#6D70B6

CSS

:root {
  --twinkle-night: #6d70b6;
  --twinkle-night-rgb: 109 112 182;
  --twinkle-night-oklch: oklch(0.573 0.107 280.6);
}

.element {
  color: var(--twinkle-night);
  background-color: hsl(238 33% 57%);
  border-color: oklch(0.573 0.107 280.6);
}

Tailwind CSS v4

@theme {
  --color-twinkle-night: #6d70b6;
  --color-twinkle-night-50: #f0f2ff;
  --color-twinkle-night-100: #e2e4ff;
  --color-twinkle-night-200: #cdcfff;
  --color-twinkle-night-300: #afb1ed;
  --color-twinkle-night-400: #9397dd;
  --color-twinkle-night-500: #7a7dcb;
  --color-twinkle-night-600: #676aac;
  --color-twinkle-night-700: #52558a;
  --color-twinkle-night-800: #3a3e67;
  --color-twinkle-night-900: #282b48;
  --color-twinkle-night-950: #16182f;
}

SCSS

$twinkle-night: #6d70b6;
$twinkle-night-rgb: 109, 112, 182;
$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);
}