#5A7511

CSS

:root {
  --over-the-hills: #5a7511;
  --over-the-hills-rgb: 90 117 17;
  --over-the-hills-oklch: oklch(0.522 0.124 124.6);
}

.element {
  color: var(--over-the-hills);
  background-color: hsl(76 75% 26%);
  border-color: oklch(0.522 0.124 124.6);
}

Tailwind CSS v4

@theme {
  --color-over-the-hills: #5a7511;
  --color-over-the-hills-50: #ecfcd6;
  --color-over-the-hills-100: #ddf0c4;
  --color-over-the-hills-200: #c6dfa5;
  --color-over-the-hills-300: #a7c37d;
  --color-over-the-hills-400: #8eab55;
  --color-over-the-hills-500: #749329;
  --color-over-the-hills-600: #627d25;
  --color-over-the-hills-700: #4f641d;
  --color-over-the-hills-800: #3b4911;
  --color-over-the-hills-900: #28330b;
  --color-over-the-hills-950: #161e01;
}

SCSS

$over-the-hills: #5a7511;
$over-the-hills-rgb: 90, 117, 17;
$over-the-hills-light: mix(#fff, $over-the-hills, 20%);
$over-the-hills-dark: mix(#000, $over-the-hills, 20%);

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