#816A1B

CSS

:root {
  --muddy-brown: #816a1b;
  --muddy-brown-rgb: 129 106 27;
  --muddy-brown-oklch: oklch(0.532 0.098 91.8);
}

.element {
  color: var(--muddy-brown);
  background-color: hsl(46 65% 31%);
  border-color: oklch(0.532 0.098 91.8);
}

Tailwind CSS v4

@theme {
  --color-muddy-brown: #816a1b;
  --color-muddy-brown-50: #fef5d6;
  --color-muddy-brown-100: #f2e8c4;
  --color-muddy-brown-200: #e2d4a5;
  --color-muddy-brown-300: #c8b77d;
  --color-muddy-brown-400: #b39d57;
  --color-muddy-brown-500: #9e842d;
  --color-muddy-brown-600: #856f28;
  --color-muddy-brown-700: #6b5920;
  --color-muddy-brown-800: #504115;
  --color-muddy-brown-900: #372d0d;
  --color-muddy-brown-950: #221902;
}

SCSS

$muddy-brown: #816a1b;
$muddy-brown-rgb: 129, 106, 27;
$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);
}