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.