#9BA7CB

CSS

:root {
  --old-world: #9ba7cb;
  --old-world-rgb: 155 167 203;
  --old-world-oklch: oklch(0.731 0.054 270.6);
}

.element {
  color: var(--old-world);
  background-color: hsl(225 32% 70%);
  border-color: oklch(0.731 0.054 270.6);
}

Tailwind CSS v4

@theme {
  --color-old-world: #9ba7cb;
  --color-old-world-50: #f0f5ff;
  --color-old-world-100: #e1e7fb;
  --color-old-world-200: #ccd3ec;
  --color-old-world-300: #aeb6d4;
  --color-old-world-400: #929dbf;
  --color-old-world-500: #7885ab;
  --color-old-world-600: #667090;
  --color-old-world-700: #515a74;
  --color-old-world-800: #3a4255;
  --color-old-world-900: #282d3c;
  --color-old-world-950: #161a25;
}

SCSS

$old-world: #9ba7cb;
$old-world-rgb: 155, 167, 203;
$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);
}