#537F75

CSS

:root {
  --turquoise-tortoise: #537f75;
  --turquoise-tortoise-rgb: 83 127 117;
  --turquoise-tortoise-oklch: oklch(0.561 0.051 178.5);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(166 21% 41%);
  border-color: oklch(0.561 0.051 178.5);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #537f75;
  --color-turquoise-tortoise-50: #e6faf6;
  --color-turquoise-tortoise-100: #d7eee8;
  --color-turquoise-tortoise-200: #bedcd5;
  --color-turquoise-tortoise-300: #9cc0b8;
  --color-turquoise-tortoise-400: #7ea99f;
  --color-turquoise-tortoise-500: #609286;
  --color-turquoise-tortoise-600: #527b72;
  --color-turquoise-tortoise-700: #41635b;
  --color-turquoise-tortoise-800: #2f4842;
  --color-turquoise-tortoise-900: #20322d;
  --color-turquoise-tortoise-950: #0f1e1a;
}

SCSS

$turquoise-tortoise: #537f75;
$turquoise-tortoise-rgb: 83, 127, 117;
$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);
}