#060804

CSS

:root {
  --black-metal: #060804;
  --black-metal-rgb: 6 8 4;
  --black-metal-oklch: oklch(0.129 0.012 127.8);
}

.element {
  color: var(--black-metal);
  background-color: hsl(90 33% 2%);
  border-color: oklch(0.129 0.012 127.8);
}

Tailwind CSS v4

@theme {
  --color-black-metal: #060804;
  --color-black-metal-50: #f4f6f2;
  --color-black-metal-100: #e6e9e4;
  --color-black-metal-200: #d2d5d0;
  --color-black-metal-300: #b5b9b2;
  --color-black-metal-400: #9ca098;
  --color-black-metal-500: #84887f;
  --color-black-metal-600: #6f736c;
  --color-black-metal-700: #595c56;
  --color-black-metal-800: #41433f;
  --color-black-metal-900: #2d2e2b;
  --color-black-metal-950: #1a1b18;
}

SCSS

$black-metal: #060804;
$black-metal-rgb: 6, 8, 4;
$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);
}