#030D00

CSS

:root {
  --blackn-t: #030d00;
  --blackn-t-rgb: 3 13 0;
  --blackn-t-oklch: oklch(0.142 0.042 135.6);
}

.element {
  color: var(--blackn-t);
  background-color: hsl(106 100% 3%);
  border-color: oklch(0.142 0.042 135.6);
}

Tailwind CSS v4

@theme {
  --color-blackn-t: #030d00;
  --color-blackn-t-50: #f0f8ed;
  --color-blackn-t-100: #e1ebde;
  --color-blackn-t-200: #ccd9c7;
  --color-blackn-t-300: #adbda8;
  --color-blackn-t-400: #94a48c;
  --color-blackn-t-500: #7a8d71;
  --color-blackn-t-600: #677760;
  --color-blackn-t-700: #535f4d;
  --color-blackn-t-800: #3d4637;
  --color-blackn-t-900: #2a3026;
  --color-blackn-t-950: #171c14;
}

SCSS

$blackn-t: #030d00;
$blackn-t-rgb: 3, 13, 0;
$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);
}