#020715

CSS

:root {
  --dark-rift: #020715;
  --dark-rift-rgb: 2 7 21;
  --dark-rift-oklch: oklch(0.131 0.035 260.3);
}

.element {
  color: var(--dark-rift);
  background-color: hsl(224 83% 5%);
  border-color: oklch(0.131 0.035 260.3);
}

Tailwind CSS v4

@theme {
  --color-dark-rift: #020715;
  --color-dark-rift-50: #f0f5ff;
  --color-dark-rift-100: #e2e8f4;
  --color-dark-rift-200: #ccd5e3;
  --color-dark-rift-300: #aeb8ca;
  --color-dark-rift-400: #939fb3;
  --color-dark-rift-500: #79879e;
  --color-dark-rift-600: #677285;
  --color-dark-rift-700: #525b6b;
  --color-dark-rift-800: #3b434f;
  --color-dark-rift-900: #292e37;
  --color-dark-rift-950: #161b21;
}

SCSS

$dark-rift: #020715;
$dark-rift-rgb: 2, 7, 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);
}