#6472AA

CSS

:root {
  --twinkle-night: #6472aa;
  --twinkle-night-rgb: 100 114 170;
  --twinkle-night-oklch: oklch(0.564 0.089 272.6);
}

.element {
  color: var(--twinkle-night);
  background-color: hsl(228 29% 53%);
  border-color: oklch(0.564 0.089 272.6);
}

Tailwind CSS v4

@theme {
  --color-twinkle-night: #6472aa;
  --color-twinkle-night-50: #edf4ff;
  --color-twinkle-night-100: #dfe6ff;
  --color-twinkle-night-200: #c8d2fb;
  --color-twinkle-night-300: #a9b5e5;
  --color-twinkle-night-400: #8c9bd3;
  --color-twinkle-night-500: #7282c1;
  --color-twinkle-night-600: #616ea3;
  --color-twinkle-night-700: #4d5883;
  --color-twinkle-night-800: #374161;
  --color-twinkle-night-900: #252d44;
  --color-twinkle-night-950: #14192c;
}

SCSS

$twinkle-night: #6472aa;
$twinkle-night-rgb: 100, 114, 170;
$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);
}