#4371CF

CSS

:root {
  --skies-of-cyberspace: #4371cf;
  --skies-of-cyberspace-rgb: 67 113 207;
  --skies-of-cyberspace-oklch: oklch(0.564 0.154 262.8);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(220 59% 54%);
  border-color: oklch(0.564 0.154 262.8);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #4371cf;
  --color-skies-of-cyberspace-50: #e0f5ff;
  --color-skies-of-cyberspace-100: #cfe8ff;
  --color-skies-of-cyberspace-200: #b4d4ff;
  --color-skies-of-cyberspace-300: #90b6ff;
  --color-skies-of-cyberspace-400: #6d9cf9;
  --color-skies-of-cyberspace-500: #4d81eb;
  --color-skies-of-cyberspace-600: #426dc6;
  --color-skies-of-cyberspace-700: #34579f;
  --color-skies-of-cyberspace-800: #224077;
  --color-skies-of-cyberspace-900: #162c54;
  --color-skies-of-cyberspace-950: #081938;
}

SCSS

$skies-of-cyberspace: #4371cf;
$skies-of-cyberspace-rgb: 67, 113, 207;
$skies-of-cyberspace-light: mix(#fff, $skies-of-cyberspace, 20%);
$skies-of-cyberspace-dark: mix(#000, $skies-of-cyberspace, 20%);

.element {
  color: $skies-of-cyberspace;
  box-shadow: 0 0 0 2px rgba($skies-of-cyberspace, 0.35);
}