Secondary Action

Notes

I've learnt a lot from this, but unfortunately, it isn't finished! Two issues:

• I can't get the 'shrinking heart' animation to work properly. The problem is that CSS animations attached to a class will only work the first time they're toggled on. Subsequent toggles don't re-trigger the animation. Here's an article from 2011, which I think explains it, but the proposed solutions don't seem to work here: Restart CSS Animation.
• The second problem is with the colour of the shrinking heart. I can't get it to be white!