#0474BC

CSS

:root {
  --french-blue: #0474bc;
  --french-blue-rgb: 4 116 188;
  --french-blue-oklch: oklch(0.543 0.141 246.8);
}

.element {
  color: var(--french-blue);
  background-color: hsl(203 96% 38%);
  border-color: oklch(0.543 0.141 246.8);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #0474bc;
  --color-french-blue-50: #d7f9ff;
  --color-french-blue-100: #c4edff;
  --color-french-blue-200: #a5daff;
  --color-french-blue-300: #7cbdfc;
  --color-french-blue-400: #50a5ed;
  --color-french-blue-500: #188bdd;
  --color-french-blue-600: #1976bb;
  --color-french-blue-700: #155f96;
  --color-french-blue-800: #06466f;
  --color-french-blue-900: #05304e;
  --color-french-blue-950: #001c34;
}

SCSS

$french-blue: #0474bc;
$french-blue-rgb: 4, 116, 188;
$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);
}