QR Code image using Flexbox and HTML

You can set the container in the middle of the screen whatever user changes it when you add these properties to it in CSS:

.container {
  position: absolute;
  top:50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

the new feature is transform, it has many lovely properties you can discover, I personally love it.

and if you wanna practice Flexbox, I prefer learning from both flexboxFroggy and flexboxZombies websites , they're grateful for education purposes. Hope it's useful