#0073C4

CSS

:root {
  --french-blue: #0073c4;
  --french-blue-rgb: 0 115 196;
  --french-blue-oklch: oklch(0.546 0.152 249.4);
}

.element {
  color: var(--french-blue);
  background-color: hsl(205 100% 38%);
  border-color: oklch(0.546 0.152 249.4);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #0073c4;
  --color-french-blue-50: #d6f9ff;
  --color-french-blue-100: #c3ecff;
  --color-french-blue-200: #a4d9ff;
  --color-french-blue-300: #7bbcff;
  --color-french-blue-400: #4ea3f4;
  --color-french-blue-500: #128ae5;
  --color-french-blue-600: #1675c1;
  --color-french-blue-700: #125d9b;
  --color-french-blue-800: #034574;
  --color-french-blue-900: #033052;
  --color-french-blue-950: #001c37;
}

SCSS

$french-blue: #0073c4;
$french-blue-rgb: 0, 115, 196;
$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);
}