#D83637

CSS

:root {
  --red-handed: #d83637;
  --red-handed-rgb: 216 54 55;
  --red-handed-oklch: oklch(0.583 0.199 25.6);
}

.element {
  color: var(--red-handed);
  background-color: hsl(360 68% 53%);
  border-color: oklch(0.583 0.199 25.6);
}

Tailwind CSS v4

@theme {
  --color-red-handed: #d83637;
  --color-red-handed-50: #ffe0d6;
  --color-red-handed-100: #ffcfc3;
  --color-red-handed-200: #ffb2a5;
  --color-red-handed-300: #ff8b7d;
  --color-red-handed-400: #fe655e;
  --color-red-handed-500: #ed3639;
  --color-red-handed-600: #c83031;
  --color-red-handed-700: #a12727;
  --color-red-handed-800: #78191e;
  --color-red-handed-900: #551114;
  --color-red-handed-950: #390206;
}

SCSS

$red-handed: #d83637;
$red-handed-rgb: 216, 54, 55;
$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);
}