#0F0409

CSS

:root {
  --dark-matter: #0f0409;
  --dark-matter-rgb: 15 4 9;
  --dark-matter-oklch: oklch(0.131 0.026 348.8);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(333 58% 4%);
  border-color: oklch(0.131 0.026 348.8);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #0f0409;
  --color-dark-matter-50: #fcf2f6;
  --color-dark-matter-100: #efe4e9;
  --color-dark-matter-200: #ded0d6;
  --color-dark-matter-300: #c3b2b9;
  --color-dark-matter-400: #ab98a1;
  --color-dark-matter-500: #947f89;
  --color-dark-matter-600: #7d6c74;
  --color-dark-matter-700: #64565d;
  --color-dark-matter-800: #4a3f44;
  --color-dark-matter-900: #332b2f;
  --color-dark-matter-950: #1f191c;
}

SCSS

$dark-matter: #0f0409;
$dark-matter-rgb: 15, 4, 9;
$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);
}