#6A74A3

CSS

:root {
  --misty-harbour: #6a74a3;
  --misty-harbour-rgb: 106 116 163;
  --misty-harbour-oklch: oklch(0.57 0.074 274.6);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(229 24% 53%);
  border-color: oklch(0.57 0.074 274.6);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #6a74a3;
  --color-misty-harbour-50: #eff4ff;
  --color-misty-harbour-100: #e1e6ff;
  --color-misty-harbour-200: #cbd2f4;
  --color-misty-harbour-300: #adb5de;
  --color-misty-harbour-400: #919ccb;
  --color-misty-harbour-500: #7782b7;
  --color-misty-harbour-600: #656f9b;
  --color-misty-harbour-700: #51587c;
  --color-misty-harbour-800: #3a415c;
  --color-misty-harbour-900: #272d41;
  --color-misty-harbour-950: #161a29;
}

SCSS

$misty-harbour: #6a74a3;
$misty-harbour-rgb: 106, 116, 163;
$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);
}