#666DC1

CSS

:root {
  --loch-ness: #666dc1;
  --loch-ness-rgb: 102 109 193;
  --loch-ness-oklch: oklch(0.568 0.129 277.9);
}

.element {
  color: var(--loch-ness);
  background-color: hsl(235 42% 58%);
  border-color: oklch(0.568 0.129 277.9);
}

Tailwind CSS v4

@theme {
  --color-loch-ness: #666dc1;
  --color-loch-ness-50: #edf2ff;
  --color-loch-ness-100: #dfe4ff;
  --color-loch-ness-200: #c9cfff;
  --color-loch-ness-300: #aab0f8;
  --color-loch-ness-400: #8d96e9;
  --color-loch-ness-500: #737bda;
  --color-loch-ness-600: #6268b7;
  --color-loch-ness-700: #4e5393;
  --color-loch-ness-800: #373d6e;
  --color-loch-ness-900: #252a4e;
  --color-loch-ness-950: #141733;
}

SCSS

$loch-ness: #666dc1;
$loch-ness-rgb: 102, 109, 193;
$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);
}