#04070C

CSS

:root {
  --eight-ball: #04070c;
  --eight-ball-rgb: 4 7 12;
  --eight-ball-oklch: oklch(0.127 0.014 254);
}

.element {
  color: var(--eight-ball);
  background-color: hsl(218 50% 3%);
  border-color: oklch(0.127 0.014 254);
}

Tailwind CSS v4

@theme {
  --color-eight-ball: #04070c;
  --color-eight-ball-50: #f2f5f9;
  --color-eight-ball-100: #e5e8ed;
  --color-eight-ball-200: #d0d5da;
  --color-eight-ball-300: #b3b8bf;
  --color-eight-ball-400: #999fa7;
  --color-eight-ball-500: #808790;
  --color-eight-ball-600: #6c7279;
  --color-eight-ball-700: #575b61;
  --color-eight-ball-800: #3f4347;
  --color-eight-ball-900: #2b2e31;
  --color-eight-ball-950: #191b1d;
}

SCSS

$eight-ball: #04070c;
$eight-ball-rgb: 4, 7, 12;
$eight-ball-light: mix(#fff, $eight-ball, 20%);
$eight-ball-dark: mix(#000, $eight-ball, 20%);

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