What animates?

The height of the box around this text, from zero to whatever the text needs. Nothing measures it and no script runs.

Why does only one stay open?

All three share name="faq". Opening one closes the others, and each of them animates.

What about a long answer?

The duration is the same for any height, so a long answer moves faster. That holds up for a few paragraphs.

In Safari and Firefox this opens and closes at once, with no animation. That is the intended result there.