#006D81

CSS

:root {
  --teal-with-it: #006d81;
  --teal-with-it-rgb: 0 109 129;
  --teal-with-it-oklch: oklch(0.493 0.088 216.3);
}

.element {
  color: var(--teal-with-it);
  background-color: hsl(189 100% 25%);
  border-color: oklch(0.493 0.088 216.3);
}

Tailwind CSS v4

@theme {
  --color-teal-with-it: #006d81;
  --color-teal-with-it-50: #dafcff;
  --color-teal-with-it-100: #c8f0fc;
  --color-teal-with-it-200: #abdeed;
  --color-teal-with-it-300: #83c3d6;
  --color-teal-with-it-400: #5cacc0;
  --color-teal-with-it-500: #2e94ab;
  --color-teal-with-it-600: #2a7d91;
  --color-teal-with-it-700: #216474;
  --color-teal-with-it-800: #154a55;
  --color-teal-with-it-900: #0e333b;
  --color-teal-with-it-950: #011f25;
}

SCSS

$teal-with-it: #006d81;
$teal-with-it-rgb: 0, 109, 129;
$teal-with-it-light: mix(#fff, $teal-with-it, 20%);
$teal-with-it-dark: mix(#000, $teal-with-it, 20%);

.element {
  color: $teal-with-it;
  box-shadow: 0 0 0 2px rgba($teal-with-it, 0.35);
}