#191718

CSS

:root {
  --dark-void: #191718;
  --dark-void-rgb: 25 23 24;
  --dark-void-oklch: oklch(0.207 0.004 345.6);
}

.element {
  color: var(--dark-void);
  background-color: hsl(330 4% 9%);
  border-color: oklch(0.207 0.004 345.6);
}

Tailwind CSS v4

@theme {
  --color-dark-void: #191718;
  --color-dark-void-50: #f6f5f5;
  --color-dark-void-100: #e9e7e8;
  --color-dark-void-200: #d5d3d4;
  --color-dark-void-300: #b9b6b8;
  --color-dark-void-400: #a09d9f;
  --color-dark-void-500: #888587;
  --color-dark-void-600: #737172;
  --color-dark-void-700: #5c5a5b;
  --color-dark-void-800: #434243;
  --color-dark-void-900: #2e2d2e;
  --color-dark-void-950: #1b1a1b;
}

SCSS

$dark-void: #191718;
$dark-void-rgb: 25, 23, 24;
$dark-void-light: mix(#fff, $dark-void, 20%);
$dark-void-dark: mix(#000, $dark-void, 20%);

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