#030D03

CSS

:root {
  --blackn-t: #030d03;
  --blackn-t-rgb: 3 13 3;
  --blackn-t-oklch: oklch(0.143 0.032 143.7);
}

.element {
  color: var(--blackn-t);
  background-color: hsl(120 63% 3%);
  border-color: oklch(0.143 0.032 143.7);
}

Tailwind CSS v4

@theme {
  --color-blackn-t: #030d03;
  --color-blackn-t-50: #f0f8f0;
  --color-blackn-t-100: #e2ebe2;
  --color-blackn-t-200: #ccd8cc;
  --color-blackn-t-300: #aebcae;
  --color-blackn-t-400: #94a493;
  --color-blackn-t-500: #7a8c79;
  --color-blackn-t-600: #677667;
  --color-blackn-t-700: #535f52;
  --color-blackn-t-800: #3c453b;
  --color-blackn-t-900: #293029;
  --color-blackn-t-950: #171c16;
}

SCSS

$blackn-t: #030d03;
$blackn-t-rgb: 3, 13, 3;
$blackn-t-light: mix(#fff, $blackn-t, 20%);
$blackn-t-dark: mix(#000, $blackn-t, 20%);

.element {
  color: $blackn-t;
  box-shadow: 0 0 0 2px rgba($blackn-t, 0.35);
}