/* ============================================
   Statistics Page — Styles
   ============================================ */

/* Date range toolbar */
.stats-page-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.stats-export-actions {
  display: flex;
  gap: 8px;
}

.stats-export-actions button,
.debt-header-actions button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.stats-export-actions button {
  padding: 8px 14px;
  font-size: 0.84rem;
  font-weight: 600;
}

.stats-toolbar {
  padding: 16px 20px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  justify-content: space-between;
  margin-bottom: 20px;
}

.stats-date-range {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  flex-wrap: wrap;
}

.date-field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.date-field label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.3px;
}

.date-field input[type="date"],
.date-field select {
  padding: 8px 12px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  font-family: 'DM Sans', sans-serif;
  font-size: 0.84rem;
  color: var(--text-primary);
  background: var(--bg-card);
  outline: none;
  transition: border-color var(--t-fast);
}

.date-field select {
  min-width: 190px;
}

.date-field input[type="date"]:focus,
.date-field select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

/* Growth badge indicators */
.stats-growth-tag {
  font-size: 11px;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  gap: 2px;
}

.stats-growth-up {
  background: rgba(34, 197, 94, 0.15);
  color: #16a34a;
}

.stats-growth-down {
  background: rgba(239, 68, 68, 0.15);
  color: #dc2626;
}

.stats-growth-neutral {
  background: var(--bg-primary);
  color: var(--text-tertiary);
}

.stats-presets {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.stats-preset-btn {
  padding: 6px 14px;
  border: 1px solid var(--card-border);
  border-radius: 20px;
  background: transparent;
  font-family: 'DM Sans', sans-serif;
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--t-fast);
}

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

.stats-preset-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.stats-preset-btn:focus-visible,
.stats-page button:focus-visible,
.stats-page input:focus-visible,
.stats-page select:focus-visible,
.stats-debt-modal button:focus-visible,
.stats-debt-modal input:focus-visible {
  outline: 3px solid var(--accent-glow);
  outline-offset: 2px;
}

.stats-page-status {
  min-height: 20px;
  margin: -10px 0 10px;
  color: var(--text-muted);
  font-size: 0.78rem;
}

.stats-error {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  padding: 12px 16px;
  border: 1px solid var(--danger);
  border-radius: var(--radius-sm);
  background: var(--danger-bg);
  color: var(--danger);
}

.stats-error[hidden] {
  display: none;
}

.stats-region-placeholder {
  display: none;
  min-height: 112px;
  place-items: center;
  padding: 24px;
  color: var(--text-muted);
  text-align: center;
}

.stats-region.is-loading > [data-stats-placeholder],
.stats-region.is-error > [data-stats-placeholder] {
  display: grid;
}

.stats-region.is-loading > [data-stats-content],
.stats-region.is-error > [data-stats-content] {
  display: none;
}

.stats-comparison-note {
  margin: -8px 0 18px;
  font-size: 0.76rem;
  color: var(--text-muted);
}

/* Summary cards */
.stats-summary {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin-bottom: 20px;
}

.stats-value-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
}

.stats-icon-accent { background: var(--accent-bg); color: var(--accent); }
.stats-icon-info { background: var(--info-bg); color: var(--info); }
.stats-icon-success { background: var(--success-bg); color: var(--success); }
.stats-icon-warning { background: var(--warning-bg); color: var(--warning); }
.stats-icon-danger { background: var(--danger-bg); color: var(--danger); }

.stat-card-v2 {
  background: var(--bg-card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 18px;
  display: flex;
  align-items: center;
  gap: 14px;
  box-shadow: var(--card-shadow);
  transition: all var(--t-base);
}

.stat-card-v2:hover {
  box-shadow: var(--card-shadow-hover);
  transform: translateY(-1px);
}

.stat-card-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.stat-card-icon .material-symbols-rounded {
  font-size: 22px;
}

.stat-card-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.stat-card-value {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
}

.stat-card-label {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--text-muted);
}

/* Charts grid */
.stats-charts-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 20px;
}

.chart-card {
  padding: 20px;
}

.chart-card h4 {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 16px;
}

.chart-card h4 .material-symbols-rounded {
  font-size: 18px;
  color: var(--accent);
}

.chart-wide {
  grid-column: 1 / -1;
}

.chart-container {
  position: relative;
  height: 280px;
}

.chart-container.is-fallback {
  display: none;
}

/* External legend keeps lớp names aligned independently of the canvas size. */
.stats-chart-legend {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 20px;
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
}

