#577E75

CSS

:root {
  --turquoise-tortoise: #577e75;
  --turquoise-tortoise-rgb: 87 126 117;
  --turquoise-tortoise-oklch: oklch(0.561 0.046 178.6);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(166 18% 42%);
  border-color: oklch(0.561 0.046 178.6);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #577e75;
  --color-turquoise-tortoise-50: #e8faf6;
  --color-turquoise-tortoise-100: #d8ede8;
  --color-turquoise-tortoise-200: #c0dbd5;
  --color-turquoise-tortoise-300: #9fc0b8;
  --color-turquoise-tortoise-400: #82a89f;
  --color-turquoise-tortoise-500: #659186;
  --color-turquoise-tortoise-600: #567a72;
  --color-turquoise-tortoise-700: #44625b;
  --color-turquoise-tortoise-800: #314842;
  --color-turquoise-tortoise-900: #21322d;
  --color-turquoise-tortoise-950: #111e1a;
}

SCSS

$turquoise-tortoise: #577e75;
$turquoise-tortoise-rgb: 87, 126, 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);
}