#16152C

CSS

:root {
  --dark-knight: #16152c;
  --dark-knight-rgb: 22 21 44;
  --dark-knight-oklch: oklch(0.21 0.045 283.8);
}

.element {
  color: var(--dark-knight);
  background-color: hsl(243 35% 13%);
  border-color: oklch(0.21 0.045 283.8);
}

Tailwind CSS v4

@theme {
  --color-dark-knight: #16152c;
  --color-dark-knight-50: #f4f4ff;
  --color-dark-knight-100: #e6e6f7;
  --color-dark-knight-200: #d2d2e7;
  --color-dark-knight-300: #b5b5ce;
  --color-dark-knight-400: #9b9bb9;
  --color-dark-knight-500: #8283a3;
  --color-dark-knight-600: #6e6f8a;
  --color-dark-knight-700: #58586f;
  --color-dark-knight-800: #404152;
  --color-dark-knight-900: #2c2d39;
  --color-dark-knight-950: #191a23;
}

SCSS

$dark-knight: #16152c;
$dark-knight-rgb: 22, 21, 44;
$dark-knight-light: mix(#fff, $dark-knight, 20%);
$dark-knight-dark: mix(#000, $dark-knight, 20%);

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