#011A29

CSS

:root {
  --oxford-by-night: #011a29;
  --oxford-by-night-rgb: 1 26 41;
  --oxford-by-night-oklch: oklch(0.207 0.044 237.6);
}

.element {
  color: var(--oxford-by-night);
  background-color: hsl(203 95% 8%);
  border-color: oklch(0.207 0.044 237.6);
}

Tailwind CSS v4

@theme {
  --color-oxford-by-night: #011a29;
  --color-oxford-by-night-50: #eaf7ff;
  --color-oxford-by-night-100: #dbeaf5;
  --color-oxford-by-night-200: #c4d7e5;
  --color-oxford-by-night-300: #a4bbcc;
  --color-oxford-by-night-400: #87a3b6;
  --color-oxford-by-night-500: #6b8ba0;
  --color-oxford-by-night-600: #5b7687;
  --color-oxford-by-night-700: #485e6c;
  --color-oxford-by-night-800: #344550;
  --color-oxford-by-night-900: #233037;
  --color-oxford-by-night-950: #121c22;
}

SCSS

$oxford-by-night: #011a29;
$oxford-by-night-rgb: 1, 26, 41;
$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);
}