#00151E

CSS

:root {
  --black-stallion: #00151e;
  --black-stallion-rgb: 0 21 30;
  --black-stallion-oklch: oklch(0.182 0.035 226.6);
}

.element {
  color: var(--black-stallion);
  background-color: hsl(198 100% 6%);
  border-color: oklch(0.182 0.035 226.6);
}

Tailwind CSS v4

@theme {
  --color-black-stallion: #00151e;
  --color-black-stallion-50: #ebf7fd;
  --color-black-stallion-100: #ddeaf1;
  --color-black-stallion-200: #c6d8e0;
  --color-black-stallion-300: #a6bbc6;
  --color-black-stallion-400: #89a3af;
  --color-black-stallion-500: #6e8b98;
  --color-black-stallion-600: #5d7681;
  --color-black-stallion-700: #4a5e67;
  --color-black-stallion-800: #36454c;
  --color-black-stallion-900: #243034;
  --color-black-stallion-950: #131c20;
}

SCSS

$black-stallion: #00151e;
$black-stallion-rgb: 0, 21, 30;
$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);
}