#0A1921

CSS

:root {
  --black-stallion: #0a1921;
  --black-stallion-rgb: 10 25 33;
  --black-stallion-oklch: oklch(0.204 0.026 233.3);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(201 53% 8%);
  border-color: oklch(0.204 0.026 233.3);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #0a1921;
  --color-black-stallion-50: #eef6fc;
  --color-black-stallion-100: #e0e9ef;
  --color-black-stallion-200: #cad6de;
  --color-black-stallion-300: #abbac3;
  --color-black-stallion-400: #90a1ac;
  --color-black-stallion-500: #768a95;
  --color-black-stallion-600: #64747e;
  --color-black-stallion-700: #505d65;
  --color-black-stallion-800: #3a444a;
  --color-black-stallion-900: #272f33;
  --color-black-stallion-950: #161c1f;
}

SCSS

$black-stallion: #0a1921;
$black-stallion-rgb: 10, 25, 33;
$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);
}