.stats-chart-legend:empty {
  display: none;
}

.stats-chart-legend-item {
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr);
  align-items: center;
  gap: 8px;
  min-width: 0;
  color: var(--text-secondary);
  font-size: 0.78rem;
}

.stats-chart-legend-swatch {
  width: 18px;
  height: 12px;
  border-radius: 2px;
}

.stats-chart-legend-label {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.stats-chart-fallback {
  max-width: 100%;
  overflow-x: auto;
}

.stats-chart-warning {
  margin: 0 0 12px;
  padding: 10px 12px;
  border: 1px solid var(--warning);
  border-radius: var(--radius-sm);
  background: var(--warning-bg);
  color: var(--text-secondary);
  font-size: 0.78rem;
}

.stats-chart-fallback table {
  width: 100%;
  min-width: 420px;
  border-collapse: collapse;
  font-size: 0.8rem;
}

.stats-chart-fallback caption {
  padding: 0 0 8px;
  color: var(--text-secondary);
  font-weight: 600;
  text-align: left;
}

.stats-chart-fallback th,
.stats-chart-fallback td {
  padding: 8px 10px;
  border: 1px solid var(--card-border);
  text-align: left;
}

.stats-chart-fallback th {
  background: var(--bg-secondary);
}

.sr-only {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* Settings grid */
.settings-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 20px;
}

.settings-card {
  padding: 22px;
}

.card-header-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--bg-secondary);
}

.card-header-row h3 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.card-header-icon {
  font-size: 22px;
  color: var(--accent);
}

.settings-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.settings-form .form-group {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.settings-form .form-group label {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.settings-form .form-group input {
  padding: 9px 14px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  font-family: 'DM Sans', sans-serif;
  font-size: 0.86rem;
  color: var(--text-primary);
  background: var(--bg-card);
  outline: none;
  transition: all var(--t-fast);
}

.settings-form .form-group input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.form-row-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.settings-actions {
  display: flex;
  justify-content: flex-end;
  padding-top: 8px;
}

/* ============================================
   Debt Section — Card-based student list
   ============================================ */
.debt-section {
  padding: 0;
  overflow: hidden;
}

.debt-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 22px;
  border-bottom: 1px solid var(--bg-secondary);
}

.debt-header-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.debt-header-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: var(--danger-bg);
  color: var(--danger);
  display: flex;
  align-items: center;
  justify-content: center;
}

.debt-header-icon .material-symbols-rounded {
  font-size: 20px;
}

.debt-header h4 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
}

.debt-header-sub {
  font-size: 0.72rem;
  color: var(--text-muted);
  display: block;
}

.debt-header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.debt-total-badge {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--danger);
  background: var(--danger-bg);
  padding: 6px 14px;
  border-radius: 20px;
}

/* List */
.debt-list {
  max-height: 480px;
  overflow-y: auto;
}

.debt-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 22px;
  border-bottom: 1px solid var(--bg-secondary);
  transition: background var(--t-fast);
}

.debt-item:last-child {
  border-bottom: none;
}

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

/* Rank */
.debt-item-rank {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-muted);
  background: var(--bg-secondary);
  flex-shrink: 0;
}

.debt-item-rank.rank-1 {
  background: linear-gradient(135deg, #ef4444, #dc2626);
  color: #fff;
  box-shadow: 0 2px 8px rgba(239, 68, 68, 0.3);
}

.debt-item-rank.rank-2 {
  background: linear-gradient(135deg, #f97316, #ea580c);
  color: #fff;
  box-shadow: 0 2px 6px rgba(249, 115, 22, 0.25);
}

.debt-item-rank.rank-3 {
  background: linear-gradient(135deg, #f59e0b, #d97706);
  color: #fff;
  box-shadow: 0 2px 6px rgba(245, 158, 11, 0.25);
}

/* Avatar */
.debt-item-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--accent-bg);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.82rem;
  font-weight: 700;
  flex-shrink: 0;
}

/* Info */
.debt-item-info {
  flex: 1;
  min-width: 0;
}

.debt-item-name {
  font-weight: 600;
  font-size: 0.84rem;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.debt-item-meta {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 6px;
}

.debt-class-chip {
  font-size: 0.66rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 10px;
  background: var(--bg-secondary);
  color: var(--text-secondary);
}

.debt-course-count {
  font-size: 0.68rem;
  color: var(--text-muted);
}

/* Bar */
.debt-bar-track {
  height: 4px;
  background: var(--bg-secondary);
  border-radius: 2px;
  overflow: hidden;
}

.debt-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--danger), #f87171);
  border-radius: 2px;
  transition: width 0.5s ease;
}

/* Amount */
.debt-item-amount {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 2px;
  flex-shrink: 0;
}

