#317395

CSS

:root {
  --harbour-blue: #317395;
  --harbour-blue-rgb: 49 115 149;
  --harbour-blue-oklch: oklch(0.528 0.085 234.1);
}

.element {
  color: var(--harbour-blue);
  background-color: hsl(200 51% 39%);
  border-color: oklch(0.528 0.085 234.1);
}

Tailwind CSS v4

@theme {
  --color-harbour-blue: #317395;
  --color-harbour-blue-50: #dffaff;
  --color-harbour-blue-100: #ceedff;
  --color-harbour-blue-200: #b2dbf4;
  --color-harbour-blue-300: #8dbfde;
  --color-harbour-blue-400: #6aa7c9;
  --color-harbour-blue-500: #468fb6;
  --color-harbour-blue-600: #3c799a;
  --color-harbour-blue-700: #30617b;
  --color-harbour-blue-800: #20475b;
  --color-harbour-blue-900: #153240;
  --color-harbour-blue-950: #061d28;
}

SCSS

$harbour-blue: #317395;
$harbour-blue-rgb: 49, 115, 149;
$harbour-blue-light: mix(#fff, $harbour-blue, 20%);
$harbour-blue-dark: mix(#000, $harbour-blue, 20%);

.element {
  color: $harbour-blue;
  box-shadow: 0 0 0 2px rgba($harbour-blue, 0.35);
}