#00050A

CSS

:root {
  --eight-ball: #00050a;
  --eight-ball-rgb: 0 5 10;
  --eight-ball-oklch: oklch(0.108 0.022 233.5);
}

.element {
  color: var(--eight-ball);
  background-color: hsl(210 100% 2%);
  border-color: oklch(0.108 0.022 233.5);
}

Tailwind CSS v4

@theme {
  --color-eight-ball: #00050a;
  --color-eight-ball-50: #eff6fb;
  --color-eight-ball-100: #e1e9ee;
  --color-eight-ball-200: #ccd6dd;
  --color-eight-ball-300: #adb9c1;
  --color-eight-ball-400: #92a1aa;
  --color-eight-ball-500: #788993;
  --color-eight-ball-600: #66747c;
  --color-eight-ball-700: #515d63;
  --color-eight-ball-800: #3b4449;
  --color-eight-ball-900: #282f33;
  --color-eight-ball-950: #161b1e;
}

SCSS

$eight-ball: #00050a;
$eight-ball-rgb: 0, 5, 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);
}