#120615

CSS

:root {
  --glossy-black: #120615;
  --glossy-black-rgb: 18 6 21;
  --glossy-black-oklch: oklch(0.151 0.037 319.7);
}

.element {
  color: var(--glossy-black);
  background-color: hsl(288 56% 5%);
  border-color: oklch(0.151 0.037 319.7);
}

Tailwind CSS v4

@theme {
  --color-glossy-black: #120615;
  --color-glossy-black-50: #faf2fc;
  --color-glossy-black-100: #eee4ef;
  --color-glossy-black-200: #dccfde;
  --color-glossy-black-300: #c1b1c3;
  --color-glossy-black-400: #a998ad;
  --color-glossy-black-500: #917f96;
  --color-glossy-black-600: #7b6b7f;
  --color-glossy-black-700: #625666;
  --color-glossy-black-800: #483e4b;
  --color-glossy-black-900: #322b34;
  --color-glossy-black-950: #1e181f;
}

SCSS

$glossy-black: #120615;
$glossy-black-rgb: 18, 6, 21;
$glossy-black-light: mix(#fff, $glossy-black, 20%);
$glossy-black-dark: mix(#000, $glossy-black, 20%);

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