#18768C

CSS

:root {
  --celestial: #18768c;
  --celestial-rgb: 24 118 140;
  --celestial-oklch: oklch(0.525 0.088 218.2);
}

.element {
  color: var(--celestial);
  background-color: hsl(191 71% 32%);
  border-color: oklch(0.525 0.088 218.2);
}

Tailwind CSS v4

@theme {
  --color-celestial: #18768c;
  --color-celestial-50: #dbfcff;
  --color-celestial-100: #c9effd;
  --color-celestial-200: #abdeef;
  --color-celestial-300: #84c2d7;
  --color-celestial-400: #5dabc1;
  --color-celestial-500: #3094ad;
  --color-celestial-600: #2b7d92;
  --color-celestial-700: #226475;
  --color-celestial-800: #164a56;
  --color-celestial-900: #0e333c;
  --color-celestial-950: #011f26;
}

SCSS

$celestial: #18768c;
$celestial-rgb: 24, 118, 140;
$celestial-light: mix(#fff, $celestial, 20%);
$celestial-dark: mix(#000, $celestial, 20%);

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