#15AAC0

CSS

:root {
  --true-sky-blue: #15aac0;
  --true-sky-blue-rgb: 21 170 192;
  --true-sky-blue-oklch: oklch(0.678 0.115 211.3);
}

.element {
  color: var(--true-sky-blue);
  background-color: hsl(188 80% 42%);
  border-color: oklch(0.678 0.115 211.3);
}

Tailwind CSS v4

@theme {
  --color-true-sky-blue: #15aac0;
  --color-true-sky-blue-50: #d1ffff;
  --color-true-sky-blue-100: #bdf3ff;
  --color-true-sky-blue-200: #9ae2f2;
  --color-true-sky-blue-300: #6bc7db;
  --color-true-sky-blue-400: #33b0c5;
  --color-true-sky-blue-500: #0099b1;
  --color-true-sky-blue-600: #008296;
  --color-true-sky-blue-700: #006878;
  --color-true-sky-blue-800: #004d58;
  --color-true-sky-blue-900: #00353d;
  --color-true-sky-blue-950: #002027;
}

SCSS

$true-sky-blue: #15aac0;
$true-sky-blue-rgb: 21, 170, 192;
$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);
}