#4BA4CC

CSS

:root {
  --mystic-blue: #4ba4cc;
  --mystic-blue-rgb: 75 164 204;
  --mystic-blue-oklch: oklch(0.681 0.103 230.3);
}

.element {
  color: var(--mystic-blue);
  background-color: hsl(199 56% 55%);
  border-color: oklch(0.681 0.103 230.3);
}

Tailwind CSS v4

@theme {
  --color-mystic-blue: #4ba4cc;
  --color-mystic-blue-50: #d9fbff;
  --color-mystic-blue-100: #c7efff;
  --color-mystic-blue-200: #a8ddf9;
  --color-mystic-blue-300: #80c1e3;
  --color-mystic-blue-400: #57aad0;
  --color-mystic-blue-500: #2592bd;
  --color-mystic-blue-600: #237ba0;
  --color-mystic-blue-700: #1c6380;
  --color-mystic-blue-800: #0f495e;
  --color-mystic-blue-900: #0a3342;
  --color-mystic-blue-950: #001e2b;
}

SCSS

$mystic-blue: #4ba4cc;
$mystic-blue-rgb: 75, 164, 204;
$mystic-blue-light: mix(#fff, $mystic-blue, 20%);
$mystic-blue-dark: mix(#000, $mystic-blue, 20%);

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