#237DB3

CSS

:root {
  --honolulu-blue: #237db3;
  --honolulu-blue-rgb: 35 125 179;
  --honolulu-blue-oklch: oklch(0.564 0.117 240.6);
}

.element {
  color: var(--honolulu-blue);
  background-color: hsl(203 67% 42%);
  border-color: oklch(0.564 0.117 240.6);
}

Tailwind CSS v4

@theme {
  --color-honolulu-blue: #237db3;
  --color-honolulu-blue-50: #d9faff;
  --color-honolulu-blue-100: #c7edff;
  --color-honolulu-blue-200: #a9dbff;
  --color-honolulu-blue-300: #81bfee;
  --color-honolulu-blue-400: #58a7dc;
  --color-honolulu-blue-500: #298ecb;
  --color-honolulu-blue-600: #2679ac;
  --color-honolulu-blue-700: #1e618a;
  --color-honolulu-blue-800: #104766;
  --color-honolulu-blue-900: #0a3148;
  --color-honolulu-blue-950: #001d2f;
}

SCSS

$honolulu-blue: #237db3;
$honolulu-blue-rgb: 35, 125, 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);
}