#19A9C5

CSS

:root {
  --true-sky-blue: #19a9c5;
  --true-sky-blue-rgb: 25 169 197;
  --true-sky-blue-oklch: oklch(0.678 0.116 215.8);
}

.element {
  color: var(--true-sky-blue);
  background-color: hsl(190 77% 44%);
  border-color: oklch(0.678 0.116 215.8);
}

Tailwind CSS v4

@theme {
  --color-true-sky-blue: #19a9c5;
  --color-true-sky-blue-50: #d1feff;
  --color-true-sky-blue-100: #bdf2ff;
  --color-true-sky-blue-200: #9ae1f5;
  --color-true-sky-blue-300: #6cc6df;
  --color-true-sky-blue-400: #35afca;
  --color-true-sky-blue-500: #0098b7;
  --color-true-sky-blue-600: #00819a;
  --color-true-sky-blue-700: #00677c;
  --color-true-sky-blue-800: #004c5b;
  --color-true-sky-blue-900: #00353f;
  --color-true-sky-blue-950: #002028;
}

SCSS

$true-sky-blue: #19a9c5;
$true-sky-blue-rgb: 25, 169, 197;
$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);
}