#030804

CSS

:root {
  --black-metal: #030804;
  --black-metal-rgb: 3 8 4;
  --black-metal-oklch: oklch(0.124 0.017 151.3);
}

.element {
  color: var(--black-metal);
  background-color: hsl(132 45% 2%);
  border-color: oklch(0.124 0.017 151.3);
}

Tailwind CSS v4

@theme {
  --color-black-metal: #030804;
  --color-black-metal-50: #f2f7f3;
  --color-black-metal-100: #e4eae5;
  --color-black-metal-200: #cfd6d1;
  --color-black-metal-300: #b1bab3;
  --color-black-metal-400: #97a199;
  --color-black-metal-500: #7e8a81;
  --color-black-metal-600: #6b746d;
  --color-black-metal-700: #555d57;
  --color-black-metal-800: #3e443f;
  --color-black-metal-900: #2b2f2b;
  --color-black-metal-950: #181c19;
}

SCSS

$black-metal: #030804;
$black-metal-rgb: 3, 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);
}