#5A7D76

CSS

:root {
  --underwater-world: #5a7d76;
  --underwater-world-rgb: 90 125 118;
  --underwater-world-oklch: oklch(0.561 0.041 181);
}

.element {
  color: var(--underwater-world);
  background-color: hsl(168 16% 42%);
  border-color: oklch(0.561 0.041 181);
}

Tailwind CSS v4

@theme {
  --color-underwater-world: #5a7d76;
  --color-underwater-world-50: #e9f9f6;
  --color-underwater-world-100: #daede9;
  --color-underwater-world-200: #c2dad6;
  --color-underwater-world-300: #a1bfb9;
  --color-underwater-world-400: #84a7a0;
  --color-underwater-world-500: #688f88;
  --color-underwater-world-600: #587973;
  --color-underwater-world-700: #46615c;
  --color-underwater-world-800: #334743;
  --color-underwater-world-900: #23312e;
  --color-underwater-world-950: #121d1b;
}

SCSS

$underwater-world: #5a7d76;
$underwater-world-rgb: 90, 125, 118;
$underwater-world-light: mix(#fff, $underwater-world, 20%);
$underwater-world-dark: mix(#000, $underwater-world, 20%);

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