#637B79

CSS

:root {
  --underwater-world: #637b79;
  --underwater-world-rgb: 99 123 121;
  --underwater-world-oklch: oklch(0.563 0.028 190.1);
}

.element {
  color: var(--underwater-world);
  background-color: hsl(175 11% 44%);
  border-color: oklch(0.563 0.028 190.1);
}

Tailwind CSS v4

@theme {
  --color-underwater-world: #637b79;
  --color-underwater-world-50: #edf8f7;
  --color-underwater-world-100: #deebea;
  --color-underwater-world-200: #c7d8d7;
  --color-underwater-world-300: #a8bcbb;
  --color-underwater-world-400: #8ca4a2;
  --color-underwater-world-500: #718c8a;
  --color-underwater-world-600: #607775;
  --color-underwater-world-700: #4d5f5e;
  --color-underwater-world-800: #384644;
  --color-underwater-world-900: #26302f;
  --color-underwater-world-950: #141c1c;
}

SCSS

$underwater-world: #637b79;
$underwater-world-rgb: 99, 123, 121;
$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);
}