#557267

CSS

:root {
  --dark-forest: #557267;
  --dark-forest-rgb: 85 114 103;
  --dark-forest-oklch: oklch(0.526 0.038 169.5);
}

.element {
  color: var(--dark-forest);
  background-color: hsl(157 15% 39%);
  border-color: oklch(0.526 0.038 169.5);
}

Tailwind CSS v4

@theme {
  --color-dark-forest: #557267;
  --color-dark-forest-50: #ebf9f4;
  --color-dark-forest-100: #dcece6;
  --color-dark-forest-200: #c5dad2;
  --color-dark-forest-300: #a5beb5;
  --color-dark-forest-400: #89a69b;
  --color-dark-forest-500: #6e8f82;
  --color-dark-forest-600: #5d796e;
  --color-dark-forest-700: #4a6158;
  --color-dark-forest-800: #364740;
  --color-dark-forest-900: #25312c;
  --color-dark-forest-950: #131d19;
}

SCSS

$dark-forest: #557267;
$dark-forest-rgb: 85, 114, 103;
$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);
}