#B55C18

CSS

:root {
  --polished-copper: #b55c18;
  --polished-copper-rgb: 181 92 24;
  --polished-copper-oklch: oklch(0.572 0.137 51.8);
}

.element {
  color: var(--polished-copper);
  background-color: hsl(26 77% 40%);
  border-color: oklch(0.572 0.137 51.8);
}

Tailwind CSS v4

@theme {
  --color-polished-copper: #b55c18;
  --color-polished-copper-50: #ffebd1;
  --color-polished-copper-100: #ffdcbd;
  --color-polished-copper-200: #ffc59d;
  --color-polished-copper-300: #eea473;
  --color-polished-copper-400: #dd854c;
  --color-polished-copper-500: #cb6718;
  --color-polished-copper-600: #ab5719;
  --color-polished-copper-700: #8a4614;
  --color-polished-copper-800: #67320e;
  --color-polished-copper-900: #482209;
  --color-polished-copper-950: #2f1000;
}

SCSS

$polished-copper: #b55c18;
$polished-copper-rgb: 181, 92, 24;
$polished-copper-light: mix(#fff, $polished-copper, 20%);
$polished-copper-dark: mix(#000, $polished-copper, 20%);

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