#B65F28

CSS

:root {
  --polished-copper: #b65f28;
  --polished-copper-rgb: 182 95 40;
  --polished-copper-oklch: oklch(0.579 0.131 49.5);
}

.element {
  color: var(--polished-copper);
  background-color: hsl(23 64% 44%);
  border-color: oklch(0.579 0.131 49.5);
}

Tailwind CSS v4

@theme {
  --color-polished-copper: #b65f28;
  --color-polished-copper-50: #ffebd4;
  --color-polished-copper-100: #ffdcc1;
  --color-polished-copper-200: #ffc5a1;
  --color-polished-copper-300: #eda478;
  --color-polished-copper-400: #dc8654;
  --color-polished-copper-500: #c96829;
  --color-polished-copper-600: #aa5825;
  --color-polished-copper-700: #88461d;
  --color-polished-copper-800: #663215;
  --color-polished-copper-900: #48220d;
  --color-polished-copper-950: #2f1102;
}

SCSS

$polished-copper: #b65f28;
$polished-copper-rgb: 182, 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);
}