#003525

CSS

:root {
  --pitch-black-forests: #003525;
  --pitch-black-forests-rgb: 0 53 37;
  --pitch-black-forests-oklch: oklch(0.292 0.06 166.5);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(162 100% 10%);
  border-color: oklch(0.292 0.06 166.5);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #003525;
  --color-pitch-black-forests-50: #e6fbf2;
  --color-pitch-black-forests-100: #d6efe4;
  --color-pitch-black-forests-200: #bcddcf;
  --color-pitch-black-forests-300: #9ac2b2;
  --color-pitch-black-forests-400: #7caa97;
  --color-pitch-black-forests-500: #5e937d;
  --color-pitch-black-forests-600: #507d6a;
  --color-pitch-black-forests-700: #406455;
  --color-pitch-black-forests-800: #2e493d;
  --color-pitch-black-forests-900: #1f332a;
  --color-pitch-black-forests-950: #0f1e17;
}

SCSS

$pitch-black-forests: #003525;
$pitch-black-forests-rgb: 0, 53, 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);
}