#B55F28

CSS

:root {
  --polished-copper: #b55f28;
  --polished-copper-rgb: 181 95 40;
  --polished-copper-oklch: oklch(0.578 0.13 49.8);
}

.element {
  color: var(--polished-copper);
  background-color: hsl(23 64% 43%);
  border-color: oklch(0.578 0.13 49.8);
}

Tailwind CSS v4

@theme {
  --color-polished-copper: #b55f28;
  --color-polished-copper-50: #ffecd4;
  --color-polished-copper-100: #ffddc1;
  --color-polished-copper-200: #ffc5a1;
  --color-polished-copper-300: #eda479;
  --color-polished-copper-400: #db8654;
  --color-polished-copper-500: #c86829;
  --color-polished-copper-600: #a95925;
  --color-polished-copper-700: #88471d;
  --color-polished-copper-800: #663215;
  --color-polished-copper-900: #47220d;
  --color-polished-copper-950: #2e1102;
}

SCSS

$polished-copper: #b55f28;
$polished-copper-rgb: 181, 95, 40;
$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);
}