#006DAE

CSS

:root {
  --french-blue: #006dae;
  --french-blue-rgb: 0 109 174;
  --french-blue-oklch: oklch(0.517 0.131 245.4);
}

.element {
  color: var(--french-blue);
  background-color: hsl(202 100% 34%);
  border-color: oklch(0.517 0.131 245.4);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #006dae;
  --color-french-blue-50: #d8faff;
  --color-french-blue-100: #c6edff;
  --color-french-blue-200: #a7daff;
  --color-french-blue-300: #7fbef7;
  --color-french-blue-400: #55a5e7;
  --color-french-blue-500: #238cd7;
  --color-french-blue-600: #2177b5;
  --color-french-blue-700: #1a5f92;
  --color-french-blue-800: #0c466c;
  --color-french-blue-900: #08314c;
  --color-french-blue-950: #001d32;
}

SCSS

$french-blue: #006dae;
$french-blue-rgb: 0, 109, 174;
$french-blue-light: mix(#fff, $french-blue, 20%);
$french-blue-dark: mix(#000, $french-blue, 20%);

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