#3A71E4

CSS

:root {
  --skies-of-cyberspace: #3a71e4;
  --skies-of-cyberspace-rgb: 58 113 228;
  --skies-of-cyberspace-oklch: oklch(0.575 0.185 262.8);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(221 76% 56%);
  border-color: oklch(0.575 0.185 262.8);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3a71e4;
  --color-skies-of-cyberspace-50: #dbf5ff;
  --color-skies-of-cyberspace-100: #cae8ff;
  --color-skies-of-cyberspace-200: #add3ff;
  --color-skies-of-cyberspace-300: #88b4ff;
  --color-skies-of-cyberspace-400: #629aff;
  --color-skies-of-cyberspace-500: #3f7dfe;
  --color-skies-of-cyberspace-600: #376ad6;
  --color-skies-of-cyberspace-700: #2b55ac;
  --color-skies-of-cyberspace-800: #193f81;
  --color-skies-of-cyberspace-900: #102b5b;
  --color-skies-of-cyberspace-950: #04183e;
}

SCSS

$skies-of-cyberspace: #3a71e4;
$skies-of-cyberspace-rgb: 58, 113, 228;
$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);
}