#242337

CSS

:root {
  --black-velvet: #242337;
  --black-velvet-rgb: 36 35 55;
  --black-velvet-oklch: oklch(0.267 0.037 285.9);
}

.element {
  color: var(--black-velvet);
  background-color: hsl(243 22% 18%);
  border-color: oklch(0.267 0.037 285.9);
}

Tailwind CSS v4

@theme {
  --color-black-velvet: #242337;
  --color-black-velvet-50: #f4f4ff;
  --color-black-velvet-100: #e7e6f4;
  --color-black-velvet-200: #d3d2e4;
  --color-black-velvet-300: #b6b5ca;
  --color-black-velvet-400: #9c9cb4;
  --color-black-velvet-500: #83839e;
  --color-black-velvet-600: #6f6f86;
  --color-black-velvet-700: #59596b;
  --color-black-velvet-800: #40414f;
  --color-black-velvet-900: #2c2d37;
  --color-black-velvet-950: #1a1a22;
}

SCSS

$black-velvet: #242337;
$black-velvet-rgb: 36, 35, 55;
$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);
}