#130303

CSS

:root {
  --dark-matter: #130303;
  --dark-matter-rgb: 19 3 3;
  --dark-matter-oklch: oklch(0.132 0.034 23);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(0 73% 4%);
  border-color: oklch(0.132 0.034 23);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #130303;
  --color-dark-matter-50: #fff2f0;
  --color-dark-matter-100: #f3e4e2;
  --color-dark-matter-200: #e3cfcd;
  --color-dark-matter-300: #c9b1af;
  --color-dark-matter-400: #b29795;
  --color-dark-matter-500: #9c7e7b;
  --color-dark-matter-600: #846a69;
  --color-dark-matter-700: #6a5554;
  --color-dark-matter-800: #4e3e3d;
  --color-dark-matter-900: #362b2a;
  --color-dark-matter-950: #211818;
}

SCSS

$dark-matter: #130303;
$dark-matter-rgb: 19, 3, 3;
$dark-matter-light: mix(#fff, $dark-matter, 20%);
$dark-matter-dark: mix(#000, $dark-matter, 20%);

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