#BD4509

CSS

:root {
  --copper-hopper: #bd4509;
  --copper-hopper-rgb: 189 69 9;
  --copper-hopper-oklch: oklch(0.55 0.166 40.8);
}

.element {
  color: var(--copper-hopper);
  background-color: hsl(20 91% 39%);
  border-color: oklch(0.55 0.166 40.8);
}

Tailwind CSS v4

@theme {
  --color-copper-hopper: #bd4509;
  --color-copper-hopper-50: #ffe7d0;
  --color-copper-hopper-100: #ffd7bc;
  --color-copper-hopper-200: #ffbd9b;
  --color-copper-hopper-300: #fe9a71;
  --color-copper-hopper-400: #ee784b;
  --color-copper-hopper-500: #dc5516;
  --color-copper-hopper-600: #ba4917;
  --color-copper-hopper-700: #953a13;
  --color-copper-hopper-800: #70280f;
  --color-copper-hopper-900: #4f1b09;
  --color-copper-hopper-950: #340a00;
}

SCSS

$copper-hopper: #bd4509;
$copper-hopper-rgb: 189, 69, 9;
$copper-hopper-light: mix(#fff, $copper-hopper, 20%);
$copper-hopper-dark: mix(#000, $copper-hopper, 20%);

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