Today, I received this email from La Redoute and was surprised to find it had working rollovers in Gmail. Really surprised.

I did a little digging and it looks like they use the aria-labelledby attribute to make rollovers work. Even in Gmail. Gmail doesn't strip this one out. It's not something I've seen before and just wanted to share it with the community. I don't know much about this attribute - not seen it used before in web or email. Can anyone forsee any problems that could arise from using this as a hook for CSS in email?