#00192F

CSS

:root {
  --oxford-by-night: #00192f;
  --oxford-by-night-rgb: 0 25 47;
  --oxford-by-night-oklch: oklch(0.208 0.055 247);
}

.element {
  color: var(--oxford-by-night);
  background-color: hsl(208 100% 9%);
  border-color: oklch(0.208 0.055 247);
}

Tailwind CSS v4

@theme {
  --color-oxford-by-night: #00192f;
  --color-oxford-by-night-50: #eaf7ff;
  --color-oxford-by-night-100: #daeafa;
  --color-oxford-by-night-200: #c3d7eb;
  --color-oxford-by-night-300: #a2bad3;
  --color-oxford-by-night-400: #85a2bd;
  --color-oxford-by-night-500: #698aa9;
  --color-oxford-by-night-600: #59758f;
  --color-oxford-by-night-700: #475d72;
  --color-oxford-by-night-800: #324554;
  --color-oxford-by-night-900: #222f3b;
  --color-oxford-by-night-950: #111c25;
}

SCSS

$oxford-by-night: #00192f;
$oxford-by-night-rgb: 0, 25, 47;
$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);
}