#6672A9

CSS

:root {
  --twinkle-night: #6672a9;
  --twinkle-night-rgb: 102 114 169;
  --twinkle-night-oklch: oklch(0.565 0.086 273.9);
}

.element {
  color: var(--twinkle-night);
  background-color: hsl(229 28% 53%);
  border-color: oklch(0.565 0.086 273.9);
}

Tailwind CSS v4

@theme {
  --color-twinkle-night: #6672a9;
  --color-twinkle-night-50: #eef4ff;
  --color-twinkle-night-100: #dfe6ff;
  --color-twinkle-night-200: #cad2fa;
  --color-twinkle-night-300: #abb4e4;
  --color-twinkle-night-400: #8e9bd2;
  --color-twinkle-night-500: #7482c0;
  --color-twinkle-night-600: #626ea2;
  --color-twinkle-night-700: #4f5882;
  --color-twinkle-night-800: #384060;
  --color-twinkle-night-900: #262c44;
  --color-twinkle-night-950: #15192c;
}

SCSS

$twinkle-night: #6672a9;
$twinkle-night-rgb: 102, 114, 169;
$twinkle-night-light: mix(#fff, $twinkle-night, 20%);
$twinkle-night-dark: mix(#000, $twinkle-night, 20%);

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