#120406

CSS

:root {
  --dark-matter: #120406;
  --dark-matter-rgb: 18 4 6;
  --dark-matter-oklch: oklch(0.135 0.029 9.7);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(351 64% 4%);
  border-color: oklch(0.135 0.029 9.7);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #120406;
  --color-dark-matter-50: #fdf2f3;
  --color-dark-matter-100: #f1e4e5;
  --color-dark-matter-200: #e0cfd1;
  --color-dark-matter-300: #c6b2b3;
  --color-dark-matter-400: #af989a;
  --color-dark-matter-500: #987f82;
  --color-dark-matter-600: #816b6e;
  --color-dark-matter-700: #675658;
  --color-dark-matter-800: #4c3e40;
  --color-dark-matter-900: #352b2c;
  --color-dark-matter-950: #201819;
}

SCSS

$dark-matter: #120406;
$dark-matter-rgb: 18, 4, 6;
$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);
}