#3970DA

CSS

:root {
  --skies-of-cyberspace: #3970da;
  --skies-of-cyberspace-rgb: 57 112 218;
  --skies-of-cyberspace-oklch: oklch(0.566 0.173 261.9);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(220 69% 54%);
  border-color: oklch(0.566 0.173 261.9);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3970da;
  --color-skies-of-cyberspace-50: #dcf6ff;
  --color-skies-of-cyberspace-100: #cbe8ff;
  --color-skies-of-cyberspace-200: #afd4ff;
  --color-skies-of-cyberspace-300: #8ab5ff;
  --color-skies-of-cyberspace-400: #649bff;
  --color-skies-of-cyberspace-500: #417ff7;
  --color-skies-of-cyberspace-600: #386cd0;
  --color-skies-of-cyberspace-700: #2c56a7;
  --color-skies-of-cyberspace-800: #1b407d;
  --color-skies-of-cyberspace-900: #112c58;
  --color-skies-of-cyberspace-950: #04193c;
}

SCSS

$skies-of-cyberspace: #3970da;
$skies-of-cyberspace-rgb: 57, 112, 218;
$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);
}