#00291C

CSS

:root {
  --pitch-black-forests: #00291c;
  --pitch-black-forests-rgb: 0 41 28;
  --pitch-black-forests-oklch: oklch(0.249 0.051 166.7);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(161 100% 8%);
  border-color: oklch(0.249 0.051 166.7);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #00291c;
  --color-pitch-black-forests-50: #e8faf2;
  --color-pitch-black-forests-100: #d8eee5;
  --color-pitch-black-forests-200: #c0dcd0;
  --color-pitch-black-forests-300: #9fc0b3;
  --color-pitch-black-forests-400: #82a998;
  --color-pitch-black-forests-500: #65917f;
  --color-pitch-black-forests-600: #567b6b;
  --color-pitch-black-forests-700: #446256;
  --color-pitch-black-forests-800: #32483e;
  --color-pitch-black-forests-900: #22322a;
  --color-pitch-black-forests-950: #111e18;
}

SCSS

$pitch-black-forests: #00291c;
$pitch-black-forests-rgb: 0, 41, 28;
$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);
}