#3670DE

CSS

:root {
  --skies-of-cyberspace: #3670de;
  --skies-of-cyberspace-rgb: 54 112 222;
  --skies-of-cyberspace-oklch: oklch(0.567 0.179 261.7);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(219 72% 54%);
  border-color: oklch(0.567 0.179 261.7);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3670de;
  --color-skies-of-cyberspace-50: #dbf6ff;
  --color-skies-of-cyberspace-100: #c9e8ff;
  --color-skies-of-cyberspace-200: #add4ff;
  --color-skies-of-cyberspace-300: #88b5ff;
  --color-skies-of-cyberspace-400: #619bff;
  --color-skies-of-cyberspace-500: #3d7ffa;
  --color-skies-of-cyberspace-600: #356cd3;
  --color-skies-of-cyberspace-700: #2a56aa;
  --color-skies-of-cyberspace-800: #18407f;
  --color-skies-of-cyberspace-900: #0f2c5a;
  --color-skies-of-cyberspace-950: #03183d;
}

SCSS

$skies-of-cyberspace: #3670de;
$skies-of-cyberspace-rgb: 54, 112, 222;
$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);
}