#046FB9

CSS

:root {
  --french-blue: #046fb9;
  --french-blue-rgb: 4 111 185;
  --french-blue-oklch: oklch(0.53 0.142 248.4);
}

.element {
  color: var(--french-blue);
  background-color: hsl(205 96% 37%);
  border-color: oklch(0.53 0.142 248.4);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #046fb9;
  --color-french-blue-50: #d7f9ff;
  --color-french-blue-100: #c5ecff;
  --color-french-blue-200: #a6d9ff;
  --color-french-blue-300: #7ebdfe;
  --color-french-blue-400: #53a4ee;
  --color-french-blue-500: #1f8bdf;
  --color-french-blue-600: #1e75bc;
  --color-french-blue-700: #185e97;
  --color-french-blue-800: #094570;
  --color-french-blue-900: #06304f;
  --color-french-blue-950: #001c35;
}

SCSS

$french-blue: #046fb9;
$french-blue-rgb: 4, 111, 185;
$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);
}