#226FB3

CSS

:root {
  --french-blue: #226fb3;
  --french-blue-rgb: 34 111 179;
  --french-blue-oklch: oklch(0.53 0.129 249.6);
}

.element {
  color: var(--french-blue);
  background-color: hsl(208 68% 42%);
  border-color: oklch(0.53 0.129 249.6);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #226fb3;
  --color-french-blue-50: #dbf9ff;
  --color-french-blue-100: #c9ecff;
  --color-french-blue-200: #acd9ff;
  --color-french-blue-300: #85bcf8;
  --color-french-blue-400: #5ea3e8;
  --color-french-blue-500: #358ad8;
  --color-french-blue-600: #2f75b6;
  --color-french-blue-700: #255e92;
  --color-french-blue-800: #16456d;
  --color-french-blue-900: #0e304c;
  --color-french-blue-950: #021c33;
}

SCSS

$french-blue: #226fb3;
$french-blue-rgb: 34, 111, 179;
$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);
}