#5A751C

CSS

:root {
  --over-the-hills: #5a751c;
  --over-the-hills-rgb: 90 117 28;
  --over-the-hills-oklch: oklch(0.523 0.118 125.2);
}

.element {
  color: var(--over-the-hills);
  background-color: hsl(78 61% 28%);
  border-color: oklch(0.523 0.118 125.2);
}

Tailwind CSS v4

@theme {
  --color-over-the-hills: #5a751c;
  --color-over-the-hills-50: #ecfcd8;
  --color-over-the-hills-100: #ddf0c6;
  --color-over-the-hills-200: #c6dea8;
  --color-over-the-hills-300: #a7c381;
  --color-over-the-hills-400: #8eab5a;
  --color-over-the-hills-500: #749332;
  --color-over-the-hills-600: #627d2c;
  --color-over-the-hills-700: #4e6423;
  --color-over-the-hills-800: #3b4915;
  --color-over-the-hills-900: #28320e;
  --color-over-the-hills-950: #161e02;
}

SCSS

$over-the-hills: #5a751c;
$over-the-hills-rgb: 90, 117, 28;
$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);
}