#5BAD39

CSS

:root {
  --grass: #5bad39;
  --grass-rgb: 91 173 57;
  --grass-oklch: oklch(0.671 0.171 137.9);
}

.element {
  color: var(--grass);
  background-color: hsl(102 50% 45%);
  border-color: oklch(0.671 0.171 137.9);
}

Tailwind CSS v4

@theme {
  --color-grass: #5bad39;
  --color-grass-50: #dcffd3;
  --color-grass-100: #caf7c0;
  --color-grass-200: #ade7a0;
  --color-grass-300: #86cd77;
  --color-grass-400: #68b54a;
  --color-grass-500: #429e09;
  --color-grass-600: #398610;
  --color-grass-700: #2e6b0e;
  --color-grass-800: #234f02;
  --color-grass-900: #183703;
  --color-grass-950: #082100;
}

SCSS

$grass: #5bad39;
$grass-rgb: 91, 173, 57;
$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);
}