QR Code Componet Using HTML and Css

Generally, I use flex to center items within a container. This means that I write the following code in CSS:

body {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
}

However, you can also use margin: auto; in the body. Such as :

body {
  margin: auto;
  height: 100vh;
}

But remember that this code is only useful for centering a single item; you can't use it for more than one item.