#5B7433

CSS

:root {
  --muddy-green: #5b7433;
  --muddy-green-rgb: 91 116 51;
  --muddy-green-oklch: oklch(0.524 0.096 126.9);
}

.element {
  color: var(--muddy-green);
  background-color: hsl(83 39% 33%);
  border-color: oklch(0.524 0.096 126.9);
}

Tailwind CSS v4

@theme {
  --color-muddy-green: #5b7433;
  --color-muddy-green-50: #edfbde;
  --color-muddy-green-100: #deefcd;
  --color-muddy-green-200: #c8ddb1;
  --color-muddy-green-300: #a8c18d;
  --color-muddy-green-400: #8fa96a;
  --color-muddy-green-500: #759248;
  --color-muddy-green-600: #637b3e;
  --color-muddy-green-700: #4f6331;
  --color-muddy-green-800: #3b4821;
  --color-muddy-green-900: #283216;
  --color-muddy-green-950: #161e07;
}

SCSS

$muddy-green: #5b7433;
$muddy-green-rgb: 91, 116, 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);
}