#070D15

CSS

:root {
  --dark-rift: #070d15;
  --dark-rift-rgb: 7 13 21;
  --dark-rift-oklch: oklch(0.157 0.02 254.7);
}

.element {
  color: var(--dark-rift);
  background-color: hsl(214 50% 5%);
  border-color: oklch(0.157 0.02 254.7);
}

Tailwind CSS v4

@theme {
  --color-dark-rift: #070d15;
  --color-dark-rift-50: #f1f5fb;
  --color-dark-rift-100: #e4e8ef;
  --color-dark-rift-200: #cfd5dd;
  --color-dark-rift-300: #b1b8c2;
  --color-dark-rift-400: #979faa;
  --color-dark-rift-500: #7d8794;
  --color-dark-rift-600: #6a727d;
  --color-dark-rift-700: #555b64;
  --color-dark-rift-800: #3e4349;
  --color-dark-rift-900: #2a2e33;
  --color-dark-rift-950: #181b1f;
}

SCSS

$dark-rift: #070d15;
$dark-rift-rgb: 7, 13, 21;
$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);
}