#557C71

CSS

:root {
  --turquoise-tortoise: #557c71;
  --turquoise-tortoise-rgb: 85 124 113;
  --turquoise-tortoise-oklch: oklch(0.554 0.047 175);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(163 19% 41%);
  border-color: oklch(0.554 0.047 175);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #557c71;
  --color-turquoise-tortoise-50: #e8faf5;
  --color-turquoise-tortoise-100: #d8ede7;
  --color-turquoise-tortoise-200: #c0dbd4;
  --color-turquoise-tortoise-300: #9fc0b7;
  --color-turquoise-tortoise-400: #82a89d;
  --color-turquoise-tortoise-500: #659184;
  --color-turquoise-tortoise-600: #567a70;
  --color-turquoise-tortoise-700: #44625a;
  --color-turquoise-tortoise-800: #314841;
  --color-turquoise-tortoise-900: #21322d;
  --color-turquoise-tortoise-950: #111e1a;
}

SCSS

$turquoise-tortoise: #557c71;
$turquoise-tortoise-rgb: 85, 124, 113;
$turquoise-tortoise-light: mix(#fff, $turquoise-tortoise, 20%);
$turquoise-tortoise-dark: mix(#000, $turquoise-tortoise, 20%);

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