#003323

CSS

:root {
  --pitch-black-forests: #003323;
  --pitch-black-forests-rgb: 0 51 35;
  --pitch-black-forests-oklch: oklch(0.285 0.059 165.8);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(161 100% 10%);
  border-color: oklch(0.285 0.059 165.8);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #003323;
  --color-pitch-black-forests-50: #e6fbf2;
  --color-pitch-black-forests-100: #d6efe4;
  --color-pitch-black-forests-200: #bdddcf;
  --color-pitch-black-forests-300: #9bc2b1;
  --color-pitch-black-forests-400: #7daa96;
  --color-pitch-black-forests-500: #5f937d;
  --color-pitch-black-forests-600: #517c6a;
  --color-pitch-black-forests-700: #416455;
  --color-pitch-black-forests-800: #2f493d;
  --color-pitch-black-forests-900: #20332a;
  --color-pitch-black-forests-950: #0f1e17;
}

SCSS

$pitch-black-forests: #003323;
$pitch-black-forests-rgb: 0, 51, 35;
$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);
}