#12344D

CSS

:root {
  --sea-of-stars: #12344d;
  --sea-of-stars-rgb: 18 52 77;
  --sea-of-stars-oklch: oklch(0.313 0.06 243.7);
}

.element {
  color: var(--sea-of-stars);
  background-color: hsl(205 62% 19%);
  border-color: oklch(0.313 0.06 243.7);
}

Tailwind CSS v4

@theme {
  --color-sea-of-stars: #12344d;
  --color-sea-of-stars-50: #e8f7ff;
  --color-sea-of-stars-100: #d8eafb;
  --color-sea-of-stars-200: #c0d7ed;
  --color-sea-of-stars-300: #9fbbd5;
  --color-sea-of-stars-400: #81a3c0;
  --color-sea-of-stars-500: #648bab;
  --color-sea-of-stars-600: #557691;
  --color-sea-of-stars-700: #435e74;
  --color-sea-of-stars-800: #304555;
  --color-sea-of-stars-900: #20303c;
  --color-sea-of-stars-950: #101c25;
}

SCSS

$sea-of-stars: #12344d;
$sea-of-stars-rgb: 18, 52, 77;
$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);
}