#180907

CSS

:root {
  --dark-matter: #180907;
  --dark-matter-rgb: 24 9 7;
  --dark-matter-oklch: oklch(0.162 0.027 29.6);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(7 55% 6%);
  border-color: oklch(0.162 0.027 29.6);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #180907;
  --color-dark-matter-50: #fdf2f0;
  --color-dark-matter-100: #f1e5e2;
  --color-dark-matter-200: #e0d0cd;
  --color-dark-matter-300: #c5b3af;
  --color-dark-matter-400: #ae9995;
  --color-dark-matter-500: #98807c;
  --color-dark-matter-600: #806c69;
  --color-dark-matter-700: #675654;
  --color-dark-matter-800: #4c3f3d;
  --color-dark-matter-900: #342b2a;
  --color-dark-matter-950: #201918;
}

SCSS

$dark-matter: #180907;
$dark-matter-rgb: 24, 9, 7;
$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);
}