#5F71B5

CSS

:root {
  --loch-ness: #5f71b5;
  --loch-ness-rgb: 95 113 181;
  --loch-ness-oklch: oklch(0.565 0.108 271.4);
}

.element {
  color: var(--loch-ness);
  background-color: hsl(227 37% 54%);
  border-color: oklch(0.565 0.108 271.4);
}

Tailwind CSS v4

@theme {
  --color-loch-ness: #5f71b5;
  --color-loch-ness-50: #ebf4ff;
  --color-loch-ness-100: #dce6ff;
  --color-loch-ness-200: #c5d2ff;
  --color-loch-ness-300: #a5b4ef;
  --color-loch-ness-400: #879bde;
  --color-loch-ness-500: #6d81cd;
  --color-loch-ness-600: #5c6dad;
  --color-loch-ness-700: #49578b;
  --color-loch-ness-800: #334068;
  --color-loch-ness-900: #232c49;
  --color-loch-ness-950: #121930;
}

SCSS

$loch-ness: #5f71b5;
$loch-ness-rgb: 95, 113, 181;
$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);
}