#03070C

CSS

:root {
  --eight-ball: #03070c;
  --eight-ball-rgb: 3 7 12;
  --eight-ball-oklch: oklch(0.125 0.016 245.5);
}

.element {
  color: var(--eight-ball);
  background-color: hsl(213 60% 3%);
  border-color: oklch(0.125 0.016 245.5);
}

Tailwind CSS v4

@theme {
  --color-eight-ball: #03070c;
  --color-eight-ball-50: #f2f6f9;
  --color-eight-ball-100: #e4e8ed;
  --color-eight-ball-200: #cfd5db;
  --color-eight-ball-300: #b1b8bf;
  --color-eight-ball-400: #97a0a7;
  --color-eight-ball-500: #7e8790;
  --color-eight-ball-600: #6b737a;
  --color-eight-ball-700: #555c62;
  --color-eight-ball-800: #3e4347;
  --color-eight-ball-900: #2b2e32;
  --color-eight-ball-950: #181b1d;
}

SCSS

$eight-ball: #03070c;
$eight-ball-rgb: 3, 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);
}