#2070B0

CSS

:root {
  --french-blue: #2070b0;
  --french-blue-rgb: 32 112 176;
  --french-blue-oklch: oklch(0.53 0.125 247.6);
}

.element {
  color: var(--french-blue);
  background-color: hsl(207 69% 41%);
  border-color: oklch(0.53 0.125 247.6);
}

Tailwind CSS v4

@theme {
  --color-french-blue: #2070b0;
  --color-french-blue-50: #dbf9ff;
  --color-french-blue-100: #c9ecff;
  --color-french-blue-200: #acd9ff;
  --color-french-blue-300: #85bdf5;
  --color-french-blue-400: #5da4e5;
  --color-french-blue-500: #348bd4;
  --color-french-blue-600: #2e76b3;
  --color-french-blue-700: #245e90;
  --color-french-blue-800: #15466b;
  --color-french-blue-900: #0e304b;
  --color-french-blue-950: #021c31;
}

SCSS

$french-blue: #2070b0;
$french-blue-rgb: 32, 112, 176;
$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);
}