#63AC40

CSS

:root {
  --grass: #63ac40;
  --grass-rgb: 99 172 64;
  --grass-oklch: oklch(0.673 0.161 137);
}

.element {
  color: var(--grass);
  background-color: hsl(101 46% 46%);
  border-color: oklch(0.673 0.161 137);
}

Tailwind CSS v4

@theme {
  --color-grass: #63ac40;
  --color-grass-50: #deffd5;
  --color-grass-100: #cdf6c2;
  --color-grass-200: #b1e5a3;
  --color-grass-300: #8ccb7a;
  --color-grass-400: #6eb44f;
  --color-grass-500: #4c9d1a;
  --color-grass-600: #41851a;
  --color-grass-700: #346a15;
  --color-grass-800: #284e08;
  --color-grass-900: #1b3606;
  --color-grass-950: #0b2100;
}

SCSS

$grass: #63ac40;
$grass-rgb: 99, 172, 64;
$grass-light: mix(#fff, $grass, 20%);
$grass-dark: mix(#000, $grass, 20%);

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