#E23000

CSS

:root {
  --vulcan-fire: #e23000;
  --vulcan-fire-rgb: 226 48 0;
  --vulcan-fire-oklch: oklch(0.593 0.217 33.2);
}

.element {
  color: var(--vulcan-fire);
  background-color: hsl(13 100% 44%);
  border-color: oklch(0.593 0.217 33.2);
}

Tailwind CSS v4

@theme {
  --color-vulcan-fire: #e23000;
  --color-vulcan-fire-50: #ffe0cb;
  --color-vulcan-fire-100: #ffceb6;
  --color-vulcan-fire-200: #ffb193;
  --color-vulcan-fire-300: #ff8966;
  --color-vulcan-fire-400: #ff5f3e;
  --color-vulcan-fire-500: #f42800;
  --color-vulcan-fire-600: #ce2600;
  --color-vulcan-fire-700: #a61f00;
  --color-vulcan-fire-800: #7d1305;
  --color-vulcan-fire-900: #580d04;
  --color-vulcan-fire-950: #3b0000;
}

SCSS

$vulcan-fire: #e23000;
$vulcan-fire-rgb: 226, 48, 0;
$vulcan-fire-light: mix(#fff, $vulcan-fire, 20%);
$vulcan-fire-dark: mix(#000, $vulcan-fire, 20%);

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