/* ==========================================================================
   Reusable Components
   ========================================================================== */

/* --------------------------------------------------------------------------
   BUTTONS
   -------------------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-tight);
  text-align: center;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  box-shadow: var(--shadow-xs);
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
  min-height: var(--touch-target-min);
  white-space: nowrap;
  -webkit-user-select: none;
  user-select: none;
}

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

.btn:disabled,
.btn.disabled {
  opacity: 0.45;
  cursor: not-allowed;
  pointer-events: none;
  transform: none;
}

.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--font-size-sm);
  min-height: 36px;
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--font-size-lg);
  min-height: 52px;
}

/* Primary button */
.btn-primary {
  background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600));
  color: var(--color-text-inverse);
  border-color: var(--color-primary-600);
}

.btn-primary:hover {
  background-color: var(--color-primary-700);
  border-color: var(--color-primary-700);
  box-shadow: var(--shadow-md);
}

.btn-primary:focus-visible {
  box-shadow: var(--shadow-focus);
}

.btn-primary:active {
  background-color: var(--color-primary-800);
  border-color: var(--color-primary-800);
}

/* Secondary button — outlined */
.btn-secondary {
  background-color: var(--color-surface);
  color: var(--color-text-secondary);
  border-color: var(--color-border);
}

.btn-secondary:hover {
  background-color: var(--color-neutral-50);
  border-color: var(--color-primary-300);
  color: var(--color-text-primary);
}

.btn-secondary:focus-visible {
  box-shadow: var(--shadow-focus);
}

.btn-secondary:active {
  background-color: var(--color-neutral-200);
}

/* Danger button — red */
.btn-danger {
  background-color: var(--color-error);
  color: var(--color-text-inverse);
  border-color: var(--color-error);
}

.btn-danger:hover {
  background-color: var(--color-error-dark);
  border-color: var(--color-error-dark);
  box-shadow: var(--shadow-md);
}

.btn-danger:focus-visible {
  box-shadow: var(--shadow-error);
}

.btn-danger:active {
  background-color: #a93226;
}

/* Ghost/text button */
.btn-ghost {
  background-color: transparent;
  color: var(--color-text-secondary);
  border-color: transparent;
  padding: var(--space-2) var(--space-3);
}

.btn-ghost:hover {
  background-color: var(--color-primary-50);
  color: var(--color-text-primary);
}

/* Teal button (for presentation mode) */
.btn-teal {
  background: linear-gradient(135deg, var(--color-secondary-500), var(--color-secondary-700));
  color: var(--color-text-inverse);
  border-color: var(--color-secondary-600);
}

.btn-teal:hover {
  background-color: var(--color-secondary-700);
  border-color: var(--color-secondary-700);
  box-shadow: var(--shadow-md);
}

/* Icon-only button */
.btn-icon {
  padding: var(--space-2);
  min-height: var(--touch-target-min);
  min-width: var(--touch-target-min);
  border-radius: var(--radius-md);
}

.btn-icon svg {
  width: 20px;
  height: 20px;
}

/* Button with loading spinner */
.btn .btn-spinner {
  display: none;
  width: 18px;
  height: 18px;
  border: 2px solid transparent;
  border-top-color: currentColor;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

.btn.loading .btn-spinner {
  display: inline-block;
}

.btn.loading .btn-text {
  margin-left: var(--space-2);
}

/* --------------------------------------------------------------------------
   CARDS
   -------------------------------------------------------------------------- */

.card {
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-light);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
}

.card:hover {
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-primary-200);
  transform: translateY(-2px);
}

.card-image {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  background-color: var(--color-neutral-100);
}

.card-body {
  padding: var(--space-3) var(--space-4);
}

.card-title {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-1);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.card-description {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: var(--line-height-normal);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: var(--space-2);
}

.card-meta {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
}

/* --------------------------------------------------------------------------
   DATE PICKER WITH PHOTO COUNTS
   -------------------------------------------------------------------------- */

.date-picker {
  position: relative;
  min-width: 280px;
}

.date-picker-native-input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.date-picker-toggle {
  width: 100%;
  min-height: 44px;
  justify-content: space-between;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3) var(--space-2) var(--space-4);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-text-primary);
  box-shadow: var(--shadow-xs);
}

.date-picker-toggle:hover {
  border-color: var(--color-primary-200);
  box-shadow: var(--shadow-sm);
}

