#766400

CSS

:root {
  --muddy-brown: #766400;
  --muddy-brown-rgb: 118 100 0;
  --muddy-brown-oklch: oklch(0.505 0.104 96.7);
}

.element {
  color: var(--muddy-brown);
  background-color: hsl(51 100% 23%);
  border-color: oklch(0.505 0.104 96.7);
}

Tailwind CSS v4

@theme {
  --color-muddy-brown: #766400;
  --color-muddy-brown-50: #fcf6d5;
  --color-muddy-brown-100: #f0e9c2;
  --color-muddy-brown-200: #dfd6a2;
  --color-muddy-brown-300: #c5b97a;
  --color-muddy-brown-400: #b09f53;
  --color-muddy-brown-500: #9a8625;
  --color-muddy-brown-600: #827122;
  --color-muddy-brown-700: #685a1b;
  --color-muddy-brown-800: #4e4210;
  --color-muddy-brown-900: #362d0a;
  --color-muddy-brown-950: #211a00;
}

SCSS

$muddy-brown: #766400;
$muddy-brown-rgb: 118, 100, 0;
$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);
}