I am struggling with Salesforce support. A couple of months ago I used the Branding feature in a Community & it wasn't taking effect in the Community. I added a Case about it & Salesforce escalated & said it was something they needed to fix & made a change & Branding worked in the Community. I have the same problem in a different Community that I just created. I have the Branding configured the same way. It is not working. Salesforce is telling me that my developers (me!) need to implement CSS, etc. The Branding feature that comes with Salesforce Community is not working. Thoughts?
If they say Branding isn't working, then we all just have to wait for them to fix it or take Branding into our own hands with custom CSS. As an aside, double check that you are using the most Recent template versions (Winter 18)