#2E72D9

CSS

:root {
  --fading-night: #2e72d9;
  --fading-night-rgb: 46 114 217;
  --fading-night-oklch: oklch(0.565 0.172 258.9);
}

.element {
  color: var(--fading-night);
  background-color: hsl(216 69% 52%);
  border-color: oklch(0.565 0.172 258.9);
}

Tailwind CSS v4

@theme {
  --color-fading-night: #2e72d9;
  --color-fading-night-50: #daf7ff;
  --color-fading-night-100: #c8e9ff;
  --color-fading-night-200: #aad5ff;
  --color-fading-night-300: #84b7ff;
  --color-fading-night-400: #5c9dff;
  --color-fading-night-500: #3582f6;
  --color-fading-night-600: #2e6ecf;
  --color-fading-night-700: #2558a6;
  --color-fading-night-800: #14417c;
  --color-fading-night-900: #0c2d58;
  --color-fading-night-950: #01193c;
}

SCSS

$fading-night: #2e72d9;
$fading-night-rgb: 46, 114, 217;
$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);
}