#020B14

CSS

:root {
  --black-knight: #020b14;
  --black-knight-rgb: 2 11 20;
  --black-knight-oklch: oklch(0.144 0.027 242.6);
}

.element {
  color: var(--black-knight);
  background-color: hsl(210 82% 4%);
  border-color: oklch(0.144 0.027 242.6);
}

Tailwind CSS v4

@theme {
  --color-black-knight: #020b14;
  --color-black-knight-50: #eff6fc;
  --color-black-knight-100: #e1e9f0;
  --color-black-knight-200: #cbd6df;
  --color-black-knight-300: #adb9c4;
  --color-black-knight-400: #91a1ad;
  --color-black-knight-500: #778997;
  --color-black-knight-600: #65747f;
  --color-black-knight-700: #515d66;
  --color-black-knight-800: #3a444b;
  --color-black-knight-900: #282f34;
  --color-black-knight-950: #161b1f;
}

SCSS

$black-knight: #020b14;
$black-knight-rgb: 2, 11, 20;
$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);
}