#28A3BC

CSS

:root {
  --true-sky-blue: #28a3bc;
  --true-sky-blue-rgb: 40 163 188;
  --true-sky-blue-oklch: oklch(0.662 0.108 215.2);
}

.element {
  color: var(--true-sky-blue);
  background-color: hsl(190 65% 45%);
  border-color: oklch(0.662 0.108 215.2);
}

Tailwind CSS v4

@theme {
  --color-true-sky-blue: #28a3bc;
  --color-true-sky-blue-50: #d4feff;
  --color-true-sky-blue-100: #c0f2ff;
  --color-true-sky-blue-200: #9fe0f3;
  --color-true-sky-blue-300: #73c5dc;
  --color-true-sky-blue-400: #42aec6;
  --color-true-sky-blue-500: #0097b3;
  --color-true-sky-blue-600: #008097;
  --color-true-sky-blue-700: #006679;
  --color-true-sky-blue-800: #004c59;
  --color-true-sky-blue-900: #00353e;
  --color-true-sky-blue-950: #002027;
}

SCSS

$true-sky-blue: #28a3bc;
$true-sky-blue-rgb: 40, 163, 188;
$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);
}