#1A3850

CSS

:root {
  --sea-of-stars: #1a3850;
  --sea-of-stars-rgb: 26 56 80;
  --sea-of-stars-oklch: oklch(0.33 0.056 244.8);
}

.element {
  color: var(--sea-of-stars);
  background-color: hsl(207 51% 21%);
  border-color: oklch(0.33 0.056 244.8);
}

Tailwind CSS v4

@theme {
  --color-sea-of-stars: #1a3850;
  --color-sea-of-stars-50: #e9f7ff;
  --color-sea-of-stars-100: #daeafa;
  --color-sea-of-stars-200: #c2d7eb;
  --color-sea-of-stars-300: #a1bbd3;
  --color-sea-of-stars-400: #83a3be;
  --color-sea-of-stars-500: #678ba9;
  --color-sea-of-stars-600: #57758f;
  --color-sea-of-stars-700: #465e73;
  --color-sea-of-stars-800: #314554;
  --color-sea-of-stars-900: #21303b;
  --color-sea-of-stars-950: #111c25;
}

SCSS

$sea-of-stars: #1a3850;
$sea-of-stars-rgb: 26, 56, 80;
$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);
}