Suggestion: use class selector instead of data attribute selector

[clairefro]

There's a lot of new stuff going on in this lesson with CSS animations etc.

To reduce cognitive load, I suggest using class names to identify the 4 cards in events.html and select them in events.js. That's something students are already familiar with

[michaelwlu]

Seconding this. Explaining the data-secret attribute and how to select it is overload at this point in the unit.