#537E77

CSS

:root {
  --turquoise-tortoise: #537e77;
  --turquoise-tortoise-rgb: 83 126 119;
  --turquoise-tortoise-oklch: oklch(0.559 0.049 183.2);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(170 21% 41%);
  border-color: oklch(0.559 0.049 183.2);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #537e77;
  --color-turquoise-tortoise-50: #e7faf7;
  --color-turquoise-tortoise-100: #d7eeea;
  --color-turquoise-tortoise-200: #bedbd7;
  --color-turquoise-tortoise-300: #9cc0bb;
  --color-turquoise-tortoise-400: #7ea8a1;
  --color-turquoise-tortoise-500: #619189;
  --color-turquoise-tortoise-600: #527b74;
  --color-turquoise-tortoise-700: #42625d;
  --color-turquoise-tortoise-800: #2f4843;
  --color-turquoise-tortoise-900: #20322e;
  --color-turquoise-tortoise-950: #0f1e1b;
}

SCSS

$turquoise-tortoise: #537e77;
$turquoise-tortoise-rgb: 83, 126, 119;
$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);
}