#6C748F

CSS

:root {
  --misty-harbour: #6c748f;
  --misty-harbour-rgb: 108 116 143;
  --misty-harbour-oklch: oklch(0.562 0.043 272);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(226 14% 49%);
  border-color: oklch(0.562 0.043 272);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #6c748f;
  --color-misty-harbour-50: #f1f5ff;
  --color-misty-harbour-100: #e3e7f7;
  --color-misty-harbour-200: #ced3e7;
  --color-misty-harbour-300: #b0b6ce;
  --color-misty-harbour-400: #959db9;
  --color-misty-harbour-500: #7c85a3;
  --color-misty-harbour-600: #69718a;
  --color-misty-harbour-700: #545a6f;
  --color-misty-harbour-800: #3c4252;
  --color-misty-harbour-900: #292d39;
  --color-misty-harbour-950: #171a23;
}

SCSS

$misty-harbour: #6c748f;
$misty-harbour-rgb: 108, 116, 143;
$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);
}