#3771D9

CSS

:root {
  --skies-of-cyberspace: #3771d9;
  --skies-of-cyberspace-rgb: 55 113 217;
  --skies-of-cyberspace-oklch: oklch(0.566 0.171 261);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(219 68% 53%);
  border-color: oklch(0.566 0.171 261);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3771d9;
  --color-skies-of-cyberspace-50: #dcf6ff;
  --color-skies-of-cyberspace-100: #cae9ff;
  --color-skies-of-cyberspace-200: #aed4ff;
  --color-skies-of-cyberspace-300: #89b6ff;
  --color-skies-of-cyberspace-400: #629cff;
  --color-skies-of-cyberspace-500: #3f80f5;
  --color-skies-of-cyberspace-600: #366dcf;
  --color-skies-of-cyberspace-700: #2b57a6;
  --color-skies-of-cyberspace-800: #19407c;
  --color-skies-of-cyberspace-900: #102c58;
  --color-skies-of-cyberspace-950: #04193b;
}

SCSS

$skies-of-cyberspace: #3771d9;
$skies-of-cyberspace-rgb: 55, 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);
}