#031619

CSS

:root {
  --black-stallion: #031619;
  --black-stallion-rgb: 3 22 25;
  --black-stallion-oklch: oklch(0.185 0.027 208.3);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(188 79% 5%);
  border-color: oklch(0.185 0.027 208.3);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #031619;
  --color-black-stallion-50: #edf7f9;
  --color-black-stallion-100: #deeaed;
  --color-black-stallion-200: #c8d8db;
  --color-black-stallion-300: #a8bbbf;
  --color-black-stallion-400: #8da3a7;
  --color-black-stallion-500: #728c90;
  --color-black-stallion-600: #617679;
  --color-black-stallion-700: #4d5e61;
  --color-black-stallion-800: #384547;
  --color-black-stallion-900: #263031;
  --color-black-stallion-950: #141c1d;
}

SCSS

$black-stallion: #031619;
$black-stallion-rgb: 3, 22, 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);
}