#666CC6

CSS

:root {
  --loch-ness: #666cc6;
  --loch-ness-rgb: 102 108 198;
  --loch-ness-oklch: oklch(0.569 0.137 278.2);
}

.element {
  color: var(--loch-ness);
  background-color: hsl(236 46% 59%);
  border-color: oklch(0.569 0.137 278.2);
}

Tailwind CSS v4

@theme {
  --color-loch-ness: #666cc6;
  --color-loch-ness-50: #edf2ff;
  --color-loch-ness-100: #dee4ff;
  --color-loch-ness-200: #c8ceff;
  --color-loch-ness-300: #aaaffd;
  --color-loch-ness-400: #8c95ee;
  --color-loch-ness-500: #737adf;
  --color-loch-ness-600: #6167bc;
  --color-loch-ness-700: #4e5297;
  --color-loch-ness-800: #363d71;
  --color-loch-ness-900: #252a50;
  --color-loch-ness-950: #141735;
}

SCSS

$loch-ness: #666cc6;
$loch-ness-rgb: 102, 108, 198;
$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);
}