#C73637

CSS

:root {
  --smouldering-red: #c73637;
  --smouldering-red-rgb: 199 54 55;
  --smouldering-red-oklch: oklch(0.554 0.182 25.1);
}

.element {
  color: var(--smouldering-red);
  background-color: hsl(360 57% 50%);
  border-color: oklch(0.554 0.182 25.1);
}

Tailwind CSS v4

@theme {
  --color-smouldering-red: #c73637;
  --color-smouldering-red-50: #ffe2d9;
  --color-smouldering-red-100: #ffd1c7;
  --color-smouldering-red-200: #ffb6aa;
  --color-smouldering-red-300: #ff9084;
  --color-smouldering-red-400: #f76c65;
  --color-smouldering-red-500: #e64343;
  --color-smouldering-red-600: #c23a3a;
  --color-smouldering-red-700: #9c2e2e;
  --color-smouldering-red-800: #752022;
  --color-smouldering-red-900: #521517;
  --color-smouldering-red-950: #370508;
}

SCSS

$smouldering-red: #c73637;
$smouldering-red-rgb: 199, 54, 55;
$smouldering-red-light: mix(#fff, $smouldering-red, 20%);
$smouldering-red-dark: mix(#000, $smouldering-red, 20%);

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