#3E7192

CSS

:root {
  --harbour-blue: #3e7192;
  --harbour-blue-rgb: 62 113 146;
  --harbour-blue-oklch: oklch(0.527 0.076 238.8);
}

.element {
  color: var(--harbour-blue);
  background-color: hsl(204 40% 41%);
  border-color: oklch(0.527 0.076 238.8);
}

Tailwind CSS v4

@theme {
  --color-harbour-blue: #3e7192;
  --color-harbour-blue-50: #e3f9ff;
  --color-harbour-blue-100: #d2ecff;
  --color-harbour-blue-200: #b8d9f2;
  --color-harbour-blue-300: #95bddb;
  --color-harbour-blue-400: #74a5c7;
  --color-harbour-blue-500: #548db3;
  --color-harbour-blue-600: #487897;
  --color-harbour-blue-700: #396079;
  --color-harbour-blue-800: #274659;
  --color-harbour-blue-900: #1a313e;
  --color-harbour-blue-950: #0b1d28;
}

SCSS

$harbour-blue: #3e7192;
$harbour-blue-rgb: 62, 113, 146;
$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);
}