#133449

CSS

:root {
  --sea-of-stars: #133449;
  --sea-of-stars-rgb: 19 52 73;
  --sea-of-stars-oklch: oklch(0.311 0.054 239.7);
}

.element {
  color: var(--sea-of-stars);
  background-color: hsl(203 59% 18%);
  border-color: oklch(0.311 0.054 239.7);
}

Tailwind CSS v4

@theme {
  --color-sea-of-stars: #133449;
  --color-sea-of-stars-50: #e8f8ff;
  --color-sea-of-stars-100: #d9ebf9;
  --color-sea-of-stars-200: #c1d8ea;
  --color-sea-of-stars-300: #a0bbd1;
  --color-sea-of-stars-400: #82a3bb;
  --color-sea-of-stars-500: #658ba7;
  --color-sea-of-stars-600: #56768d;
  --color-sea-of-stars-700: #445e71;
  --color-sea-of-stars-800: #314553;
  --color-sea-of-stars-900: #21303a;
  --color-sea-of-stars-950: #101c24;
}

SCSS

$sea-of-stars: #133449;
$sea-of-stars-rgb: 19, 52, 73;
$sea-of-stars-light: mix(#fff, $sea-of-stars, 20%);
$sea-of-stars-dark: mix(#000, $sea-of-stars, 20%);

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