#866819

CSS

:root {
  --muddy-brown: #866819;
  --muddy-brown-rgb: 134 104 25;
  --muddy-brown-oklch: oklch(0.533 0.1 86.4);
}

.element {
  color: var(--muddy-brown);
  background-color: hsl(43 69% 31%);
  border-color: oklch(0.533 0.1 86.4);
}

Tailwind CSS v4

@theme {
  --color-muddy-brown: #866819;
  --color-muddy-brown-50: #fff4d6;
  --color-muddy-brown-100: #f6e7c3;
  --color-muddy-brown-200: #e6d3a4;
  --color-muddy-brown-300: #ccb57c;
  --color-muddy-brown-400: #b89a56;
  --color-muddy-brown-500: #a3812b;
  --color-muddy-brown-600: #8a6d27;
  --color-muddy-brown-700: #6e571f;
  --color-muddy-brown-800: #523f14;
  --color-muddy-brown-900: #392c0d;
  --color-muddy-brown-950: #241902;
}

SCSS

$muddy-brown: #866819;
$muddy-brown-rgb: 134, 104, 25;
$muddy-brown-light: mix(#fff, $muddy-brown, 20%);
$muddy-brown-dark: mix(#000, $muddy-brown, 20%);

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