#0075CD

CSS

:root {
  --french-blue: #0075cd;
  --french-blue-rgb: 0 117 205;
  --french-blue-oklch: oklch(0.556 0.161 250.9);
}

.element {
  color: var(--french-blue);
  background-color: hsl(206 100% 40%);
  border-color: oklch(0.556 0.161 250.9);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #0075cd;
  --color-french-blue-50: #d5f9ff;
  --color-french-blue-100: #c2ecff;
  --color-french-blue-200: #a3d9ff;
  --color-french-blue-300: #79bbff;
  --color-french-blue-400: #4ba3f9;
  --color-french-blue-500: #0888ec;
  --color-french-blue-600: #1073c7;
  --color-french-blue-700: #0e5ca0;
  --color-french-blue-800: #004477;
  --color-french-blue-900: #022f54;
  --color-french-blue-950: #001b38;
}

SCSS

$french-blue: #0075cd;
$french-blue-rgb: 0, 117, 205;
$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);
}