#106FBA

CSS

:root {
  --french-blue: #106fba;
  --french-blue-rgb: 16 111 186;
  --french-blue-oklch: oklch(0.531 0.142 249.5);
}

.element {
  color: var(--french-blue);
  background-color: hsl(206 84% 40%);
  border-color: oklch(0.531 0.142 249.5);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #106fba;
  --color-french-blue-50: #d8f9ff;
  --color-french-blue-100: #c6ecff;
  --color-french-blue-200: #a7d9ff;
  --color-french-blue-300: #80bcfe;
  --color-french-blue-400: #55a3ee;
  --color-french-blue-500: #268adf;
  --color-french-blue-600: #2375bc;
  --color-french-blue-700: #1c5e97;
  --color-french-blue-800: #0d4570;
  --color-french-blue-900: #08304f;
  --color-french-blue-950: #001c35;
}

SCSS

$french-blue: #106fba;
$french-blue-rgb: 16, 111, 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);
}