#46718F

CSS

:root {
  --harbour-blue: #46718f;
  --harbour-blue-rgb: 70 113 143;
  --harbour-blue-oklch: oklch(0.53 0.067 240.2);
}

.element {
  color: var(--harbour-blue);
  background-color: hsl(205 34% 42%);
  border-color: oklch(0.53 0.067 240.2);
}

Tailwind CSS v4

@theme {
  --color-harbour-blue: #46718f;
  --color-harbour-blue-50: #e5f8ff;
  --color-harbour-blue-100: #d5ebfd;
  --color-harbour-blue-200: #bcd8ef;
  --color-harbour-blue-300: #9abcd7;
  --color-harbour-blue-400: #7aa4c3;
  --color-harbour-blue-500: #5c8caf;
  --color-harbour-blue-600: #4e7793;
  --color-harbour-blue-700: #3e5f76;
  --color-harbour-blue-800: #2b4657;
  --color-harbour-blue-900: #1d303d;
  --color-harbour-blue-950: #0d1c26;
}

SCSS

$harbour-blue: #46718f;
$harbour-blue-rgb: 70, 113, 143;
$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);
}