#051319

CSS

:root {
  --black-stallion: #051319;
  --black-stallion-rgb: 5 19 25;
  --black-stallion-oklch: oklch(0.177 0.024 226.6);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(198 67% 6%);
  border-color: oklch(0.177 0.024 226.6);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #051319;
  --color-black-stallion-50: #eef7fb;
  --color-black-stallion-100: #e0eaee;
  --color-black-stallion-200: #cad6dc;
  --color-black-stallion-300: #abbac1;
  --color-black-stallion-400: #90a2a9;
  --color-black-stallion-500: #768a93;
  --color-black-stallion-600: #64757c;
  --color-black-stallion-700: #505d63;
  --color-black-stallion-800: #3a4449;
  --color-black-stallion-900: #282f32;
  --color-black-stallion-950: #161c1e;
}

SCSS

$black-stallion: #051319;
$black-stallion-rgb: 5, 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);
}