#537C77

CSS

:root {
  --turquoise-tortoise: #537c77;
  --turquoise-tortoise-rgb: 83 124 119;
  --turquoise-tortoise-oklch: oklch(0.555 0.046 186.4);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(173 20% 41%);
  border-color: oklch(0.555 0.046 186.4);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #537c77;
  --color-turquoise-tortoise-50: #e7faf8;
  --color-turquoise-tortoise-100: #d7edeb;
  --color-turquoise-tortoise-200: #bfdbd8;
  --color-turquoise-tortoise-300: #9dbfbc;
  --color-turquoise-tortoise-400: #80a8a3;
  --color-turquoise-tortoise-500: #62918b;
  --color-turquoise-tortoise-600: #547a75;
  --color-turquoise-tortoise-700: #43625e;
  --color-turquoise-tortoise-800: #304844;
  --color-turquoise-tortoise-900: #20322f;
  --color-turquoise-tortoise-950: #101e1c;
}

SCSS

$turquoise-tortoise: #537c77;
$turquoise-tortoise-rgb: 83, 124, 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);
}