#9DABD6

CSS

:root {
  --old-world: #9dabd6;
  --old-world-rgb: 157 171 214;
  --old-world-oklch: oklch(0.745 0.064 270.7);
}

.element {
  color: var(--old-world);
  background-color: hsl(225 41% 73%);
  border-color: oklch(0.745 0.064 270.7);
}

Tailwind CSS v4

@theme {
  --color-old-world: #9dabd6;
  --color-old-world-50: #eff4ff;
  --color-old-world-100: #e0e7fe;
  --color-old-world-200: #cbd3f1;
  --color-old-world-300: #acb6d9;
  --color-old-world-400: #909dc5;
  --color-old-world-500: #7684b1;
  --color-old-world-600: #647096;
  --color-old-world-700: #505a78;
  --color-old-world-800: #394259;
  --color-old-world-900: #272d3e;
  --color-old-world-950: #151a27;
}

SCSS

$old-world: #9dabd6;
$old-world-rgb: 157, 171, 214;
$old-world-light: mix(#fff, $old-world, 20%);
$old-world-dark: mix(#000, $old-world, 20%);

.element {
  color: $old-world;
  box-shadow: 0 0 0 2px rgba($old-world, 0.35);
}