#657975

CSS

:root {
  --underwater-world: #657975;
  --underwater-world-rgb: 101 121 117;
  --underwater-world-oklch: oklch(0.559 0.024 181.9);
}

.element {
  color: var(--underwater-world);
  background-color: hsl(168 9% 44%);
  border-color: oklch(0.559 0.024 181.9);
}

Tailwind CSS v4

@theme {
  --color-underwater-world: #657975;
  --color-underwater-world-50: #eef7f6;
  --color-underwater-world-100: #e0ebe9;
  --color-underwater-world-200: #cad8d5;
  --color-underwater-world-300: #aabcb9;
  --color-underwater-world-400: #90a39f;
  --color-underwater-world-500: #758c87;
  --color-underwater-world-600: #637672;
  --color-underwater-world-700: #4f5f5b;
  --color-underwater-world-800: #3a4543;
  --color-underwater-world-900: #27302e;
  --color-underwater-world-950: #161c1b;
}

SCSS

$underwater-world: #657975;
$underwater-world-rgb: 101, 121, 117;
$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);
}