#66713B

CSS

:root {
  --muddy-green: #66713b;
  --muddy-green-rgb: 102 113 59;
  --muddy-green-oklch: oklch(0.526 0.078 118.6);
}

.element {
  color: var(--muddy-green);
  background-color: hsl(72 31% 34%);
  border-color: oklch(0.526 0.078 118.6);
}

Tailwind CSS v4

@theme {
  --color-muddy-green: #66713b;
  --color-muddy-green-50: #f2f9e0;
  --color-muddy-green-100: #e4ecd0;
  --color-muddy-green-200: #cfdab5;
  --color-muddy-green-300: #b1be91;
  --color-muddy-green-400: #99a570;
  --color-muddy-green-500: #818e50;
  --color-muddy-green-600: #6d7845;
  --color-muddy-green-700: #576037;
  --color-muddy-green-800: #414626;
  --color-muddy-green-900: #2c3019;
  --color-muddy-green-950: #1a1d0a;
}

SCSS

$muddy-green: #66713b;
$muddy-green-rgb: 102, 113, 59;
$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);
}