#6567A0

CSS

:root {
  --twinkle-night: #6567a0;
  --twinkle-night-rgb: 101 103 160;
  --twinkle-night-oklch: oklch(0.537 0.089 281.4);
}

.element {
  color: var(--twinkle-night);
  background-color: hsl(238 24% 51%);
  border-color: oklch(0.537 0.089 281.4);
}

Tailwind CSS v4

@theme {
  --color-twinkle-night: #6567a0;
  --color-twinkle-night-50: #f1f2ff;
  --color-twinkle-night-100: #e3e5ff;
  --color-twinkle-night-200: #ced0fa;
  --color-twinkle-night-300: #b1b2e4;
  --color-twinkle-night-400: #9598d2;
  --color-twinkle-night-500: #7c7fc0;
  --color-twinkle-night-600: #696ba2;
  --color-twinkle-night-700: #545682;
  --color-twinkle-night-800: #3c3f61;
  --color-twinkle-night-900: #292b44;
  --color-twinkle-night-950: #17182c;
}

SCSS

$twinkle-night: #6567a0;
$twinkle-night-rgb: 101, 103, 160;
$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);
}