There is no restore option for templates in BC, Templates do not work like they do on say wordpress. You should be able to go into your partner portal and download template files though.
Thanks Liam. I suspected I would have to start over. In the future I will download the selected template prior to trashing :-).
At one point when I was developing in BC I had the same question. I took a hiatus; but now I'm back and have the same question. Previously, I remember being given a download link to one. I also remember the original site getting an upgrade... and, all this was prior to liquid layouts... which I'm guessing were like responsive... but that was about when I stopped developing for a bit. So, now my question is; what advances have been made in 5 years and what is the current default "partner site"?
Liquid is a server side template and not related to "responsive".
There is no "Download" or backup for a template.
Your ideal coding methodology at its most basic should involve connecting to your site via SFTP and ensuring any development / coding on files you do is local and uploaded. This way you always have your local copies.
Expanding on this people use things like Git to track and log coding and work changes on projects for things like this.
It is not to do with BC or enhancements but moreover your process and changing to something you really should be doing.