#6475A5

CSS

:root {
  --misty-harbour: #6475a5;
  --misty-harbour-rgb: 100 117 165;
  --misty-harbour-oklch: oklch(0.568 0.077 268.9);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(224 27% 52%);
  border-color: oklch(0.568 0.077 268.9);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #6475a5;
  --color-misty-harbour-50: #edf5ff;
  --color-misty-harbour-100: #dee7ff;
  --color-misty-harbour-200: #c8d3f6;
  --color-misty-harbour-300: #a8b6e0;
  --color-misty-harbour-400: #8b9dcd;
  --color-misty-harbour-500: #7184ba;
  --color-misty-harbour-600: #60709d;
  --color-misty-harbour-700: #4c597e;
  --color-misty-harbour-800: #36425d;
  --color-misty-harbour-900: #252d41;
  --color-misty-harbour-950: #141a2a;
}

SCSS

$misty-harbour: #6475a5;
$misty-harbour-rgb: 100, 117, 165;
$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);
}