
  .filter-btn {
    flex: 1;
  }
  
  .card-item {
    grid-template-columns: 1fr;
  }
}