#637C73

CSS

:root {
  --underwater-world: #637c73;
  --underwater-world-rgb: 99 124 115;
  --underwater-world-oklch: oklch(0.564 0.032 171.2);
}

.element {
  color: var(--underwater-world);
  background-color: hsl(158 11% 44%);
  border-color: oklch(0.564 0.032 171.2);
}

Tailwind CSS v4

@theme {
  --color-underwater-world: #637c73;
  --color-underwater-world-50: #ecf8f4;
  --color-underwater-world-100: #deece7;
  --color-underwater-world-200: #c7d9d3;
  --color-underwater-world-300: #a8bdb6;
  --color-underwater-world-400: #8ca59c;
  --color-underwater-world-500: #718d83;
  --color-underwater-world-600: #60786f;
  --color-underwater-world-700: #4d6059;
  --color-underwater-world-800: #384640;
  --color-underwater-world-900: #26312c;
  --color-underwater-world-950: #141d19;
}

SCSS

$underwater-world: #637c73;
$underwater-world-rgb: 99, 124, 115;
$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);
}