#307396

CSS

:root {
  --harbour-blue: #307396;
  --harbour-blue-rgb: 48 115 150;
  --harbour-blue-oklch: oklch(0.528 0.087 234.6);
}

.element {
  color: var(--harbour-blue);
  background-color: hsl(201 52% 39%);
  border-color: oklch(0.528 0.087 234.6);
}

Tailwind CSS v4

@theme {
  --color-harbour-blue: #307396;
  --color-harbour-blue-50: #dffaff;
  --color-harbour-blue-100: #ceedff;
  --color-harbour-blue-200: #b2dbf5;
  --color-harbour-blue-300: #8dbfde;
  --color-harbour-blue-400: #69a7ca;
  --color-harbour-blue-500: #458fb7;
  --color-harbour-blue-600: #3b799b;
  --color-harbour-blue-700: #2f617c;
  --color-harbour-blue-800: #1f475b;
  --color-harbour-blue-900: #153240;
  --color-harbour-blue-950: #061d29;
}

SCSS

$harbour-blue: #307396;
$harbour-blue-rgb: 48, 115, 150;
$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);
}