#0F0204

CSS

:root {
  --dark-matter: #0f0204;
  --dark-matter-rgb: 15 2 4;
  --dark-matter-oklch: oklch(0.12 0.032 8.3);
}

.element {
  color: var(--dark-matter);
  background-color: hsl(351 76% 3%);
  border-color: oklch(0.12 0.032 8.3);
}

Tailwind CSS v4

@theme {
  --color-dark-matter: #0f0204;
  --color-dark-matter-50: #fef2f3;
  --color-dark-matter-100: #f2e4e5;
  --color-dark-matter-200: #e1cfd1;
  --color-dark-matter-300: #c7b1b3;
  --color-dark-matter-400: #b0979b;
  --color-dark-matter-500: #9a7e82;
  --color-dark-matter-600: #826b6e;
  --color-dark-matter-700: #685558;
  --color-dark-matter-800: #4d3e41;
  --color-dark-matter-900: #352b2c;
  --color-dark-matter-950: #20181a;
}

SCSS

$dark-matter: #0f0204;
$dark-matter-rgb: 15, 2, 4;
$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);
}