Each of these grey-bordered summary boxes has a related "body" div that is hidden directly after it in the DOM.

Except this one, which is shown by default
:-P

Click any summary box to bring up its related body box (indicated by colour).

Normally the body would show up *between* the summaries but flexbox allows us to adjust the order.

There are four columns in this grid but you can change that by adjusting the flex-basis of the summaries in CSS, and the 'cols' variable in the JS