#836951

CSS

:root {
  --pastel-brown: #836951;
  --pastel-brown-rgb: 131 105 81;
  --pastel-brown-oklch: oklch(0.54 0.049 64.2);
}

.element {
  color: var(--pastel-brown);
  background-color: hsl(29 24% 42%);
  border-color: oklch(0.54 0.049 64.2);
}

Tailwind CSS v4

@theme {
  --color-pastel-brown: #836951;
  --color-pastel-brown-50: #fff3e7;
  --color-pastel-brown-100: #f4e5d7;
  --color-pastel-brown-200: #e3d1bf;
  --color-pastel-brown-300: #c9b39e;
  --color-pastel-brown-400: #b39981;
  --color-pastel-brown-500: #9d8065;
  --color-pastel-brown-600: #856c55;
  --color-pastel-brown-700: #6b5644;
  --color-pastel-brown-800: #4f3f31;
  --color-pastel-brown-900: #372b21;
  --color-pastel-brown-950: #221911;
}

SCSS

$pastel-brown: #836951;
$pastel-brown-rgb: 131, 105, 81;
$pastel-brown-light: mix(#fff, $pastel-brown, 20%);
$pastel-brown-dark: mix(#000, $pastel-brown, 20%);

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