#7F7900

CSS

:root {
  --olive: #7f7900;
  --olive-rgb: 127 121 0;
  --olive-oklch: oklch(0.563 0.12 106.2);
}

.element {
  color: var(--olive);
  background-color: hsl(57 100% 25%);
  border-color: oklch(0.563 0.12 106.2);
}

Tailwind CSS v4

@theme {
  --color-olive: #7f7900;
  --color-olive-50: #f8f8d1;
  --color-olive-100: #ebecbe;
  --color-olive-200: #d8d99d;
  --color-olive-300: #bdbc72;
  --color-olive-400: #a8a347;
  --color-olive-500: #918a00;
  --color-olive-600: #7b750b;
  --color-olive-700: #625e0a;
  --color-olive-800: #494404;
  --color-olive-900: #332f03;
  --color-olive-950: #1f1b00;
}

SCSS

$olive: #7f7900;
$olive-rgb: 127, 121, 0;
$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);
}