#12819D

CSS

:root {
  --ahoy-blue: #12819d;
  --ahoy-blue-rgb: 18 129 157;
  --ahoy-blue-oklch: oklch(0.56 0.099 221);
}

.element {
  color: var(--ahoy-blue);
  background-color: hsl(192 79% 34%);
  border-color: oklch(0.56 0.099 221);
}

Tailwind CSS v4

@theme {
  --color-ahoy-blue: #12819d;
  --color-ahoy-blue-50: #d8fcff;
  --color-ahoy-blue-100: #c5f0ff;
  --color-ahoy-blue-200: #a6def3;
  --color-ahoy-blue-300: #7dc3dc;
  --color-ahoy-blue-400: #53acc7;
  --color-ahoy-blue-500: #1994b4;
  --color-ahoy-blue-600: #1a7e98;
  --color-ahoy-blue-700: #16657a;
  --color-ahoy-blue-800: #0b4a59;
  --color-ahoy-blue-900: #07333f;
  --color-ahoy-blue-950: #001f28;
}

SCSS

$ahoy-blue: #12819d;
$ahoy-blue-rgb: 18, 129, 157;
$ahoy-blue-light: mix(#fff, $ahoy-blue, 20%);
$ahoy-blue-dark: mix(#000, $ahoy-blue, 20%);

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