#6B729C

CSS

:root {
  --misty-harbour: #6b729c;
  --misty-harbour-rgb: 107 114 156;
  --misty-harbour-oklch: oklch(0.563 0.066 276.8);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(231 20% 52%);
  border-color: oklch(0.563 0.066 276.8);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #6b729c;
  --color-misty-harbour-50: #f0f4ff;
  --color-misty-harbour-100: #e2e6fe;
  --color-misty-harbour-200: #cdd2f1;
  --color-misty-harbour-300: #afb5d9;
  --color-misty-harbour-400: #949bc6;
  --color-misty-harbour-500: #7b82b2;
  --color-misty-harbour-600: #686f96;
  --color-misty-harbour-700: #535878;
  --color-misty-harbour-800: #3b4159;
  --color-misty-harbour-900: #292d3e;
  --color-misty-harbour-950: #171a28;
}

SCSS

$misty-harbour: #6b729c;
$misty-harbour-rgb: 107, 114, 156;
$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);
}