#FF4800

CSS

:root {
  --inferno-orange: #ff4800;
  --inferno-orange-rgb: 255 72 0;
  --inferno-orange-oklch: oklch(0.663 0.227 36);
}

.element {
  color: var(--inferno-orange);
  background-color: hsl(17 100% 50%);
  border-color: oklch(0.663 0.227 36);
}

Tailwind CSS v4

@theme {
  --color-inferno-orange: #ff4800;
  --color-inferno-orange-50: #ffdfc6;
  --color-inferno-orange-100: #ffceb1;
  --color-inferno-orange-200: #ffb08b;
  --color-inferno-orange-300: #ff875b;
  --color-inferno-orange-400: #ff5c2b;
  --color-inferno-orange-500: #f81e00;
  --color-inferno-orange-600: #d11f00;
  --color-inferno-orange-700: #a81a00;
  --color-inferno-orange-800: #7e0f00;
  --color-inferno-orange-900: #5a0a00;
  --color-inferno-orange-950: #3c0000;
}

SCSS

$inferno-orange: #ff4800;
$inferno-orange-rgb: 255, 72, 0;
$inferno-orange-light: mix(#fff, $inferno-orange, 20%);
$inferno-orange-dark: mix(#000, $inferno-orange, 20%);

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