#647B74

CSS

:root {
  --underwater-world: #647b74;
  --underwater-world-rgb: 100 123 116;
  --underwater-world-oklch: oklch(0.562 0.029 174.8);
}

.element {
  color: var(--underwater-world);
  background-color: hsl(162 10% 44%);
  border-color: oklch(0.562 0.029 174.8);
}

Tailwind CSS v4

@theme {
  --color-underwater-world: #647b74;
  --color-underwater-world-50: #edf8f5;
  --color-underwater-world-100: #deebe7;
  --color-underwater-world-200: #c8d8d4;
  --color-underwater-world-300: #a9bdb7;
  --color-underwater-world-400: #8ea49d;
  --color-underwater-world-500: #738d85;
  --color-underwater-world-600: #617770;
  --color-underwater-world-700: #4e5f5a;
  --color-underwater-world-800: #384641;
  --color-underwater-world-900: #27302d;
  --color-underwater-world-950: #151d1a;
}

SCSS

$underwater-world: #647b74;
$underwater-world-rgb: 100, 123, 116;
$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);
}