#4171D1

CSS

:root {
  --skies-of-cyberspace: #4171d1;
  --skies-of-cyberspace-rgb: 65 113 209;
  --skies-of-cyberspace-oklch: oklch(0.565 0.157 262.5);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(220 61% 54%);
  border-color: oklch(0.565 0.157 262.5);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #4171d1;
  --color-skies-of-cyberspace-50: #dff6ff;
  --color-skies-of-cyberspace-100: #cee8ff;
  --color-skies-of-cyberspace-200: #b3d4ff;
  --color-skies-of-cyberspace-300: #8fb6ff;
  --color-skies-of-cyberspace-400: #6b9cfb;
  --color-skies-of-cyberspace-500: #4b81ed;
  --color-skies-of-cyberspace-600: #406dc8;
  --color-skies-of-cyberspace-700: #3357a1;
  --color-skies-of-cyberspace-800: #204078;
  --color-skies-of-cyberspace-900: #152c55;
  --color-skies-of-cyberspace-950: #071939;
}

SCSS

$skies-of-cyberspace: #4171d1;
$skies-of-cyberspace-rgb: 65, 113, 209;
$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);
}