#47718E

CSS

:root {
  --harbour-blue: #47718e;
  --harbour-blue-rgb: 71 113 142;
  --harbour-blue-oklch: oklch(0.53 0.066 239.8);
}

.element {
  color: var(--harbour-blue);
  background-color: hsl(205 33% 42%);
  border-color: oklch(0.53 0.066 239.8);
}

Tailwind CSS v4

@theme {
  --color-harbour-blue: #47718e;
  --color-harbour-blue-50: #e6f8ff;
  --color-harbour-blue-100: #d6ebfc;
  --color-harbour-blue-200: #bdd8ee;
  --color-harbour-blue-300: #9abcd7;
  --color-harbour-blue-400: #7ba4c2;
  --color-harbour-blue-500: #5d8cad;
  --color-harbour-blue-600: #4f7792;
  --color-harbour-blue-700: #3f5f75;
  --color-harbour-blue-800: #2c4657;
  --color-harbour-blue-900: #1e303c;
  --color-harbour-blue-950: #0d1c26;
}

SCSS

$harbour-blue: #47718e;
$harbour-blue-rgb: 71, 113, 142;
$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);
}