#277CB3

CSS

:root {
  --honolulu-blue: #277cb3;
  --honolulu-blue-rgb: 39 124 179;
  --honolulu-blue-oklch: oklch(0.563 0.116 242);
}

.element {
  color: var(--honolulu-blue);
  background-color: hsl(204 64% 43%);
  border-color: oklch(0.563 0.116 242);
}

Tailwind CSS v4

@theme {
  --color-honolulu-blue: #277cb3;
  --color-honolulu-blue-50: #dafaff;
  --color-honolulu-blue-100: #c8edff;
  --color-honolulu-blue-200: #aadbff;
  --color-honolulu-blue-300: #83beef;
  --color-honolulu-blue-400: #5ba6dd;
  --color-honolulu-blue-500: #2e8ecc;
  --color-honolulu-blue-600: #2978ac;
  --color-honolulu-blue-700: #21608a;
  --color-honolulu-blue-800: #134766;
  --color-honolulu-blue-900: #0c3148;
  --color-honolulu-blue-950: #011d2f;
}

SCSS

$honolulu-blue: #277cb3;
$honolulu-blue-rgb: 39, 124, 179;
$honolulu-blue-light: mix(#fff, $honolulu-blue, 20%);
$honolulu-blue-dark: mix(#000, $honolulu-blue, 20%);

.element {
  color: $honolulu-blue;
  box-shadow: 0 0 0 2px rgba($honolulu-blue, 0.35);
}