#587169

CSS

:root {
  --dark-forest: #587169;
  --dark-forest-rgb: 88 113 105;
  --dark-forest-oklch: oklch(0.526 0.032 173.5);
}

.element {
  color: var(--dark-forest);
  background-color: hsl(161 12% 39%);
  border-color: oklch(0.526 0.032 173.5);
}

Tailwind CSS v4

@theme {
  --color-dark-forest: #587169;
  --color-dark-forest-50: #ecf8f5;
  --color-dark-forest-100: #deece7;
  --color-dark-forest-200: #c7d9d3;
  --color-dark-forest-300: #a7bdb6;
  --color-dark-forest-400: #8ca59d;
  --color-dark-forest-500: #718d84;
  --color-dark-forest-600: #607870;
  --color-dark-forest-700: #4c6059;
  --color-dark-forest-800: #374641;
  --color-dark-forest-900: #26312d;
  --color-dark-forest-950: #141d1a;
}

SCSS

$dark-forest: #587169;
$dark-forest-rgb: 88, 113, 105;
$dark-forest-light: mix(#fff, $dark-forest, 20%);
$dark-forest-dark: mix(#000, $dark-forest, 20%);

.element {
  color: $dark-forest;
  box-shadow: 0 0 0 2px rgba($dark-forest, 0.35);
}