#E62138

CSS

:root {
  --transfusion: #e62138;
  --transfusion-rgb: 230 33 56;
  --transfusion-oklch: oklch(0.594 0.225 22.9);
}

.element {
  color: var(--transfusion);
  background-color: hsl(353 80% 52%);
  border-color: oklch(0.594 0.225 22.9);
}

Tailwind CSS v4

@theme {
  --color-transfusion: #e62138;
  --color-transfusion-50: #ffddd5;
  --color-transfusion-100: #ffcbc2;
  --color-transfusion-200: #ffaca3;
  --color-transfusion-300: #ff837b;
  --color-transfusion-400: #ff575c;
  --color-transfusion-500: #f80a36;
  --color-transfusion-600: #d1142f;
  --color-transfusion-700: #a91225;
  --color-transfusion-800: #7e091d;
  --color-transfusion-900: #590713;
  --color-transfusion-950: #3c0005;
}

SCSS

$transfusion: #e62138;
$transfusion-rgb: 230, 33, 56;
$transfusion-light: mix(#fff, $transfusion, 20%);
$transfusion-dark: mix(#000, $transfusion, 20%);

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