#07192A

CSS

:root {
  --oxford-by-night: #07192a;
  --oxford-by-night-rgb: 7 25 42;
  --oxford-by-night-oklch: oklch(0.208 0.042 249);
}

.element {
  color: var(--oxford-by-night);
  background-color: hsl(209 71% 10%);
  border-color: oklch(0.208 0.042 249);
}

Tailwind CSS v4

@theme {
  --color-oxford-by-night: #07192a;
  --color-oxford-by-night-50: #edf6ff;
  --color-oxford-by-night-100: #dee9f6;
  --color-oxford-by-night-200: #c8d6e6;
  --color-oxford-by-night-300: #a8b9cd;
  --color-oxford-by-night-400: #8ca1b7;
  --color-oxford-by-night-500: #7189a1;
  --color-oxford-by-night-600: #607488;
  --color-oxford-by-night-700: #4d5d6d;
  --color-oxford-by-night-800: #374450;
  --color-oxford-by-night-900: #262f38;
  --color-oxford-by-night-950: #141b22;
}

SCSS

$oxford-by-night: #07192a;
$oxford-by-night-rgb: 7, 25, 42;
$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);
}