#45756D

CSS

:root {
  --turquoise-tortoise: #45756d;
  --turquoise-tortoise-rgb: 69 117 109;
  --turquoise-tortoise-oklch: oklch(0.526 0.054 182.4);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(170 26% 36%);
  border-color: oklch(0.526 0.054 182.4);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #45756d;
  --color-turquoise-tortoise-50: #e5fbf7;
  --color-turquoise-tortoise-100: #d5eeea;
  --color-turquoise-tortoise-200: #bcdcd7;
  --color-turquoise-tortoise-300: #99c1bb;
  --color-turquoise-tortoise-400: #7ba9a1;
  --color-turquoise-tortoise-500: #5c9289;
  --color-turquoise-tortoise-600: #4e7c74;
  --color-turquoise-tortoise-700: #3e635d;
  --color-turquoise-tortoise-800: #2d4943;
  --color-turquoise-tortoise-900: #1e322e;
  --color-turquoise-tortoise-950: #0e1e1b;
}

SCSS

$turquoise-tortoise: #45756d;
$turquoise-tortoise-rgb: 69, 117, 109;
$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);
}