#003725

CSS

:root {
  --pitch-black-forests: #003725;
  --pitch-black-forests-rgb: 0 55 37;
  --pitch-black-forests-oklch: oklch(0.298 0.063 164.5);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(160 100% 11%);
  border-color: oklch(0.298 0.063 164.5);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #003725;
  --color-pitch-black-forests-50: #e5fbf1;
  --color-pitch-black-forests-100: #d5efe3;
  --color-pitch-black-forests-200: #bcddce;
  --color-pitch-black-forests-300: #99c2b0;
  --color-pitch-black-forests-400: #7bab95;
  --color-pitch-black-forests-500: #5d947b;
  --color-pitch-black-forests-600: #4f7d68;
  --color-pitch-black-forests-700: #3f6453;
  --color-pitch-black-forests-800: #2e493c;
  --color-pitch-black-forests-900: #1f3329;
  --color-pitch-black-forests-950: #0e1f17;
}

SCSS

$pitch-black-forests: #003725;
$pitch-black-forests-rgb: 0, 55, 37;
$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);
}