#3277CE

CSS

:root {
  --fading-night: #3277ce;
  --fading-night-rgb: 50 119 206;
  --fading-night-oklch: oklch(0.57 0.151 255.8);
}

.element {
  color: var(--fading-night);
  background-color: hsl(213 61% 50%);
  border-color: oklch(0.57 0.151 255.8);
}

Tailwind CSS v4

@theme {
  --color-fading-night: #3277ce;
  --color-fading-night-50: #dbf7ff;
  --color-fading-night-100: #c9eaff;
  --color-fading-night-200: #acd7ff;
  --color-fading-night-300: #86b9ff;
  --color-fading-night-400: #5fa0f6;
  --color-fading-night-500: #3886e7;
  --color-fading-night-600: #3171c3;
  --color-fading-night-700: #275b9d;
  --color-fading-night-800: #164375;
  --color-fading-night-900: #0e2e52;
  --color-fading-night-950: #021a37;
}

SCSS

$fading-night: #3277ce;
$fading-night-rgb: 50, 119, 206;
$fading-night-light: mix(#fff, $fading-night, 20%);
$fading-night-dark: mix(#000, $fading-night, 20%);

.element {
  color: $fading-night;
  box-shadow: 0 0 0 2px rgba($fading-night, 0.35);
}