#003E31

CSS

:root {
  --pitch-black-forests: #003e31;
  --pitch-black-forests-rgb: 0 62 49;
  --pitch-black-forests-oklch: oklch(0.324 0.062 173.2);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(167 100% 12%);
  border-color: oklch(0.324 0.062 173.2);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #003e31;
  --color-pitch-black-forests-50: #e4fbf4;
  --color-pitch-black-forests-100: #d4efe7;
  --color-pitch-black-forests-200: #baddd3;
  --color-pitch-black-forests-300: #97c2b6;
  --color-pitch-black-forests-400: #78ab9b;
  --color-pitch-black-forests-500: #589482;
  --color-pitch-black-forests-600: #4b7d6e;
  --color-pitch-black-forests-700: #3c6458;
  --color-pitch-black-forests-800: #2b4940;
  --color-pitch-black-forests-900: #1d332c;
  --color-pitch-black-forests-950: #0d1f19;
}

SCSS

$pitch-black-forests: #003e31;
$pitch-black-forests-rgb: 0, 62, 49;
$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);
}