Child theme issues

Hi, I have a child theme working fine with GeneratePress. However I'm getting this error message:

GP Premium requires GeneratePress to be your active theme.

The theme is working fine, as is GP Premium. But the message won't go away. If I dismiss it, it just comes back again. Any suggestions?

Specifically, I have a lot of CSS. And Simple CSS seems to have a 1000 line limit. So I setup a child theme to handle the CSS. If you have a better suggestion here, perhaps I can skip the child theme altogether : )