#6D73A6

CSS

:root {
  --twinkle-night: #6d73a6;
  --twinkle-night-rgb: 109 115 166;
  --twinkle-night-oklch: oklch(0.571 0.079 278.4);
}

.element {
  color: var(--twinkle-night);
  background-color: hsl(234 24% 54%);
  border-color: oklch(0.571 0.079 278.4);
}

Tailwind CSS v4

@theme {
  --color-twinkle-night: #6d73a6;
  --color-twinkle-night-50: #f0f3ff;
  --color-twinkle-night-100: #e2e6ff;
  --color-twinkle-night-200: #cdd1f6;
  --color-twinkle-night-300: #afb3e0;
  --color-twinkle-night-400: #939acd;
  --color-twinkle-night-500: #7a81ba;
  --color-twinkle-night-600: #676d9d;
  --color-twinkle-night-700: #53577e;
  --color-twinkle-night-800: #3b405e;
  --color-twinkle-night-900: #282c42;
  --color-twinkle-night-950: #16192a;
}

SCSS

$twinkle-night: #6d73a6;
$twinkle-night-rgb: 109, 115, 166;
$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);
}