#050706

CSS

:root {
  --black-metal: #050706;
  --black-metal-rgb: 5 7 6;
  --black-metal-oklch: oklch(0.125 0.005 165.2);
}

.element {
  color: var(--black-metal);
  background-color: hsl(150 17% 2%);
  border-color: oklch(0.125 0.005 165.2);
}

Tailwind CSS v4

@theme {
  --color-black-metal: #050706;
  --color-black-metal-50: #f4f6f5;
  --color-black-metal-100: #e6e8e7;
  --color-black-metal-200: #d2d5d4;
  --color-black-metal-300: #b5b8b7;
  --color-black-metal-400: #9c9f9d;
  --color-black-metal-500: #838785;
  --color-black-metal-600: #6f7271;
  --color-black-metal-700: #595c5a;
  --color-black-metal-800: #414342;
  --color-black-metal-900: #2d2e2d;
  --color-black-metal-950: #1a1b1a;
}

SCSS

$black-metal: #050706;
$black-metal-rgb: 5, 7, 6;
$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);
}