#347393

CSS

:root {
  --harbour-blue: #347393;
  --harbour-blue-rgb: 52 115 147;
  --harbour-blue-oklch: oklch(0.528 0.082 233.4);
}

.element {
  color: var(--harbour-blue);
  background-color: hsl(200 48% 39%);
  border-color: oklch(0.528 0.082 233.4);
}

Tailwind CSS v4

@theme {
  --color-harbour-blue: #347393;
  --color-harbour-blue-50: #e0faff;
  --color-harbour-blue-100: #cfedff;
  --color-harbour-blue-200: #b3dbf3;
  --color-harbour-blue-300: #8fbfdc;
  --color-harbour-blue-400: #6ca7c7;
  --color-harbour-blue-500: #498fb4;
  --color-harbour-blue-600: #3f7998;
  --color-harbour-blue-700: #32617a;
  --color-harbour-blue-800: #22475a;
  --color-harbour-blue-900: #16313f;
  --color-harbour-blue-950: #071d28;
}

SCSS

$harbour-blue: #347393;
$harbour-blue-rgb: 52, 115, 147;
$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);
}