#DA001B

CSS

:root {
  --piercing-red: #da001b;
  --piercing-red-rgb: 218 0 27;
  --piercing-red-oklch: oklch(0.559 0.227 26.5);
}

.element {
  color: var(--piercing-red);
  background-color: hsl(353 100% 43%);
  border-color: oklch(0.559 0.227 26.5);
}

Tailwind CSS v4

@theme {
  --color-piercing-red: #da001b;
  --color-piercing-red-50: #ffddd0;
  --color-piercing-red-100: #ffcbbd;
  --color-piercing-red-200: #ffad9c;
  --color-piercing-red-300: #ff8372;
  --color-piercing-red-400: #ff5750;
  --color-piercing-red-500: #f90822;
  --color-piercing-red-600: #d21420;
  --color-piercing-red-700: #a91219;
  --color-piercing-red-800: #7f0815;
  --color-piercing-red-900: #5a070d;
  --color-piercing-red-950: #3c0002;
}

SCSS

$piercing-red: #da001b;
$piercing-red-rgb: 218, 0, 27;
$piercing-red-light: mix(#fff, $piercing-red, 20%);
$piercing-red-dark: mix(#000, $piercing-red, 20%);

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