#5D3500

CSS

:root {
  --brown: #5d3500;
  --brown-rgb: 93 53 0;
  --brown-oklch: oklch(0.37 0.083 65.3);
}

.element {
  color: var(--brown);
  background-color: hsl(34 100% 18%);
  border-color: oklch(0.37 0.083 65.3);
}

Tailwind CSS v4

@theme {
  --color-brown: #5d3500;
  --color-brown-50: #fff1dd;
  --color-brown-100: #fbe3cb;
  --color-brown-200: #edceaf;
  --color-brown-300: #d5b08a;
  --color-brown-400: #c1956a;
  --color-brown-500: #ac7a48;
  --color-brown-600: #91683e;
  --color-brown-700: #755331;
  --color-brown-800: #573c23;
  --color-brown-900: #3d2917;
  --color-brown-950: #261708;
}

SCSS

$brown: #5d3500;
$brown-rgb: 93, 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);
}