All solutions

What challenges did you encounter, and how did you overcome them?

The black border behind the card is a bit tricky, by the look of it it seems to be easily implemented by border-shadow, but it will not work. So to implement this black box you need to use ::before (Pseudo Element).

What challenges did you encounter, and how did you overcome them?

Positioning the Container class in the middle of the screen. I have solved this issue by flexbox.