#003522

CSS

:root {
  --pitch-black-forests: #003522;
  --pitch-black-forests-rgb: 0 53 34;
  --pitch-black-forests-oklch: oklch(0.291 0.063 162.6);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(158 100% 10%);
  border-color: oklch(0.291 0.063 162.6);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #003522;
  --color-pitch-black-forests-50: #e5fbf0;
  --color-pitch-black-forests-100: #d6efe2;
  --color-pitch-black-forests-200: #bcddcd;
  --color-pitch-black-forests-300: #9ac2af;
  --color-pitch-black-forests-400: #7cab93;
  --color-pitch-black-forests-500: #5e947a;
  --color-pitch-black-forests-600: #507d67;
  --color-pitch-black-forests-700: #406452;
  --color-pitch-black-forests-800: #2e493b;
  --color-pitch-black-forests-900: #1f3329;
  --color-pitch-black-forests-950: #0f1e16;
}

SCSS

$pitch-black-forests: #003522;
$pitch-black-forests-rgb: 0, 53, 34;
$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);
}