Good code offers free Adobe XD templates for you to download and use to sharpen your HTML and CSS skills. All assets used are included in the compressed file and you can use them however you like, except for commercial use.
Get as close as possible to the design. Don't bother too much with pixel-perfection, as long as you have the basic layout, you're good to go!
You can post your results on the /r/GoodCodeChallenge subreddit, created just for this website.
I'm always looking for feedback to improve any project I work, if you have any, please DM me at my e-mail over at moeminmamdouh@hotmail.com Thank you and have a wonderful day!