How do I get my sideberry like his?

[zitaled]

I recently downloaded sideberry and while searching through styles I had came across jvscholz video a youtuber i was familiar with already and had really liked his style specially with the tab icon at the top. He had his dot files linked I put the userchrome.css file in my firefox folder like im suppose to didn't know what to do with the sideberry.json file and i copied the sideberry.css file in my styles menu in the sideberry settings but my icons still werent tat the top like his for reference I'll put screenshots of mine and his