#060709

CSS

:root {
  --black-metal: #060709;
  --black-metal-rgb: 6 7 9;
  --black-metal-oklch: oklch(0.128 0.006 262);
}

.element {
  color: var(--black-metal);
  background-color: hsl(220 20% 3%);
  border-color: oklch(0.128 0.006 262);
}

Tailwind CSS v4

@theme {
  --color-black-metal: #060709;
  --color-black-metal-50: #f4f5f7;
  --color-black-metal-100: #e7e8ea;
  --color-black-metal-200: #d3d4d7;
  --color-black-metal-300: #b6b7ba;
  --color-black-metal-400: #9c9ea2;
  --color-black-metal-500: #84868a;
  --color-black-metal-600: #707275;
  --color-black-metal-700: #595b5d;
  --color-black-metal-800: #414244;
  --color-black-metal-900: #2d2e2f;
  --color-black-metal-950: #1a1b1c;
}

SCSS

$black-metal: #060709;
$black-metal-rgb: 6, 7, 9;
$black-metal-light: mix(#fff, $black-metal, 20%);
$black-metal-dark: mix(#000, $black-metal, 20%);

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