.chi-card {
    --chi-primary: #f59e0b;
    --chi-primary-dark: #d97706;
    --chi-primary-deep: #92400e;
    --chi-primary-light: rgba(245, 158, 11, 0.08);
    --chi-primary-border: rgba(245, 158, 11, 0.2);
    --chi-primary-border-light: rgba(245, 158, 11, 0.15);
    --chi-sidebar-bg: rgba(254, 252, 232, 0.6);
    --chi-card-bg: #fff;
    --chi-surface-bg: #f8fafc;
    --chi-surface-bg-2: #f1f5f9;
    --chi-border: #e2e8f0;
    --chi-border-cell: #cbd5e1;
    --chi-text: #0f172a;
    --chi-text-muted: #475569;
    --chi-text-label: #334155;
    --chi-text-secondary: #64748b;
    --chi-shadow: rgba(245, 158, 11, 0.08);
    --chi-info-text: #78350f;
    --chi-alert-bg: #fffbeb;
    --chi-alert-border: #fde68a;
    --chi-alert-title: #d97706;
    --chi-alert-text: #92400e;

    display: flex;
    flex-direction: column;
    background: var(--chi-card-bg);
    border-radius: 1.5rem;
    border: 1px solid var(--chi-primary-border);
    box-shadow: 0 10px 40px var(--chi-shadow);
    overflow: hidden;
    margin: 2rem 0;
  }

  .theme-dark .chi-card {
    --chi-primary: #fbbf24;
    --chi-primary-dark: #f59e0b;
    --chi-primary-deep: #fde68a;
    --chi-primary-light: rgba(251, 191, 36, 0.06);
    --chi-primary-border: rgba(251, 191, 36, 0.18);
    --chi-primary-border-light: rgba(251, 191, 36, 0.1);
    --chi-sidebar-bg: #1c1917;
    --chi-card-bg: #18181b;
    --chi-surface-bg: #27272a;
    --chi-surface-bg-2: #3f3f46;
    --chi-border: #3f3f46;
    --chi-border-cell: #52525b;
    --chi-text: #f4f4f5;
    --chi-text-muted: #a1a1aa;
    --chi-text-label: #d4d4d8;
    --chi-text-secondary: #71717a;
    --chi-shadow: rgba(0, 0, 0, 0.5);
    --chi-info-text: #fde68a;
    --chi-alert-bg: #1c1917;
    --chi-alert-border: rgba(251, 191, 36, 0.22);
    --chi-alert-title: #fbbf24;
    --chi-alert-text: #fde68a;
  }

  .chi-sidebar {
    background: var(--chi-sidebar-bg);
    border-bottom: 1px solid var(--chi-primary-border-light);
    padding: 1.5rem;
  }

  @media (min-width: 768px) {
    .chi-card {
      flex-direction: row;
    }

    .chi-sidebar {
      width: 340px;
      flex-shrink: 0;
      border-bottom: none;
      border-right: 1px solid var(--chi-primary-border-light);
      display: flex;
      flex-direction: column;
      gap: 1.5rem;
    }
  }

  .chi-sidebar-heading {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--chi-text);
    margin-bottom: 1.25rem;
  }

  .chi-sidebar-heading [data-icon] {
    color: var(--chi-primary);
    font-size: 1.5em;
  }

  .chi-group-section {
    background: var(--chi-card-bg);
    border: 1px solid var(--chi-border);
    border-radius: 1rem;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }

  .chi-input-row {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
  }

  .chi-input-row label {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--chi-text-label);
    display: flex;
    justify-content: space-between;
  }

  .chi-input-row select {
    width: 100%;
    padding: 0.75rem 1rem;
    padding-right: 2.5rem;
    border-radius: 0.75rem;
    border: 1px solid var(--chi-border-cell);
    background: var(--chi-card-bg)
      url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%23475569'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E")
      no-repeat right 0.85rem center / 1.25rem;
    color: var(--chi-text);
    font-size: 0.95rem;
    font-weight: 600;
    transition: all 0.2s;
    appearance: none;
    cursor: pointer;
  }

