#6A7698

CSS

:root {
  --misty-harbour: #6a7698;
  --misty-harbour-rgb: 106 118 152;
  --misty-harbour-oklch: oklch(0.569 0.055 269.5);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(224 18% 51%);
  border-color: oklch(0.569 0.055 269.5);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #6a7698;
  --color-misty-harbour-50: #eff5ff;
  --color-misty-harbour-100: #e1e7fb;
  --color-misty-harbour-200: #cbd3ec;
  --color-misty-harbour-300: #adb6d4;
  --color-misty-harbour-400: #919ec0;
  --color-misty-harbour-500: #7785ab;
  --color-misty-harbour-600: #657191;
  --color-misty-harbour-700: #515a74;
  --color-misty-harbour-800: #3a4256;
  --color-misty-harbour-900: #282e3c;
  --color-misty-harbour-950: #161a26;
}

SCSS

$misty-harbour: #6a7698;
$misty-harbour-rgb: 106, 118, 152;
$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);
}