#2D7397

CSS

:root {
  --harbour-blue: #2d7397;
  --harbour-blue-rgb: 45 115 151;
  --harbour-blue-oklch: oklch(0.528 0.089 234.6);
}

.element {
  color: var(--harbour-blue);
  background-color: hsl(200 54% 38%);
  border-color: oklch(0.528 0.089 234.6);
}

Tailwind CSS v4

@theme {
  --color-harbour-blue: #2d7397;
  --color-harbour-blue-50: #defaff;
  --color-harbour-blue-100: #cdedff;
  --color-harbour-blue-200: #b1dbf6;
  --color-harbour-blue-300: #8bbfe0;
  --color-harbour-blue-400: #67a7cc;
  --color-harbour-blue-500: #428fb9;
  --color-harbour-blue-600: #39799c;
  --color-harbour-blue-700: #2d617d;
  --color-harbour-blue-800: #1e485c;
  --color-harbour-blue-900: #143240;
  --color-harbour-blue-950: #051d29;
}

SCSS

$harbour-blue: #2d7397;
$harbour-blue-rgb: 45, 115, 151;
$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);
}