#BE4404

CSS

:root {
  --copper-hopper: #be4404;
  --copper-hopper-rgb: 190 68 4;
  --copper-hopper-oklch: oklch(0.55 0.168 40.8);
}

.element {
  color: var(--copper-hopper);
  background-color: hsl(21 96% 38%);
  border-color: oklch(0.55 0.168 40.8);
}

Tailwind CSS v4

@theme {
  --color-copper-hopper: #be4404;
  --color-copper-hopper-50: #ffe6cf;
  --color-copper-hopper-100: #ffd6bc;
  --color-copper-hopper-200: #ffbd9a;
  --color-copper-hopper-300: #ff996f;
  --color-copper-hopper-400: #ef7749;
  --color-copper-hopper-500: #dd5311;
  --color-copper-hopper-600: #bb4814;
  --color-copper-hopper-700: #963910;
  --color-copper-hopper-800: #70280d;
  --color-copper-hopper-900: #4f1b08;
  --color-copper-hopper-950: #340a00;
}

SCSS

$copper-hopper: #be4404;
$copper-hopper-rgb: 190, 68, 4;
$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);
}