#63779D

CSS

:root {
  --misty-harbour: #63779d;
  --misty-harbour-rgb: 99 119 157;
  --misty-harbour-oklch: oklch(0.568 0.064 262.9);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(219 23% 50%);
  border-color: oklch(0.568 0.064 262.9);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #63779d;
  --color-misty-harbour-50: #ecf5ff;
  --color-misty-harbour-100: #dde8fe;
  --color-misty-harbour-200: #c7d4f0;
  --color-misty-harbour-300: #a8b8d9;
  --color-misty-harbour-400: #8b9fc5;
  --color-misty-harbour-500: #7086b1;
  --color-misty-harbour-600: #5f7296;
  --color-misty-harbour-700: #4c5b78;
  --color-misty-harbour-800: #364359;
  --color-misty-harbour-900: #252e3e;
  --color-misty-harbour-950: #131b27;
}

SCSS

$misty-harbour: #63779d;
$misty-harbour-rgb: 99, 119, 157;
$misty-harbour-light: mix(#fff, $misty-harbour, 20%);
$misty-harbour-dark: mix(#000, $misty-harbour, 20%);

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