Qr Code Using CSS & HTML5

I have completed the QR code component! Please let me know your thoughts!

QUESTIONS:

-I used negative margins in my code. Is it OK to do that going forward?

-I used a <h3> heading instead of solely using <p> tags. Was it OK that I deviated slightly from the style guide?

-Was it OK to add the QR image to GitHub, save it as a https:// link and add the URL to my code?

-I tried to drag and drop the .gitignore file to GitHub, but the file was listed as hidden and would not upload. Was it OK that I created a new .gitignore file on GitHub then copied and pasted everything into that file? Also, did I need to add that file?

-Does my code follow best practices? How can I tell if it does?

-I used: min-width: 375px; and max-width: 1440px; in the body CSS to account for the mobile and desktop dimensions specified in the style guide. Was that correct?

-Did I upload everything that I was supposed to? For example, I did not upload the fav-icon image that was included in my HTML code, the image folder or the design folder.

-Should I have added a separate CSS folder?

-Does my code read well / should I style it differently?

-Do you have any additional feedback?

Thank you for your help!! :)

-Angie