#2271E0

CSS

:root {
  --fading-night: #2271e0;
  --fading-night-rgb: 34 113 224;
  --fading-night-oklch: oklch(0.565 0.185 258.3);
}

.element {
  color: var(--fading-night);
  background-color: hsl(215 75% 51%);
  border-color: oklch(0.565 0.185 258.3);
}

Tailwind CSS v4

@theme {
  --color-fading-night: #2271e0;
  --color-fading-night-50: #d7f7ff;
  --color-fading-night-100: #c4e9ff;
  --color-fading-night-200: #a6d5ff;
  --color-fading-night-300: #7fb7ff;
  --color-fading-night-400: #549dff;
  --color-fading-night-500: #2781fe;
  --color-fading-night-600: #246dd6;
  --color-fading-night-700: #1c57ac;
  --color-fading-night-800: #0b4180;
  --color-fading-night-900: #072d5b;
  --color-fading-night-950: #00193e;
}

SCSS

$fading-night: #2271e0;
$fading-night-rgb: 34, 113, 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);
}