#3DA5B9

CSS

:root {
  --true-sky-blue: #3da5b9;
  --true-sky-blue-rgb: 61 165 185;
  --true-sky-blue-oklch: oklch(0.671 0.098 212.8);
}

.element {
  color: var(--true-sky-blue);
  background-color: hsl(190 50% 48%);
  border-color: oklch(0.671 0.098 212.8);
}

Tailwind CSS v4

@theme {
  --color-true-sky-blue: #3da5b9;
  --color-true-sky-blue-50: #d7fdff;
  --color-true-sky-blue-100: #c4f1fc;
  --color-true-sky-blue-200: #a4e0ee;
  --color-true-sky-blue-300: #7ac5d7;
  --color-true-sky-blue-400: #4faec1;
  --color-true-sky-blue-500: #0696ac;
  --color-true-sky-blue-600: #107f92;
  --color-true-sky-blue-700: #0f6675;
  --color-true-sky-blue-800: #064b55;
  --color-true-sky-blue-900: #05343c;
  --color-true-sky-blue-950: #001f25;
}

SCSS

$true-sky-blue: #3da5b9;
$true-sky-blue-rgb: 61, 165, 185;
$true-sky-blue-light: mix(#fff, $true-sky-blue, 20%);
$true-sky-blue-dark: mix(#000, $true-sky-blue, 20%);

.element {
  color: $true-sky-blue;
  box-shadow: 0 0 0 2px rgba($true-sky-blue, 0.35);
}