#1A3B70

CSS

:root {
  --lost-in-space: #1a3b70;
  --lost-in-space-rgb: 26 59 112;
  --lost-in-space-oklch: oklch(0.359 0.1 259.5);
}

.element {
  color: var(--lost-in-space);
  background-color: hsl(217 62% 27%);
  border-color: oklch(0.359 0.1 259.5);
}

Tailwind CSS v4

@theme {
  --color-lost-in-space: #1a3b70;
  --color-lost-in-space-50: #e6f6ff;
  --color-lost-in-space-100: #d6e9ff;
  --color-lost-in-space-200: #bdd5ff;
  --color-lost-in-space-300: #9bb8eb;
  --color-lost-in-space-400: #7b9fd9;
  --color-lost-in-space-500: #5e86c8;
  --color-lost-in-space-600: #5072a9;
  --color-lost-in-space-700: #3f5b87;
  --color-lost-in-space-800: #2c4365;
  --color-lost-in-space-900: #1d2e47;
  --color-lost-in-space-950: #0d1b2e;
}

SCSS

$lost-in-space: #1a3b70;
$lost-in-space-rgb: 26, 59, 112;
$lost-in-space-light: mix(#fff, $lost-in-space, 20%);
$lost-in-space-dark: mix(#000, $lost-in-space, 20%);

.element {
  color: $lost-in-space;
  box-shadow: 0 0 0 2px rgba($lost-in-space, 0.35);
}