#140000

CSS

:root {
  --dark-matter: #140000;
  --dark-matter-rgb: 20 0 0;
  --dark-matter-oklch: oklch(0.12 0.049 29.2);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(0 100% 4%);
  border-color: oklch(0.12 0.049 29.2);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #140000;
  --color-dark-matter-50: #fff0ed;
  --color-dark-matter-100: #f8e2de;
  --color-dark-matter-200: #e9cdc8;
  --color-dark-matter-300: #cfafa8;
  --color-dark-matter-400: #ba948e;
  --color-dark-matter-500: #a47a73;
  --color-dark-matter-600: #8b6862;
  --color-dark-matter-700: #6f534e;
  --color-dark-matter-800: #523c39;
  --color-dark-matter-900: #392927;
  --color-dark-matter-950: #241715;
}

SCSS

$dark-matter: #140000;
$dark-matter-rgb: 20, 0, 0;
$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);
}