Content creation

First of all, I'm not certain if I am posting in the right place and if this has already been answered, but I don't think it has been answered, I'm sorry if it's not the case.

Is there a way to change the colour on the left side bar of the Documentation Tool? I think users may not realize they can click through the pages using the left side bar tool - having colour would draw attention to it and would also make the activity pop on the page: Also wondering if there is a way to change formatting in activity heading (ie changing to bold and/or adding colour)

Some content types, even though available and working in the content bank, gives the following error when trying to access from the content bank: 

invalid-library-json-file : Could not find library.json file with valid json format for library filesaver-1.0