#5A72B6

CSS

:root {
  --loch-ness: #5a72b6;
  --loch-ness-rgb: 90 114 182;
  --loch-ness-oklch: oklch(0.564 0.109 268.1);
}

.element {
  color: var(--loch-ness);
  background-color: hsl(224 39% 53%);
  border-color: oklch(0.564 0.109 268.1);
}

Tailwind CSS v4

@theme {
  --color-loch-ness: #5a72b6;
  --color-loch-ness-50: #e9f4ff;
  --color-loch-ness-100: #d9e7ff;
  --color-loch-ness-200: #c2d3ff;
  --color-loch-ness-300: #a1b5f0;
  --color-loch-ness-400: #839ce0;
  --color-loch-ness-500: #6782cf;
  --color-loch-ness-600: #576eae;
  --color-loch-ness-700: #46588c;
  --color-loch-ness-800: #304168;
  --color-loch-ness-900: #212d49;
  --color-loch-ness-950: #101930;
}

SCSS

$loch-ness: #5a72b6;
$loch-ness-rgb: 90, 114, 182;
$loch-ness-light: mix(#fff, $loch-ness, 20%);
$loch-ness-dark: mix(#000, $loch-ness, 20%);

.element {
  color: $loch-ness;
  box-shadow: 0 0 0 2px rgba($loch-ness, 0.35);
}