#000B11

CSS

:root {
  --black-knight: #000b11;
  --black-knight-rgb: 0 11 17;
  --black-knight-oklch: oklch(0.139 0.026 224.9);
}

.element {
  color: var(--black-knight);
  background-color: hsl(201 100% 3%);
  border-color: oklch(0.139 0.026 224.9);
}

Tailwind CSS v4

@theme {
  --color-black-knight: #000b11;
  --color-black-knight-50: #eef7fb;
  --color-black-knight-100: #dfeaef;
  --color-black-knight-200: #c9d7dd;
  --color-black-knight-300: #aabac2;
  --color-black-knight-400: #8fa2aa;
  --color-black-knight-500: #748a93;
  --color-black-knight-600: #62757d;
  --color-black-knight-700: #4f5e64;
  --color-black-knight-800: #394549;
  --color-black-knight-900: #272f33;
  --color-black-knight-950: #151c1e;
}

SCSS

$black-knight: #000b11;
$black-knight-rgb: 0, 11, 17;
$black-knight-light: mix(#fff, $black-knight, 20%);
$black-knight-dark: mix(#000, $black-knight, 20%);

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