Ask HN: Is there a website with advanced CSS puzzles?

I am looking for question like :

1) How would you transform this div from middle of page to end of page etc 2) Why is this div only 20px height even though the image inside is 100px height 3) Given this moderately complex CSS, how will you add a extra text div of dimensions 20px * 30px and how will you style it with minnimum classes.

Something like this: https://www.w3schools.com/css/exercise.asp?filename=exercise_positioning5