to complete the challenge, I use only basic html and css.

Congrats on completing this challenge 🎉🎉. You did a really great job. Here's my thought on this challenge 😇.

1. I found it really hard finding your solution in your GitHub repo (I found out you joined GitHub about three days ago 😉. Congrats on that 🤗). You should try to make sure that the solution link you provide when submitting your solution should point to the repo where your code for that solution lives. This will make it easier for other developers to find your code and give helpful feedback on your solution 😇. You could check out this freecodecamp article on getting started with Git and GitHub ☺️ or if you prefer a video tutorial you could checkout this YouTube playlist by The NetNinja on YouTube 🤗.
2. You should consider renaming your 'qr-code.css' and 'qr-code.html' to 'style.css' and 'index.html' respectively 😉. This is by convention though 😁. That's all from me 😄. Hope this helps. Please do well to also check out the generated report on your solution. It will help you a lot. Happy Coding 💪🏿