#030503

CSS

:root {
  --black-metal: #030503;
  --black-metal-rgb: 3 5 3;
  --black-metal-oklch: oklch(0.109 0.01 144.9);
}

.element {
  color: var(--black-metal);
  background-color: hsl(120 25% 2%);
  border-color: oklch(0.109 0.01 144.9);
}

Tailwind CSS v4

@theme {
  --color-black-metal: #030503;
  --color-black-metal-50: #f3f6f3;
  --color-black-metal-100: #e6e9e6;
  --color-black-metal-200: #d1d5d2;
  --color-black-metal-300: #b4b9b4;
  --color-black-metal-400: #9ba09b;
  --color-black-metal-500: #828882;
  --color-black-metal-600: #6e736e;
  --color-black-metal-700: #585c58;
  --color-black-metal-800: #404340;
  --color-black-metal-900: #2c2e2c;
  --color-black-metal-950: #191b19;
}

SCSS

$black-metal: #030503;
$black-metal-rgb: 3, 5, 3;
$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);
}