Firmament Blue

CSS

:root {
  --firmament-blue: #11353f;
  --firmament-blue-rgb: 17 53 63;
  --firmament-blue-oklch: oklch(0.308 0.044 219.3);
}

.element {
  color: var(--firmament-blue);
  background-color: hsl(193 58% 16%);
  border-color: oklch(0.308 0.044 219.3);
}

Tailwind CSS v4

@theme {
  --color-firmament-blue: #11353f;
  --color-firmament-blue-50: #e8f8fe;
  --color-firmament-blue-100: #d9ecf2;
  --color-firmament-blue-200: #c1d9e2;
  --color-firmament-blue-300: #9fbdc8;
  --color-firmament-blue-400: #82a5b0;
  --color-firmament-blue-500: #658e9a;
  --color-firmament-blue-600: #567882;
  --color-firmament-blue-700: #446068;
  --color-firmament-blue-800: #31464c;
  --color-firmament-blue-900: #213135;
  --color-firmament-blue-950: #101d20;
}

SCSS

$firmament-blue: #11353f;
$firmament-blue-rgb: 17, 53, 63;
$firmament-blue-light: mix(#fff, $firmament-blue, 20%);
$firmament-blue-dark: mix(#000, $firmament-blue, 20%);

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