/* Onyx — Dark neutral, polished stone, sophisticated. */
[data-theme="onyx"] {
  --brand-50:  #d4d4d8;
  --brand-100: #b5b5bb;
  --brand-200: #93939b;
  --brand-300: #71717a;
  --brand-400: #53535b;
  --brand-500: #3f3f46;
  --brand-600: #2c2c31;
  --brand-700: #202024;
  --brand-800: #151518;
  --brand-900: #0b0b0d;
  --brand-950: #050506;

  --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);
}