#00171C

CSS

:root {
  --black-stallion: #00171c;
  --black-stallion-rgb: 0 23 28;
  --black-stallion-oklch: oklch(0.188 0.033 212.9);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(191 100% 5%);
  border-color: oklch(0.188 0.033 212.9);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #00171c;
  --color-black-stallion-50: #ebf8fb;
  --color-black-stallion-100: #dcebef;
  --color-black-stallion-200: #c5d8dd;
  --color-black-stallion-300: #a5bcc2;
  --color-black-stallion-400: #89a4aa;
  --color-black-stallion-500: #6e8c93;
  --color-black-stallion-600: #5d777c;
  --color-black-stallion-700: #4a5f64;
  --color-black-stallion-800: #354649;
  --color-black-stallion-900: #243032;
  --color-black-stallion-950: #131c1e;
}

SCSS

$black-stallion: #00171c;
$black-stallion-rgb: 0, 23, 28;
$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);
}