#0E3657

CSS

:root {
  --beyond-the-stars: #0e3657;
  --beyond-the-stars-rgb: 14 54 87;
  --beyond-the-stars-oklch: oklch(0.324 0.073 247.7);
}

.element {
  color: var(--beyond-the-stars);
  background-color: hsl(207 72% 20%);
  border-color: oklch(0.324 0.073 247.7);
}

Tailwind CSS v4

@theme {
  --color-beyond-the-stars: #0e3657;
  --color-beyond-the-stars-50: #e6f7ff;
  --color-beyond-the-stars-100: #d6eaff;
  --color-beyond-the-stars-200: #bdd7f3;
  --color-beyond-the-stars-300: #9bbbdc;
  --color-beyond-the-stars-400: #7ca3c8;
  --color-beyond-the-stars-500: #5e8bb5;
  --color-beyond-the-stars-600: #507598;
  --color-beyond-the-stars-700: #405e7a;
  --color-beyond-the-stars-800: #2c455a;
  --color-beyond-the-stars-900: #1e303f;
  --color-beyond-the-stars-950: #0e1c28;
}

SCSS

$beyond-the-stars: #0e3657;
$beyond-the-stars-rgb: 14, 54, 87;
$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);
}