#0070BA

CSS

:root {
  --french-blue: #0070ba;
  --french-blue-rgb: 0 112 186;
  --french-blue-oklch: oklch(0.532 0.143 247.9);
}

.element {
  color: var(--french-blue);
  background-color: hsl(204 100% 36%);
  border-color: oklch(0.532 0.143 247.9);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #0070ba;
  --color-french-blue-50: #d7f9ff;
  --color-french-blue-100: #c4ecff;
  --color-french-blue-200: #a5d9ff;
  --color-french-blue-300: #7dbdfe;
  --color-french-blue-400: #51a4ee;
  --color-french-blue-500: #1b8bdf;
  --color-french-blue-600: #1b76bc;
  --color-french-blue-700: #165e97;
  --color-french-blue-800: #074670;
  --color-french-blue-900: #05304f;
  --color-french-blue-950: #001c35;
}

SCSS

$french-blue: #0070ba;
$french-blue-rgb: 0, 112, 186;
$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);
}