#27407E

CSS

:root {
  --napoleonic-blue: #27407e;
  --napoleonic-blue-rgb: 39 64 126;
  --napoleonic-blue-oklch: oklch(0.387 0.109 265.2);
}

.element {
  color: var(--napoleonic-blue);
  background-color: hsl(223 53% 32%);
  border-color: oklch(0.387 0.109 265.2);
}

Tailwind CSS v4

@theme {
  --color-napoleonic-blue: #27407e;
  --color-napoleonic-blue-50: #e7f5ff;
  --color-napoleonic-blue-100: #d8e8ff;
  --color-napoleonic-blue-200: #bfd4ff;
  --color-napoleonic-blue-300: #9eb6f0;
  --color-napoleonic-blue-400: #7f9de0;
  --color-napoleonic-blue-500: #6383cf;
  --color-napoleonic-blue-600: #546fae;
  --color-napoleonic-blue-700: #43598c;
  --color-napoleonic-blue-800: #2e4168;
  --color-napoleonic-blue-900: #1f2d49;
  --color-napoleonic-blue-950: #0f1a30;
}

SCSS

$napoleonic-blue: #27407e;
$napoleonic-blue-rgb: 39, 64, 126;
$napoleonic-blue-light: mix(#fff, $napoleonic-blue, 20%);
$napoleonic-blue-dark: mix(#000, $napoleonic-blue, 20%);

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