#061722

CSS

:root {
  --oxford-by-night: #061722;
  --oxford-by-night-rgb: 6 23 34;
  --oxford-by-night-oklch: oklch(0.196 0.032 238.8);
}

.element {
  color: var(--oxford-by-night);
  background-color: hsl(204 70% 8%);
  border-color: oklch(0.196 0.032 238.8);
}

Tailwind CSS v4

@theme {
  --color-oxford-by-night: #061722;
  --color-oxford-by-night-50: #edf7fe;
  --color-oxford-by-night-100: #dfeaf2;
  --color-oxford-by-night-200: #c9d6e1;
  --color-oxford-by-night-300: #a9bac7;
  --color-oxford-by-night-400: #8ea2b0;
  --color-oxford-by-night-500: #738a9a;
  --color-oxford-by-night-600: #627482;
  --color-oxford-by-night-700: #4e5d68;
  --color-oxford-by-night-800: #38444c;
  --color-oxford-by-night-900: #262f35;
  --color-oxford-by-night-950: #151c20;
}

SCSS

$oxford-by-night: #061722;
$oxford-by-night-rgb: 6, 23, 34;
$oxford-by-night-light: mix(#fff, $oxford-by-night, 20%);
$oxford-by-night-dark: mix(#000, $oxford-by-night, 20%);

.element {
  color: $oxford-by-night;
  box-shadow: 0 0 0 2px rgba($oxford-by-night, 0.35);
}