.date-picker-label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
}

.date-picker-selected-count {
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-full);
  background: var(--color-accent-100);
  color: var(--color-accent-900);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-bold);
  white-space: nowrap;
}

.date-picker-popover {
  position: absolute;
  top: calc(100% + var(--space-2));
  right: 0;
  width: min(340px, calc(100vw - var(--space-8)));
  padding: var(--space-4);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  background:
    linear-gradient(180deg, rgba(255, 251, 234, 0.96), rgba(255, 255, 255, 0.98)),
    var(--color-surface);
  box-shadow: var(--shadow-xl);
  z-index: var(--z-dropdown);
}

.date-picker-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.date-picker-month {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
}

.date-picker-nav {
  width: 34px;
  height: 34px;
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-full);
  background: var(--color-surface);
  color: var(--color-text-secondary);
}

.date-picker-nav:hover:not(:disabled) {
  background: var(--color-primary-50);
  color: var(--color-primary-700);
  border-color: var(--color-primary-200);
}

.date-picker-nav:disabled {
  opacity: 0.35;
}

.date-picker-weekdays,
.date-picker-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: var(--space-1);
}

.date-picker-weekday {
  padding: var(--space-1) 0;
  text-align: center;
  color: var(--color-text-tertiary);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-bold);
}

.date-picker-empty-cell {
  min-height: 48px;
}

.date-picker-day {
  min-width: 0;
  min-height: 48px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  align-items: center;
  justify-content: center;
  padding: var(--space-1);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.72);
  color: var(--color-text-secondary);
}

.date-picker-day:hover:not(:disabled) {
  border-color: var(--color-primary-200);
  background: var(--color-primary-50);
  color: var(--color-primary-800);
  transform: translateY(-1px);
}

.date-picker-day:disabled {
  opacity: 0.28;
}

.date-picker-day-number {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
  line-height: 1;
}

.date-picker-day-count {
  min-height: 15px;
  color: var(--color-text-tertiary);
  font-size: 0.65rem;
  font-weight: var(--font-weight-semibold);
  line-height: 1;
}

.date-picker-day.has-photos {
  background: var(--color-accent-100);
  color: var(--color-accent-900);
  border-color: var(--color-accent-200);
}

.date-picker-day.has-photos .date-picker-day-count {
  color: var(--color-primary-700);
}

.date-picker-day.is-today {
  box-shadow: inset 0 0 0 2px var(--color-secondary-300);
}

.date-picker-day.is-selected {
  background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-700));
  color: var(--color-text-inverse);
  border-color: var(--color-primary-700);
  box-shadow: var(--shadow-md);
}

.date-picker-day.is-selected .date-picker-day-count {
  color: rgba(255, 255, 255, 0.88);
}

.presentation-page .date-picker {
  min-width: min(320px, 74vw);
}

.presentation-page .date-picker-toggle {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.22);
  color: var(--color-present-text);
  box-shadow: none;
}

.presentation-page .date-picker-selected-count {
  background: rgba(255, 212, 59, 0.22);
  color: var(--color-present-sub);
}

.presentation-page .date-picker-popover {
  left: 0;
  right: auto;
  color: var(--color-text-primary);
}

@media (max-width: 767px) {
  .date-picker {
    width: 100%;
    min-width: 0;
  }

  .date-picker-popover {
    left: 0;
    right: auto;
  }
}

/* Clickable card */
.card-clickable {
  cursor: pointer;
}

.card-clickable:active {
  transform: translateY(0);
}

/* Skeleton loading card */
.card-skeleton .card-image,
.card-skeleton .card-title,
.card-skeleton .card-description {
  background: linear-gradient(
    90deg,
    var(--color-neutral-100) 0%,
    var(--color-neutral-200) 50%,
    var(--color-neutral-100) 100%
  );
  background-size: 200% 100%;
  animation: skeleton-pulse 1.5s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

.card-skeleton .card-title {
  height: 16px;
  width: 70%;
}

.card-skeleton .card-description {
  height: 12px;
  width: 90%;
}

/* --------------------------------------------------------------------------
   PHOTO GRID
   -------------------------------------------------------------------------- */

.photo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: var(--space-4);
}

@media (min-width: 768px) {
  .photo-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  }
}

