#623100

CSS

:root {
  --brown: #623100;
  --brown-rgb: 98 49 0;
  --brown-oklch: oklch(0.37 0.09 57.1);
}

.element {
  color: var(--brown);
  background-color: hsl(30 100% 19%);
  border-color: oklch(0.37 0.09 57.1);
}

Tailwind CSS v4

@theme {
  --color-brown: #623100;
  --color-brown-50: #fff0dc;
  --color-brown-100: #ffe1cb;
  --color-brown-200: #f2ccaf;
  --color-brown-300: #daad8a;
  --color-brown-400: #c79169;
  --color-brown-500: #b37648;
  --color-brown-600: #97643e;
  --color-brown-700: #795031;
  --color-brown-800: #5a3a23;
  --color-brown-900: #3f2817;
  --color-brown-950: #281508;
}

SCSS

$brown: #623100;
$brown-rgb: 98, 49, 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);
}