CSS List Display Horizontal Alignment

I must be missing something understanding your tutorial on CSS. Using the Dev. Tools in Chrome, when I test changing the vertical-align to horizontal-align, the result doesn’t change, and the horizontal-align changes into strike-through text, which I assume means it’s not allowed?

Ultimately, to change from a “vertical list” format to a “horizontal summary” format that includes the photo with a horizontal line separating each listing is my target result. Possible?

Thanks.

https://wordpress.org/plugins/participants-database/