#020811

CSS

:root {
  --dark-rift: #020811;
  --dark-rift-rgb: 2 8 17;
  --dark-rift-oklch: oklch(0.131 0.025 249.2);
}

.element {
  color: var(--dark-rift);
  background-color: hsl(216 79% 4%);
  border-color: oklch(0.131 0.025 249.2);
}

Tailwind CSS v4

@theme {
  --color-dark-rift: #020811;
  --color-dark-rift-50: #f0f6fc;
  --color-dark-rift-100: #e2e9f0;
  --color-dark-rift-200: #cdd5df;
  --color-dark-rift-300: #aeb9c4;
  --color-dark-rift-400: #93a0ad;
  --color-dark-rift-500: #7a8897;
  --color-dark-rift-600: #67737f;
  --color-dark-rift-700: #525c66;
  --color-dark-rift-800: #3c434b;
  --color-dark-rift-900: #292f34;
  --color-dark-rift-950: #171b1f;
}

SCSS

$dark-rift: #020811;
$dark-rift-rgb: 2, 8, 17;
$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);
}