#004113

CSS

:root {
  --realm-of-the-underworld: #004113;
  --realm-of-the-underworld-rgb: 0 65 19;
  --realm-of-the-underworld-oklch: oklch(0.327 0.097 147.2);
}

.element {
  color: var(--realm-of-the-underworld);
  background-color: hsl(138 100% 13%);
  border-color: oklch(0.327 0.097 147.2);
}

Tailwind CSS v4

@theme {
  --color-realm-of-the-underworld: #004113;
  --color-realm-of-the-underworld-50: #e3fde7;
  --color-realm-of-the-underworld-100: #d2f1d7;
  --color-realm-of-the-underworld-200: #b8e0be;
  --color-realm-of-the-underworld-300: #95c69d;
  --color-realm-of-the-underworld-400: #77ae7d;
  --color-realm-of-the-underworld-500: #579760;
  --color-realm-of-the-underworld-600: #4b8052;
  --color-realm-of-the-underworld-700: #3b6741;
  --color-realm-of-the-underworld-800: #2c4b2d;
  --color-realm-of-the-underworld-900: #1d341e;
  --color-realm-of-the-underworld-950: #0d200e;
}

SCSS

$realm-of-the-underworld: #004113;
$realm-of-the-underworld-rgb: 0, 65, 19;
$realm-of-the-underworld-light: mix(#fff, $realm-of-the-underworld, 20%);
$realm-of-the-underworld-dark: mix(#000, $realm-of-the-underworld, 20%);

.element {
  color: $realm-of-the-underworld;
  box-shadow: 0 0 0 2px rgba($realm-of-the-underworld, 0.35);
}