#0D1921

CSS

:root {
  --black-stallion: #0d1921;
  --black-stallion-rgb: 13 25 33;
  --black-stallion-oklch: oklch(0.206 0.023 238.6);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(204 43% 9%);
  border-color: oklch(0.206 0.023 238.6);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #0d1921;
  --color-black-stallion-50: #eff6fb;
  --color-black-stallion-100: #e1e9ef;
  --color-black-stallion-200: #ccd6dd;
  --color-black-stallion-300: #adb9c2;
  --color-black-stallion-400: #92a1ab;
  --color-black-stallion-500: #788994;
  --color-black-stallion-600: #66747d;
  --color-black-stallion-700: #515d64;
  --color-black-stallion-800: #3b444a;
  --color-black-stallion-900: #282f33;
  --color-black-stallion-950: #161b1f;
}

SCSS

$black-stallion: #0d1921;
$black-stallion-rgb: 13, 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);
}