#0778D6

CSS

:root {
  --fading-night: #0778d6;
  --fading-night-rgb: 7 120 214;
  --fading-night-oklch: oklch(0.57 0.168 252.1);
}

.element {
  color: var(--fading-night);
  background-color: hsl(207 94% 43%);
  border-color: oklch(0.57 0.168 252.1);
}

Tailwind CSS v4

@theme {
  --color-fading-night: #0778d6;
  --color-fading-night-50: #d5f9ff;
  --color-fading-night-100: #c2ecff;
  --color-fading-night-200: #a2d8ff;
  --color-fading-night-300: #78bbff;
  --color-fading-night-400: #4aa2fe;
  --color-fading-night-500: #0387f1;
  --color-fading-night-600: #0d72cb;
  --color-fading-night-700: #0c5ca3;
  --color-fading-night-800: #004479;
  --color-fading-night-900: #012f56;
  --color-fading-night-950: #001b3a;
}

SCSS

$fading-night: #0778d6;
$fading-night-rgb: 7, 120, 214;
$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);
}