  .chi-input-row select:hover {
    border-color: #94a3b8;
  }

  .chi-input-row select:focus {
    outline: none;
    border-color: var(--chi-primary);
    box-shadow: 0 0 0 3px rgba(245, 158, 11, 0.15);
  }

  .chi-info-box {
    margin-top: auto;
    padding: 1.25rem;
    background: var(--chi-primary-light);
    border-radius: 1rem;
    border: 1px dashed var(--chi-primary-border);
    display: flex;
    gap: 0.75rem;
  }

  .chi-info-icon {
    flex-shrink: 0;
    color: var(--chi-primary-dark);
    font-size: 1.25rem;
  }

  .chi-info-text {
    font-size: 0.75rem;
    color: var(--chi-info-text);
    line-height: 1.5;
    margin: 0;
    font-weight: 500;
  }

  .chi-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    gap: 2rem;
  }

  .chi-table-container {
    overflow-x: auto;
    background: var(--chi-surface-bg);
    border: 1px solid var(--chi-border);
    border-radius: 1rem;
    padding: 1rem;
  }

  .chi-table-title {
    font-weight: 700;
    color: var(--chi-text-label);
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.95rem;
  }

  .chi-table-title [data-icon] {
    color: var(--chi-primary);
  }

  .chi-contingency-table {
    width: 100%;
    border-collapse: collapse;
    table-layout: fixed;
  }

  .chi-contingency-table th,
  .chi-contingency-table td {
    padding: 0.5rem;
    text-align: center;
    border: 1px solid var(--chi-border-cell);
  }

  .chi-contingency-table th {
    background: var(--chi-surface-bg-2);
    font-size: 0.85rem;
    color: var(--chi-text-muted);
  }

  .chi-header-row th {
    color: var(--chi-text);
    font-weight: 700;
  }

  .chi-contingency-table .chi-header-col {
    background: var(--chi-surface-bg-2);
    font-size: 0.85rem;
    color: var(--chi-text);
    font-weight: 700;
    width: 50px;
  }

  .chi-cell-input {
    width: 100%;
    box-sizing: border-box;
    padding: 0.5rem;
    text-align: center;
    border: 1px solid transparent;
    border-radius: 0.25rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--chi-text);
    background: transparent;
    transition: all 0.2s;
  }

  .chi-cell-input:focus {
    background: var(--chi-card-bg);
    border: 1px solid var(--chi-primary);
    outline: none;
    box-shadow: 0 0 0 2px rgba(245, 158, 11, 0.15);
  }

  .chi-contingency-table .chi-total-cell {
    background: var(--chi-border-cell);
    font-weight: 700;
    color: var(--chi-text-label);
  }

  .chi-contingency-table .chi-grand-total {
    background: var(--chi-border);
  }

  .chi-expected-area {
    margin-top: 1rem;
    border-top: 1px solid var(--chi-border);
    padding-top: 1rem;
  }

  .chi-expected-toggle {
    background: none;
    border: none;
    color: var(--chi-primary);
    font-weight: 700;
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0;
  }

  .chi-expected-toggle:hover {
    text-decoration: underline;
  }

  .chi-expected-content {
    display: none;
    margin-top: 1rem;
  }

  .chi-expected-content.open {
    display: block;
  }

  .chi-expected-desc {
    font-size: 0.8rem;
    color: var(--chi-text-secondary);
    margin-bottom: 0.75rem;
    margin-top: 0;
  }

  .chi-alert {
    background: var(--chi-alert-bg);
    border: 1px solid var(--chi-alert-border);
    padding: 1rem;
    border-radius: 0.75rem;
  }

  .chi-alert-title {
    color: var(--chi-alert-title);
    font-weight: 800;
    font-size: 0.9rem;
    margin-bottom: 0.25rem;
  }

  .chi-alert-body {
    color: var(--chi-alert-text);
    font-size: 0.85rem;
    margin: 0;
    font-weight: 500;
  }

  .chi-results-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  @media (min-width: 640px) {
    .chi-results-grid {
      grid-template-columns: 1fr 1fr;
    }
  }

