#1E1F0A

CSS

:root {
  --underworld: #1e1f0a;
  --underworld-rgb: 30 31 10;
  --underworld-oklch: oklch(0.232 0.036 111.3);
}

.element {
  color: var(--underworld);
  background-color: hsl(63 51% 8%);
  border-color: oklch(0.232 0.036 111.3);
}

Tailwind CSS v4

@theme {
  --color-underworld: #1e1f0a;
  --color-underworld-50: #f5f6eb;
  --color-underworld-100: #e7e9dc;
  --color-underworld-200: #d4d6c5;
  --color-underworld-300: #b7baa5;
  --color-underworld-400: #9fa189;
  --color-underworld-500: #87896e;
  --color-underworld-600: #72745d;
  --color-underworld-700: #5b5d4a;
  --color-underworld-800: #434435;
  --color-underworld-900: #2e2f24;
  --color-underworld-950: #1b1b13;
}

SCSS

$underworld: #1e1f0a;
$underworld-rgb: 30, 31, 10;
$underworld-light: mix(#fff, $underworld, 20%);
$underworld-dark: mix(#000, $underworld, 20%);

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