#6B7691

CSS

:root {
  --misty-harbour: #6b7691;
  --misty-harbour-rgb: 107 118 145;
  --misty-harbour-oklch: oklch(0.567 0.044 267.6);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(223 15% 49%);
  border-color: oklch(0.567 0.044 267.6);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #6b7691;
  --color-misty-harbour-50: #f0f5ff;
  --color-misty-harbour-100: #e2e8f7;
  --color-misty-harbour-200: #cdd4e8;
  --color-misty-harbour-300: #aeb7cf;
  --color-misty-harbour-400: #939eb9;
  --color-misty-harbour-500: #7986a4;
  --color-misty-harbour-600: #67718b;
  --color-misty-harbour-700: #525a6f;
  --color-misty-harbour-800: #3b4252;
  --color-misty-harbour-900: #292e39;
  --color-misty-harbour-950: #161b23;
}

SCSS

$misty-harbour: #6b7691;
$misty-harbour-rgb: 107, 118, 145;
$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);
}