Creating new project for SP online

Uptill now I was developing small projects in Visual Studio for SP 2013 on premises, like creating content types, lists and simple workflows. I would create new SharePoint 2013 project, add templates in Visual Studio and then deployed that (XML templates and some CSOM) with Powershell.

Now, I would like to try develop same thing for SP online. Can I use the same project (same wsp)?

Wsp uses only XML and CSOM (not SSOM).

Is that possible or do I need to create new project for that? Do I need to create new project of type "App for SharePoint"? How do I deploy to SP online?