#6A3500

CSS

:root {
  --brown: #6a3500;
  --brown-rgb: 106 53 0;
  --brown-oklch: oklch(0.39 0.095 56.6);
}

.element {
  color: var(--brown);
  background-color: hsl(30 100% 21%);
  border-color: oklch(0.39 0.095 56.6);
}

Tailwind CSS v4

@theme {
  --color-brown: #6a3500;
  --color-brown-50: #ffefdb;
  --color-brown-100: #ffe1c9;
  --color-brown-200: #f4cbad;
  --color-brown-300: #ddac87;
  --color-brown-400: #ca9066;
  --color-brown-500: #b67543;
  --color-brown-600: #99633a;
  --color-brown-700: #7b4f2e;
  --color-brown-800: #5c3921;
  --color-brown-900: #402716;
  --color-brown-950: #291507;
}

SCSS

$brown: #6a3500;
$brown-rgb: 106, 53, 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);
}