#637F43

CSS

:root {
  --beyond-the-pines: #637f43;
  --beyond-the-pines-rgb: 99 127 67;
  --beyond-the-pines-oklch: oklch(0.56 0.092 129.5);
}

.element {
  color: var(--beyond-the-pines);
  background-color: hsl(88 31% 38%);
  border-color: oklch(0.56 0.092 129.5);
}

Tailwind CSS v4

@theme {
  --color-beyond-the-pines: #637f43;
  --color-beyond-the-pines-50: #ecfbe0;
  --color-beyond-the-pines-100: #ddefcf;
  --color-beyond-the-pines-200: #c6ddb4;
  --color-beyond-the-pines-300: #a7c291;
  --color-beyond-the-pines-400: #8da96f;
  --color-beyond-the-pines-500: #73924f;
  --color-beyond-the-pines-600: #617c43;
  --color-beyond-the-pines-700: #4d6335;
  --color-beyond-the-pines-800: #394824;
  --color-beyond-the-pines-900: #273218;
  --color-beyond-the-pines-950: #151e09;
}

SCSS

$beyond-the-pines: #637f43;
$beyond-the-pines-rgb: 99, 127, 67;
$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);
}