#030B15

CSS

:root {
  --dark-rift: #030b15;
  --dark-rift-rgb: 3 11 21;
  --dark-rift-oklch: oklch(0.146 0.027 249.1);
}

.element {
  color: var(--dark-rift);
  background-color: hsl(213 75% 5%);
  border-color: oklch(0.146 0.027 249.1);
}

Tailwind CSS v4

@theme {
  --color-dark-rift: #030b15;
  --color-dark-rift-50: #f0f6fd;
  --color-dark-rift-100: #e2e9f1;
  --color-dark-rift-200: #ccd5e0;
  --color-dark-rift-300: #aeb9c5;
  --color-dark-rift-400: #93a0ae;
  --color-dark-rift-500: #798898;
  --color-dark-rift-600: #667380;
  --color-dark-rift-700: #525c67;
  --color-dark-rift-800: #3b434b;
  --color-dark-rift-900: #292f34;
  --color-dark-rift-950: #161b20;
}

SCSS

$dark-rift: #030b15;
$dark-rift-rgb: 3, 11, 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);
}