Delta theme - Latest classifieds - make them smaller

Hello!
How could I make the lastest classfields make smaller on delta theme? Now they are to big, they are 4 in a row, but I want them for example 8 in a row.. Look at the attached picture.

Try this.
It may require to customize much more then width to look good:
#latest.products.grid .simple-prod {
    width: calc(12.5% - 16px);
}

In which file is this?

style.css, or appearance > customization > css

That's exactly what I want. Thank you verry much! Please just tell me where can I increase number of showed ads here.. Now I have them 12, I want them 32: Thanks!

Settings > General > Latest items