Well, there seems to be an image slider between the main nav and the content article which is occupying (and thus creating) a chunk of white space.
Otherwise, you can try this . . . .
If you haven’t yet done so, create a new file called “custom.css” within file path –> /templates/ja-bookshop/css/
(so the final file path will be –> /templates/ja_bookshop/css/custom.css )
Within that custom.css file, paste the following CSS rule:
.t3-mainbody {
padding-top: 0;
}
This will move the content up a bit . . . but I’m not sure how you are wanting things to look.
Perhaps you can throw together a screenshot mock-up of how you’re wanting things to display?