#C55003

CSS

:root {
  --dark-orange: #c55003;
  --dark-orange-rgb: 197 80 3;
  --dark-orange-oklch: oklch(0.577 0.165 44.4);
}

.element {
  color: var(--dark-orange);
  background-color: hsl(24 97% 39%);
  border-color: oklch(0.577 0.165 44.4);
}

Tailwind CSS v4

@theme {
  --color-dark-orange: #c55003;
  --color-dark-orange-50: #ffe7ce;
  --color-dark-orange-100: #ffd8b9;
  --color-dark-orange-200: #ffbe97;
  --color-dark-orange-300: #fc9b6b;
  --color-dark-orange-400: #ec7a43;
  --color-dark-orange-500: #da5700;
  --color-dark-orange-600: #b84b04;
  --color-dark-orange-700: #943c06;
  --color-dark-orange-800: #6f2a07;
  --color-dark-orange-900: #4e1c05;
  --color-dark-orange-950: #340b00;
}

SCSS

$dark-orange: #c55003;
$dark-orange-rgb: 197, 80, 3;
$dark-orange-light: mix(#fff, $dark-orange, 20%);
$dark-orange-dark: mix(#000, $dark-orange, 20%);

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