This is the first item's accordion body. It is hidden
by default, until the collapse plugin adds the appropriate classes that
we use to style each element. These classes control the overall
appearance, as well as the showing and hiding via CSS transitions. You
can modify any of this with custom CSS or overriding our default
variables. It's also worth noting that just about any HTML can go within
the .accordion-body
, though the transition does limit
overflow.