#D41F1F

CSS

:root {
  --heroic-red: #d41f1f;
  --heroic-red-rgb: 212 31 31;
  --heroic-red-oklch: oklch(0.558 0.213 27.7);
}

.element {
  color: var(--heroic-red);
  background-color: hsl(0 74% 48%);
  border-color: oklch(0.558 0.213 27.7);
}

Tailwind CSS v4

@theme {
  --color-heroic-red: #d41f1f;
  --color-heroic-red-50: #ffdfd2;
  --color-heroic-red-100: #ffcdbe;
  --color-heroic-red-200: #ffb09e;
  --color-heroic-red-300: #ff8874;
  --color-heroic-red-400: #ff5f53;
  --color-heroic-red-500: #f32827;
  --color-heroic-red-600: #cd2623;
  --color-heroic-red-700: #a51f1c;
  --color-heroic-red-800: #7c1316;
  --color-heroic-red-900: #570d0e;
  --color-heroic-red-950: #3b0003;
}

SCSS

$heroic-red: #d41f1f;
$heroic-red-rgb: 212, 31, 31;
$heroic-red-light: mix(#fff, $heroic-red, 20%);
$heroic-red-dark: mix(#000, $heroic-red, 20%);

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