#5B7436

CSS

:root {
  --muddy-green: #5b7436;
  --muddy-green-rgb: 91 116 54;
  --muddy-green-oklch: oklch(0.524 0.093 127.5);
}

.element {
  color: var(--muddy-green);
  background-color: hsl(84 36% 33%);
  border-color: oklch(0.524 0.093 127.5);
}

Tailwind CSS v4

@theme {
  --color-muddy-green: #5b7436;
  --color-muddy-green-50: #edfbdf;
  --color-muddy-green-100: #deefce;
  --color-muddy-green-200: #c8ddb3;
  --color-muddy-green-300: #a8c18f;
  --color-muddy-green-400: #8fa96d;
  --color-muddy-green-500: #75924c;
  --color-muddy-green-600: #637b41;
  --color-muddy-green-700: #4f6333;
  --color-muddy-green-800: #3b4823;
  --color-muddy-green-900: #283217;
  --color-muddy-green-950: #161e08;
}

SCSS

$muddy-green: #5b7436;
$muddy-green-rgb: 91, 116, 54;
$muddy-green-light: mix(#fff, $muddy-green, 20%);
$muddy-green-dark: mix(#000, $muddy-green, 20%);

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