Wordpress CSS Modification to Existing Theme

I have an existing website which uses Wordpress. I will need a modification to the css that will change the way posts are listed and displayed when clicking on a specific category. Current way post are listed: ?![][1] Mock up of what I would like or make similar too using content for each post using information already contained in the post: ![][2] Live website can be seen here: [[login to view URL]][3] I just want to update the above category in the website link.