#D9012D

CSS

:root {
  --rare-red: #d9012d;
  --rare-red-rgb: 217 1 45;
  --rare-red-oklch: oklch(0.559 0.225 22.9);
}

.element {
  color: var(--rare-red);
  background-color: hsl(348 99% 43%);
  border-color: oklch(0.559 0.225 22.9);
}

Tailwind CSS v4

@theme {
  --color-rare-red: #d9012d;
  --color-rare-red-50: #ffddd5;
  --color-rare-red-100: #ffcac2;
  --color-rare-red-200: #ffaca3;
  --color-rare-red-300: #ff827b;
  --color-rare-red-400: #ff565c;
  --color-rare-red-500: #f80936;
  --color-rare-red-600: #d2142f;
  --color-rare-red-700: #a91225;
  --color-rare-red-800: #7e091d;
  --color-rare-red-900: #590713;
  --color-rare-red-950: #3c0005;
}

SCSS

$rare-red: #d9012d;
$rare-red-rgb: 217, 1, 45;
$rare-red-light: mix(#fff, $rare-red, 20%);
$rare-red-dark: mix(#000, $rare-red, 20%);

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