#507D78

CSS

:root {
  --turquoise-tortoise: #507d78;
  --turquoise-tortoise-rgb: 80 125 120;
  --turquoise-tortoise-oklch: oklch(0.556 0.05 187);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(173 22% 40%);
  border-color: oklch(0.556 0.05 187);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #507d78;
  --color-turquoise-tortoise-50: #e6faf8;
  --color-turquoise-tortoise-100: #d6eeeb;
  --color-turquoise-tortoise-200: #bddcd8;
  --color-turquoise-tortoise-300: #9bc0bc;
  --color-turquoise-tortoise-400: #7da8a3;
  --color-turquoise-tortoise-500: #5f918c;
  --color-turquoise-tortoise-600: #517b76;
  --color-turquoise-tortoise-700: #40625e;
  --color-turquoise-tortoise-800: #2e4845;
  --color-turquoise-tortoise-900: #1f322f;
  --color-turquoise-tortoise-950: #0f1e1c;
}

SCSS

$turquoise-tortoise: #507d78;
$turquoise-tortoise-rgb: 80, 125, 120;
$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);
}