Accordion with Checkboxes, JS for Keyboard Navigation

What are you most proud of, and what would you do differently next time?

Nothing special to be proud of in it =\

Next time I'd try HTML5 and tags (mdn)

What challenges did you encounter, and how did you overcome them?

I thought to use only html and css for expaning accordion content, but so it happened that keyboard events on a label don't pass to the checkbox, and I had to add js event handlers to the labels =(

What specific areas of your project would you like help with?

Is there any way to apply shadow on an element, so that shadow was only on part of the element, like upper half has no shadow, but lower part with shadow? (and that shadow doesn't spread to the upper half)