#3E7F78

CSS

:root {
  --turquoise-tortoise: #3e7f78;
  --turquoise-tortoise-rgb: 62 127 120;
  --turquoise-tortoise-oklch: oklch(0.552 0.068 186.2);
}

.element {
  color: var(--turquoise-tortoise);
  background-color: hsl(174 34% 37%);
  border-color: oklch(0.552 0.068 186.2);
}

Tailwind CSS v4

@theme {
  --color-turquoise-tortoise: #3e7f78;
  --color-turquoise-tortoise-50: #e0fcf9;
  --color-turquoise-tortoise-100: #d0f0ec;
  --color-turquoise-tortoise-200: #b4deda;
  --color-turquoise-tortoise-300: #90c3be;
  --color-turquoise-tortoise-400: #6faca4;
  --color-turquoise-tortoise-500: #4c958d;
  --color-turquoise-tortoise-600: #417e77;
  --color-turquoise-tortoise-700: #34655f;
  --color-turquoise-tortoise-800: #254a45;
  --color-turquoise-tortoise-900: #183330;
  --color-turquoise-tortoise-950: #091f1c;
}

SCSS

$turquoise-tortoise: #3e7f78;
$turquoise-tortoise-rgb: 62, 127, 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);
}