#0F030F

CSS

:root {
  --noir-fiction: #0f030f;
  --noir-fiction-rgb: 15 3 15;
  --noir-fiction-oklch: oklch(0.131 0.038 327.5);
}

.element {
  color: var(--noir-fiction);
  background-color: hsl(300 67% 4%);
  border-color: oklch(0.131 0.038 327.5);
}

Tailwind CSS v4

@theme {
  --color-noir-fiction: #0f030f;
  --color-noir-fiction-50: #fcf1fa;
  --color-noir-fiction-100: #efe4ee;
  --color-noir-fiction-200: #decfdc;
  --color-noir-fiction-300: #c3b1c1;
  --color-noir-fiction-400: #ab97aa;
  --color-noir-fiction-500: #947e93;
  --color-noir-fiction-600: #7d6a7d;
  --color-noir-fiction-700: #645564;
  --color-noir-fiction-800: #493e4a;
  --color-noir-fiction-900: #332b33;
  --color-noir-fiction-950: #1f181f;
}

SCSS

$noir-fiction: #0f030f;
$noir-fiction-rgb: 15, 3, 15;
$noir-fiction-light: mix(#fff, $noir-fiction, 20%);
$noir-fiction-dark: mix(#000, $noir-fiction, 20%);

.element {
  color: $noir-fiction;
  box-shadow: 0 0 0 2px rgba($noir-fiction, 0.35);
}