#040712

CSS

:root {
  --dark-rift: #040712;
  --dark-rift-rgb: 4 7 18;
  --dark-rift-oklch: oklch(0.131 0.026 267);
}

.element {
  color: var(--dark-rift);
  background-color: hsl(227 64% 4%);
  border-color: oklch(0.131 0.026 267);
}

Tailwind CSS v4

@theme {
  --color-dark-rift: #040712;
  --color-dark-rift-50: #f2f5fd;
  --color-dark-rift-100: #e4e8f1;
  --color-dark-rift-200: #cfd4e0;
  --color-dark-rift-300: #b2b7c5;
  --color-dark-rift-400: #979eaf;
  --color-dark-rift-500: #7e8698;
  --color-dark-rift-600: #6b7181;
  --color-dark-rift-700: #555b67;
  --color-dark-rift-800: #3e424c;
  --color-dark-rift-900: #2b2e35;
  --color-dark-rift-950: #181b20;
}

SCSS

$dark-rift: #040712;
$dark-rift-rgb: 4, 7, 18;
$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);
}