#0D6FBB

CSS

:root {
  --french-blue: #0d6fbb;
  --french-blue-rgb: 13 111 187;
  --french-blue-oklch: oklch(0.532 0.144 249.5);
}

.element {
  color: var(--french-blue);
  background-color: hsl(206 87% 39%);
  border-color: oklch(0.532 0.144 249.5);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #0d6fbb;
  --color-french-blue-50: #d8f9ff;
  --color-french-blue-100: #c5ecff;
  --color-french-blue-200: #a7d9ff;
  --color-french-blue-300: #7fbcff;
  --color-french-blue-400: #54a3ef;
  --color-french-blue-500: #238ae0;
  --color-french-blue-600: #2175bd;
  --color-french-blue-700: #1b5e98;
  --color-french-blue-800: #0b4571;
  --color-french-blue-900: #073050;
  --color-french-blue-950: #001c35;
}

SCSS

$french-blue: #0d6fbb;
$french-blue-rgb: 13, 111, 187;
$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);
}