#62699B

CSS

:root {
  --twinkle-night: #62699b;
  --twinkle-night-rgb: 98 105 155;
  --twinkle-night-oklch: oklch(0.536 0.079 277.3);
}

.element {
  color: var(--twinkle-night);
  background-color: hsl(233 23% 50%);
  border-color: oklch(0.536 0.079 277.3);
}

Tailwind CSS v4

@theme {
  --color-twinkle-night: #62699b;
  --color-twinkle-night-50: #f0f3ff;
  --color-twinkle-night-100: #e2e6ff;
  --color-twinkle-night-200: #ccd1f6;
  --color-twinkle-night-300: #aeb4e0;
  --color-twinkle-night-400: #929acd;
  --color-twinkle-night-500: #7981ba;
  --color-twinkle-night-600: #676d9d;
  --color-twinkle-night-700: #52577e;
  --color-twinkle-night-800: #3a405e;
  --color-twinkle-night-900: #282c42;
  --color-twinkle-night-950: #16192a;
}

SCSS

$twinkle-night: #62699b;
$twinkle-night-rgb: 98, 105, 155;
$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);
}