#676767

CSS

:root {
  --volcanic-rock: #676767;
  --volcanic-rock-rgb: 103 103 103;
  --volcanic-rock-oklch: oklch(0.514 0 0);
}

.element {
  color: var(--volcanic-rock);
  background-color: hsl(0 0% 40%);
  border-color: oklch(0.514 0 0);
}

Tailwind CSS v4

@theme {
  --color-volcanic-rock: #676767;
  --color-volcanic-rock-50: #f5f5f5;
  --color-volcanic-rock-100: #e8e8e8;
  --color-volcanic-rock-200: #d4d4d4;
  --color-volcanic-rock-300: #b7b7b7;
  --color-volcanic-rock-400: #9e9e9e;
  --color-volcanic-rock-500: #868686;
  --color-volcanic-rock-600: #717171;
  --color-volcanic-rock-700: #5b5b5b;
  --color-volcanic-rock-800: #424242;
  --color-volcanic-rock-900: #2e2e2e;
  --color-volcanic-rock-950: #1b1b1b;
}

SCSS

$volcanic-rock: #676767;
$volcanic-rock-rgb: 103, 103, 103;
$volcanic-rock-light: mix(#fff, $volcanic-rock, 20%);
$volcanic-rock-dark: mix(#000, $volcanic-rock, 20%);

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