I feel like I'm not looking in the right place or am not interpreting it or extrapolating what to do correctly because all I see changing is <button class="accordion"> to <button class="accordion active"> and a line of style for the panel, and I'm not quite sure what to do. I've attached a couple screencaps of what changes on the open/close click. (I used chrome inspector).
Before click (accordion closed):
After click (accordion open):