#BF0000

CSS

:root {
  --ghost-pepper: #bf0000;
  --ghost-pepper-rgb: 191 0 0;
  --ghost-pepper-oklch: oklch(0.505 0.207 29.2);
}

.element {
  color: var(--ghost-pepper);
  background-color: hsl(0 100% 37%);
  border-color: oklch(0.505 0.207 29.2);
}

Tailwind CSS v4

@theme {
  --color-ghost-pepper: #bf0000;
  --color-ghost-pepper-50: #ffe0d1;
  --color-ghost-pepper-100: #ffcebd;
  --color-ghost-pepper-200: #ffb29d;
  --color-ghost-pepper-300: #ff8a73;
  --color-ghost-pepper-400: #ff6251;
  --color-ghost-pepper-500: #f13023;
  --color-ghost-pepper-600: #cb2c20;
  --color-ghost-pepper-700: #a4231a;
  --color-ghost-pepper-800: #7a1715;
  --color-ghost-pepper-900: #570f0d;
  --color-ghost-pepper-950: #3a0102;
}

SCSS

$ghost-pepper: #bf0000;
$ghost-pepper-rgb: 191, 0, 0;
$ghost-pepper-light: mix(#fff, $ghost-pepper, 20%);
$ghost-pepper-dark: mix(#000, $ghost-pepper, 20%);

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