#BD4410

CSS

:root {
  --copper-hopper: #bd4410;
  --copper-hopper-rgb: 189 68 16;
  --copper-hopper-oklch: oklch(0.549 0.166 39.6);
}

.element {
  color: var(--copper-hopper);
  background-color: hsl(18 84% 40%);
  border-color: oklch(0.549 0.166 39.6);
}

Tailwind CSS v4

@theme {
  --color-copper-hopper: #bd4410;
  --color-copper-hopper-50: #ffe6d1;
  --color-copper-hopper-100: #ffd6bd;
  --color-copper-hopper-200: #ffbd9d;
  --color-copper-hopper-300: #fe9972;
  --color-copper-hopper-400: #ee774e;
  --color-copper-hopper-500: #dc541c;
  --color-copper-hopper-600: #ba481b;
  --color-copper-hopper-700: #963916;
  --color-copper-hopper-800: #702811;
  --color-copper-hopper-900: #4f1b0a;
  --color-copper-hopper-950: #340a01;
}

SCSS

$copper-hopper: #bd4410;
$copper-hopper-rgb: 189, 68, 16;
$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);
}