#697695

CSS

:root {
  --misty-harbour: #697695;
  --misty-harbour-rgb: 105 118 149;
  --misty-harbour-oklch: oklch(0.567 0.051 267);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(222 17% 50%);
  border-color: oklch(0.567 0.051 267);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #697695;
  --color-misty-harbour-50: #eff5ff;
  --color-misty-harbour-100: #e1e8f9;
  --color-misty-harbour-200: #cbd4eb;
  --color-misty-harbour-300: #adb7d2;
  --color-misty-harbour-400: #919ebd;
  --color-misty-harbour-500: #7786a9;
  --color-misty-harbour-600: #65718e;
  --color-misty-harbour-700: #515a72;
  --color-misty-harbour-800: #3a4254;
  --color-misty-harbour-900: #282e3b;
  --color-misty-harbour-950: #161b25;
}

SCSS

$misty-harbour: #697695;
$misty-harbour-rgb: 105, 118, 149;
$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);
}