#001516

CSS

:root {
  --black-stallion: #001516;
  --black-stallion-rgb: 0 21 22;
  --black-stallion-oklch: oklch(0.178 0.03 198.7);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(183 100% 4%);
  border-color: oklch(0.178 0.03 198.7);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #001516;
  --color-black-stallion-50: #ecf8f9;
  --color-black-stallion-100: #ddebec;
  --color-black-stallion-200: #c6d8d9;
  --color-black-stallion-300: #a6bcbe;
  --color-black-stallion-400: #8aa4a5;
  --color-black-stallion-500: #6f8d8e;
  --color-black-stallion-600: #5e7778;
  --color-black-stallion-700: #4b5f60;
  --color-black-stallion-800: #364646;
  --color-black-stallion-900: #253030;
  --color-black-stallion-950: #141d1d;
}

SCSS

$black-stallion: #001516;
$black-stallion-rgb: 0, 21, 22;
$black-stallion-light: mix(#fff, $black-stallion, 20%);
$black-stallion-dark: mix(#000, $black-stallion, 20%);

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