#050B13

CSS

:root {
  --dark-rift: #050b13;
  --dark-rift-rgb: 5 11 19;
  --dark-rift-oklch: oklch(0.147 0.021 252.4);
}

.element {
  color: var(--dark-rift);
  background-color: hsl(214 58% 5%);
  border-color: oklch(0.147 0.021 252.4);
}

Tailwind CSS v4

@theme {
  --color-dark-rift: #050b13;
  --color-dark-rift-50: #f1f6fb;
  --color-dark-rift-100: #e3e8ef;
  --color-dark-rift-200: #ced5dd;
  --color-dark-rift-300: #b0b8c2;
  --color-dark-rift-400: #969fab;
  --color-dark-rift-500: #7d8794;
  --color-dark-rift-600: #6a737d;
  --color-dark-rift-700: #545c64;
  --color-dark-rift-800: #3d4349;
  --color-dark-rift-900: #2a2e33;
  --color-dark-rift-950: #181b1f;
}

SCSS

$dark-rift: #050b13;
$dark-rift-rgb: 5, 11, 19;
$dark-rift-light: mix(#fff, $dark-rift, 20%);
$dark-rift-dark: mix(#000, $dark-rift, 20%);

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