#502F86

CSS

:root {
  --night-fever: #502f86;
  --night-fever-rgb: 80 47 134;
  --night-fever-oklch: oklch(0.394 0.139 297);
}

.element {
  color: var(--night-fever);
  background-color: hsl(263 48% 35%);
  border-color: oklch(0.394 0.139 297);
}

Tailwind CSS v4

@theme {
  --color-night-fever: #502f86;
  --color-night-fever-50: #faedff;
  --color-night-fever-100: #eedeff;
  --color-night-fever-200: #dcc8ff;
  --color-night-fever-300: #c1a7f5;
  --color-night-fever-400: #a78ce6;
  --color-night-fever-500: #916fd6;
  --color-night-fever-600: #7b5eb4;
  --color-night-fever-700: #624b91;
  --color-night-fever-800: #46376d;
  --color-night-fever-900: #31264d;
  --color-night-fever-950: #1d1433;
}

SCSS

$night-fever: #502f86;
$night-fever-rgb: 80, 47, 134;
$night-fever-light: mix(#fff, $night-fever, 20%);
$night-fever-dark: mix(#000, $night-fever, 20%);

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