#4173CB

CSS

:root {
  --skies-of-cyberspace: #4173cb;
  --skies-of-cyberspace-rgb: 65 115 203;
  --skies-of-cyberspace-oklch: oklch(0.565 0.147 260.8);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(218 57% 53%);
  border-color: oklch(0.565 0.147 260.8);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #4173cb;
  --color-skies-of-cyberspace-50: #dff6ff;
  --color-skies-of-cyberspace-100: #cee9ff;
  --color-skies-of-cyberspace-200: #b3d5ff;
  --color-skies-of-cyberspace-300: #8fb7ff;
  --color-skies-of-cyberspace-400: #6b9df4;
  --color-skies-of-cyberspace-500: #4a83e6;
  --color-skies-of-cyberspace-600: #406fc2;
  --color-skies-of-cyberspace-700: #33599c;
  --color-skies-of-cyberspace-800: #204174;
  --color-skies-of-cyberspace-900: #152d52;
  --color-skies-of-cyberspace-950: #071a37;
}

SCSS

$skies-of-cyberspace: #4173cb;
$skies-of-cyberspace-rgb: 65, 115, 203;
$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);
}