#3A74D6

CSS

:root {
  --skies-of-cyberspace: #3a74d6;
  --skies-of-cyberspace-rgb: 58 116 214;
  --skies-of-cyberspace-oklch: oklch(0.572 0.163 260.2);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(218 66% 53%);
  border-color: oklch(0.572 0.163 260.2);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3a74d6;
  --color-skies-of-cyberspace-50: #dcf6ff;
  --color-skies-of-cyberspace-100: #cbe9ff;
  --color-skies-of-cyberspace-200: #afd5ff;
  --color-skies-of-cyberspace-300: #8ab7ff;
  --color-skies-of-cyberspace-400: #649dfd;
  --color-skies-of-cyberspace-500: #4082f0;
  --color-skies-of-cyberspace-600: #386eca;
  --color-skies-of-cyberspace-700: #2c58a3;
  --color-skies-of-cyberspace-800: #1a4179;
  --color-skies-of-cyberspace-900: #112d56;
  --color-skies-of-cyberspace-950: #04193a;
}

SCSS

$skies-of-cyberspace: #3a74d6;
$skies-of-cyberspace-rgb: 58, 116, 214;
$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);
}