#657D33

CSS

:root {
  --muddy-green: #657d33;
  --muddy-green-rgb: 101 125 51;
  --muddy-green-oklch: oklch(0.554 0.105 124.8);
}

.element {
  color: var(--muddy-green);
  background-color: hsl(79 42% 35%);
  border-color: oklch(0.554 0.105 124.8);
}

Tailwind CSS v4

@theme {
  --color-muddy-green: #657d33;
  --color-muddy-green-50: #edfbdb;
  --color-muddy-green-100: #dfefca;
  --color-muddy-green-200: #c8ddad;
  --color-muddy-green-300: #a9c287;
  --color-muddy-green-400: #91a963;
  --color-muddy-green-500: #77923f;
  --color-muddy-green-600: #657b36;
  --color-muddy-green-700: #50632b;
  --color-muddy-green-800: #3c481c;
  --color-muddy-green-900: #293212;
  --color-muddy-green-950: #171e05;
}

SCSS

$muddy-green: #657d33;
$muddy-green-rgb: 101, 125, 51;
$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);
}