#5969A8

CSS

:root {
  --bellflower: #5969a8;
  --bellflower-rgb: 89 105 168;
  --bellflower-oklch: oklch(0.536 0.101 271.8);
}

.element {
  color: var(--bellflower);
  background-color: hsl(228 31% 50%);
  border-color: oklch(0.536 0.101 271.8);
}

Tailwind CSS v4

@theme {
  --color-bellflower: #5969a8;
  --color-bellflower-50: #ecf4ff;
  --color-bellflower-100: #dde6ff;
  --color-bellflower-200: #c6d2ff;
  --color-bellflower-300: #a7b4ec;
  --color-bellflower-400: #899bda;
  --color-bellflower-500: #6f81c9;
  --color-bellflower-600: #5e6daa;
  --color-bellflower-700: #4b5888;
  --color-bellflower-800: #354065;
  --color-bellflower-900: #242c47;
  --color-bellflower-950: #13192e;
}

SCSS

$bellflower: #5969a8;
$bellflower-rgb: 89, 105, 168;
$bellflower-light: mix(#fff, $bellflower, 20%);
$bellflower-dark: mix(#000, $bellflower, 20%);

.element {
  color: $bellflower;
  box-shadow: 0 0 0 2px rgba($bellflower, 0.35);
}