#120411

CSS

:root {
  --noir-fiction: #120411;
  --noir-fiction-rgb: 18 4 17;
  --noir-fiction-oklch: oklch(0.142 0.039 329.9);
}

.element {
  color: var(--noir-fiction);
  background-color: hsl(304 64% 4%);
  border-color: oklch(0.142 0.039 329.9);
}

Tailwind CSS v4

@theme {
  --color-noir-fiction: #120411;
  --color-noir-fiction-50: #fcf1fa;
  --color-noir-fiction-100: #f0e3ee;
  --color-noir-fiction-200: #dfcedc;
  --color-noir-fiction-300: #c4b0c0;
  --color-noir-fiction-400: #ac97aa;
  --color-noir-fiction-500: #957d93;
  --color-noir-fiction-600: #7e6a7c;
  --color-noir-fiction-700: #655563;
  --color-noir-fiction-800: #4a3e49;
  --color-noir-fiction-900: #332a33;
  --color-noir-fiction-950: #1f181f;
}

SCSS

$noir-fiction: #120411;
$noir-fiction-rgb: 18, 4, 17;
$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);
}