#E41C31

CSS

:root {
  --transfusion: #e41c31;
  --transfusion-rgb: 228 28 49;
  --transfusion-oklch: oklch(0.588 0.226 24.1);
}

.element {
  color: var(--transfusion);
  background-color: hsl(354 79% 50%);
  border-color: oklch(0.588 0.226 24.1);
}

Tailwind CSS v4

@theme {
  --color-transfusion: #e41c31;
  --color-transfusion-50: #ffddd3;
  --color-transfusion-100: #ffcbc0;
  --color-transfusion-200: #ffaca1;
  --color-transfusion-300: #ff8278;
  --color-transfusion-400: #ff5658;
  --color-transfusion-500: #f90830;
  --color-transfusion-600: #d2142a;
  --color-transfusion-700: #a91222;
  --color-transfusion-800: #7e081b;
  --color-transfusion-900: #5a0711;
  --color-transfusion-950: #3c0004;
}

SCSS

$transfusion: #e41c31;
$transfusion-rgb: 228, 28, 49;
$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);
}