@media (min-width: 1280px) {
  .photo-grid {
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  }
}

/* Photo group by student */
.photo-group {
  margin-bottom: var(--space-10);
}

.photo-group-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xs);
}

.photo-group-name {
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
}

.photo-group-id {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
}

/* Highlight animation for scrolling to student group */
.photo-group.highlight {
  animation: highlight-flash 1s ease;
}

/* --------------------------------------------------------------------------
   FORM COMPONENTS
   -------------------------------------------------------------------------- */

.form-group {
  margin-bottom: var(--space-5);
}

.form-label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.form-label-required::after {
  content: " *";
  color: var(--color-error);
}

.form-input {
  display: block;
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xs);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-fast);
}

.form-input:hover {
  border-color: var(--color-primary-300);
}

.form-input:focus {
  border-color: var(--color-primary-500);
  box-shadow: var(--shadow-focus);
  outline: none;
}

.form-input.error {
  border-color: var(--color-error);
  box-shadow: var(--shadow-error);
}

.form-input.error:focus {
  border-color: var(--color-error);
  box-shadow: var(--shadow-error);
}

.form-textarea {
  display: block;
  width: 100%;
  min-height: 140px;
  padding: var(--space-3) var(--space-4);
  font-size: var(--font-size-base);
  color: var(--color-text-primary);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xs);
  resize: vertical;
  line-height: var(--line-height-relaxed);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-textarea:hover {
  border-color: var(--color-primary-300);
}

.form-textarea:focus {
  border-color: var(--color-primary-500);
  box-shadow: var(--shadow-focus);
  outline: none;
}

.form-textarea.error {
  border-color: var(--color-error);
  box-shadow: var(--shadow-error);
}

.form-helper {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  margin-top: var(--space-1);
}

.form-error {
  font-size: var(--font-size-xs);
  color: var(--color-error);
  margin-top: var(--space-1);
  display: none;
}

.form-group.has-error .form-error {
  display: block;
}

.form-group.has-error .form-input,
.form-group.has-error .form-textarea {
  border-color: var(--color-error);
}

/* --------------------------------------------------------------------------
   CHARACTER COUNTER
   -------------------------------------------------------------------------- */

.char-counter {
  display: flex;
  justify-content: flex-end;
  margin-top: var(--space-1);
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  transition: color var(--transition-base);
}

.char-counter.insufficient {
  color: var(--color-error);
}

.char-counter.sufficient {
  color: var(--color-success);
}

.char-counter.insufficient.bold {
  font-weight: var(--font-weight-bold);
}

/* --------------------------------------------------------------------------
   FILE PREVIEW
   -------------------------------------------------------------------------- */

.file-preview {
  position: relative;
  width: 200px;
  height: 200px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background-color: var(--color-neutral-100);
  border: 2px dashed var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-3);
}

.file-preview.has-image {
  border-style: solid;
  border-color: var(--color-border-light);
}

.file-preview img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.file-preview-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-tertiary);
}

.file-preview-placeholder svg {
  width: 48px;
  height: 48px;
  opacity: 0.4;
}

.file-preview-placeholder span {
  font-size: var(--font-size-xs);
}

.file-info {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  margin-top: var(--space-1);
}

/* File drop zone (the clickable label) */
.file-dropzone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  width: 100%;
  padding: var(--space-8) var(--space-4);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-lg);
  background-color: var(--color-neutral-50);
  cursor: pointer;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
  text-align: center;
}

.file-dropzone:hover {
  border-color: var(--color-primary-400);
  background-color: var(--color-primary-50);
}

.file-dropzone svg {
  width: 40px;
  height: 40px;
  color: var(--color-text-tertiary);
}

.file-dropzone-text {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
}

.file-dropzone-hint {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
}

/* --------------------------------------------------------------------------
   MODAL / LIGHTBOX
   -------------------------------------------------------------------------- */

.modal-overlay {
  position: fixed;
  inset: 0;
  background-color: var(--color-overlay);
  z-index: var(--z-modal);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-modal);
  border: 1px solid rgba(255, 255, 255, 0.7);
  max-width: 90vw;
  max-height: 90vh;
  overflow: hidden;
  transform: scale(0.92);
  transition: transform var(--transition-base);
  display: flex;
  flex-direction: column;
}

.modal-overlay.active .modal-content {
  transform: scale(1);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--color-border-light);
}

