question about a breadcrumb plugin you recommend

I have a multisite, buddypress, pro site config.

I read this post:

I have installed the recommended plugin, but have not network activated it, as I want to add it on to some but not all sites on the network. I have not activated it yet on any site, because of the notes for installation on this page:

Can I install that snippet of code directly into “my custom css” for the site I want it installed on, to have it accomplish what it needs to accomplish?

If not, how do I need to modify it? Thanks in advance! Linda @iempoweru