I currently have a smartphone site and a PC site
I decided to make it responsive.

The URL is as follows.

・ PC Domain.com/index.html
・ SP domain.com/sp/index.html

Because other lower-layer pages have the same file name for PC and smartphone,
I just lost "sp", but

I don't know how to write

I asked a question here.

I'd be happy if you could teach me.