#0D311E

CSS

:root {
  --pitch-black-forests: #0d311e;
  --pitch-black-forests-rgb: 13 49 30;
  --pitch-black-forests-oklch: oklch(0.281 0.054 156.9);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(148 58% 12%);
  border-color: oklch(0.281 0.054 156.9);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #0d311e;
  --color-pitch-black-forests-50: #e9faef;
  --color-pitch-black-forests-100: #d9eee1;
  --color-pitch-black-forests-200: #c2dccc;
  --color-pitch-black-forests-300: #a1c0ad;
  --color-pitch-black-forests-400: #85a992;
  --color-pitch-black-forests-500: #689178;
  --color-pitch-black-forests-600: #587b65;
  --color-pitch-black-forests-700: #476251;
  --color-pitch-black-forests-800: #33483a;
  --color-pitch-black-forests-900: #233228;
  --color-pitch-black-forests-950: #121e16;
}

SCSS

$pitch-black-forests: #0d311e;
$pitch-black-forests-rgb: 13, 49, 30;
$pitch-black-forests-light: mix(#fff, $pitch-black-forests, 20%);
$pitch-black-forests-dark: mix(#000, $pitch-black-forests, 20%);

.element {
  color: $pitch-black-forests;
  box-shadow: 0 0 0 2px rgba($pitch-black-forests, 0.35);
}