#150705

CSS

:root {
  --dark-matter: #150705;
  --dark-matter-rgb: 21 7 5;
  --dark-matter-oklch: oklch(0.151 0.027 31.7);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(8 62% 5%);
  border-color: oklch(0.151 0.027 31.7);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #150705;
  --color-dark-matter-50: #fdf3f0;
  --color-dark-matter-100: #f1e5e2;
  --color-dark-matter-200: #dfd0cd;
  --color-dark-matter-300: #c5b3af;
  --color-dark-matter-400: #ae9995;
  --color-dark-matter-500: #97807b;
  --color-dark-matter-600: #806c68;
  --color-dark-matter-700: #665753;
  --color-dark-matter-800: #4b3f3d;
  --color-dark-matter-900: #342b2a;
  --color-dark-matter-950: #201917;
}

SCSS

$dark-matter: #150705;
$dark-matter-rgb: 21, 7, 5;
$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);
}