  .chi-stat-block {
    background: var(--chi-surface-bg);
    border: 1px solid var(--chi-border);
    border-radius: 1rem;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
  }

  .chi-stat-block.significant {
    background: linear-gradient(
      135deg,
      rgba(16, 185, 129, 0.05),
      rgba(209, 250, 229, 0.4)
    );
    border-color: rgba(16, 185, 129, 0.3);
  }

  .chi-stat-block.not-significant {
    background: linear-gradient(
      135deg,
      rgba(239, 68, 68, 0.05),
      rgba(254, 226, 226, 0.4)
    );
    border-color: rgba(239, 68, 68, 0.3);
  }

  .theme-dark .chi-stat-block.significant {
    background: linear-gradient(
      135deg,
      rgba(16, 185, 129, 0.12),
      rgba(6, 78, 59, 0.3)
    );
  }

  .theme-dark .chi-stat-block.not-significant {
    background: linear-gradient(
      135deg,
      rgba(239, 68, 68, 0.12),
      rgba(127, 29, 29, 0.3)
    );
  }

  .chi-stat-title {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--chi-text-muted);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
  }

  .chi-stat-value {
    font-size: 2.5rem;
    font-weight: 800;
    line-height: 1;
    color: var(--chi-text);
  }

  .chi-stat-block.significant .chi-stat-value {
    color: #059669;
  }

  .chi-stat-block.not-significant .chi-stat-value {
    color: #dc2626;
  }

  .chi-stat-desc {
    font-size: 0.9rem;
    font-weight: 600;
    margin-top: 0.75rem;
    color: var(--chi-text-muted);
  }

  .chi-stat-secondary-row {
    display: flex;
    gap: 2rem;
    justify-content: center;
    align-items: baseline;
    margin-top: 0.5rem;
  }

  .chi-secondary-label {
    font-size: 0.75rem;
    color: var(--chi-text-secondary);
    font-weight: 700;
  }

  .chi-secondary-stat {
    font-size: 2rem;
    font-weight: 800;
    color: var(--chi-primary);
  }

  .chi-cramer-row {
    margin-top: 1rem;
    padding-top: 0.5rem;
    border-top: 1px dashed var(--chi-border-cell);
    width: 100%;
  }

  .chi-cramer-value {
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--chi-text);
  }

  .chi-cramer-text {
    font-size: 0.8rem;
    color: var(--chi-text-muted);
    font-weight: 500;
  }

  .chi-visual-section {
    background: var(--chi-card-bg);
    border: 1px solid var(--chi-border);
    border-radius: 1rem;
    padding: 1.5rem;
  }

  #bar-canvas {
    width: 100%;
    height: 250px;
    display: block;
    background: var(--chi-surface-bg);
    border-radius: 0.75rem;
  }

  .chi-heatmap-info {
    font-size: 0.8rem;
    color: var(--chi-text-secondary);
    text-align: right;
    margin-top: 0.5rem;
    font-style: italic;
  }

  .chi-copy-block {
    background: var(--chi-primary-light);
    border: 1px dashed var(--chi-primary-border);
    border-radius: 1rem;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }

  .chi-copy-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--chi-primary-dark);
    font-weight: 800;
    font-size: 0.9rem;
  }

  .chi-copy-text {
    font-size: 1.05rem;
    line-height: 1.6;
    color: var(--chi-text);
    margin: 0;
    font-style: italic;
    font-weight: 500;
  }

  .chi-copy-btn {
    align-self: flex-end;
    background: var(--chi-primary);
    color: white;
    border: none;
    border-radius: 0.5rem;
    padding: 0.6rem 1rem;
    font-size: 0.8rem;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    cursor: pointer;
    transition: all 0.2s;
  }

  .chi-copy-btn:hover {
    background: var(--chi-primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 10px rgba(245, 158, 11, 0.2);
  }

  .chi-copy-btn:active {
    transform: translateY(0);
    box-shadow: none;
  }

  .chi-math-sym {
    font-style: italic;
    font-weight: 600;
  }