#002A45

CSS

:root {
  --beyond-the-stars: #002a45;
  --beyond-the-stars-rgb: 0 42 69;
  --beyond-the-stars-oklch: oklch(0.274 0.066 243.1);
}

.element {
  color: var(--beyond-the-stars);
  background-color: hsl(203 100% 14%);
  border-color: oklch(0.274 0.066 243.1);
}

Tailwind CSS v4

@theme {
  --color-beyond-the-stars: #002a45;
  --color-beyond-the-stars-50: #e6f8ff;
  --color-beyond-the-stars-100: #d6ebfd;
  --color-beyond-the-stars-200: #bed8ef;
  --color-beyond-the-stars-300: #9cbcd8;
  --color-beyond-the-stars-400: #7ca4c3;
  --color-beyond-the-stars-500: #5f8caf;
  --color-beyond-the-stars-600: #517694;
  --color-beyond-the-stars-700: #405e77;
  --color-beyond-the-stars-800: #2d4557;
  --color-beyond-the-stars-900: #1e303d;
  --color-beyond-the-stars-950: #0e1c27;
}

SCSS

$beyond-the-stars: #002a45;
$beyond-the-stars-rgb: 0, 42, 69;
$beyond-the-stars-light: mix(#fff, $beyond-the-stars, 20%);
$beyond-the-stars-dark: mix(#000, $beyond-the-stars, 20%);

.element {
  color: $beyond-the-stars;
  box-shadow: 0 0 0 2px rgba($beyond-the-stars, 0.35);
}