#00310B

CSS

:root {
  --haunted-hills: #00310b;
  --haunted-hills-rgb: 0 49 11;
  --haunted-hills-oklch: oklch(0.273 0.082 146.7);
}

.element {
  color: var(--haunted-hills);
  background-color: hsl(133 100% 10%);
  border-color: oklch(0.273 0.082 146.7);
}

Tailwind CSS v4

@theme {
  --color-haunted-hills: #00310b;
  --color-haunted-hills-50: #e6fce9;
  --color-haunted-hills-100: #d6f0d9;
  --color-haunted-hills-200: #bddfc1;
  --color-haunted-hills-300: #9bc4a1;
  --color-haunted-hills-400: #7fac82;
  --color-haunted-hills-500: #619566;
  --color-haunted-hills-600: #527e56;
  --color-haunted-hills-700: #426545;
  --color-haunted-hills-800: #304a30;
  --color-haunted-hills-900: #213321;
  --color-haunted-hills-950: #101f10;
}

SCSS

$haunted-hills: #00310b;
$haunted-hills-rgb: 0, 49, 11;
$haunted-hills-light: mix(#fff, $haunted-hills, 20%);
$haunted-hills-dark: mix(#000, $haunted-hills, 20%);

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