.debt-amount-value {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--danger);
}

.debt-amount-paid {
  font-size: 0.66rem;
  color: var(--text-muted);
}

/* Empty state */
.debt-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 50px 20px;
  color: var(--text-muted);
  gap: 8px;
}

.debt-empty .material-symbols-rounded {
  font-size: 40px;
  color: var(--success);
  opacity: 0.5;
}

.debt-empty p {
  font-size: 0.86rem;
  margin: 0;
}

/* Full debt dialog */
#stats-full-debt-modal {
  z-index: 10000;
}

.stats-debt-modal {
  width: min(900px, 95vw);
  max-height: 90vh;
  overflow: hidden;
  border-radius: var(--radius-lg);
}

.stats-debt-modal .modal-title {
  display: flex;
  align-items: center;
  gap: 8px;
}

.stats-debt-modal-body {
  max-height: 68vh;
  overflow: hidden;
  background: var(--bg-primary);
  padding: 20px;
}

#stats-debt-search {
  width: 100%;
  margin-bottom: 16px;
  padding: 10px 14px;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  color: var(--text-primary);
  font: inherit;
}

.stats-table-scroll {
  max-width: 100%;
  max-height: calc(68vh - 64px);
  overflow: auto;
  -webkit-overflow-scrolling: touch;
}

.stats-debt-table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
  font-size: 0.82rem;
}

.stats-debt-table th,
.stats-debt-table td {
  padding: 10px;
  border-bottom: 1px solid var(--card-border);
  text-align: left;
  vertical-align: top;
}

.stats-debt-table th,
.stats-debt-table tfoot {
  background: var(--bg-card);
  color: var(--text-secondary);
  font-weight: 700;
}

.stats-debt-table .number {
  text-align: right;
  white-space: nowrap;
}

.stats-debt-table .debt-value {
  color: var(--danger);
  font-weight: 700;
}

.stats-debt-modal-footer {
  justify-content: space-between;
  gap: 12px;
}

/* ---- Responsive ---- */
@media (max-width: 1100px) {
  .stats-summary {
    grid-template-columns: repeat(3, 1fr);
  }
  .settings-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .stats-summary {
    grid-template-columns: repeat(2, 1fr);
  }
  .stats-charts-grid {
    grid-template-columns: 1fr;
  }
  .stats-toolbar {
    flex-direction: column;
    align-items: stretch;
  }
  .stats-date-range {
    flex-direction: column;
    align-items: stretch;
  }
  .date-field input[type="date"],
  .date-field select,
  #btn-stats-apply {
    width: 100%;
  }
  .stats-presets {
    justify-content: center;
  }
  .stat-card-v2 {
    padding: 14px;
  }
  .stat-card-value {
    font-size: 1rem;
  }
  .form-row-2 {
    grid-template-columns: 1fr;
  }
  .chart-container {
    height: 220px;
  }

  /* Debt mobile */
  .debt-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }
  .debt-header-actions {
    width: 100%;
    flex-wrap: wrap;
    justify-content: space-between;
  }
  .debt-item {
    padding: 12px 16px;
    gap: 10px;
  }
  .debt-item-avatar {
    display: none;
  }
  .debt-amount-value {
    font-size: 0.78rem;
  }

  .stats-page-header,
  .stats-export-actions {
    align-items: stretch;
  }

  .stats-export-actions {
    width: 100%;
  }

  .stats-export-actions button {
    flex: 1;
    justify-content: center;
  }

  .stats-debt-modal {
    width: 96vw;
    max-width: 96vw;
  }

  .stats-debt-modal-body {
    padding: 12px;
  }
}

@media (max-width: 480px) {
  .stats-summary {
    grid-template-columns: 1fr;
  }

  .debt-item-rank {
    display: none;
  }

  .debt-item {
    align-items: flex-start;
  }

  .debt-item-amount {
    max-width: 38%;
  }

  .stats-chart-legend {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Statistics Homework Section
   ============================================ */
.stats-homework-section {
  margin-top: 24px;
}

.stats-homework-header {
  margin-bottom: 16px;
}

.stats-homework-icon {
  background: rgba(234, 179, 8, 0.15);
  color: #eab308;
}

.stats-homework-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
}

.stats-homework-card {
  background: var(--bg-secondary);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
}

.stats-homework-card-label {
  font-size: 12px;
  color: var(--text-tertiary);
  margin-bottom: 4px;
}

.stats-homework-card-value {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
}

.stats-homework-card-value.accent {
  color: var(--accent);
}

.stats-homework-card-value.success {
  color: var(--success);
}