#3B74D3

CSS

:root {
  --skies-of-cyberspace: #3b74d3;
  --skies-of-cyberspace-rgb: 59 116 211;
  --skies-of-cyberspace-oklch: oklch(0.57 0.158 260);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(218 63% 53%);
  border-color: oklch(0.57 0.158 260);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3b74d3;
  --color-skies-of-cyberspace-50: #ddf6ff;
  --color-skies-of-cyberspace-100: #cbe9ff;
  --color-skies-of-cyberspace-200: #afd5ff;
  --color-skies-of-cyberspace-300: #8bb7ff;
  --color-skies-of-cyberspace-400: #659dfb;
  --color-skies-of-cyberspace-500: #4282ed;
  --color-skies-of-cyberspace-600: #396ec8;
  --color-skies-of-cyberspace-700: #2d58a1;
  --color-skies-of-cyberspace-800: #1c4178;
  --color-skies-of-cyberspace-900: #122d55;
  --color-skies-of-cyberspace-950: #041939;
}

SCSS

$skies-of-cyberspace: #3b74d3;
$skies-of-cyberspace-rgb: 59, 116, 211;
$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);
}