#597265

CSS

:root {
  --dark-forest: #597265;
  --dark-forest-rgb: 89 114 101;
  --dark-forest-oklch: oklch(0.528 0.036 162.2);
}

.element {
  color: var(--dark-forest);
  background-color: hsl(149 12% 40%);
  border-color: oklch(0.528 0.036 162.2);
}

Tailwind CSS v4

@theme {
  --color-dark-forest: #597265;
  --color-dark-forest-50: #ecf9f2;
  --color-dark-forest-100: #deece5;
  --color-dark-forest-200: #c7d9d0;
  --color-dark-forest-300: #a7bdb3;
  --color-dark-forest-400: #8ca598;
  --color-dark-forest-500: #718e7f;
  --color-dark-forest-600: #60786c;
  --color-dark-forest-700: #4d6056;
  --color-dark-forest-800: #38463e;
  --color-dark-forest-900: #26312b;
  --color-dark-forest-950: #151d18;
}

SCSS

$dark-forest: #597265;
$dark-forest-rgb: 89, 114, 101;
$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);
}