#170606

CSS

:root {
  --dark-matter: #170606;
  --dark-matter-rgb: 23 6 6;
  --dark-matter-oklch: oklch(0.152 0.032 21.6);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(0 59% 6%);
  border-color: oklch(0.152 0.032 21.6);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #170606;
  --color-dark-matter-50: #fef2f1;
  --color-dark-matter-100: #f2e4e3;
  --color-dark-matter-200: #e2cfce;
  --color-dark-matter-300: #c7b1b0;
  --color-dark-matter-400: #b19796;
  --color-dark-matter-500: #9a7e7d;
  --color-dark-matter-600: #836b6a;
  --color-dark-matter-700: #695554;
  --color-dark-matter-800: #4d3e3e;
  --color-dark-matter-900: #352b2b;
  --color-dark-matter-950: #211818;
}

SCSS

$dark-matter: #170606;
$dark-matter-rgb: 23, 6, 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);
}