#81781B

CSS

:root {
  --olive: #81781b;
  --olive-rgb: 129 120 27;
  --olive-oklch: oklch(0.564 0.109 103.6);
}

.element {
  color: var(--olive);
  background-color: hsl(55 65% 31%);
  border-color: oklch(0.564 0.109 103.6);
}

Tailwind CSS v4

@theme {
  --color-olive: #81781b;
  --color-olive-50: #f9f8d4;
  --color-olive-100: #ecebc1;
  --color-olive-200: #dad8a2;
  --color-olive-300: #bfbb79;
  --color-olive-400: #a9a150;
  --color-olive-500: #938920;
  --color-olive-600: #7c741e;
  --color-olive-700: #635d18;
  --color-olive-800: #4a430e;
  --color-olive-900: #342e09;
  --color-olive-950: #1f1b00;
}

SCSS

$olive: #81781b;
$olive-rgb: 129, 120, 27;
$olive-light: mix(#fff, $olive, 20%);
$olive-dark: mix(#000, $olive, 20%);

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