#637D3B

CSS

:root {
  --beyond-the-pines: #637d3b;
  --beyond-the-pines-rgb: 99 125 59;
  --beyond-the-pines-oklch: oklch(0.554 0.097 127.1);
}

.element {
  color: var(--beyond-the-pines);
  background-color: hsl(84 36% 36%);
  border-color: oklch(0.554 0.097 127.1);
}

Tailwind CSS v4

@theme {
  --color-beyond-the-pines: #637d3b;
  --color-beyond-the-pines-50: #ecfbde;
  --color-beyond-the-pines-100: #deefcd;
  --color-beyond-the-pines-200: #c7ddb1;
  --color-beyond-the-pines-300: #a8c28c;
  --color-beyond-the-pines-400: #8fa96a;
  --color-beyond-the-pines-500: #759248;
  --color-beyond-the-pines-600: #637c3d;
  --color-beyond-the-pines-700: #4f6331;
  --color-beyond-the-pines-800: #3b4821;
  --color-beyond-the-pines-900: #283216;
  --color-beyond-the-pines-950: #161e07;
}

SCSS

$beyond-the-pines: #637d3b;
$beyond-the-pines-rgb: 99, 125, 59;
$beyond-the-pines-light: mix(#fff, $beyond-the-pines, 20%);
$beyond-the-pines-dark: mix(#000, $beyond-the-pines, 20%);

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