#294070

CSS

:root {
  --napoleonic-blue: #294070;
  --napoleonic-blue-rgb: 41 64 112;
  --napoleonic-blue-oklch: oklch(0.378 0.087 263.5);
}

.element {
  color: var(--napoleonic-blue);
  background-color: hsl(221 46% 30%);
  border-color: oklch(0.378 0.087 263.5);
}

Tailwind CSS v4

@theme {
  --color-napoleonic-blue: #294070;
  --color-napoleonic-blue-50: #e9f5ff;
  --color-napoleonic-blue-100: #dae8ff;
  --color-napoleonic-blue-200: #c2d4fb;
  --color-napoleonic-blue-300: #a2b7e5;
  --color-napoleonic-blue-400: #849ed3;
  --color-napoleonic-blue-500: #6885c0;
  --color-napoleonic-blue-600: #5871a2;
  --color-napoleonic-blue-700: #465a82;
  --color-napoleonic-blue-800: #314261;
  --color-napoleonic-blue-900: #212e44;
  --color-napoleonic-blue-950: #111a2c;
}

SCSS

$napoleonic-blue: #294070;
$napoleonic-blue-rgb: 41, 64, 112;
$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);
}