#04070A

CSS

:root {
  --eight-ball: #04070a;
  --eight-ball-rgb: 4 7 10;
  --eight-ball-oklch: oklch(0.126 0.01 241.8);
}

.element {
  color: var(--eight-ball);
  background-color: hsl(210 43% 3%);
  border-color: oklch(0.126 0.01 241.8);
}

Tailwind CSS v4

@theme {
  --color-eight-ball: #04070a;
  --color-eight-ball-50: #f3f5f8;
  --color-eight-ball-100: #e5e8eb;
  --color-eight-ball-200: #d1d5d8;
  --color-eight-ball-300: #b3b8bc;
  --color-eight-ball-400: #999fa4;
  --color-eight-ball-500: #80878d;
  --color-eight-ball-600: #6d7277;
  --color-eight-ball-700: #575b5f;
  --color-eight-ball-800: #3f4346;
  --color-eight-ball-900: #2c2e30;
  --color-eight-ball-950: #191b1c;
}

SCSS

$eight-ball: #04070a;
$eight-ball-rgb: 4, 7, 10;
$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);
}