#262638

CSS

:root {
  --black-velvet: #262638;
  --black-velvet-rgb: 38 38 56;
  --black-velvet-oklch: oklch(0.277 0.033 284);
}

.element {
  color: var(--black-velvet);
  background-color: hsl(240 19% 18%);
  border-color: oklch(0.277 0.033 284);
}

Tailwind CSS v4

@theme {
  --color-black-velvet: #262638;
  --color-black-velvet-50: #f4f4ff;
  --color-black-velvet-100: #e6e6f3;
  --color-black-velvet-200: #d3d2e2;
  --color-black-velvet-300: #b5b5c8;
  --color-black-velvet-400: #9b9cb2;
  --color-black-velvet-500: #83849c;
  --color-black-velvet-600: #6f6f84;
  --color-black-velvet-700: #59596a;
  --color-black-velvet-800: #40414e;
  --color-black-velvet-900: #2c2d36;
  --color-black-velvet-950: #191a21;
}

SCSS

$black-velvet: #262638;
$black-velvet-rgb: 38, 38, 56;
$black-velvet-light: mix(#fff, $black-velvet, 20%);
$black-velvet-dark: mix(#000, $black-velvet, 20%);

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