#4FA4CD

CSS

:root {
  --mystic-blue: #4fa4cd;
  --mystic-blue-rgb: 79 164 205;
  --mystic-blue-oklch: oklch(0.683 0.102 231.9);
}

.element {
  color: var(--mystic-blue);
  background-color: hsl(200 56% 56%);
  border-color: oklch(0.683 0.102 231.9);
}

Tailwind CSS v4

@theme {
  --color-mystic-blue: #4fa4cd;
  --color-mystic-blue-50: #dafbff;
  --color-mystic-blue-100: #c8eeff;
  --color-mystic-blue-200: #aadcfa;
  --color-mystic-blue-300: #82c1e4;
  --color-mystic-blue-400: #5aa9d0;
  --color-mystic-blue-500: #2b91be;
  --color-mystic-blue-600: #277ba0;
  --color-mystic-blue-700: #1f6280;
  --color-mystic-blue-800: #12495f;
  --color-mystic-blue-900: #0c3242;
  --color-mystic-blue-950: #001e2b;
}

SCSS

$mystic-blue: #4fa4cd;
$mystic-blue-rgb: 79, 164, 205;
$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);
}