basic html css for qr card component

Hello, @tatsuya98!

Your project is looking fantastic!

I'd like to suggest a way to make it even better:

• Using margin isn't always the most effective method for centering an element.

Here's a highly efficient approach to position an element at the center of the page both vertically and horizontally:

📌 Apply this CSS to the body (avoid using position or margins in order to work correctly):

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

I hope you find this helpful!

Keep up the excellent work!