#B45D13

CSS

:root {
  --polished-copper: #b45d13;
  --polished-copper-rgb: 180 93 19;
  --polished-copper-oklch: oklch(0.572 0.137 53.6);
}

.element {
  color: var(--polished-copper);
  background-color: hsl(28 81% 39%);
  border-color: oklch(0.572 0.137 53.6);
}

Tailwind CSS v4

@theme {
  --color-polished-copper: #b45d13;
  --color-polished-copper-50: #ffecd0;
  --color-polished-copper-100: #ffddbd;
  --color-polished-copper-200: #ffc59c;
  --color-polished-copper-300: #eda571;
  --color-polished-copper-400: #dc864a;
  --color-polished-copper-500: #ca6812;
  --color-polished-copper-600: #aa5814;
  --color-polished-copper-700: #894711;
  --color-polished-copper-800: #66320c;
  --color-polished-copper-900: #482208;
  --color-polished-copper-950: #2f1100;
}

SCSS

$polished-copper: #b45d13;
$polished-copper-rgb: 180, 93, 19;
$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);
}