#5D75A4

CSS

:root {
  --misty-harbour: #5d75a4;
  --misty-harbour-rgb: 93 117 164;
  --misty-harbour-oklch: oklch(0.563 0.079 263.3);
}

.element {
  color: var(--misty-harbour);
  background-color: hsl(220 28% 50%);
  border-color: oklch(0.563 0.079 263.3);
}

Tailwind CSS v4

@theme {
  --color-misty-harbour: #5d75a4;
  --color-misty-harbour-50: #eaf5ff;
  --color-misty-harbour-100: #dbe8ff;
  --color-misty-harbour-200: #c4d4f7;
  --color-misty-harbour-300: #a4b7e1;
  --color-misty-harbour-400: #869fce;
  --color-misty-harbour-500: #6b86bb;
  --color-misty-harbour-600: #5b719e;
  --color-misty-harbour-700: #485b7f;
  --color-misty-harbour-800: #33435e;
  --color-misty-harbour-900: #232e42;
  --color-misty-harbour-950: #121b2a;
}

SCSS

$misty-harbour: #5d75a4;
$misty-harbour-rgb: 93, 117, 164;
$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);
}