#0F352C

CSS

:root {
  --pitch-black-forests: #0f352c;
  --pitch-black-forests-rgb: 15 53 44;
  --pitch-black-forests-oklch: oklch(0.299 0.046 174.6);
}

.element {
  color: var(--pitch-black-forests);
  background-color: hsl(166 56% 13%);
  border-color: oklch(0.299 0.046 174.6);
}

Tailwind CSS v4

@theme {
  --color-pitch-black-forests: #0f352c;
  --color-pitch-black-forests-50: #e8faf5;
  --color-pitch-black-forests-100: #d9ede7;
  --color-pitch-black-forests-200: #c1dbd4;
  --color-pitch-black-forests-300: #a0c0b7;
  --color-pitch-black-forests-400: #83a89d;
  --color-pitch-black-forests-500: #669084;
  --color-pitch-black-forests-600: #577a70;
  --color-pitch-black-forests-700: #456259;
  --color-pitch-black-forests-800: #324841;
  --color-pitch-black-forests-900: #22322d;
  --color-pitch-black-forests-950: #111e1a;
}

SCSS

$pitch-black-forests: #0f352c;
$pitch-black-forests-rgb: 15, 53, 44;
$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);
}