/* Slate — Neutral gray, professional, understated. */
[data-theme="slate"] {
  --brand-50:  #f8fafc;
  --brand-100: #f1f5f9;
  --brand-200: #e2e8f0;
  --brand-300: #cbd5e1;
  --brand-400: #94a3b8;
  --brand-500: #64748b;
  --brand-600: #475569;
  --brand-700: #334155;
  --brand-800: #1e293b;
  --brand-900: #0f172a;
  --brand-950: #020617;

  --chart-theme-1: var(--brand-800);
  --chart-theme-2: var(--brand-500);
  --chart-theme-3: var(--brand-300);
  --chart-theme-4: var(--brand-700);
  --chart-theme-5: var(--brand-400);
  --chart-theme-6: var(--brand-600);
  --chart-theme-7: var(--brand-200);
  --chart-theme-8: var(--brand-900);

  /* Chart neutrals (subtle, NOT brand-saturated) + single-hue heat ramp */
  --chart-grid:      rgba(15, 23, 42, 0.06);  /* identical neutral across ALL themes */
  --chart-plot-bg:   var(--brand-50);
  --chart-heat-from: var(--brand-100);
  --chart-heat-to:   var(--brand-900);
}