Using a drop-down hotspot indicator icon that change from + to -

RH8 HTML 8.0.2

hi all,

I'm adding some drop down hotspots to a few topics that I'm working on and I'd like to have some indicator to show this.

We are wanting to use a + (plus) icon, that will then become a - (minus) when it is clicked, just something visual to show it.

Any ideas of how i can accomplish this easily?

Thanks,

Nick