#7B781C

CSS

:root {
  --olive: #7b781c;
  --olive-rgb: 123 120 28;
  --olive-oklch: oklch(0.558 0.109 107.5);
}

.element {
  color: var(--olive);
  background-color: hsl(58 63% 30%);
  border-color: oklch(0.558 0.109 107.5);
}

Tailwind CSS v4

@theme {
  --color-olive: #7b781c;
  --color-olive-50: #f7f8d5;
  --color-olive-100: #eaecc2;
  --color-olive-200: #d7d9a3;
  --color-olive-300: #bbbd7a;
  --color-olive-400: #a5a352;
  --color-olive-500: #8e8b24;
  --color-olive-600: #787521;
  --color-olive-700: #605e1a;
  --color-olive-800: #484410;
  --color-olive-900: #322f0a;
  --color-olive-950: #1e1c00;
}

SCSS

$olive: #7b781c;
$olive-rgb: 123, 120, 28;
$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);
}