#91000B

CSS

:root {
  --jack-and-coke: #91000b;
  --jack-and-coke-rgb: 145 0 11;
  --jack-and-coke-oklch: oklch(0.413 0.168 27.1);
}

.element {
  color: var(--jack-and-coke);
  background-color: hsl(355 100% 28%);
  border-color: oklch(0.413 0.168 27.1);
}

Tailwind CSS v4

@theme {
  --color-jack-and-coke: #91000b;
  --color-jack-and-coke-50: #ffe4da;
  --color-jack-and-coke-100: #ffd3c8;
  --color-jack-and-coke-200: #ffb9ab;
  --color-jack-and-coke-300: #ff9485;
  --color-jack-and-coke-400: #f17166;
  --color-jack-and-coke-500: #e04c44;
  --color-jack-and-coke-600: #bd423a;
  --color-jack-and-coke-700: #98342e;
  --color-jack-and-coke-800: #712423;
  --color-jack-and-coke-900: #501817;
  --color-jack-and-coke-950: #350808;
}

SCSS

$jack-and-coke: #91000b;
$jack-and-coke-rgb: 145, 0, 11;
$jack-and-coke-light: mix(#fff, $jack-and-coke, 20%);
$jack-and-coke-dark: mix(#000, $jack-and-coke, 20%);

.element {
  color: $jack-and-coke;
  box-shadow: 0 0 0 2px rgba($jack-and-coke, 0.35);
}