.modal-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
}

.modal-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-tertiary);
  transition: background-color var(--transition-fast), color var(--transition-fast);
  cursor: pointer;
  background: none;
  border: none;
  flex-shrink: 0;
}

.modal-close:hover {
  background-color: var(--color-neutral-100);
  color: var(--color-text-primary);
}

.modal-close svg {
  width: 20px;
  height: 20px;
}

.modal-body {
  padding: var(--space-5);
  overflow-y: auto;
  flex: 1;
}

.modal-image {
  max-width: 80vw;
  max-height: 65vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  margin: 0 auto var(--space-4);
  display: block;
}

.modal-photo-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.modal-photo-description {
  font-size: var(--font-size-base);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-3);
  white-space: pre-wrap;
}

.modal-photo-meta {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
}

/* Lightbox variant (admin, darker overlay) */
.lightbox-overlay {
  background-color: var(--color-overlay-heavy);
}

/* --------------------------------------------------------------------------
   TOAST NOTIFICATIONS
   -------------------------------------------------------------------------- */

.toast-container {
  position: fixed;
  top: var(--space-4);
  left: 50%;
  transform: translateX(-50%);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  width: 100%;
  max-width: 440px;
  padding: 0 var(--space-4);
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border-light);
  border-left: 4px solid var(--color-neutral-400);
  pointer-events: auto;
  animation: toast-slide-in 0.3s var(--ease-out);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.toast.hiding {
  opacity: 0;
  transform: translateY(-8px);
}

.toast-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  margin-top: 2px;
}

.toast-content {
  flex: 1;
  min-width: 0;
}

.toast-message {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  line-height: var(--line-height-snug);
}

.toast-detail {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  margin-top: var(--space-1);
}

.toast-close {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  color: var(--color-text-tertiary);
  cursor: pointer;
  background: none;
  border: none;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.toast-close:hover {
  background-color: var(--color-neutral-100);
  color: var(--color-text-primary);
}

.toast-close svg {
  width: 14px;
  height: 14px;
}

/* Toast variants */
.toast-success {
  border-left-color: var(--color-success);
}

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

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

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

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

.toast-info .toast-icon {
  color: var(--color-info);
}

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

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

/* Toast with thumbnail */
.toast-thumbnail {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  object-fit: cover;
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   BADGE
   -------------------------------------------------------------------------- */

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 22px;
  height: 22px;
  padding: 0 var(--space-2);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-bold);
  line-height: 1;
  color: var(--color-text-inverse);
  background-color: var(--color-primary-600);
  border-radius: var(--radius-full);
}

.badge-secondary {
  background-color: var(--color-neutral-500);
}

.badge-success {
  background-color: var(--color-success);
}

.badge-error {
  background-color: var(--color-error);
}

.badge-teal {
  background-color: var(--color-secondary-600);
  color: var(--color-text-inverse);
}

.badge-sm {
  min-width: 18px;
  height: 18px;
  font-size: 10px;
  padding: 0 5px;
}

/* --------------------------------------------------------------------------
   STUDENT CARD (Admin sidebar)
   -------------------------------------------------------------------------- */

.student-card {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
  border: 1px solid transparent;
}

.student-card:hover {
  background-color: var(--color-primary-50);
  border-color: var(--color-primary-200);
  transform: translateY(-1px);
}

.student-card.active {
  background-color: var(--color-primary-50);
  border-color: var(--color-primary-200);
}

.student-card-avatar {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-100);
  color: var(--color-primary-700);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.student-card-avatar svg {
  width: 20px;
  height: 20px;
}

.student-card-info {
  flex: 1;
  min-width: 0;
}

.student-card-name {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.student-card-id {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
}

.student-card-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   HEADER / NAVIGATION
   -------------------------------------------------------------------------- */

.header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border-light);
  padding: 0 var(--space-4);
  height: var(--header-height);
  display: flex;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
}

.header-logo {
  width: 36px;
  height: 36px;
}

.header-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  letter-spacing: var(--letter-spacing-tight);
}

.header-subtitle {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  font-weight: var(--font-weight-normal);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-text-primary);
  background-color: var(--color-neutral-100);
  text-decoration: none;
}

.nav-link.active {
  color: var(--color-primary-700);
  background-color: var(--color-primary-50);
}

