You mention folders. Do you mean in the Files list (usually in the left sidebar)? The default theme and Minimal both display the chevron > for all open or closed folders. If you can’t see it, it could be your theme.
If you mean the > for headings and lists within your notes, this should always display them:
Progress stuck at this point. Hopefully you can follow my path in this picture.
So, what do I do now?
I’ve accessed through the ‘gear’ to ‘Appearance’ then ‘CSS snippets’ ‘folder’ icon on far right. Copied your code to ‘Notebook’ …then I get confused at how to put that code into ‘obsidian.css’