#666FB9

CSS

:root {
  --loch-ness: #666fb9;
  --loch-ness-rgb: 102 111 185;
  --loch-ness-oklch: oklch(0.568 0.114 276.9);
}

.element {
  color: var(--loch-ness);
  background-color: hsl(233 37% 56%);
  border-color: oklch(0.568 0.114 276.9);
}

Tailwind CSS v4

@theme {
  --color-loch-ness: #666fb9;
  --color-loch-ness-50: #edf3ff;
  --color-loch-ness-100: #dfe5ff;
  --color-loch-ness-200: #c9d0ff;
  --color-loch-ness-300: #aab2f2;
  --color-loch-ness-400: #8d98e1;
  --color-loch-ness-500: #737ed1;
  --color-loch-ness-600: #626ab0;
  --color-loch-ness-700: #4e558d;
  --color-loch-ness-800: #373e6a;
  --color-loch-ness-900: #252b4a;
  --color-loch-ness-950: #141831;
}

SCSS

$loch-ness: #666fb9;
$loch-ness-rgb: 102, 111, 185;
$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);
}