#657319

CSS

:root {
  --topiary-green: #657319;
  --topiary-green-rgb: 101 115 25;
  --topiary-green-oklch: oklch(0.526 0.112 118.3);
}

.element {
  color: var(--topiary-green);
  background-color: hsl(69 64% 27%);
  border-color: oklch(0.526 0.112 118.3);
}

Tailwind CSS v4

@theme {
  --color-topiary-green: #657319;
  --color-topiary-green-50: #f0fbd7;
  --color-topiary-green-100: #e2eec5;
  --color-topiary-green-200: #cddca6;
  --color-topiary-green-300: #afc07f;
  --color-topiary-green-400: #98a858;
  --color-topiary-green-500: #7f902e;
  --color-topiary-green-600: #6c7a29;
  --color-topiary-green-700: #566120;
  --color-topiary-green-800: #404714;
  --color-topiary-green-900: #2c310d;
  --color-topiary-green-950: #191d01;
}

SCSS

$topiary-green: #657319;
$topiary-green-rgb: 101, 115, 25;
$topiary-green-light: mix(#fff, $topiary-green, 20%);
$topiary-green-dark: mix(#000, $topiary-green, 20%);

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