#006FE0

CSS

:root {
  --fading-night: #006fe0;
  --fading-night-rgb: 0 111 224;
  --fading-night-oklch: oklch(0.556 0.192 256.3);
}

.element {
  color: var(--fading-night);
  background-color: hsl(210 100% 44%);
  border-color: oklch(0.556 0.192 256.3);
}

Tailwind CSS v4

@theme {
  --color-fading-night: #006fe0;
  --color-fading-night-50: #d4f8ff;
  --color-fading-night-100: #c1eaff;
  --color-fading-night-200: #a1d6ff;
  --color-fading-night-300: #78b8ff;
  --color-fading-night-400: #499eff;
  --color-fading-night-500: #0781ff;
  --color-fading-night-600: #0f6ed9;
  --color-fading-night-700: #0d58ae;
  --color-fading-night-800: #004182;
  --color-fading-night-900: #002d5c;
  --color-fading-night-950: #00193f;
}

SCSS

$fading-night: #006fe0;
$fading-night-rgb: 0, 111, 224;
$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);
}