#3D74D5

CSS

:root {
  --skies-of-cyberspace: #3d74d5;
  --skies-of-cyberspace-rgb: 61 116 213;
  --skies-of-cyberspace-oklch: oklch(0.572 0.16 260.8);
}

.element {
  color: var(--skies-of-cyberspace);
  background-color: hsl(218 64% 54%);
  border-color: oklch(0.572 0.16 260.8);
}

Tailwind CSS v4

@theme {
  --color-skies-of-cyberspace: #3d74d5;
  --color-skies-of-cyberspace-50: #ddf6ff;
  --color-skies-of-cyberspace-100: #cce9ff;
  --color-skies-of-cyberspace-200: #b0d4ff;
  --color-skies-of-cyberspace-300: #8bb6ff;
  --color-skies-of-cyberspace-400: #669dfc;
  --color-skies-of-cyberspace-500: #4481ee;
  --color-skies-of-cyberspace-600: #3a6ec9;
  --color-skies-of-cyberspace-700: #2e58a2;
  --color-skies-of-cyberspace-800: #1c4179;
  --color-skies-of-cyberspace-900: #122d55;
  --color-skies-of-cyberspace-950: #051939;
}

SCSS

$skies-of-cyberspace: #3d74d5;
$skies-of-cyberspace-rgb: 61, 116, 213;
$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);
}