Wrap a div around each post on the category page

Hello again,

I am finding difficulty styling my posts in the category page. I am trying to wrap a div round each post to help with styling but I can’t figure out how to do this.

I am using the Starkers theme.

I have tried to add the div in the category.php file but this just wraps a div round all of the posts.

I have tried to add the div in the page.php file but this only applies the div to the post in the post view, not the category page.

I have also tried with the single.php but this had no visible effect at all.

I would appreciate some guidance with this.

Thanks.