#004000

CSS

:root {
  --woodland-grass: #004000;
  --woodland-grass-rgb: 0 64 0;
  --woodland-grass-oklch: oklch(0.322 0.11 142.5);
}

.element {
  color: var(--woodland-grass);
  background-color: hsl(120 100% 13%);
  border-color: oklch(0.322 0.11 142.5);
}

Tailwind CSS v4

@theme {
  --color-woodland-grass: #004000;
  --color-woodland-grass-50: #e3fee2;
  --color-woodland-grass-100: #d2f2d2;
  --color-woodland-grass-200: #b8e1b7;
  --color-woodland-grass-300: #95c794;
  --color-woodland-grass-400: #78af73;
  --color-woodland-grass-500: #589853;
  --color-woodland-grass-600: #4b8147;
  --color-woodland-grass-700: #3c6738;
  --color-woodland-grass-800: #2c4c26;
  --color-woodland-grass-900: #1e341a;
  --color-woodland-grass-950: #0e200a;
}

SCSS

$woodland-grass: #004000;
$woodland-grass-rgb: 0, 64, 0;
$woodland-grass-light: mix(#fff, $woodland-grass, 20%);
$woodland-grass-dark: mix(#000, $woodland-grass, 20%);

.element {
  color: $woodland-grass;
  box-shadow: 0 0 0 2px rgba($woodland-grass, 0.35);
}