#6E3600

CSS

:root {
  --brown: #6e3600;
  --brown-rgb: 110 54 0;
  --brown-oklch: oklch(0.398 0.098 55.4);
}

.element {
  color: var(--brown);
  background-color: hsl(29 100% 22%);
  border-color: oklch(0.398 0.098 55.4);
}

Tailwind CSS v4

@theme {
  --color-brown: #6e3600;
  --color-brown-50: #ffefda;
  --color-brown-100: #ffe0c9;
  --color-brown-200: #f5caac;
  --color-brown-300: #deab86;
  --color-brown-400: #cc8f65;
  --color-brown-500: #b87342;
  --color-brown-600: #9b6239;
  --color-brown-700: #7c4e2d;
  --color-brown-800: #5d3820;
  --color-brown-900: #412715;
  --color-brown-950: #291507;
}

SCSS

$brown: #6e3600;
$brown-rgb: 110, 54, 0;
$brown-light: mix(#fff, $brown, 20%);
$brown-dark: mix(#000, $brown, 20%);

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