#4273CA

CSS

:root {
  --skies-of-cyberspace: #4273ca;
  --skies-of-cyberspace-rgb: 66 115 202;
  --skies-of-cyberspace-oklch: oklch(0.565 0.145 261);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(218 56% 53%);
  border-color: oklch(0.565 0.145 261);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #4273ca;
  --color-skies-of-cyberspace-50: #e0f6ff;
  --color-skies-of-cyberspace-100: #cfe9ff;
  --color-skies-of-cyberspace-200: #b4d5ff;
  --color-skies-of-cyberspace-300: #90b7ff;
  --color-skies-of-cyberspace-400: #6c9df3;
  --color-skies-of-cyberspace-500: #4c83e5;
  --color-skies-of-cyberspace-600: #416fc1;
  --color-skies-of-cyberspace-700: #33599b;
  --color-skies-of-cyberspace-800: #214174;
  --color-skies-of-cyberspace-900: #162d52;
  --color-skies-of-cyberspace-950: #071a37;
}

SCSS

$skies-of-cyberspace: #4273ca;
$skies-of-cyberspace-rgb: 66, 115, 202;
$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);
}