#3871E2

CSS

:root {
  --skies-of-cyberspace: #3871e2;
  --skies-of-cyberspace-rgb: 56 113 226;
  --skies-of-cyberspace-oklch: oklch(0.573 0.183 262.2);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(220 75% 55%);
  border-color: oklch(0.573 0.183 262.2);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3871e2;
  --color-skies-of-cyberspace-50: #dbf6ff;
  --color-skies-of-cyberspace-100: #c9e8ff;
  --color-skies-of-cyberspace-200: #add3ff;
  --color-skies-of-cyberspace-300: #88b5ff;
  --color-skies-of-cyberspace-400: #619aff;
  --color-skies-of-cyberspace-500: #3e7efd;
  --color-skies-of-cyberspace-600: #356bd5;
  --color-skies-of-cyberspace-700: #2a56ab;
  --color-skies-of-cyberspace-800: #183f80;
  --color-skies-of-cyberspace-900: #102c5b;
  --color-skies-of-cyberspace-950: #03183e;
}

SCSS

$skies-of-cyberspace: #3871e2;
$skies-of-cyberspace-rgb: 56, 113, 226;
$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);
}