#0A0A0F

CSS

:root {
  --eight-ball: #0a0a0f;
  --eight-ball-rgb: 10 10 15;
  --eight-ball-oklch: oklch(0.147 0.011 285);
}

.element {
  color: var(--eight-ball);
  background-color: hsl(240 20% 5%);
  border-color: oklch(0.147 0.011 285);
}

Tailwind CSS v4

@theme {
  --color-eight-ball: #0a0a0f;
  --color-eight-ball-50: #f5f5f8;
  --color-eight-ball-100: #e7e7eb;
  --color-eight-ball-200: #d4d4d9;
  --color-eight-ball-300: #b7b7bd;
  --color-eight-ball-400: #9d9ea5;
  --color-eight-ball-500: #85858d;
  --color-eight-ball-600: #717177;
  --color-eight-ball-700: #5a5a60;
  --color-eight-ball-800: #424246;
  --color-eight-ball-900: #2d2d30;
  --color-eight-ball-950: #1a1a1d;
}

SCSS

$eight-ball: #0a0a0f;
$eight-ball-rgb: 10, 10, 15;
$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);
}