#623D25

CSS

:root {
  --van-dyke-brown: #623d25;
  --van-dyke-brown-rgb: 98 61 37;
  --van-dyke-brown-oklch: oklch(0.398 0.064 52.9);
}

.element {
  color: var(--van-dyke-brown);
  background-color: hsl(24 45% 26%);
  border-color: oklch(0.398 0.064 52.9);
}

Tailwind CSS v4

@theme {
  --color-van-dyke-brown: #623d25;
  --color-van-dyke-brown-50: #fff1e4;
  --color-van-dyke-brown-100: #fae3d4;
  --color-van-dyke-brown-200: #ebcebb;
  --color-van-dyke-brown-300: #d2af99;
  --color-van-dyke-brown-400: #bd957c;
  --color-van-dyke-brown-500: #a87b5e;
  --color-van-dyke-brown-600: #8e6850;
  --color-van-dyke-brown-700: #725340;
  --color-van-dyke-brown-800: #543c2e;
  --color-van-dyke-brown-900: #3b291f;
  --color-van-dyke-brown-950: #25170f;
}

SCSS

$van-dyke-brown: #623d25;
$van-dyke-brown-rgb: 98, 61, 37;
$van-dyke-brown-light: mix(#fff, $van-dyke-brown, 20%);
$van-dyke-brown-dark: mix(#000, $van-dyke-brown, 20%);

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