#6D7595

CSS

:root {
  --misty-harbour: #6d7595;
  --misty-harbour-rgb: 109 117 149;
  --misty-harbour-oklch: oklch(0.568 0.05 273.8);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(228 16% 51%);
  border-color: oklch(0.568 0.05 273.8);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #6d7595;
  --color-misty-harbour-50: #f1f4ff;
  --color-misty-harbour-100: #e3e7f9;
  --color-misty-harbour-200: #ced3ea;
  --color-misty-harbour-300: #b0b6d2;
  --color-misty-harbour-400: #959dbd;
  --color-misty-harbour-500: #7b84a8;
  --color-misty-harbour-600: #68708e;
  --color-misty-harbour-700: #535a72;
  --color-misty-harbour-800: #3c4254;
  --color-misty-harbour-900: #292d3b;
  --color-misty-harbour-950: #171a25;
}

SCSS

$misty-harbour: #6d7595;
$misty-harbour-rgb: 109, 117, 149;
$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);
}