#006DB7

CSS

:root {
  --french-blue: #006db7;
  --french-blue-rgb: 0 109 183;
  --french-blue-oklch: oklch(0.523 0.142 248.5);
}

.element {
  color: var(--french-blue);
  background-color: hsl(204 100% 36%);
  border-color: oklch(0.523 0.142 248.5);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #006db7;
  --color-french-blue-50: #d7f9ff;
  --color-french-blue-100: #c5ecff;
  --color-french-blue-200: #a6d9ff;
  --color-french-blue-300: #7ebcfe;
  --color-french-blue-400: #53a4ee;
  --color-french-blue-500: #208adf;
  --color-french-blue-600: #1e75bc;
  --color-french-blue-700: #195e97;
  --color-french-blue-800: #094570;
  --color-french-blue-900: #06304f;
  --color-french-blue-950: #001c35;
}

SCSS

$french-blue: #006db7;
$french-blue-rgb: 0, 109, 183;
$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);
}