React component working with state and onClick

I got some good practice with this. I'm learning React so it was great to work with a little component, mapping out state for the questions and using an onClick method to toggle the question. Plus I got to work on things like the accordion css animation showing the answer and rotating the arrow.

The only thing that really got me was how do you hide the left side on the larger image when on desktop? I thought z-index would be involved but I could never figure it out. Thanks!