#0E3351

CSS

:root {
  --beyond-the-stars: #0e3351;
  --beyond-the-stars-rgb: 14 51 81;
  --beyond-the-stars-oklch: oklch(0.312 0.068 247);
}

.element {
  color: var(--beyond-the-stars);
  background-color: hsl(207 71% 19%);
  border-color: oklch(0.312 0.068 247);
}

Tailwind CSS v4

@theme {
  --color-beyond-the-stars: #0e3351;
  --color-beyond-the-stars-50: #e7f7ff;
  --color-beyond-the-stars-100: #d7eafe;
  --color-beyond-the-stars-200: #bfd7f1;
  --color-beyond-the-stars-300: #9dbbd9;
  --color-beyond-the-stars-400: #7ea3c5;
  --color-beyond-the-stars-500: #618bb1;
  --color-beyond-the-stars-600: #527596;
  --color-beyond-the-stars-700: #415e78;
  --color-beyond-the-stars-800: #2e4559;
  --color-beyond-the-stars-900: #1f303e;
  --color-beyond-the-stars-950: #0f1c27;
}

SCSS

$beyond-the-stars: #0e3351;
$beyond-the-stars-rgb: 14, 51, 81;
$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);
}