#001319

CSS

:root {
  --black-stallion: #001319;
  --black-stallion-rgb: 0 19 25;
  --black-stallion-oklch: oklch(0.172 0.031 218.5);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(194 100% 5%);
  border-color: oklch(0.172 0.031 218.5);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #001319;
  --color-black-stallion-50: #ecf7fb;
  --color-black-stallion-100: #ddebef;
  --color-black-stallion-200: #c7d8de;
  --color-black-stallion-300: #a7bbc3;
  --color-black-stallion-400: #8ba3ab;
  --color-black-stallion-500: #708c94;
  --color-black-stallion-600: #5f767d;
  --color-black-stallion-700: #4c5e64;
  --color-black-stallion-800: #364549;
  --color-black-stallion-900: #253033;
  --color-black-stallion-950: #141c1f;
}

SCSS

$black-stallion: #001319;
$black-stallion-rgb: 0, 19, 25;
$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);
}