I recently had a technical front end interview. I did not do as well on the CSS portion of the interview as I had hoped. As a result, I have been practicing my CSS skills over the last week. I found a site called https://www.frontendmentor.io/ that has been a great practice tool.
If you are just getting started with frontend web developer, or are practicing for an interview, then I highly recommend this site.
I have been going through the newbie and junior challenges. I am able to get this done in an hour or two, similar to the length of an interview.
There are often different ways to do the same thing in CSS, so I found that re-doing the challenges in different ways is a good way to learn. For example, do a challenge with display flex, then re-do it with display grid.