#6371B3

CSS

:root {
  --loch-ness: #6371b3;
  --loch-ness-rgb: 99 113 179;
  --loch-ness-oklch: oklch(0.566 0.103 273.6);
}

.element {
  color: var(--loch-ness);
  background-color: hsl(230 34% 55%);
  border-color: oklch(0.566 0.103 273.6);
}

Tailwind CSS v4

@theme {
  --color-loch-ness: #6371b3;
  --color-loch-ness-50: #ecf3ff;
  --color-loch-ness-100: #dee6ff;
  --color-loch-ness-200: #c7d1ff;
  --color-loch-ness-300: #a8b4ed;
  --color-loch-ness-400: #8b9adc;
  --color-loch-ness-500: #7080ca;
  --color-loch-ness-600: #5f6dab;
  --color-loch-ness-700: #4c5789;
  --color-loch-ness-800: #364066;
  --color-loch-ness-900: #242c48;
  --color-loch-ness-950: #13192f;
}

SCSS

$loch-ness: #6371b3;
$loch-ness-rgb: 99, 113, 179;
$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);
}