#3571D9

CSS

:root {
  --skies-of-cyberspace: #3571d9;
  --skies-of-cyberspace-rgb: 53 113 217;
  --skies-of-cyberspace-oklch: oklch(0.566 0.172 260.6);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(218 68% 53%);
  border-color: oklch(0.566 0.172 260.6);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3571d9;
  --color-skies-of-cyberspace-50: #dbf6ff;
  --color-skies-of-cyberspace-100: #c9e9ff;
  --color-skies-of-cyberspace-200: #add4ff;
  --color-skies-of-cyberspace-300: #88b6ff;
  --color-skies-of-cyberspace-400: #619cff;
  --color-skies-of-cyberspace-500: #3d80f5;
  --color-skies-of-cyberspace-600: #356dcf;
  --color-skies-of-cyberspace-700: #2a57a6;
  --color-skies-of-cyberspace-800: #18407c;
  --color-skies-of-cyberspace-900: #0f2c58;
  --color-skies-of-cyberspace-950: #03193c;
}

SCSS

$skies-of-cyberspace: #3571d9;
$skies-of-cyberspace-rgb: 53, 113, 217;
$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);
}