#020B10

CSS

:root {
  --black-knight: #020b10;
  --black-knight-rgb: 2 11 16;
  --black-knight-oklch: oklch(0.141 0.021 227);
}

.element {
  color: var(--black-knight);
  background-color: hsl(201 78% 4%);
  border-color: oklch(0.141 0.021 227);
}

Tailwind CSS v4

@theme {
  --color-black-knight: #020b10;
  --color-black-knight-50: #eff6fa;
  --color-black-knight-100: #e1e9ed;
  --color-black-knight-200: #ccd6db;
  --color-black-knight-300: #adbac0;
  --color-black-knight-400: #92a1a8;
  --color-black-knight-500: #788991;
  --color-black-knight-600: #66747b;
  --color-black-knight-700: #515d62;
  --color-black-knight-800: #3b4448;
  --color-black-knight-900: #282f32;
  --color-black-knight-950: #161c1e;
}

SCSS

$black-knight: #020b10;
$black-knight-rgb: 2, 11, 16;
$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);
}