#797821

CSS

:root {
  --olive: #797821;
  --olive-rgb: 121 120 33;
  --olive-oklch: oklch(0.557 0.106 108.8);
}

.element {
  color: var(--olive);
  background-color: hsl(59 57% 30%);
  border-color: oklch(0.557 0.106 108.8);
}

Tailwind CSS v4

@theme {
  --color-olive: #797821;
  --color-olive-50: #f6f9d6;
  --color-olive-100: #e9ecc3;
  --color-olive-200: #d6d9a5;
  --color-olive-300: #babd7d;
  --color-olive-400: #a4a456;
  --color-olive-500: #8c8b2a;
  --color-olive-600: #777626;
  --color-olive-700: #5f5e1e;
  --color-olive-800: #474512;
  --color-olive-900: #312f0c;
  --color-olive-950: #1d1c01;
}

SCSS

$olive: #797821;
$olive-rgb: 121, 120, 33;
$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);
}