#D83636

CSS

:root {
  --red-handed: #d83636;
  --red-handed-rgb: 216 54 54;
  --red-handed-oklch: oklch(0.583 0.199 25.9);
}

.element {
  color: var(--red-handed);
  background-color: hsl(0 68% 53%);
  border-color: oklch(0.583 0.199 25.9);
}

Tailwind CSS v4

@theme {
  --color-red-handed: #d83636;
  --color-red-handed-50: #ffe0d6;
  --color-red-handed-100: #ffcfc3;
  --color-red-handed-200: #ffb3a5;
  --color-red-handed-300: #ff8c7d;
  --color-red-handed-400: #fe655d;
  --color-red-handed-500: #ed3638;
  --color-red-handed-600: #c83031;
  --color-red-handed-700: #a12726;
  --color-red-handed-800: #78191d;
  --color-red-handed-900: #551113;
  --color-red-handed-950: #390205;
}

SCSS

$red-handed: #d83636;
$red-handed-rgb: 216, 54, 54;
$red-handed-light: mix(#fff, $red-handed, 20%);
$red-handed-dark: mix(#000, $red-handed, 20%);

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