How to edit widget css

Hi guys
The theme I'm using for needs a small bit of theme hacking.
for example I can't get Custom Sidebars to work with Buddypress Groups, and the theme owner says I should use this CSS:

"#sidebar #bp_core_members_widget-5 {display:none }
.single-item.groups #sidebar #bp_core_members_widget-5 { display:block; "

With the additional step:
"You have to change unique id of widget – #bp_core_members_widget-5, unique id you can find browsing code source in web browser."

I have no idea how to do that, so he said:

"Under google chrome make ctrl + u, search for sidebar-box, next to sidebar-box should be id (inique id of widget), for example id="text-7"

I still don't know :slight_smile:
Could you guys shed some light?

Thanks, Neil.