Qr Code - HTML e CSS

Hello Guilherme Aparecido, how are you? I truly loved your project's outcome, however I have some advice that I hope you'll find useful:

A good practice to center content is using grid or flex-box, avoid using margin or padding to make placements, use only in the latter case! we can do it like this:

Flex-box:

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

GRID

body {
    display: grid;
    min height: 100vh;
    place-content: center;
}

Since this project is only based on a single page component, there is no need for a h1 tag. It's always a good idea to prevent accessibility errors, so I believe it would be beneficial for you to add a "h1" in this component. Don't worry if you forget about "h1," though; it's a good practice for when you are developing larger sites.

<h1 class="titulo">Improve your front-end skills by building projects</h1>

The remainder is excellent.

I hope it's useful. 👍