#4971CE

CSS

:root {
  --skies-of-cyberspace: #4971ce;
  --skies-of-cyberspace-rgb: 73 113 206;
  --skies-of-cyberspace-oklch: oklch(0.567 0.15 264.6);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(222 58% 55%);
  border-color: oklch(0.567 0.15 264.6);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #4971ce;
  --color-skies-of-cyberspace-50: #e1f5ff;
  --color-skies-of-cyberspace-100: #d1e7ff;
  --color-skies-of-cyberspace-200: #b7d3ff;
  --color-skies-of-cyberspace-300: #94b5ff;
  --color-skies-of-cyberspace-400: #729bf7;
  --color-skies-of-cyberspace-500: #5380e9;
  --color-skies-of-cyberspace-600: #476dc4;
  --color-skies-of-cyberspace-700: #38579e;
  --color-skies-of-cyberspace-800: #254076;
  --color-skies-of-cyberspace-900: #192c53;
  --color-skies-of-cyberspace-950: #0a1938;
}

SCSS

$skies-of-cyberspace: #4971ce;
$skies-of-cyberspace-rgb: 73, 113, 206;
$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);
}