/* --------------------------------------------------------------------------
   LOADING SPINNER
   -------------------------------------------------------------------------- */

.loading-spinner {
  display: inline-block;
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-neutral-200);
  border-top-color: var(--color-primary-600);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

.loading-spinner-sm {
  width: 18px;
  height: 18px;
  border-width: 2px;
}

.loading-spinner-lg {
  width: 48px;
  height: 48px;
  border-width: 4px;
}

/* Loading overlay for sections */
.loading-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: rgba(250, 249, 245, 0.8);
  z-index: var(--z-overlay);
  border-radius: inherit;
}

/* --------------------------------------------------------------------------
   EMPTY STATE
   -------------------------------------------------------------------------- */

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-12) var(--space-4);
  text-align: center;
}

.empty-state-icon {
  width: 80px;
  height: 80px;
  color: var(--color-neutral-300);
  margin-bottom: var(--space-4);
}

.empty-state-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.empty-state-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
  max-width: 360px;
  line-height: var(--line-height-relaxed);
}

/* --------------------------------------------------------------------------
   ALERT / INLINE ERROR
   -------------------------------------------------------------------------- */

.alert {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-snug);
}

.alert-error {
  background-color: var(--color-error-light);
  color: var(--color-error-dark);
  border: 1px solid rgba(231, 76, 60, 0.2);
}

.alert-success {
  background-color: var(--color-success-light);
  color: var(--color-success-dark);
  border: 1px solid rgba(39, 174, 96, 0.2);
}

.alert-warning {
  background-color: var(--color-warning-light);
  color: var(--color-warning-dark);
  border: 1px solid rgba(243, 156, 18, 0.2);
}

.alert-info {
  background-color: var(--color-info-light);
  color: var(--color-info-dark);
  border: 1px solid rgba(33, 150, 243, 0.2);
}

.alert-icon {
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  margin-top: 1px;
}

/* --------------------------------------------------------------------------
   STATS BAR
   -------------------------------------------------------------------------- */

.stats-bar {
  display: flex;
  gap: var(--space-6);
  flex-wrap: wrap;
}

.stat-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.stat-value {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  line-height: 1;
}

.stat-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  font-weight: var(--font-weight-medium);
}

/* --------------------------------------------------------------------------
   SKELETON LOADING
   -------------------------------------------------------------------------- */

.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-neutral-100) 0%,
    var(--color-neutral-200) 50%,
    var(--color-neutral-100) 100%
  );
  background-size: 200% 100%;
  animation: skeleton-pulse 1.5s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

.skeleton-text {
  height: 14px;
  margin-bottom: var(--space-2);
}

.skeleton-text:last-child {
  width: 60%;
}

.skeleton-avatar {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
}

.skeleton-image {
  aspect-ratio: 1 / 1;
  border-radius: var(--radius-md);
}

/* --------------------------------------------------------------------------
   DIVIDER
   -------------------------------------------------------------------------- */

.divider {
  height: 1px;
  background-color: var(--color-border-light);
  margin: var(--space-4) 0;
}

.divider-thick {
  height: 2px;
  background-color: var(--color-border);
}

/* --------------------------------------------------------------------------
   ANIMATIONS / KEYFRAMES
   -------------------------------------------------------------------------- */

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

@keyframes skeleton-pulse {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

@keyframes toast-slide-in {
  from {
    opacity: 0;
    transform: translateY(-16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fade-in {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@keyframes fade-out {
  from {
    opacity: 1;
  }
  to {
    opacity: 0;
  }
}

@keyframes slide-up {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slide-down {
  from {
    opacity: 0;
    transform: translateY(-12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scale-in {
  from {
    opacity: 0;
    transform: scale(0.92);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes highlight-flash {
  0% {
    background-color: transparent;
  }
  20% {
    background-color: var(--color-primary-100);
  }
  100% {
    background-color: transparent;
  }
}

@keyframes number-flip {
  0% {
    opacity: 0;
    transform: translateY(-6px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Utility animation classes */
.animate-fade-in {
  animation: fade-in 0.3s var(--ease-out);
}

.animate-slide-up {
  animation: slide-up 0.3s var(--ease-out);
}

.animate-slide-down {
  animation: slide-down 0.3s var(--ease-out);
}

.animate-scale-in {
  animation: scale-in 0.2s var(--ease-out);
}